1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file implements routines for folding instructions into simpler forms
10 // that do not require creating new instructions. This does constant folding
11 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
12 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
13 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
14 // simplified: This is usually true and assuming it simplifies the logic (if
15 // they have not been simplified then results are correct but maybe suboptimal).
17 //===----------------------------------------------------------------------===//
19 #include "llvm/Analysis/InstructionSimplify.h"
21 #include "llvm/ADT/STLExtras.h"
22 #include "llvm/ADT/SetVector.h"
23 #include "llvm/ADT/Statistic.h"
24 #include "llvm/Analysis/AliasAnalysis.h"
25 #include "llvm/Analysis/AssumptionCache.h"
26 #include "llvm/Analysis/CaptureTracking.h"
27 #include "llvm/Analysis/CmpInstAnalysis.h"
28 #include "llvm/Analysis/ConstantFolding.h"
29 #include "llvm/Analysis/InstSimplifyFolder.h"
30 #include "llvm/Analysis/LoopAnalysisManager.h"
31 #include "llvm/Analysis/MemoryBuiltins.h"
32 #include "llvm/Analysis/OverflowInstAnalysis.h"
33 #include "llvm/Analysis/ValueTracking.h"
34 #include "llvm/Analysis/VectorUtils.h"
35 #include "llvm/IR/ConstantRange.h"
36 #include "llvm/IR/DataLayout.h"
37 #include "llvm/IR/Dominators.h"
38 #include "llvm/IR/InstrTypes.h"
39 #include "llvm/IR/Instructions.h"
40 #include "llvm/IR/Operator.h"
41 #include "llvm/IR/PatternMatch.h"
42 #include "llvm/IR/Statepoint.h"
43 #include "llvm/Support/KnownBits.h"
47 using namespace llvm::PatternMatch
;
49 #define DEBUG_TYPE "instsimplify"
51 enum { RecursionLimit
= 3 };
53 STATISTIC(NumExpand
, "Number of expansions");
54 STATISTIC(NumReassoc
, "Number of reassociations");
56 static Value
*simplifyAndInst(Value
*, Value
*, const SimplifyQuery
&,
58 static Value
*simplifyUnOp(unsigned, Value
*, const SimplifyQuery
&, unsigned);
59 static Value
*simplifyFPUnOp(unsigned, Value
*, const FastMathFlags
&,
60 const SimplifyQuery
&, unsigned);
61 static Value
*simplifyBinOp(unsigned, Value
*, Value
*, const SimplifyQuery
&,
63 static Value
*simplifyBinOp(unsigned, Value
*, Value
*, const FastMathFlags
&,
64 const SimplifyQuery
&, unsigned);
65 static Value
*simplifyCmpInst(unsigned, Value
*, Value
*, const SimplifyQuery
&,
67 static Value
*simplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
68 const SimplifyQuery
&Q
, unsigned MaxRecurse
);
69 static Value
*simplifyOrInst(Value
*, Value
*, const SimplifyQuery
&, unsigned);
70 static Value
*simplifyXorInst(Value
*, Value
*, const SimplifyQuery
&,
72 static Value
*simplifyCastInst(unsigned, Value
*, Type
*, const SimplifyQuery
&,
74 static Value
*simplifyGEPInst(Type
*, Value
*, ArrayRef
<Value
*>,
75 GEPNoWrapFlags
, const SimplifyQuery
&, unsigned);
76 static Value
*simplifySelectInst(Value
*, Value
*, Value
*,
77 const SimplifyQuery
&, unsigned);
78 static Value
*simplifyInstructionWithOperands(Instruction
*I
,
79 ArrayRef
<Value
*> NewOps
,
80 const SimplifyQuery
&SQ
,
83 static Value
*foldSelectWithBinaryOp(Value
*Cond
, Value
*TrueVal
,
85 BinaryOperator::BinaryOps BinOpCode
;
86 if (auto *BO
= dyn_cast
<BinaryOperator
>(Cond
))
87 BinOpCode
= BO
->getOpcode();
91 CmpInst::Predicate ExpectedPred
, Pred1
, Pred2
;
92 if (BinOpCode
== BinaryOperator::Or
) {
93 ExpectedPred
= ICmpInst::ICMP_NE
;
94 } else if (BinOpCode
== BinaryOperator::And
) {
95 ExpectedPred
= ICmpInst::ICMP_EQ
;
99 // %A = icmp eq %TV, %FV
100 // %B = icmp eq %X, %Y (and one of these is a select operand)
102 // %D = select %C, %TV, %FV
106 // %A = icmp ne %TV, %FV
107 // %B = icmp ne %X, %Y (and one of these is a select operand)
109 // %D = select %C, %TV, %FV
113 if (!match(Cond
, m_c_BinOp(m_c_ICmp(Pred1
, m_Specific(TrueVal
),
114 m_Specific(FalseVal
)),
115 m_ICmp(Pred2
, m_Value(X
), m_Value(Y
)))) ||
116 Pred1
!= Pred2
|| Pred1
!= ExpectedPred
)
119 if (X
== TrueVal
|| X
== FalseVal
|| Y
== TrueVal
|| Y
== FalseVal
)
120 return BinOpCode
== BinaryOperator::Or
? TrueVal
: FalseVal
;
125 /// For a boolean type or a vector of boolean type, return false or a vector
126 /// with every element false.
127 static Constant
*getFalse(Type
*Ty
) { return ConstantInt::getFalse(Ty
); }
129 /// For a boolean type or a vector of boolean type, return true or a vector
130 /// with every element true.
131 static Constant
*getTrue(Type
*Ty
) { return ConstantInt::getTrue(Ty
); }
133 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
134 static bool isSameCompare(Value
*V
, CmpInst::Predicate Pred
, Value
*LHS
,
136 CmpInst
*Cmp
= dyn_cast
<CmpInst
>(V
);
139 CmpInst::Predicate CPred
= Cmp
->getPredicate();
140 Value
*CLHS
= Cmp
->getOperand(0), *CRHS
= Cmp
->getOperand(1);
141 if (CPred
== Pred
&& CLHS
== LHS
&& CRHS
== RHS
)
143 return CPred
== CmpInst::getSwappedPredicate(Pred
) && CLHS
== RHS
&&
147 /// Simplify comparison with true or false branch of select:
148 /// %sel = select i1 %cond, i32 %tv, i32 %fv
149 /// %cmp = icmp sle i32 %sel, %rhs
150 /// Compose new comparison by substituting %sel with either %tv or %fv
151 /// and see if it simplifies.
152 static Value
*simplifyCmpSelCase(CmpInst::Predicate Pred
, Value
*LHS
,
153 Value
*RHS
, Value
*Cond
,
154 const SimplifyQuery
&Q
, unsigned MaxRecurse
,
155 Constant
*TrueOrFalse
) {
156 Value
*SimplifiedCmp
= simplifyCmpInst(Pred
, LHS
, RHS
, Q
, MaxRecurse
);
157 if (SimplifiedCmp
== Cond
) {
158 // %cmp simplified to the select condition (%cond).
160 } else if (!SimplifiedCmp
&& isSameCompare(Cond
, Pred
, LHS
, RHS
)) {
161 // It didn't simplify. However, if composed comparison is equivalent
162 // to the select condition (%cond) then we can replace it.
165 return SimplifiedCmp
;
168 /// Simplify comparison with true branch of select
169 static Value
*simplifyCmpSelTrueCase(CmpInst::Predicate Pred
, Value
*LHS
,
170 Value
*RHS
, Value
*Cond
,
171 const SimplifyQuery
&Q
,
172 unsigned MaxRecurse
) {
173 return simplifyCmpSelCase(Pred
, LHS
, RHS
, Cond
, Q
, MaxRecurse
,
174 getTrue(Cond
->getType()));
177 /// Simplify comparison with false branch of select
178 static Value
*simplifyCmpSelFalseCase(CmpInst::Predicate Pred
, Value
*LHS
,
179 Value
*RHS
, Value
*Cond
,
180 const SimplifyQuery
&Q
,
181 unsigned MaxRecurse
) {
182 return simplifyCmpSelCase(Pred
, LHS
, RHS
, Cond
, Q
, MaxRecurse
,
183 getFalse(Cond
->getType()));
186 /// We know comparison with both branches of select can be simplified, but they
187 /// are not equal. This routine handles some logical simplifications.
188 static Value
*handleOtherCmpSelSimplifications(Value
*TCmp
, Value
*FCmp
,
190 const SimplifyQuery
&Q
,
191 unsigned MaxRecurse
) {
192 // If the false value simplified to false, then the result of the compare
193 // is equal to "Cond && TCmp". This also catches the case when the false
194 // value simplified to false and the true value to true, returning "Cond".
195 // Folding select to and/or isn't poison-safe in general; impliesPoison
196 // checks whether folding it does not convert a well-defined value into
198 if (match(FCmp
, m_Zero()) && impliesPoison(TCmp
, Cond
))
199 if (Value
*V
= simplifyAndInst(Cond
, TCmp
, Q
, MaxRecurse
))
201 // If the true value simplified to true, then the result of the compare
202 // is equal to "Cond || FCmp".
203 if (match(TCmp
, m_One()) && impliesPoison(FCmp
, Cond
))
204 if (Value
*V
= simplifyOrInst(Cond
, FCmp
, Q
, MaxRecurse
))
206 // Finally, if the false value simplified to true and the true value to
207 // false, then the result of the compare is equal to "!Cond".
208 if (match(FCmp
, m_One()) && match(TCmp
, m_Zero()))
209 if (Value
*V
= simplifyXorInst(
210 Cond
, Constant::getAllOnesValue(Cond
->getType()), Q
, MaxRecurse
))
215 /// Does the given value dominate the specified phi node?
216 static bool valueDominatesPHI(Value
*V
, PHINode
*P
, const DominatorTree
*DT
) {
217 Instruction
*I
= dyn_cast
<Instruction
>(V
);
219 // Arguments and constants dominate all instructions.
222 // If we have a DominatorTree then do a precise test.
224 return DT
->dominates(I
, P
);
226 // Otherwise, if the instruction is in the entry block and is not an invoke,
227 // then it obviously dominates all phi nodes.
228 if (I
->getParent()->isEntryBlock() && !isa
<InvokeInst
>(I
) &&
235 /// Try to simplify a binary operator of form "V op OtherOp" where V is
236 /// "(B0 opex B1)" by distributing 'op' across 'opex' as
237 /// "(B0 op OtherOp) opex (B1 op OtherOp)".
238 static Value
*expandBinOp(Instruction::BinaryOps Opcode
, Value
*V
,
239 Value
*OtherOp
, Instruction::BinaryOps OpcodeToExpand
,
240 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
241 auto *B
= dyn_cast
<BinaryOperator
>(V
);
242 if (!B
|| B
->getOpcode() != OpcodeToExpand
)
244 Value
*B0
= B
->getOperand(0), *B1
= B
->getOperand(1);
246 simplifyBinOp(Opcode
, B0
, OtherOp
, Q
.getWithoutUndef(), MaxRecurse
);
250 simplifyBinOp(Opcode
, B1
, OtherOp
, Q
.getWithoutUndef(), MaxRecurse
);
254 // Does the expanded pair of binops simplify to the existing binop?
255 if ((L
== B0
&& R
== B1
) ||
256 (Instruction::isCommutative(OpcodeToExpand
) && L
== B1
&& R
== B0
)) {
261 // Otherwise, return "L op' R" if it simplifies.
262 Value
*S
= simplifyBinOp(OpcodeToExpand
, L
, R
, Q
, MaxRecurse
);
270 /// Try to simplify binops of form "A op (B op' C)" or the commuted variant by
271 /// distributing op over op'.
272 static Value
*expandCommutativeBinOp(Instruction::BinaryOps Opcode
, Value
*L
,
274 Instruction::BinaryOps OpcodeToExpand
,
275 const SimplifyQuery
&Q
,
276 unsigned MaxRecurse
) {
277 // Recursion is always used, so bail out at once if we already hit the limit.
281 if (Value
*V
= expandBinOp(Opcode
, L
, R
, OpcodeToExpand
, Q
, MaxRecurse
))
283 if (Value
*V
= expandBinOp(Opcode
, R
, L
, OpcodeToExpand
, Q
, MaxRecurse
))
288 /// Generic simplifications for associative binary operations.
289 /// Returns the simpler value, or null if none was found.
290 static Value
*simplifyAssociativeBinOp(Instruction::BinaryOps Opcode
,
291 Value
*LHS
, Value
*RHS
,
292 const SimplifyQuery
&Q
,
293 unsigned MaxRecurse
) {
294 assert(Instruction::isAssociative(Opcode
) && "Not an associative operation!");
296 // Recursion is always used, so bail out at once if we already hit the limit.
300 BinaryOperator
*Op0
= dyn_cast
<BinaryOperator
>(LHS
);
301 BinaryOperator
*Op1
= dyn_cast
<BinaryOperator
>(RHS
);
303 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
304 if (Op0
&& Op0
->getOpcode() == Opcode
) {
305 Value
*A
= Op0
->getOperand(0);
306 Value
*B
= Op0
->getOperand(1);
309 // Does "B op C" simplify?
310 if (Value
*V
= simplifyBinOp(Opcode
, B
, C
, Q
, MaxRecurse
)) {
311 // It does! Return "A op V" if it simplifies or is already available.
312 // If V equals B then "A op V" is just the LHS.
315 // Otherwise return "A op V" if it simplifies.
316 if (Value
*W
= simplifyBinOp(Opcode
, A
, V
, Q
, MaxRecurse
)) {
323 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
324 if (Op1
&& Op1
->getOpcode() == Opcode
) {
326 Value
*B
= Op1
->getOperand(0);
327 Value
*C
= Op1
->getOperand(1);
329 // Does "A op B" simplify?
330 if (Value
*V
= simplifyBinOp(Opcode
, A
, B
, Q
, MaxRecurse
)) {
331 // It does! Return "V op C" if it simplifies or is already available.
332 // If V equals B then "V op C" is just the RHS.
335 // Otherwise return "V op C" if it simplifies.
336 if (Value
*W
= simplifyBinOp(Opcode
, V
, C
, Q
, MaxRecurse
)) {
343 // The remaining transforms require commutativity as well as associativity.
344 if (!Instruction::isCommutative(Opcode
))
347 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
348 if (Op0
&& Op0
->getOpcode() == Opcode
) {
349 Value
*A
= Op0
->getOperand(0);
350 Value
*B
= Op0
->getOperand(1);
353 // Does "C op A" simplify?
354 if (Value
*V
= simplifyBinOp(Opcode
, C
, A
, Q
, MaxRecurse
)) {
355 // It does! Return "V op B" if it simplifies or is already available.
356 // If V equals A then "V op B" is just the LHS.
359 // Otherwise return "V op B" if it simplifies.
360 if (Value
*W
= simplifyBinOp(Opcode
, V
, B
, Q
, MaxRecurse
)) {
367 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
368 if (Op1
&& Op1
->getOpcode() == Opcode
) {
370 Value
*B
= Op1
->getOperand(0);
371 Value
*C
= Op1
->getOperand(1);
373 // Does "C op A" simplify?
374 if (Value
*V
= simplifyBinOp(Opcode
, C
, A
, Q
, MaxRecurse
)) {
375 // It does! Return "B op V" if it simplifies or is already available.
376 // If V equals C then "B op V" is just the RHS.
379 // Otherwise return "B op V" if it simplifies.
380 if (Value
*W
= simplifyBinOp(Opcode
, B
, V
, Q
, MaxRecurse
)) {
390 /// In the case of a binary operation with a select instruction as an operand,
391 /// try to simplify the binop by seeing whether evaluating it on both branches
392 /// of the select results in the same value. Returns the common value if so,
393 /// otherwise returns null.
394 static Value
*threadBinOpOverSelect(Instruction::BinaryOps Opcode
, Value
*LHS
,
395 Value
*RHS
, const SimplifyQuery
&Q
,
396 unsigned MaxRecurse
) {
397 // Recursion is always used, so bail out at once if we already hit the limit.
402 if (isa
<SelectInst
>(LHS
)) {
403 SI
= cast
<SelectInst
>(LHS
);
405 assert(isa
<SelectInst
>(RHS
) && "No select instruction operand!");
406 SI
= cast
<SelectInst
>(RHS
);
409 // Evaluate the BinOp on the true and false branches of the select.
413 TV
= simplifyBinOp(Opcode
, SI
->getTrueValue(), RHS
, Q
, MaxRecurse
);
414 FV
= simplifyBinOp(Opcode
, SI
->getFalseValue(), RHS
, Q
, MaxRecurse
);
416 TV
= simplifyBinOp(Opcode
, LHS
, SI
->getTrueValue(), Q
, MaxRecurse
);
417 FV
= simplifyBinOp(Opcode
, LHS
, SI
->getFalseValue(), Q
, MaxRecurse
);
420 // If they simplified to the same value, then return the common value.
421 // If they both failed to simplify then return null.
425 // If one branch simplified to undef, return the other one.
426 if (TV
&& Q
.isUndefValue(TV
))
428 if (FV
&& Q
.isUndefValue(FV
))
431 // If applying the operation did not change the true and false select values,
432 // then the result of the binop is the select itself.
433 if (TV
== SI
->getTrueValue() && FV
== SI
->getFalseValue())
436 // If one branch simplified and the other did not, and the simplified
437 // value is equal to the unsimplified one, return the simplified value.
438 // For example, select (cond, X, X & Z) & Z -> X & Z.
439 if ((FV
&& !TV
) || (TV
&& !FV
)) {
440 // Check that the simplified value has the form "X op Y" where "op" is the
441 // same as the original operation.
442 Instruction
*Simplified
= dyn_cast
<Instruction
>(FV
? FV
: TV
);
443 if (Simplified
&& Simplified
->getOpcode() == unsigned(Opcode
) &&
444 !Simplified
->hasPoisonGeneratingFlags()) {
445 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
446 // We already know that "op" is the same as for the simplified value. See
447 // if the operands match too. If so, return the simplified value.
448 Value
*UnsimplifiedBranch
= FV
? SI
->getTrueValue() : SI
->getFalseValue();
449 Value
*UnsimplifiedLHS
= SI
== LHS
? UnsimplifiedBranch
: LHS
;
450 Value
*UnsimplifiedRHS
= SI
== LHS
? RHS
: UnsimplifiedBranch
;
451 if (Simplified
->getOperand(0) == UnsimplifiedLHS
&&
452 Simplified
->getOperand(1) == UnsimplifiedRHS
)
454 if (Simplified
->isCommutative() &&
455 Simplified
->getOperand(1) == UnsimplifiedLHS
&&
456 Simplified
->getOperand(0) == UnsimplifiedRHS
)
464 /// In the case of a comparison with a select instruction, try to simplify the
465 /// comparison by seeing whether both branches of the select result in the same
466 /// value. Returns the common value if so, otherwise returns null.
467 /// For example, if we have:
468 /// %tmp = select i1 %cmp, i32 1, i32 2
469 /// %cmp1 = icmp sle i32 %tmp, 3
470 /// We can simplify %cmp1 to true, because both branches of select are
471 /// less than 3. We compose new comparison by substituting %tmp with both
472 /// branches of select and see if it can be simplified.
473 static Value
*threadCmpOverSelect(CmpInst::Predicate Pred
, Value
*LHS
,
474 Value
*RHS
, const SimplifyQuery
&Q
,
475 unsigned MaxRecurse
) {
476 // Recursion is always used, so bail out at once if we already hit the limit.
480 // Make sure the select is on the LHS.
481 if (!isa
<SelectInst
>(LHS
)) {
483 Pred
= CmpInst::getSwappedPredicate(Pred
);
485 assert(isa
<SelectInst
>(LHS
) && "Not comparing with a select instruction!");
486 SelectInst
*SI
= cast
<SelectInst
>(LHS
);
487 Value
*Cond
= SI
->getCondition();
488 Value
*TV
= SI
->getTrueValue();
489 Value
*FV
= SI
->getFalseValue();
491 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
492 // Does "cmp TV, RHS" simplify?
493 Value
*TCmp
= simplifyCmpSelTrueCase(Pred
, TV
, RHS
, Cond
, Q
, MaxRecurse
);
497 // Does "cmp FV, RHS" simplify?
498 Value
*FCmp
= simplifyCmpSelFalseCase(Pred
, FV
, RHS
, Cond
, Q
, MaxRecurse
);
502 // If both sides simplified to the same value, then use it as the result of
503 // the original comparison.
507 // The remaining cases only make sense if the select condition has the same
508 // type as the result of the comparison, so bail out if this is not so.
509 if (Cond
->getType()->isVectorTy() == RHS
->getType()->isVectorTy())
510 return handleOtherCmpSelSimplifications(TCmp
, FCmp
, Cond
, Q
, MaxRecurse
);
515 /// In the case of a binary operation with an operand that is a PHI instruction,
516 /// try to simplify the binop by seeing whether evaluating it on the incoming
517 /// phi values yields the same result for every value. If so returns the common
518 /// value, otherwise returns null.
519 static Value
*threadBinOpOverPHI(Instruction::BinaryOps Opcode
, Value
*LHS
,
520 Value
*RHS
, const SimplifyQuery
&Q
,
521 unsigned MaxRecurse
) {
522 // Recursion is always used, so bail out at once if we already hit the limit.
527 if (isa
<PHINode
>(LHS
)) {
528 PI
= cast
<PHINode
>(LHS
);
529 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
530 if (!valueDominatesPHI(RHS
, PI
, Q
.DT
))
533 assert(isa
<PHINode
>(RHS
) && "No PHI instruction operand!");
534 PI
= cast
<PHINode
>(RHS
);
535 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
536 if (!valueDominatesPHI(LHS
, PI
, Q
.DT
))
540 // Evaluate the BinOp on the incoming phi values.
541 Value
*CommonValue
= nullptr;
542 for (Use
&Incoming
: PI
->incoming_values()) {
543 // If the incoming value is the phi node itself, it can safely be skipped.
546 Instruction
*InTI
= PI
->getIncomingBlock(Incoming
)->getTerminator();
548 ? simplifyBinOp(Opcode
, Incoming
, RHS
,
549 Q
.getWithInstruction(InTI
), MaxRecurse
)
550 : simplifyBinOp(Opcode
, LHS
, Incoming
,
551 Q
.getWithInstruction(InTI
), MaxRecurse
);
552 // If the operation failed to simplify, or simplified to a different value
553 // to previously, then give up.
554 if (!V
|| (CommonValue
&& V
!= CommonValue
))
562 /// In the case of a comparison with a PHI instruction, try to simplify the
563 /// comparison by seeing whether comparing with all of the incoming phi values
564 /// yields the same result every time. If so returns the common result,
565 /// otherwise returns null.
566 static Value
*threadCmpOverPHI(CmpInst::Predicate Pred
, Value
*LHS
, Value
*RHS
,
567 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
568 // Recursion is always used, so bail out at once if we already hit the limit.
572 // Make sure the phi is on the LHS.
573 if (!isa
<PHINode
>(LHS
)) {
575 Pred
= CmpInst::getSwappedPredicate(Pred
);
577 assert(isa
<PHINode
>(LHS
) && "Not comparing with a phi instruction!");
578 PHINode
*PI
= cast
<PHINode
>(LHS
);
580 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
581 if (!valueDominatesPHI(RHS
, PI
, Q
.DT
))
584 // Evaluate the BinOp on the incoming phi values.
585 Value
*CommonValue
= nullptr;
586 for (unsigned u
= 0, e
= PI
->getNumIncomingValues(); u
< e
; ++u
) {
587 Value
*Incoming
= PI
->getIncomingValue(u
);
588 Instruction
*InTI
= PI
->getIncomingBlock(u
)->getTerminator();
589 // If the incoming value is the phi node itself, it can safely be skipped.
592 // Change the context instruction to the "edge" that flows into the phi.
593 // This is important because that is where incoming is actually "evaluated"
594 // even though it is used later somewhere else.
595 Value
*V
= simplifyCmpInst(Pred
, Incoming
, RHS
, Q
.getWithInstruction(InTI
),
597 // If the operation failed to simplify, or simplified to a different value
598 // to previously, then give up.
599 if (!V
|| (CommonValue
&& V
!= CommonValue
))
607 static Constant
*foldOrCommuteConstant(Instruction::BinaryOps Opcode
,
608 Value
*&Op0
, Value
*&Op1
,
609 const SimplifyQuery
&Q
) {
610 if (auto *CLHS
= dyn_cast
<Constant
>(Op0
)) {
611 if (auto *CRHS
= dyn_cast
<Constant
>(Op1
)) {
615 case Instruction::FAdd
:
616 case Instruction::FSub
:
617 case Instruction::FMul
:
618 case Instruction::FDiv
:
619 case Instruction::FRem
:
620 if (Q
.CxtI
!= nullptr)
621 return ConstantFoldFPInstOperands(Opcode
, CLHS
, CRHS
, Q
.DL
, Q
.CxtI
);
623 return ConstantFoldBinaryOpOperands(Opcode
, CLHS
, CRHS
, Q
.DL
);
626 // Canonicalize the constant to the RHS if this is a commutative operation.
627 if (Instruction::isCommutative(Opcode
))
633 /// Given operands for an Add, see if we can fold the result.
634 /// If not, this returns null.
635 static Value
*simplifyAddInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
636 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
637 if (Constant
*C
= foldOrCommuteConstant(Instruction::Add
, Op0
, Op1
, Q
))
640 // X + poison -> poison
641 if (isa
<PoisonValue
>(Op1
))
644 // X + undef -> undef
645 if (Q
.isUndefValue(Op1
))
649 if (match(Op1
, m_Zero()))
652 // If two operands are negative, return 0.
653 if (isKnownNegation(Op0
, Op1
))
654 return Constant::getNullValue(Op0
->getType());
660 if (match(Op1
, m_Sub(m_Value(Y
), m_Specific(Op0
))) ||
661 match(Op0
, m_Sub(m_Value(Y
), m_Specific(Op1
))))
664 // X + ~X -> -1 since ~X = -X-1
665 Type
*Ty
= Op0
->getType();
666 if (match(Op0
, m_Not(m_Specific(Op1
))) || match(Op1
, m_Not(m_Specific(Op0
))))
667 return Constant::getAllOnesValue(Ty
);
669 // add nsw/nuw (xor Y, signmask), signmask --> Y
670 // The no-wrapping add guarantees that the top bit will be set by the add.
671 // Therefore, the xor must be clearing the already set sign bit of Y.
672 if ((IsNSW
|| IsNUW
) && match(Op1
, m_SignMask()) &&
673 match(Op0
, m_Xor(m_Value(Y
), m_SignMask())))
676 // add nuw %x, -1 -> -1, because %x can only be 0.
677 if (IsNUW
&& match(Op1
, m_AllOnes()))
678 return Op1
; // Which is -1.
681 if (MaxRecurse
&& Op0
->getType()->isIntOrIntVectorTy(1))
682 if (Value
*V
= simplifyXorInst(Op0
, Op1
, Q
, MaxRecurse
- 1))
685 // Try some generic simplifications for associative operations.
687 simplifyAssociativeBinOp(Instruction::Add
, Op0
, Op1
, Q
, MaxRecurse
))
690 // Threading Add over selects and phi nodes is pointless, so don't bother.
691 // Threading over the select in "A + select(cond, B, C)" means evaluating
692 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
693 // only if B and C are equal. If B and C are equal then (since we assume
694 // that operands have already been simplified) "select(cond, B, C)" should
695 // have been simplified to the common value of B and C already. Analysing
696 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
697 // for threading over phi nodes.
702 Value
*llvm::simplifyAddInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
703 const SimplifyQuery
&Query
) {
704 return ::simplifyAddInst(Op0
, Op1
, IsNSW
, IsNUW
, Query
, RecursionLimit
);
707 /// Compute the base pointer and cumulative constant offsets for V.
709 /// This strips all constant offsets off of V, leaving it the base pointer, and
710 /// accumulates the total constant offset applied in the returned constant.
711 /// It returns zero if there are no constant offsets applied.
713 /// This is very similar to stripAndAccumulateConstantOffsets(), except it
714 /// normalizes the offset bitwidth to the stripped pointer type, not the
715 /// original pointer type.
716 static APInt
stripAndComputeConstantOffsets(const DataLayout
&DL
, Value
*&V
,
717 bool AllowNonInbounds
= false) {
718 assert(V
->getType()->isPtrOrPtrVectorTy());
720 APInt Offset
= APInt::getZero(DL
.getIndexTypeSizeInBits(V
->getType()));
721 V
= V
->stripAndAccumulateConstantOffsets(DL
, Offset
, AllowNonInbounds
);
722 // As that strip may trace through `addrspacecast`, need to sext or trunc
723 // the offset calculated.
724 return Offset
.sextOrTrunc(DL
.getIndexTypeSizeInBits(V
->getType()));
727 /// Compute the constant difference between two pointer values.
728 /// If the difference is not a constant, returns zero.
729 static Constant
*computePointerDifference(const DataLayout
&DL
, Value
*LHS
,
731 APInt LHSOffset
= stripAndComputeConstantOffsets(DL
, LHS
);
732 APInt RHSOffset
= stripAndComputeConstantOffsets(DL
, RHS
);
734 // If LHS and RHS are not related via constant offsets to the same base
735 // value, there is nothing we can do here.
739 // Otherwise, the difference of LHS - RHS can be computed as:
741 // = (LHSOffset + Base) - (RHSOffset + Base)
742 // = LHSOffset - RHSOffset
743 Constant
*Res
= ConstantInt::get(LHS
->getContext(), LHSOffset
- RHSOffset
);
744 if (auto *VecTy
= dyn_cast
<VectorType
>(LHS
->getType()))
745 Res
= ConstantVector::getSplat(VecTy
->getElementCount(), Res
);
749 /// Test if there is a dominating equivalence condition for the
750 /// two operands. If there is, try to reduce the binary operation
751 /// between the two operands.
752 /// Example: Op0 - Op1 --> 0 when Op0 == Op1
753 static Value
*simplifyByDomEq(unsigned Opcode
, Value
*Op0
, Value
*Op1
,
754 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
755 // Recursive run it can not get any benefit
756 if (MaxRecurse
!= RecursionLimit
)
759 std::optional
<bool> Imp
=
760 isImpliedByDomCondition(CmpInst::ICMP_EQ
, Op0
, Op1
, Q
.CxtI
, Q
.DL
);
762 Type
*Ty
= Op0
->getType();
764 case Instruction::Sub
:
765 case Instruction::Xor
:
766 case Instruction::URem
:
767 case Instruction::SRem
:
768 return Constant::getNullValue(Ty
);
770 case Instruction::SDiv
:
771 case Instruction::UDiv
:
772 return ConstantInt::get(Ty
, 1);
774 case Instruction::And
:
775 case Instruction::Or
:
776 // Could be either one - choose Op1 since that's more likely a constant.
785 /// Given operands for a Sub, see if we can fold the result.
786 /// If not, this returns null.
787 static Value
*simplifySubInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
788 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
789 if (Constant
*C
= foldOrCommuteConstant(Instruction::Sub
, Op0
, Op1
, Q
))
792 // X - poison -> poison
793 // poison - X -> poison
794 if (isa
<PoisonValue
>(Op0
) || isa
<PoisonValue
>(Op1
))
795 return PoisonValue::get(Op0
->getType());
797 // X - undef -> undef
798 // undef - X -> undef
799 if (Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
))
800 return UndefValue::get(Op0
->getType());
803 if (match(Op1
, m_Zero()))
808 return Constant::getNullValue(Op0
->getType());
810 // Is this a negation?
811 if (match(Op0
, m_Zero())) {
812 // 0 - X -> 0 if the sub is NUW.
814 return Constant::getNullValue(Op0
->getType());
816 KnownBits Known
= computeKnownBits(Op1
, /* Depth */ 0, Q
);
817 if (Known
.Zero
.isMaxSignedValue()) {
818 // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
819 // Op1 must be 0 because negating the minimum signed value is undefined.
821 return Constant::getNullValue(Op0
->getType());
823 // 0 - X -> X if X is 0 or the minimum signed value.
828 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
829 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
830 Value
*X
= nullptr, *Y
= nullptr, *Z
= Op1
;
831 if (MaxRecurse
&& match(Op0
, m_Add(m_Value(X
), m_Value(Y
)))) { // (X + Y) - Z
832 // See if "V === Y - Z" simplifies.
833 if (Value
*V
= simplifyBinOp(Instruction::Sub
, Y
, Z
, Q
, MaxRecurse
- 1))
834 // It does! Now see if "X + V" simplifies.
835 if (Value
*W
= simplifyBinOp(Instruction::Add
, X
, V
, Q
, MaxRecurse
- 1)) {
836 // It does, we successfully reassociated!
840 // See if "V === X - Z" simplifies.
841 if (Value
*V
= simplifyBinOp(Instruction::Sub
, X
, Z
, Q
, MaxRecurse
- 1))
842 // It does! Now see if "Y + V" simplifies.
843 if (Value
*W
= simplifyBinOp(Instruction::Add
, Y
, V
, Q
, MaxRecurse
- 1)) {
844 // It does, we successfully reassociated!
850 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
851 // For example, X - (X + 1) -> -1
853 if (MaxRecurse
&& match(Op1
, m_Add(m_Value(Y
), m_Value(Z
)))) { // X - (Y + Z)
854 // See if "V === X - Y" simplifies.
855 if (Value
*V
= simplifyBinOp(Instruction::Sub
, X
, Y
, Q
, MaxRecurse
- 1))
856 // It does! Now see if "V - Z" simplifies.
857 if (Value
*W
= simplifyBinOp(Instruction::Sub
, V
, Z
, Q
, MaxRecurse
- 1)) {
858 // It does, we successfully reassociated!
862 // See if "V === X - Z" simplifies.
863 if (Value
*V
= simplifyBinOp(Instruction::Sub
, X
, Z
, Q
, MaxRecurse
- 1))
864 // It does! Now see if "V - Y" simplifies.
865 if (Value
*W
= simplifyBinOp(Instruction::Sub
, V
, Y
, Q
, MaxRecurse
- 1)) {
866 // It does, we successfully reassociated!
872 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
873 // For example, X - (X - Y) -> Y.
875 if (MaxRecurse
&& match(Op1
, m_Sub(m_Value(X
), m_Value(Y
)))) // Z - (X - Y)
876 // See if "V === Z - X" simplifies.
877 if (Value
*V
= simplifyBinOp(Instruction::Sub
, Z
, X
, Q
, MaxRecurse
- 1))
878 // It does! Now see if "V + Y" simplifies.
879 if (Value
*W
= simplifyBinOp(Instruction::Add
, V
, Y
, Q
, MaxRecurse
- 1)) {
880 // It does, we successfully reassociated!
885 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
886 if (MaxRecurse
&& match(Op0
, m_Trunc(m_Value(X
))) &&
887 match(Op1
, m_Trunc(m_Value(Y
))))
888 if (X
->getType() == Y
->getType())
889 // See if "V === X - Y" simplifies.
890 if (Value
*V
= simplifyBinOp(Instruction::Sub
, X
, Y
, Q
, MaxRecurse
- 1))
891 // It does! Now see if "trunc V" simplifies.
892 if (Value
*W
= simplifyCastInst(Instruction::Trunc
, V
, Op0
->getType(),
894 // It does, return the simplified "trunc V".
897 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
898 if (match(Op0
, m_PtrToInt(m_Value(X
))) && match(Op1
, m_PtrToInt(m_Value(Y
))))
899 if (Constant
*Result
= computePointerDifference(Q
.DL
, X
, Y
))
900 return ConstantFoldIntegerCast(Result
, Op0
->getType(), /*IsSigned*/ true,
904 if (MaxRecurse
&& Op0
->getType()->isIntOrIntVectorTy(1))
905 if (Value
*V
= simplifyXorInst(Op0
, Op1
, Q
, MaxRecurse
- 1))
908 // Threading Sub over selects and phi nodes is pointless, so don't bother.
909 // Threading over the select in "A - select(cond, B, C)" means evaluating
910 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
911 // only if B and C are equal. If B and C are equal then (since we assume
912 // that operands have already been simplified) "select(cond, B, C)" should
913 // have been simplified to the common value of B and C already. Analysing
914 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
915 // for threading over phi nodes.
917 if (Value
*V
= simplifyByDomEq(Instruction::Sub
, Op0
, Op1
, Q
, MaxRecurse
))
923 Value
*llvm::simplifySubInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
924 const SimplifyQuery
&Q
) {
925 return ::simplifySubInst(Op0
, Op1
, IsNSW
, IsNUW
, Q
, RecursionLimit
);
928 /// Given operands for a Mul, see if we can fold the result.
929 /// If not, this returns null.
930 static Value
*simplifyMulInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
931 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
932 if (Constant
*C
= foldOrCommuteConstant(Instruction::Mul
, Op0
, Op1
, Q
))
935 // X * poison -> poison
936 if (isa
<PoisonValue
>(Op1
))
941 if (Q
.isUndefValue(Op1
) || match(Op1
, m_Zero()))
942 return Constant::getNullValue(Op0
->getType());
945 if (match(Op1
, m_One()))
948 // (X / Y) * Y -> X if the division is exact.
950 if (Q
.IIQ
.UseInstrInfo
&&
952 m_Exact(m_IDiv(m_Value(X
), m_Specific(Op1
)))) || // (X / Y) * Y
953 match(Op1
, m_Exact(m_IDiv(m_Value(X
), m_Specific(Op0
)))))) // Y * (X / Y)
956 if (Op0
->getType()->isIntOrIntVectorTy(1)) {
957 // mul i1 nsw is a special-case because -1 * -1 is poison (+1 is not
958 // representable). All other cases reduce to 0, so just return 0.
960 return ConstantInt::getNullValue(Op0
->getType());
962 // Treat "mul i1" as "and i1".
964 if (Value
*V
= simplifyAndInst(Op0
, Op1
, Q
, MaxRecurse
- 1))
968 // Try some generic simplifications for associative operations.
970 simplifyAssociativeBinOp(Instruction::Mul
, Op0
, Op1
, Q
, MaxRecurse
))
973 // Mul distributes over Add. Try some generic simplifications based on this.
974 if (Value
*V
= expandCommutativeBinOp(Instruction::Mul
, Op0
, Op1
,
975 Instruction::Add
, Q
, MaxRecurse
))
978 // If the operation is with the result of a select instruction, check whether
979 // operating on either branch of the select always yields the same value.
980 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
982 threadBinOpOverSelect(Instruction::Mul
, Op0
, Op1
, Q
, MaxRecurse
))
985 // If the operation is with the result of a phi instruction, check whether
986 // operating on all incoming values of the phi always yields the same value.
987 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
989 threadBinOpOverPHI(Instruction::Mul
, Op0
, Op1
, Q
, MaxRecurse
))
995 Value
*llvm::simplifyMulInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
996 const SimplifyQuery
&Q
) {
997 return ::simplifyMulInst(Op0
, Op1
, IsNSW
, IsNUW
, Q
, RecursionLimit
);
1000 /// Given a predicate and two operands, return true if the comparison is true.
1001 /// This is a helper for div/rem simplification where we return some other value
1002 /// when we can prove a relationship between the operands.
1003 static bool isICmpTrue(ICmpInst::Predicate Pred
, Value
*LHS
, Value
*RHS
,
1004 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1005 Value
*V
= simplifyICmpInst(Pred
, LHS
, RHS
, Q
, MaxRecurse
);
1006 Constant
*C
= dyn_cast_or_null
<Constant
>(V
);
1007 return (C
&& C
->isAllOnesValue());
1010 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
1011 /// to simplify X % Y to X.
1012 static bool isDivZero(Value
*X
, Value
*Y
, const SimplifyQuery
&Q
,
1013 unsigned MaxRecurse
, bool IsSigned
) {
1014 // Recursion is always used, so bail out at once if we already hit the limit.
1019 // (X srem Y) sdiv Y --> 0
1020 if (match(X
, m_SRem(m_Value(), m_Specific(Y
))))
1025 // We require that 1 operand is a simple constant. That could be extended to
1026 // 2 variables if we computed the sign bit for each.
1028 // Make sure that a constant is not the minimum signed value because taking
1029 // the abs() of that is undefined.
1030 Type
*Ty
= X
->getType();
1032 if (match(X
, m_APInt(C
)) && !C
->isMinSignedValue()) {
1033 // Is the variable divisor magnitude always greater than the constant
1034 // dividend magnitude?
1035 // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
1036 Constant
*PosDividendC
= ConstantInt::get(Ty
, C
->abs());
1037 Constant
*NegDividendC
= ConstantInt::get(Ty
, -C
->abs());
1038 if (isICmpTrue(CmpInst::ICMP_SLT
, Y
, NegDividendC
, Q
, MaxRecurse
) ||
1039 isICmpTrue(CmpInst::ICMP_SGT
, Y
, PosDividendC
, Q
, MaxRecurse
))
1042 if (match(Y
, m_APInt(C
))) {
1043 // Special-case: we can't take the abs() of a minimum signed value. If
1044 // that's the divisor, then all we have to do is prove that the dividend
1045 // is also not the minimum signed value.
1046 if (C
->isMinSignedValue())
1047 return isICmpTrue(CmpInst::ICMP_NE
, X
, Y
, Q
, MaxRecurse
);
1049 // Is the variable dividend magnitude always less than the constant
1050 // divisor magnitude?
1051 // |X| < |C| --> X > -abs(C) and X < abs(C)
1052 Constant
*PosDivisorC
= ConstantInt::get(Ty
, C
->abs());
1053 Constant
*NegDivisorC
= ConstantInt::get(Ty
, -C
->abs());
1054 if (isICmpTrue(CmpInst::ICMP_SGT
, X
, NegDivisorC
, Q
, MaxRecurse
) &&
1055 isICmpTrue(CmpInst::ICMP_SLT
, X
, PosDivisorC
, Q
, MaxRecurse
))
1061 // IsSigned == false.
1063 // Is the unsigned dividend known to be less than a constant divisor?
1064 // TODO: Convert this (and above) to range analysis
1065 // ("computeConstantRangeIncludingKnownBits")?
1067 if (match(Y
, m_APInt(C
)) &&
1068 computeKnownBits(X
, /* Depth */ 0, Q
).getMaxValue().ult(*C
))
1071 // Try again for any divisor:
1072 // Is the dividend unsigned less than the divisor?
1073 return isICmpTrue(ICmpInst::ICMP_ULT
, X
, Y
, Q
, MaxRecurse
);
1076 /// Check for common or similar folds of integer division or integer remainder.
1077 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
1078 static Value
*simplifyDivRem(Instruction::BinaryOps Opcode
, Value
*Op0
,
1079 Value
*Op1
, const SimplifyQuery
&Q
,
1080 unsigned MaxRecurse
) {
1081 bool IsDiv
= (Opcode
== Instruction::SDiv
|| Opcode
== Instruction::UDiv
);
1082 bool IsSigned
= (Opcode
== Instruction::SDiv
|| Opcode
== Instruction::SRem
);
1084 Type
*Ty
= Op0
->getType();
1086 // X / undef -> poison
1087 // X % undef -> poison
1088 if (Q
.isUndefValue(Op1
) || isa
<PoisonValue
>(Op1
))
1089 return PoisonValue::get(Ty
);
1093 // We don't need to preserve faults!
1094 if (match(Op1
, m_Zero()))
1095 return PoisonValue::get(Ty
);
1097 // If any element of a constant divisor fixed width vector is zero or undef
1098 // the behavior is undefined and we can fold the whole op to poison.
1099 auto *Op1C
= dyn_cast
<Constant
>(Op1
);
1100 auto *VTy
= dyn_cast
<FixedVectorType
>(Ty
);
1102 unsigned NumElts
= VTy
->getNumElements();
1103 for (unsigned i
= 0; i
!= NumElts
; ++i
) {
1104 Constant
*Elt
= Op1C
->getAggregateElement(i
);
1105 if (Elt
&& (Elt
->isNullValue() || Q
.isUndefValue(Elt
)))
1106 return PoisonValue::get(Ty
);
1110 // poison / X -> poison
1111 // poison % X -> poison
1112 if (isa
<PoisonValue
>(Op0
))
1117 if (Q
.isUndefValue(Op0
))
1118 return Constant::getNullValue(Ty
);
1122 if (match(Op0
, m_Zero()))
1123 return Constant::getNullValue(Op0
->getType());
1128 return IsDiv
? ConstantInt::get(Ty
, 1) : Constant::getNullValue(Ty
);
1130 KnownBits Known
= computeKnownBits(Op1
, /* Depth */ 0, Q
);
1133 // If the divisor is known to be zero, just return poison. This can happen in
1134 // some cases where its provable indirectly the denominator is zero but it's
1135 // not trivially simplifiable (i.e known zero through a phi node).
1137 return PoisonValue::get(Ty
);
1141 // If the divisor can only be zero or one, we can't have division-by-zero
1142 // or remainder-by-zero, so assume the divisor is 1.
1143 // e.g. 1, zext (i8 X), sdiv X (Y and 1)
1144 if (Known
.countMinLeadingZeros() == Known
.getBitWidth() - 1)
1145 return IsDiv
? Op0
: Constant::getNullValue(Ty
);
1147 // If X * Y does not overflow, then:
1151 if (match(Op0
, m_c_Mul(m_Value(X
), m_Specific(Op1
)))) {
1152 auto *Mul
= cast
<OverflowingBinaryOperator
>(Op0
);
1153 // The multiplication can't overflow if it is defined not to, or if
1154 // X == A / Y for some A.
1155 if ((IsSigned
&& Q
.IIQ
.hasNoSignedWrap(Mul
)) ||
1156 (!IsSigned
&& Q
.IIQ
.hasNoUnsignedWrap(Mul
)) ||
1157 (IsSigned
&& match(X
, m_SDiv(m_Value(), m_Specific(Op1
)))) ||
1158 (!IsSigned
&& match(X
, m_UDiv(m_Value(), m_Specific(Op1
))))) {
1159 return IsDiv
? X
: Constant::getNullValue(Op0
->getType());
1163 if (isDivZero(Op0
, Op1
, Q
, MaxRecurse
, IsSigned
))
1164 return IsDiv
? Constant::getNullValue(Op0
->getType()) : Op0
;
1166 if (Value
*V
= simplifyByDomEq(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1169 // If the operation is with the result of a select instruction, check whether
1170 // operating on either branch of the select always yields the same value.
1171 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1172 if (Value
*V
= threadBinOpOverSelect(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1175 // If the operation is with the result of a phi instruction, check whether
1176 // operating on all incoming values of the phi always yields the same value.
1177 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1178 if (Value
*V
= threadBinOpOverPHI(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1184 /// These are simplifications common to SDiv and UDiv.
1185 static Value
*simplifyDiv(Instruction::BinaryOps Opcode
, Value
*Op0
, Value
*Op1
,
1186 bool IsExact
, const SimplifyQuery
&Q
,
1187 unsigned MaxRecurse
) {
1188 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1191 if (Value
*V
= simplifyDivRem(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1195 if (IsExact
&& match(Op1
, m_APInt(DivC
))) {
1196 // If this is an exact divide by a constant, then the dividend (Op0) must
1197 // have at least as many trailing zeros as the divisor to divide evenly. If
1198 // it has less trailing zeros, then the result must be poison.
1199 if (DivC
->countr_zero()) {
1200 KnownBits KnownOp0
= computeKnownBits(Op0
, /* Depth */ 0, Q
);
1201 if (KnownOp0
.countMaxTrailingZeros() < DivC
->countr_zero())
1202 return PoisonValue::get(Op0
->getType());
1205 // udiv exact (mul nsw X, C), C --> X
1206 // sdiv exact (mul nuw X, C), C --> X
1207 // where C is not a power of 2.
1209 if (!DivC
->isPowerOf2() &&
1210 (Opcode
== Instruction::UDiv
1211 ? match(Op0
, m_NSWMul(m_Value(X
), m_Specific(Op1
)))
1212 : match(Op0
, m_NUWMul(m_Value(X
), m_Specific(Op1
)))))
1219 /// These are simplifications common to SRem and URem.
1220 static Value
*simplifyRem(Instruction::BinaryOps Opcode
, Value
*Op0
, Value
*Op1
,
1221 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1222 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1225 if (Value
*V
= simplifyDivRem(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1228 // (X << Y) % X -> 0
1229 if (Q
.IIQ
.UseInstrInfo
) {
1230 if ((Opcode
== Instruction::SRem
&&
1231 match(Op0
, m_NSWShl(m_Specific(Op1
), m_Value()))) ||
1232 (Opcode
== Instruction::URem
&&
1233 match(Op0
, m_NUWShl(m_Specific(Op1
), m_Value()))))
1234 return Constant::getNullValue(Op0
->getType());
1237 if (match(Op1
, m_APInt(C0
))) {
1238 // (srem (mul nsw X, C1), C0) -> 0 if C1 s% C0 == 0
1239 // (urem (mul nuw X, C1), C0) -> 0 if C1 u% C0 == 0
1240 if (Opcode
== Instruction::SRem
1242 m_NSWMul(m_Value(), m_CheckedInt([C0
](const APInt
&C
) {
1243 return C
.srem(*C0
).isZero();
1246 m_NUWMul(m_Value(), m_CheckedInt([C0
](const APInt
&C
) {
1247 return C
.urem(*C0
).isZero();
1249 return Constant::getNullValue(Op0
->getType());
1255 /// Given operands for an SDiv, see if we can fold the result.
1256 /// If not, this returns null.
1257 static Value
*simplifySDivInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1258 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1259 // If two operands are negated and no signed overflow, return -1.
1260 if (isKnownNegation(Op0
, Op1
, /*NeedNSW=*/true))
1261 return Constant::getAllOnesValue(Op0
->getType());
1263 return simplifyDiv(Instruction::SDiv
, Op0
, Op1
, IsExact
, Q
, MaxRecurse
);
1266 Value
*llvm::simplifySDivInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1267 const SimplifyQuery
&Q
) {
1268 return ::simplifySDivInst(Op0
, Op1
, IsExact
, Q
, RecursionLimit
);
1271 /// Given operands for a UDiv, see if we can fold the result.
1272 /// If not, this returns null.
1273 static Value
*simplifyUDivInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1274 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1275 return simplifyDiv(Instruction::UDiv
, Op0
, Op1
, IsExact
, Q
, MaxRecurse
);
1278 Value
*llvm::simplifyUDivInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1279 const SimplifyQuery
&Q
) {
1280 return ::simplifyUDivInst(Op0
, Op1
, IsExact
, Q
, RecursionLimit
);
1283 /// Given operands for an SRem, see if we can fold the result.
1284 /// If not, this returns null.
1285 static Value
*simplifySRemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1286 unsigned MaxRecurse
) {
1287 // If the divisor is 0, the result is undefined, so assume the divisor is -1.
1288 // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
1290 if (match(Op1
, m_SExt(m_Value(X
))) && X
->getType()->isIntOrIntVectorTy(1))
1291 return ConstantInt::getNullValue(Op0
->getType());
1293 // If the two operands are negated, return 0.
1294 if (isKnownNegation(Op0
, Op1
))
1295 return ConstantInt::getNullValue(Op0
->getType());
1297 return simplifyRem(Instruction::SRem
, Op0
, Op1
, Q
, MaxRecurse
);
1300 Value
*llvm::simplifySRemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1301 return ::simplifySRemInst(Op0
, Op1
, Q
, RecursionLimit
);
1304 /// Given operands for a URem, see if we can fold the result.
1305 /// If not, this returns null.
1306 static Value
*simplifyURemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1307 unsigned MaxRecurse
) {
1308 return simplifyRem(Instruction::URem
, Op0
, Op1
, Q
, MaxRecurse
);
1311 Value
*llvm::simplifyURemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1312 return ::simplifyURemInst(Op0
, Op1
, Q
, RecursionLimit
);
1315 /// Returns true if a shift by \c Amount always yields poison.
1316 static bool isPoisonShift(Value
*Amount
, const SimplifyQuery
&Q
) {
1317 Constant
*C
= dyn_cast
<Constant
>(Amount
);
1321 // X shift by undef -> poison because it may shift by the bitwidth.
1322 if (Q
.isUndefValue(C
))
1325 // Shifting by the bitwidth or more is poison. This covers scalars and
1326 // fixed/scalable vectors with splat constants.
1327 const APInt
*AmountC
;
1328 if (match(C
, m_APInt(AmountC
)) && AmountC
->uge(AmountC
->getBitWidth()))
1331 // Try harder for fixed-length vectors:
1332 // If all lanes of a vector shift are poison, the whole shift is poison.
1333 if (isa
<ConstantVector
>(C
) || isa
<ConstantDataVector
>(C
)) {
1334 for (unsigned I
= 0,
1335 E
= cast
<FixedVectorType
>(C
->getType())->getNumElements();
1337 if (!isPoisonShift(C
->getAggregateElement(I
), Q
))
1345 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1346 /// If not, this returns null.
1347 static Value
*simplifyShift(Instruction::BinaryOps Opcode
, Value
*Op0
,
1348 Value
*Op1
, bool IsNSW
, const SimplifyQuery
&Q
,
1349 unsigned MaxRecurse
) {
1350 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1353 // poison shift by X -> poison
1354 if (isa
<PoisonValue
>(Op0
))
1357 // 0 shift by X -> 0
1358 if (match(Op0
, m_Zero()))
1359 return Constant::getNullValue(Op0
->getType());
1361 // X shift by 0 -> X
1362 // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
1365 if (match(Op1
, m_Zero()) ||
1366 (match(Op1
, m_SExt(m_Value(X
))) && X
->getType()->isIntOrIntVectorTy(1)))
1369 // Fold undefined shifts.
1370 if (isPoisonShift(Op1
, Q
))
1371 return PoisonValue::get(Op0
->getType());
1373 // If the operation is with the result of a select instruction, check whether
1374 // operating on either branch of the select always yields the same value.
1375 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1376 if (Value
*V
= threadBinOpOverSelect(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1379 // If the operation is with the result of a phi instruction, check whether
1380 // operating on all incoming values of the phi always yields the same value.
1381 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1382 if (Value
*V
= threadBinOpOverPHI(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1385 // If any bits in the shift amount make that value greater than or equal to
1386 // the number of bits in the type, the shift is undefined.
1387 KnownBits KnownAmt
= computeKnownBits(Op1
, /* Depth */ 0, Q
);
1388 if (KnownAmt
.getMinValue().uge(KnownAmt
.getBitWidth()))
1389 return PoisonValue::get(Op0
->getType());
1391 // If all valid bits in the shift amount are known zero, the first operand is
1393 unsigned NumValidShiftBits
= Log2_32_Ceil(KnownAmt
.getBitWidth());
1394 if (KnownAmt
.countMinTrailingZeros() >= NumValidShiftBits
)
1397 // Check for nsw shl leading to a poison value.
1399 assert(Opcode
== Instruction::Shl
&& "Expected shl for nsw instruction");
1400 KnownBits KnownVal
= computeKnownBits(Op0
, /* Depth */ 0, Q
);
1401 KnownBits KnownShl
= KnownBits::shl(KnownVal
, KnownAmt
);
1403 if (KnownVal
.Zero
.isSignBitSet())
1404 KnownShl
.Zero
.setSignBit();
1405 if (KnownVal
.One
.isSignBitSet())
1406 KnownShl
.One
.setSignBit();
1408 if (KnownShl
.hasConflict())
1409 return PoisonValue::get(Op0
->getType());
1415 /// Given operands for an LShr or AShr, see if we can fold the result. If not,
1416 /// this returns null.
1417 static Value
*simplifyRightShift(Instruction::BinaryOps Opcode
, Value
*Op0
,
1418 Value
*Op1
, bool IsExact
,
1419 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1421 simplifyShift(Opcode
, Op0
, Op1
, /*IsNSW*/ false, Q
, MaxRecurse
))
1426 return Constant::getNullValue(Op0
->getType());
1429 // undef >> X -> undef (if it's exact)
1430 if (Q
.isUndefValue(Op0
))
1431 return IsExact
? Op0
: Constant::getNullValue(Op0
->getType());
1433 // The low bit cannot be shifted out of an exact shift if it is set.
1434 // TODO: Generalize by counting trailing zeros (see fold for exact division).
1436 KnownBits Op0Known
= computeKnownBits(Op0
, /* Depth */ 0, Q
);
1437 if (Op0Known
.One
[0])
1444 /// Given operands for an Shl, see if we can fold the result.
1445 /// If not, this returns null.
1446 static Value
*simplifyShlInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
1447 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1449 simplifyShift(Instruction::Shl
, Op0
, Op1
, IsNSW
, Q
, MaxRecurse
))
1452 Type
*Ty
= Op0
->getType();
1454 // undef << X -> undef if (if it's NSW/NUW)
1455 if (Q
.isUndefValue(Op0
))
1456 return IsNSW
|| IsNUW
? Op0
: Constant::getNullValue(Ty
);
1458 // (X >> A) << A -> X
1460 if (Q
.IIQ
.UseInstrInfo
&&
1461 match(Op0
, m_Exact(m_Shr(m_Value(X
), m_Specific(Op1
)))))
1464 // shl nuw i8 C, %x -> C iff C has sign bit set.
1465 if (IsNUW
&& match(Op0
, m_Negative()))
1467 // NOTE: could use computeKnownBits() / LazyValueInfo,
1468 // but the cost-benefit analysis suggests it isn't worth it.
1470 // "nuw" guarantees that only zeros are shifted out, and "nsw" guarantees
1471 // that the sign-bit does not change, so the only input that does not
1472 // produce poison is 0, and "0 << (bitwidth-1) --> 0".
1473 if (IsNSW
&& IsNUW
&&
1474 match(Op1
, m_SpecificInt(Ty
->getScalarSizeInBits() - 1)))
1475 return Constant::getNullValue(Ty
);
1480 Value
*llvm::simplifyShlInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
1481 const SimplifyQuery
&Q
) {
1482 return ::simplifyShlInst(Op0
, Op1
, IsNSW
, IsNUW
, Q
, RecursionLimit
);
1485 /// Given operands for an LShr, see if we can fold the result.
1486 /// If not, this returns null.
1487 static Value
*simplifyLShrInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1488 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1489 if (Value
*V
= simplifyRightShift(Instruction::LShr
, Op0
, Op1
, IsExact
, Q
,
1493 // (X << A) >> A -> X
1495 if (Q
.IIQ
.UseInstrInfo
&& match(Op0
, m_NUWShl(m_Value(X
), m_Specific(Op1
))))
1498 // ((X << A) | Y) >> A -> X if effective width of Y is not larger than A.
1499 // We can return X as we do in the above case since OR alters no bits in X.
1500 // SimplifyDemandedBits in InstCombine can do more general optimization for
1501 // bit manipulation. This pattern aims to provide opportunities for other
1502 // optimizers by supporting a simple but common case in InstSimplify.
1504 const APInt
*ShRAmt
, *ShLAmt
;
1505 if (Q
.IIQ
.UseInstrInfo
&& match(Op1
, m_APInt(ShRAmt
)) &&
1506 match(Op0
, m_c_Or(m_NUWShl(m_Value(X
), m_APInt(ShLAmt
)), m_Value(Y
))) &&
1507 *ShRAmt
== *ShLAmt
) {
1508 const KnownBits YKnown
= computeKnownBits(Y
, /* Depth */ 0, Q
);
1509 const unsigned EffWidthY
= YKnown
.countMaxActiveBits();
1510 if (ShRAmt
->uge(EffWidthY
))
1517 Value
*llvm::simplifyLShrInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1518 const SimplifyQuery
&Q
) {
1519 return ::simplifyLShrInst(Op0
, Op1
, IsExact
, Q
, RecursionLimit
);
1522 /// Given operands for an AShr, see if we can fold the result.
1523 /// If not, this returns null.
1524 static Value
*simplifyAShrInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1525 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1526 if (Value
*V
= simplifyRightShift(Instruction::AShr
, Op0
, Op1
, IsExact
, Q
,
1531 // (-1 << X) a>> X --> -1
1532 // We could return the original -1 constant to preserve poison elements.
1533 if (match(Op0
, m_AllOnes()) ||
1534 match(Op0
, m_Shl(m_AllOnes(), m_Specific(Op1
))))
1535 return Constant::getAllOnesValue(Op0
->getType());
1537 // (X << A) >> A -> X
1539 if (Q
.IIQ
.UseInstrInfo
&& match(Op0
, m_NSWShl(m_Value(X
), m_Specific(Op1
))))
1542 // Arithmetic shifting an all-sign-bit value is a no-op.
1543 unsigned NumSignBits
= ComputeNumSignBits(Op0
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1544 if (NumSignBits
== Op0
->getType()->getScalarSizeInBits())
1550 Value
*llvm::simplifyAShrInst(Value
*Op0
, Value
*Op1
, bool IsExact
,
1551 const SimplifyQuery
&Q
) {
1552 return ::simplifyAShrInst(Op0
, Op1
, IsExact
, Q
, RecursionLimit
);
1555 /// Commuted variants are assumed to be handled by calling this function again
1556 /// with the parameters swapped.
1557 static Value
*simplifyUnsignedRangeCheck(ICmpInst
*ZeroICmp
,
1558 ICmpInst
*UnsignedICmp
, bool IsAnd
,
1559 const SimplifyQuery
&Q
) {
1562 ICmpInst::Predicate EqPred
;
1563 if (!match(ZeroICmp
, m_ICmp(EqPred
, m_Value(Y
), m_Zero())) ||
1564 !ICmpInst::isEquality(EqPred
))
1567 ICmpInst::Predicate UnsignedPred
;
1571 if (match(Y
, m_Sub(m_Value(A
), m_Value(B
)))) {
1572 if (match(UnsignedICmp
,
1573 m_c_ICmp(UnsignedPred
, m_Specific(A
), m_Specific(B
))) &&
1574 ICmpInst::isUnsigned(UnsignedPred
)) {
1575 // A >=/<= B || (A - B) != 0 <--> true
1576 if ((UnsignedPred
== ICmpInst::ICMP_UGE
||
1577 UnsignedPred
== ICmpInst::ICMP_ULE
) &&
1578 EqPred
== ICmpInst::ICMP_NE
&& !IsAnd
)
1579 return ConstantInt::getTrue(UnsignedICmp
->getType());
1580 // A </> B && (A - B) == 0 <--> false
1581 if ((UnsignedPred
== ICmpInst::ICMP_ULT
||
1582 UnsignedPred
== ICmpInst::ICMP_UGT
) &&
1583 EqPred
== ICmpInst::ICMP_EQ
&& IsAnd
)
1584 return ConstantInt::getFalse(UnsignedICmp
->getType());
1586 // A </> B && (A - B) != 0 <--> A </> B
1587 // A </> B || (A - B) != 0 <--> (A - B) != 0
1588 if (EqPred
== ICmpInst::ICMP_NE
&& (UnsignedPred
== ICmpInst::ICMP_ULT
||
1589 UnsignedPred
== ICmpInst::ICMP_UGT
))
1590 return IsAnd
? UnsignedICmp
: ZeroICmp
;
1592 // A <=/>= B && (A - B) == 0 <--> (A - B) == 0
1593 // A <=/>= B || (A - B) == 0 <--> A <=/>= B
1594 if (EqPred
== ICmpInst::ICMP_EQ
&& (UnsignedPred
== ICmpInst::ICMP_ULE
||
1595 UnsignedPred
== ICmpInst::ICMP_UGE
))
1596 return IsAnd
? ZeroICmp
: UnsignedICmp
;
1599 // Given Y = (A - B)
1600 // Y >= A && Y != 0 --> Y >= A iff B != 0
1601 // Y < A || Y == 0 --> Y < A iff B != 0
1602 if (match(UnsignedICmp
,
1603 m_c_ICmp(UnsignedPred
, m_Specific(Y
), m_Specific(A
)))) {
1604 if (UnsignedPred
== ICmpInst::ICMP_UGE
&& IsAnd
&&
1605 EqPred
== ICmpInst::ICMP_NE
&& isKnownNonZero(B
, Q
))
1606 return UnsignedICmp
;
1607 if (UnsignedPred
== ICmpInst::ICMP_ULT
&& !IsAnd
&&
1608 EqPred
== ICmpInst::ICMP_EQ
&& isKnownNonZero(B
, Q
))
1609 return UnsignedICmp
;
1613 if (match(UnsignedICmp
, m_ICmp(UnsignedPred
, m_Value(X
), m_Specific(Y
))) &&
1614 ICmpInst::isUnsigned(UnsignedPred
))
1616 else if (match(UnsignedICmp
,
1617 m_ICmp(UnsignedPred
, m_Specific(Y
), m_Value(X
))) &&
1618 ICmpInst::isUnsigned(UnsignedPred
))
1619 UnsignedPred
= ICmpInst::getSwappedPredicate(UnsignedPred
);
1623 // X > Y && Y == 0 --> Y == 0 iff X != 0
1624 // X > Y || Y == 0 --> X > Y iff X != 0
1625 if (UnsignedPred
== ICmpInst::ICMP_UGT
&& EqPred
== ICmpInst::ICMP_EQ
&&
1626 isKnownNonZero(X
, Q
))
1627 return IsAnd
? ZeroICmp
: UnsignedICmp
;
1629 // X <= Y && Y != 0 --> X <= Y iff X != 0
1630 // X <= Y || Y != 0 --> Y != 0 iff X != 0
1631 if (UnsignedPred
== ICmpInst::ICMP_ULE
&& EqPred
== ICmpInst::ICMP_NE
&&
1632 isKnownNonZero(X
, Q
))
1633 return IsAnd
? UnsignedICmp
: ZeroICmp
;
1635 // The transforms below here are expected to be handled more generally with
1636 // simplifyAndOrOfICmpsWithLimitConst() or in InstCombine's
1637 // foldAndOrOfICmpsWithConstEq(). If we are looking to trim optimizer overlap,
1638 // these are candidates for removal.
1640 // X < Y && Y != 0 --> X < Y
1641 // X < Y || Y != 0 --> Y != 0
1642 if (UnsignedPred
== ICmpInst::ICMP_ULT
&& EqPred
== ICmpInst::ICMP_NE
)
1643 return IsAnd
? UnsignedICmp
: ZeroICmp
;
1645 // X >= Y && Y == 0 --> Y == 0
1646 // X >= Y || Y == 0 --> X >= Y
1647 if (UnsignedPred
== ICmpInst::ICMP_UGE
&& EqPred
== ICmpInst::ICMP_EQ
)
1648 return IsAnd
? ZeroICmp
: UnsignedICmp
;
1650 // X < Y && Y == 0 --> false
1651 if (UnsignedPred
== ICmpInst::ICMP_ULT
&& EqPred
== ICmpInst::ICMP_EQ
&&
1653 return getFalse(UnsignedICmp
->getType());
1655 // X >= Y || Y != 0 --> true
1656 if (UnsignedPred
== ICmpInst::ICMP_UGE
&& EqPred
== ICmpInst::ICMP_NE
&&
1658 return getTrue(UnsignedICmp
->getType());
1663 /// Test if a pair of compares with a shared operand and 2 constants has an
1664 /// empty set intersection, full set union, or if one compare is a superset of
1666 static Value
*simplifyAndOrOfICmpsWithConstants(ICmpInst
*Cmp0
, ICmpInst
*Cmp1
,
1668 // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1669 if (Cmp0
->getOperand(0) != Cmp1
->getOperand(0))
1672 const APInt
*C0
, *C1
;
1673 if (!match(Cmp0
->getOperand(1), m_APInt(C0
)) ||
1674 !match(Cmp1
->getOperand(1), m_APInt(C1
)))
1677 auto Range0
= ConstantRange::makeExactICmpRegion(Cmp0
->getPredicate(), *C0
);
1678 auto Range1
= ConstantRange::makeExactICmpRegion(Cmp1
->getPredicate(), *C1
);
1680 // For and-of-compares, check if the intersection is empty:
1681 // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1682 if (IsAnd
&& Range0
.intersectWith(Range1
).isEmptySet())
1683 return getFalse(Cmp0
->getType());
1685 // For or-of-compares, check if the union is full:
1686 // (icmp X, C0) || (icmp X, C1) --> full set --> true
1687 if (!IsAnd
&& Range0
.unionWith(Range1
).isFullSet())
1688 return getTrue(Cmp0
->getType());
1690 // Is one range a superset of the other?
1691 // If this is and-of-compares, take the smaller set:
1692 // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1693 // If this is or-of-compares, take the larger set:
1694 // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1695 if (Range0
.contains(Range1
))
1696 return IsAnd
? Cmp1
: Cmp0
;
1697 if (Range1
.contains(Range0
))
1698 return IsAnd
? Cmp0
: Cmp1
;
1703 static Value
*simplifyAndOfICmpsWithAdd(ICmpInst
*Op0
, ICmpInst
*Op1
,
1704 const InstrInfoQuery
&IIQ
) {
1705 // (icmp (add V, C0), C1) & (icmp V, C0)
1706 ICmpInst::Predicate Pred0
, Pred1
;
1707 const APInt
*C0
, *C1
;
1709 if (!match(Op0
, m_ICmp(Pred0
, m_Add(m_Value(V
), m_APInt(C0
)), m_APInt(C1
))))
1712 if (!match(Op1
, m_ICmp(Pred1
, m_Specific(V
), m_Value())))
1715 auto *AddInst
= cast
<OverflowingBinaryOperator
>(Op0
->getOperand(0));
1716 if (AddInst
->getOperand(1) != Op1
->getOperand(1))
1719 Type
*ITy
= Op0
->getType();
1720 bool IsNSW
= IIQ
.hasNoSignedWrap(AddInst
);
1721 bool IsNUW
= IIQ
.hasNoUnsignedWrap(AddInst
);
1723 const APInt Delta
= *C1
- *C0
;
1724 if (C0
->isStrictlyPositive()) {
1726 if (Pred0
== ICmpInst::ICMP_ULT
&& Pred1
== ICmpInst::ICMP_SGT
)
1727 return getFalse(ITy
);
1728 if (Pred0
== ICmpInst::ICMP_SLT
&& Pred1
== ICmpInst::ICMP_SGT
&& IsNSW
)
1729 return getFalse(ITy
);
1732 if (Pred0
== ICmpInst::ICMP_ULE
&& Pred1
== ICmpInst::ICMP_SGT
)
1733 return getFalse(ITy
);
1734 if (Pred0
== ICmpInst::ICMP_SLE
&& Pred1
== ICmpInst::ICMP_SGT
&& IsNSW
)
1735 return getFalse(ITy
);
1738 if (C0
->getBoolValue() && IsNUW
) {
1740 if (Pred0
== ICmpInst::ICMP_ULT
&& Pred1
== ICmpInst::ICMP_UGT
)
1741 return getFalse(ITy
);
1743 if (Pred0
== ICmpInst::ICMP_ULE
&& Pred1
== ICmpInst::ICMP_UGT
)
1744 return getFalse(ITy
);
1750 /// Try to simplify and/or of icmp with ctpop intrinsic.
1751 static Value
*simplifyAndOrOfICmpsWithCtpop(ICmpInst
*Cmp0
, ICmpInst
*Cmp1
,
1753 ICmpInst::Predicate Pred0
, Pred1
;
1756 if (!match(Cmp0
, m_ICmp(Pred0
, m_Intrinsic
<Intrinsic::ctpop
>(m_Value(X
)),
1758 !match(Cmp1
, m_ICmp(Pred1
, m_Specific(X
), m_ZeroInt())) || C
->isZero())
1761 // (ctpop(X) == C) || (X != 0) --> X != 0 where C > 0
1762 if (!IsAnd
&& Pred0
== ICmpInst::ICMP_EQ
&& Pred1
== ICmpInst::ICMP_NE
)
1764 // (ctpop(X) != C) && (X == 0) --> X == 0 where C > 0
1765 if (IsAnd
&& Pred0
== ICmpInst::ICMP_NE
&& Pred1
== ICmpInst::ICMP_EQ
)
1771 static Value
*simplifyAndOfICmps(ICmpInst
*Op0
, ICmpInst
*Op1
,
1772 const SimplifyQuery
&Q
) {
1773 if (Value
*X
= simplifyUnsignedRangeCheck(Op0
, Op1
, /*IsAnd=*/true, Q
))
1775 if (Value
*X
= simplifyUnsignedRangeCheck(Op1
, Op0
, /*IsAnd=*/true, Q
))
1778 if (Value
*X
= simplifyAndOrOfICmpsWithConstants(Op0
, Op1
, true))
1781 if (Value
*X
= simplifyAndOrOfICmpsWithCtpop(Op0
, Op1
, true))
1783 if (Value
*X
= simplifyAndOrOfICmpsWithCtpop(Op1
, Op0
, true))
1786 if (Value
*X
= simplifyAndOfICmpsWithAdd(Op0
, Op1
, Q
.IIQ
))
1788 if (Value
*X
= simplifyAndOfICmpsWithAdd(Op1
, Op0
, Q
.IIQ
))
1794 static Value
*simplifyOrOfICmpsWithAdd(ICmpInst
*Op0
, ICmpInst
*Op1
,
1795 const InstrInfoQuery
&IIQ
) {
1796 // (icmp (add V, C0), C1) | (icmp V, C0)
1797 ICmpInst::Predicate Pred0
, Pred1
;
1798 const APInt
*C0
, *C1
;
1800 if (!match(Op0
, m_ICmp(Pred0
, m_Add(m_Value(V
), m_APInt(C0
)), m_APInt(C1
))))
1803 if (!match(Op1
, m_ICmp(Pred1
, m_Specific(V
), m_Value())))
1806 auto *AddInst
= cast
<BinaryOperator
>(Op0
->getOperand(0));
1807 if (AddInst
->getOperand(1) != Op1
->getOperand(1))
1810 Type
*ITy
= Op0
->getType();
1811 bool IsNSW
= IIQ
.hasNoSignedWrap(AddInst
);
1812 bool IsNUW
= IIQ
.hasNoUnsignedWrap(AddInst
);
1814 const APInt Delta
= *C1
- *C0
;
1815 if (C0
->isStrictlyPositive()) {
1817 if (Pred0
== ICmpInst::ICMP_UGE
&& Pred1
== ICmpInst::ICMP_SLE
)
1818 return getTrue(ITy
);
1819 if (Pred0
== ICmpInst::ICMP_SGE
&& Pred1
== ICmpInst::ICMP_SLE
&& IsNSW
)
1820 return getTrue(ITy
);
1823 if (Pred0
== ICmpInst::ICMP_UGT
&& Pred1
== ICmpInst::ICMP_SLE
)
1824 return getTrue(ITy
);
1825 if (Pred0
== ICmpInst::ICMP_SGT
&& Pred1
== ICmpInst::ICMP_SLE
&& IsNSW
)
1826 return getTrue(ITy
);
1829 if (C0
->getBoolValue() && IsNUW
) {
1831 if (Pred0
== ICmpInst::ICMP_UGE
&& Pred1
== ICmpInst::ICMP_ULE
)
1832 return getTrue(ITy
);
1834 if (Pred0
== ICmpInst::ICMP_UGT
&& Pred1
== ICmpInst::ICMP_ULE
)
1835 return getTrue(ITy
);
1841 static Value
*simplifyOrOfICmps(ICmpInst
*Op0
, ICmpInst
*Op1
,
1842 const SimplifyQuery
&Q
) {
1843 if (Value
*X
= simplifyUnsignedRangeCheck(Op0
, Op1
, /*IsAnd=*/false, Q
))
1845 if (Value
*X
= simplifyUnsignedRangeCheck(Op1
, Op0
, /*IsAnd=*/false, Q
))
1848 if (Value
*X
= simplifyAndOrOfICmpsWithConstants(Op0
, Op1
, false))
1851 if (Value
*X
= simplifyAndOrOfICmpsWithCtpop(Op0
, Op1
, false))
1853 if (Value
*X
= simplifyAndOrOfICmpsWithCtpop(Op1
, Op0
, false))
1856 if (Value
*X
= simplifyOrOfICmpsWithAdd(Op0
, Op1
, Q
.IIQ
))
1858 if (Value
*X
= simplifyOrOfICmpsWithAdd(Op1
, Op0
, Q
.IIQ
))
1864 static Value
*simplifyAndOrOfFCmps(const SimplifyQuery
&Q
, FCmpInst
*LHS
,
1865 FCmpInst
*RHS
, bool IsAnd
) {
1866 Value
*LHS0
= LHS
->getOperand(0), *LHS1
= LHS
->getOperand(1);
1867 Value
*RHS0
= RHS
->getOperand(0), *RHS1
= RHS
->getOperand(1);
1868 if (LHS0
->getType() != RHS0
->getType())
1871 FCmpInst::Predicate PredL
= LHS
->getPredicate(), PredR
= RHS
->getPredicate();
1872 if ((PredL
== FCmpInst::FCMP_ORD
|| PredL
== FCmpInst::FCMP_UNO
) &&
1873 ((FCmpInst::isOrdered(PredR
) && IsAnd
) ||
1874 (FCmpInst::isUnordered(PredR
) && !IsAnd
))) {
1875 // (fcmp ord X, 0) & (fcmp o** X, Y) --> fcmp o** X, Y
1876 // (fcmp uno X, 0) & (fcmp o** X, Y) --> false
1877 // (fcmp uno X, 0) | (fcmp u** X, Y) --> fcmp u** X, Y
1878 // (fcmp ord X, 0) | (fcmp u** X, Y) --> true
1879 if ((LHS0
== RHS0
|| LHS0
== RHS1
) && match(LHS1
, m_PosZeroFP()))
1880 return FCmpInst::isOrdered(PredL
) == FCmpInst::isOrdered(PredR
)
1881 ? static_cast<Value
*>(RHS
)
1882 : ConstantInt::getBool(LHS
->getType(), !IsAnd
);
1885 if ((PredR
== FCmpInst::FCMP_ORD
|| PredR
== FCmpInst::FCMP_UNO
) &&
1886 ((FCmpInst::isOrdered(PredL
) && IsAnd
) ||
1887 (FCmpInst::isUnordered(PredL
) && !IsAnd
))) {
1888 // (fcmp o** X, Y) & (fcmp ord X, 0) --> fcmp o** X, Y
1889 // (fcmp o** X, Y) & (fcmp uno X, 0) --> false
1890 // (fcmp u** X, Y) | (fcmp uno X, 0) --> fcmp u** X, Y
1891 // (fcmp u** X, Y) | (fcmp ord X, 0) --> true
1892 if ((RHS0
== LHS0
|| RHS0
== LHS1
) && match(RHS1
, m_PosZeroFP()))
1893 return FCmpInst::isOrdered(PredL
) == FCmpInst::isOrdered(PredR
)
1894 ? static_cast<Value
*>(LHS
)
1895 : ConstantInt::getBool(LHS
->getType(), !IsAnd
);
1901 static Value
*simplifyAndOrOfCmps(const SimplifyQuery
&Q
, Value
*Op0
,
1902 Value
*Op1
, bool IsAnd
) {
1903 // Look through casts of the 'and' operands to find compares.
1904 auto *Cast0
= dyn_cast
<CastInst
>(Op0
);
1905 auto *Cast1
= dyn_cast
<CastInst
>(Op1
);
1906 if (Cast0
&& Cast1
&& Cast0
->getOpcode() == Cast1
->getOpcode() &&
1907 Cast0
->getSrcTy() == Cast1
->getSrcTy()) {
1908 Op0
= Cast0
->getOperand(0);
1909 Op1
= Cast1
->getOperand(0);
1913 auto *ICmp0
= dyn_cast
<ICmpInst
>(Op0
);
1914 auto *ICmp1
= dyn_cast
<ICmpInst
>(Op1
);
1916 V
= IsAnd
? simplifyAndOfICmps(ICmp0
, ICmp1
, Q
)
1917 : simplifyOrOfICmps(ICmp0
, ICmp1
, Q
);
1919 auto *FCmp0
= dyn_cast
<FCmpInst
>(Op0
);
1920 auto *FCmp1
= dyn_cast
<FCmpInst
>(Op1
);
1922 V
= simplifyAndOrOfFCmps(Q
, FCmp0
, FCmp1
, IsAnd
);
1929 // If we looked through casts, we can only handle a constant simplification
1930 // because we are not allowed to create a cast instruction here.
1931 if (auto *C
= dyn_cast
<Constant
>(V
))
1932 return ConstantFoldCastOperand(Cast0
->getOpcode(), C
, Cast0
->getType(),
1938 static Value
*simplifyWithOpReplaced(Value
*V
, Value
*Op
, Value
*RepOp
,
1939 const SimplifyQuery
&Q
,
1940 bool AllowRefinement
,
1941 SmallVectorImpl
<Instruction
*> *DropFlags
,
1942 unsigned MaxRecurse
);
1944 static Value
*simplifyAndOrWithICmpEq(unsigned Opcode
, Value
*Op0
, Value
*Op1
,
1945 const SimplifyQuery
&Q
,
1946 unsigned MaxRecurse
) {
1947 assert((Opcode
== Instruction::And
|| Opcode
== Instruction::Or
) &&
1949 ICmpInst::Predicate Pred
;
1951 if (!match(Op0
, m_ICmp(Pred
, m_Value(A
), m_Value(B
))) ||
1952 !ICmpInst::isEquality(Pred
))
1955 auto Simplify
= [&](Value
*Res
) -> Value
* {
1956 Constant
*Absorber
= ConstantExpr::getBinOpAbsorber(Opcode
, Res
->getType());
1958 // and (icmp eq a, b), x implies (a==b) inside x.
1959 // or (icmp ne a, b), x implies (a==b) inside x.
1960 // If x simplifies to true/false, we can simplify the and/or.
1962 (Opcode
== Instruction::And
? ICmpInst::ICMP_EQ
: ICmpInst::ICMP_NE
)) {
1963 if (Res
== Absorber
)
1965 if (Res
== ConstantExpr::getBinOpIdentity(Opcode
, Res
->getType()))
1970 // If we have and (icmp ne a, b), x and for a==b we can simplify x to false,
1971 // then we can drop the icmp, as x will already be false in the case where
1972 // the icmp is false. Similar for or and true.
1973 if (Res
== Absorber
)
1978 // In the final case (Res == Absorber with inverted predicate), it is safe to
1979 // refine poison during simplification, but not undef. For simplicity always
1980 // disable undef-based folds here.
1981 if (Value
*Res
= simplifyWithOpReplaced(Op1
, A
, B
, Q
.getWithoutUndef(),
1982 /* AllowRefinement */ true,
1983 /* DropFlags */ nullptr, MaxRecurse
))
1984 return Simplify(Res
);
1985 if (Value
*Res
= simplifyWithOpReplaced(Op1
, B
, A
, Q
.getWithoutUndef(),
1986 /* AllowRefinement */ true,
1987 /* DropFlags */ nullptr, MaxRecurse
))
1988 return Simplify(Res
);
1993 /// Given a bitwise logic op, check if the operands are add/sub with a common
1994 /// source value and inverted constant (identity: C - X -> ~(X + ~C)).
1995 static Value
*simplifyLogicOfAddSub(Value
*Op0
, Value
*Op1
,
1996 Instruction::BinaryOps Opcode
) {
1997 assert(Op0
->getType() == Op1
->getType() && "Mismatched binop types");
1998 assert(BinaryOperator::isBitwiseLogicOp(Opcode
) && "Expected logic op");
2001 if ((match(Op0
, m_Add(m_Value(X
), m_Constant(C1
))) &&
2002 match(Op1
, m_Sub(m_Constant(C2
), m_Specific(X
)))) ||
2003 (match(Op1
, m_Add(m_Value(X
), m_Constant(C1
))) &&
2004 match(Op0
, m_Sub(m_Constant(C2
), m_Specific(X
))))) {
2005 if (ConstantExpr::getNot(C1
) == C2
) {
2006 // (X + C) & (~C - X) --> (X + C) & ~(X + C) --> 0
2007 // (X + C) | (~C - X) --> (X + C) | ~(X + C) --> -1
2008 // (X + C) ^ (~C - X) --> (X + C) ^ ~(X + C) --> -1
2009 Type
*Ty
= Op0
->getType();
2010 return Opcode
== Instruction::And
? ConstantInt::getNullValue(Ty
)
2011 : ConstantInt::getAllOnesValue(Ty
);
2017 // Commutative patterns for and that will be tried with both operand orders.
2018 static Value
*simplifyAndCommutative(Value
*Op0
, Value
*Op1
,
2019 const SimplifyQuery
&Q
,
2020 unsigned MaxRecurse
) {
2022 if (match(Op0
, m_Not(m_Specific(Op1
))))
2023 return Constant::getNullValue(Op0
->getType());
2026 if (match(Op0
, m_c_Or(m_Specific(Op1
), m_Value())))
2029 // (X | ~Y) & (X | Y) --> X
2031 if (match(Op0
, m_c_Or(m_Value(X
), m_Not(m_Value(Y
)))) &&
2032 match(Op1
, m_c_Or(m_Specific(X
), m_Specific(Y
))))
2035 // If we have a multiplication overflow check that is being 'and'ed with a
2036 // check that one of the multipliers is not zero, we can omit the 'and', and
2037 // only keep the overflow check.
2038 if (isCheckForZeroAndMulWithOverflow(Op0
, Op1
, true))
2041 // -A & A = A if A is a power of two or zero.
2042 if (match(Op0
, m_Neg(m_Specific(Op1
))) &&
2043 isKnownToBeAPowerOfTwo(Op1
, Q
.DL
, /*OrZero*/ true, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2046 // This is a similar pattern used for checking if a value is a power-of-2:
2047 // (A - 1) & A --> 0 (if A is a power-of-2 or 0)
2048 if (match(Op0
, m_Add(m_Specific(Op1
), m_AllOnes())) &&
2049 isKnownToBeAPowerOfTwo(Op1
, Q
.DL
, /*OrZero*/ true, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2050 return Constant::getNullValue(Op1
->getType());
2052 // (x << N) & ((x << M) - 1) --> 0, where x is known to be a power of 2 and
2054 const APInt
*Shift1
, *Shift2
;
2055 if (match(Op0
, m_Shl(m_Value(X
), m_APInt(Shift1
))) &&
2056 match(Op1
, m_Add(m_Shl(m_Specific(X
), m_APInt(Shift2
)), m_AllOnes())) &&
2057 isKnownToBeAPowerOfTwo(X
, Q
.DL
, /*OrZero*/ true, /*Depth*/ 0, Q
.AC
,
2059 Shift1
->uge(*Shift2
))
2060 return Constant::getNullValue(Op0
->getType());
2063 simplifyAndOrWithICmpEq(Instruction::And
, Op0
, Op1
, Q
, MaxRecurse
))
2069 /// Given operands for an And, see if we can fold the result.
2070 /// If not, this returns null.
2071 static Value
*simplifyAndInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
2072 unsigned MaxRecurse
) {
2073 if (Constant
*C
= foldOrCommuteConstant(Instruction::And
, Op0
, Op1
, Q
))
2076 // X & poison -> poison
2077 if (isa
<PoisonValue
>(Op1
))
2081 if (Q
.isUndefValue(Op1
))
2082 return Constant::getNullValue(Op0
->getType());
2089 if (match(Op1
, m_Zero()))
2090 return Constant::getNullValue(Op0
->getType());
2093 if (match(Op1
, m_AllOnes()))
2096 if (Value
*Res
= simplifyAndCommutative(Op0
, Op1
, Q
, MaxRecurse
))
2098 if (Value
*Res
= simplifyAndCommutative(Op1
, Op0
, Q
, MaxRecurse
))
2101 if (Value
*V
= simplifyLogicOfAddSub(Op0
, Op1
, Instruction::And
))
2104 // A mask that only clears known zeros of a shifted value is a no-op.
2108 if (match(Op1
, m_APInt(Mask
))) {
2109 // If all bits in the inverted and shifted mask are clear:
2110 // and (shl X, ShAmt), Mask --> shl X, ShAmt
2111 if (match(Op0
, m_Shl(m_Value(X
), m_APInt(ShAmt
))) &&
2112 (~(*Mask
)).lshr(*ShAmt
).isZero())
2115 // If all bits in the inverted and shifted mask are clear:
2116 // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
2117 if (match(Op0
, m_LShr(m_Value(X
), m_APInt(ShAmt
))) &&
2118 (~(*Mask
)).shl(*ShAmt
).isZero())
2122 // and 2^x-1, 2^C --> 0 where x <= C.
2123 const APInt
*PowerC
;
2125 if (match(Op1
, m_Power2(PowerC
)) &&
2126 match(Op0
, m_Add(m_Value(Shift
), m_AllOnes())) &&
2127 isKnownToBeAPowerOfTwo(Shift
, Q
.DL
, /*OrZero*/ false, 0, Q
.AC
, Q
.CxtI
,
2129 KnownBits Known
= computeKnownBits(Shift
, /* Depth */ 0, Q
);
2130 // Use getActiveBits() to make use of the additional power of two knowledge
2131 if (PowerC
->getActiveBits() >= Known
.getMaxValue().getActiveBits())
2132 return ConstantInt::getNullValue(Op1
->getType());
2135 if (Value
*V
= simplifyAndOrOfCmps(Q
, Op0
, Op1
, true))
2138 // Try some generic simplifications for associative operations.
2140 simplifyAssociativeBinOp(Instruction::And
, Op0
, Op1
, Q
, MaxRecurse
))
2143 // And distributes over Or. Try some generic simplifications based on this.
2144 if (Value
*V
= expandCommutativeBinOp(Instruction::And
, Op0
, Op1
,
2145 Instruction::Or
, Q
, MaxRecurse
))
2148 // And distributes over Xor. Try some generic simplifications based on this.
2149 if (Value
*V
= expandCommutativeBinOp(Instruction::And
, Op0
, Op1
,
2150 Instruction::Xor
, Q
, MaxRecurse
))
2153 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
)) {
2154 if (Op0
->getType()->isIntOrIntVectorTy(1)) {
2155 // A & (A && B) -> A && B
2156 if (match(Op1
, m_Select(m_Specific(Op0
), m_Value(), m_Zero())))
2158 else if (match(Op0
, m_Select(m_Specific(Op1
), m_Value(), m_Zero())))
2161 // If the operation is with the result of a select instruction, check
2162 // whether operating on either branch of the select always yields the same
2165 threadBinOpOverSelect(Instruction::And
, Op0
, Op1
, Q
, MaxRecurse
))
2169 // If the operation is with the result of a phi instruction, check whether
2170 // operating on all incoming values of the phi always yields the same value.
2171 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
2173 threadBinOpOverPHI(Instruction::And
, Op0
, Op1
, Q
, MaxRecurse
))
2176 // Assuming the effective width of Y is not larger than A, i.e. all bits
2177 // from X and Y are disjoint in (X << A) | Y,
2178 // if the mask of this AND op covers all bits of X or Y, while it covers
2179 // no bits from the other, we can bypass this AND op. E.g.,
2180 // ((X << A) | Y) & Mask -> Y,
2181 // if Mask = ((1 << effective_width_of(Y)) - 1)
2182 // ((X << A) | Y) & Mask -> X << A,
2183 // if Mask = ((1 << effective_width_of(X)) - 1) << A
2184 // SimplifyDemandedBits in InstCombine can optimize the general case.
2185 // This pattern aims to help other passes for a common case.
2187 if (Q
.IIQ
.UseInstrInfo
&& match(Op1
, m_APInt(Mask
)) &&
2188 match(Op0
, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X
), m_APInt(ShAmt
)),
2191 const unsigned Width
= Op0
->getType()->getScalarSizeInBits();
2192 const unsigned ShftCnt
= ShAmt
->getLimitedValue(Width
);
2193 const KnownBits YKnown
= computeKnownBits(Y
, /* Depth */ 0, Q
);
2194 const unsigned EffWidthY
= YKnown
.countMaxActiveBits();
2195 if (EffWidthY
<= ShftCnt
) {
2196 const KnownBits XKnown
= computeKnownBits(X
, /* Depth */ 0, Q
);
2197 const unsigned EffWidthX
= XKnown
.countMaxActiveBits();
2198 const APInt EffBitsY
= APInt::getLowBitsSet(Width
, EffWidthY
);
2199 const APInt EffBitsX
= APInt::getLowBitsSet(Width
, EffWidthX
) << ShftCnt
;
2200 // If the mask is extracting all bits from X or Y as is, we can skip
2202 if (EffBitsY
.isSubsetOf(*Mask
) && !EffBitsX
.intersects(*Mask
))
2204 if (EffBitsX
.isSubsetOf(*Mask
) && !EffBitsY
.intersects(*Mask
))
2209 // ((X | Y) ^ X ) & ((X | Y) ^ Y) --> 0
2210 // ((X | Y) ^ Y ) & ((X | Y) ^ X) --> 0
2212 if (match(Op0
, m_c_Xor(m_Value(X
),
2213 m_CombineAnd(m_BinOp(Or
),
2214 m_c_Or(m_Deferred(X
), m_Value(Y
))))) &&
2215 match(Op1
, m_c_Xor(m_Specific(Or
), m_Specific(Y
))))
2216 return Constant::getNullValue(Op0
->getType());
2220 // (A ^ C) & (A ^ ~C) -> 0
2221 if (match(Op0
, m_Xor(m_Value(A
), m_APInt(C1
))) &&
2222 match(Op1
, m_Xor(m_Specific(A
), m_SpecificInt(~*C1
))))
2223 return Constant::getNullValue(Op0
->getType());
2225 if (Op0
->getType()->isIntOrIntVectorTy(1)) {
2226 if (std::optional
<bool> Implied
= isImpliedCondition(Op0
, Op1
, Q
.DL
)) {
2227 // If Op0 is true implies Op1 is true, then Op0 is a subset of Op1.
2228 if (*Implied
== true)
2230 // If Op0 is true implies Op1 is false, then they are not true together.
2231 if (*Implied
== false)
2232 return ConstantInt::getFalse(Op0
->getType());
2234 if (std::optional
<bool> Implied
= isImpliedCondition(Op1
, Op0
, Q
.DL
)) {
2235 // If Op1 is true implies Op0 is true, then Op1 is a subset of Op0.
2238 // If Op1 is true implies Op0 is false, then they are not true together.
2240 return ConstantInt::getFalse(Op1
->getType());
2244 if (Value
*V
= simplifyByDomEq(Instruction::And
, Op0
, Op1
, Q
, MaxRecurse
))
2250 Value
*llvm::simplifyAndInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
2251 return ::simplifyAndInst(Op0
, Op1
, Q
, RecursionLimit
);
2254 // TODO: Many of these folds could use LogicalAnd/LogicalOr.
2255 static Value
*simplifyOrLogic(Value
*X
, Value
*Y
) {
2256 assert(X
->getType() == Y
->getType() && "Expected same type for 'or' ops");
2257 Type
*Ty
= X
->getType();
2260 if (match(Y
, m_Not(m_Specific(X
))))
2261 return ConstantInt::getAllOnesValue(Ty
);
2263 // X | ~(X & ?) = -1
2264 if (match(Y
, m_Not(m_c_And(m_Specific(X
), m_Value()))))
2265 return ConstantInt::getAllOnesValue(Ty
);
2267 // X | (X & ?) --> X
2268 if (match(Y
, m_c_And(m_Specific(X
), m_Value())))
2273 // (A ^ B) | (A | B) --> A | B
2274 // (A ^ B) | (B | A) --> B | A
2275 if (match(X
, m_Xor(m_Value(A
), m_Value(B
))) &&
2276 match(Y
, m_c_Or(m_Specific(A
), m_Specific(B
))))
2279 // ~(A ^ B) | (A | B) --> -1
2280 // ~(A ^ B) | (B | A) --> -1
2281 if (match(X
, m_Not(m_Xor(m_Value(A
), m_Value(B
)))) &&
2282 match(Y
, m_c_Or(m_Specific(A
), m_Specific(B
))))
2283 return ConstantInt::getAllOnesValue(Ty
);
2285 // (A & ~B) | (A ^ B) --> A ^ B
2286 // (~B & A) | (A ^ B) --> A ^ B
2287 // (A & ~B) | (B ^ A) --> B ^ A
2288 // (~B & A) | (B ^ A) --> B ^ A
2289 if (match(X
, m_c_And(m_Value(A
), m_Not(m_Value(B
)))) &&
2290 match(Y
, m_c_Xor(m_Specific(A
), m_Specific(B
))))
2293 // (~A ^ B) | (A & B) --> ~A ^ B
2294 // (B ^ ~A) | (A & B) --> B ^ ~A
2295 // (~A ^ B) | (B & A) --> ~A ^ B
2296 // (B ^ ~A) | (B & A) --> B ^ ~A
2297 if (match(X
, m_c_Xor(m_Not(m_Value(A
)), m_Value(B
))) &&
2298 match(Y
, m_c_And(m_Specific(A
), m_Specific(B
))))
2301 // (~A | B) | (A ^ B) --> -1
2302 // (~A | B) | (B ^ A) --> -1
2303 // (B | ~A) | (A ^ B) --> -1
2304 // (B | ~A) | (B ^ A) --> -1
2305 if (match(X
, m_c_Or(m_Not(m_Value(A
)), m_Value(B
))) &&
2306 match(Y
, m_c_Xor(m_Specific(A
), m_Specific(B
))))
2307 return ConstantInt::getAllOnesValue(Ty
);
2309 // (~A & B) | ~(A | B) --> ~A
2310 // (~A & B) | ~(B | A) --> ~A
2311 // (B & ~A) | ~(A | B) --> ~A
2312 // (B & ~A) | ~(B | A) --> ~A
2314 if (match(X
, m_c_And(m_CombineAnd(m_Value(NotA
), m_Not(m_Value(A
))),
2316 match(Y
, m_Not(m_c_Or(m_Specific(A
), m_Specific(B
)))))
2318 // The same is true of Logical And
2319 // TODO: This could share the logic of the version above if there was a
2320 // version of LogicalAnd that allowed more than just i1 types.
2321 if (match(X
, m_c_LogicalAnd(m_CombineAnd(m_Value(NotA
), m_Not(m_Value(A
))),
2323 match(Y
, m_Not(m_c_LogicalOr(m_Specific(A
), m_Specific(B
)))))
2326 // ~(A ^ B) | (A & B) --> ~(A ^ B)
2327 // ~(A ^ B) | (B & A) --> ~(A ^ B)
2329 if (match(X
, m_CombineAnd(m_Not(m_Xor(m_Value(A
), m_Value(B
))),
2331 match(Y
, m_c_And(m_Specific(A
), m_Specific(B
))))
2334 // ~(A & B) | (A ^ B) --> ~(A & B)
2335 // ~(A & B) | (B ^ A) --> ~(A & B)
2336 if (match(X
, m_CombineAnd(m_Not(m_And(m_Value(A
), m_Value(B
))),
2338 match(Y
, m_c_Xor(m_Specific(A
), m_Specific(B
))))
2344 /// Given operands for an Or, see if we can fold the result.
2345 /// If not, this returns null.
2346 static Value
*simplifyOrInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
2347 unsigned MaxRecurse
) {
2348 if (Constant
*C
= foldOrCommuteConstant(Instruction::Or
, Op0
, Op1
, Q
))
2351 // X | poison -> poison
2352 if (isa
<PoisonValue
>(Op1
))
2357 // Do not return Op1 because it may contain undef elements if it's a vector.
2358 if (Q
.isUndefValue(Op1
) || match(Op1
, m_AllOnes()))
2359 return Constant::getAllOnesValue(Op0
->getType());
2363 if (Op0
== Op1
|| match(Op1
, m_Zero()))
2366 if (Value
*R
= simplifyOrLogic(Op0
, Op1
))
2368 if (Value
*R
= simplifyOrLogic(Op1
, Op0
))
2371 if (Value
*V
= simplifyLogicOfAddSub(Op0
, Op1
, Instruction::Or
))
2374 // Rotated -1 is still -1:
2375 // (-1 << X) | (-1 >> (C - X)) --> -1
2376 // (-1 >> X) | (-1 << (C - X)) --> -1
2377 // ...with C <= bitwidth (and commuted variants).
2379 if ((match(Op0
, m_Shl(m_AllOnes(), m_Value(X
))) &&
2380 match(Op1
, m_LShr(m_AllOnes(), m_Value(Y
)))) ||
2381 (match(Op1
, m_Shl(m_AllOnes(), m_Value(X
))) &&
2382 match(Op0
, m_LShr(m_AllOnes(), m_Value(Y
))))) {
2384 if ((match(X
, m_Sub(m_APInt(C
), m_Specific(Y
))) ||
2385 match(Y
, m_Sub(m_APInt(C
), m_Specific(X
)))) &&
2386 C
->ule(X
->getType()->getScalarSizeInBits())) {
2387 return ConstantInt::getAllOnesValue(X
->getType());
2391 // A funnel shift (rotate) can be decomposed into simpler shifts. See if we
2392 // are mixing in another shift that is redundant with the funnel shift.
2394 // (fshl X, ?, Y) | (shl X, Y) --> fshl X, ?, Y
2395 // (shl X, Y) | (fshl X, ?, Y) --> fshl X, ?, Y
2397 m_Intrinsic
<Intrinsic::fshl
>(m_Value(X
), m_Value(), m_Value(Y
))) &&
2398 match(Op1
, m_Shl(m_Specific(X
), m_Specific(Y
))))
2401 m_Intrinsic
<Intrinsic::fshl
>(m_Value(X
), m_Value(), m_Value(Y
))) &&
2402 match(Op0
, m_Shl(m_Specific(X
), m_Specific(Y
))))
2405 // (fshr ?, X, Y) | (lshr X, Y) --> fshr ?, X, Y
2406 // (lshr X, Y) | (fshr ?, X, Y) --> fshr ?, X, Y
2408 m_Intrinsic
<Intrinsic::fshr
>(m_Value(), m_Value(X
), m_Value(Y
))) &&
2409 match(Op1
, m_LShr(m_Specific(X
), m_Specific(Y
))))
2412 m_Intrinsic
<Intrinsic::fshr
>(m_Value(), m_Value(X
), m_Value(Y
))) &&
2413 match(Op0
, m_LShr(m_Specific(X
), m_Specific(Y
))))
2417 simplifyAndOrWithICmpEq(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2420 simplifyAndOrWithICmpEq(Instruction::Or
, Op1
, Op0
, Q
, MaxRecurse
))
2423 if (Value
*V
= simplifyAndOrOfCmps(Q
, Op0
, Op1
, false))
2426 // If we have a multiplication overflow check that is being 'and'ed with a
2427 // check that one of the multipliers is not zero, we can omit the 'and', and
2428 // only keep the overflow check.
2429 if (isCheckForZeroAndMulWithOverflow(Op0
, Op1
, false))
2431 if (isCheckForZeroAndMulWithOverflow(Op1
, Op0
, false))
2434 // Try some generic simplifications for associative operations.
2436 simplifyAssociativeBinOp(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2439 // Or distributes over And. Try some generic simplifications based on this.
2440 if (Value
*V
= expandCommutativeBinOp(Instruction::Or
, Op0
, Op1
,
2441 Instruction::And
, Q
, MaxRecurse
))
2444 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
)) {
2445 if (Op0
->getType()->isIntOrIntVectorTy(1)) {
2446 // A | (A || B) -> A || B
2447 if (match(Op1
, m_Select(m_Specific(Op0
), m_One(), m_Value())))
2449 else if (match(Op0
, m_Select(m_Specific(Op1
), m_One(), m_Value())))
2452 // If the operation is with the result of a select instruction, check
2453 // whether operating on either branch of the select always yields the same
2456 threadBinOpOverSelect(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2460 // (A & C1)|(B & C2)
2462 const APInt
*C1
, *C2
;
2463 if (match(Op0
, m_And(m_Value(A
), m_APInt(C1
))) &&
2464 match(Op1
, m_And(m_Value(B
), m_APInt(C2
)))) {
2466 // (A & C1)|(B & C2)
2467 // If we have: ((V + N) & C1) | (V & C2)
2468 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
2469 // replace with V+N.
2471 if (C2
->isMask() && // C2 == 0+1+
2472 match(A
, m_c_Add(m_Specific(B
), m_Value(N
)))) {
2473 // Add commutes, try both ways.
2474 if (MaskedValueIsZero(N
, *C2
, Q
))
2477 // Or commutes, try both ways.
2478 if (C1
->isMask() && match(B
, m_c_Add(m_Specific(A
), m_Value(N
)))) {
2479 // Add commutes, try both ways.
2480 if (MaskedValueIsZero(N
, *C1
, Q
))
2486 // If the operation is with the result of a phi instruction, check whether
2487 // operating on all incoming values of the phi always yields the same value.
2488 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
2489 if (Value
*V
= threadBinOpOverPHI(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2492 // (A ^ C) | (A ^ ~C) -> -1, i.e. all bits set to one.
2493 if (match(Op0
, m_Xor(m_Value(A
), m_APInt(C1
))) &&
2494 match(Op1
, m_Xor(m_Specific(A
), m_SpecificInt(~*C1
))))
2495 return Constant::getAllOnesValue(Op0
->getType());
2497 if (Op0
->getType()->isIntOrIntVectorTy(1)) {
2498 if (std::optional
<bool> Implied
=
2499 isImpliedCondition(Op0
, Op1
, Q
.DL
, false)) {
2500 // If Op0 is false implies Op1 is false, then Op1 is a subset of Op0.
2501 if (*Implied
== false)
2503 // If Op0 is false implies Op1 is true, then at least one is always true.
2504 if (*Implied
== true)
2505 return ConstantInt::getTrue(Op0
->getType());
2507 if (std::optional
<bool> Implied
=
2508 isImpliedCondition(Op1
, Op0
, Q
.DL
, false)) {
2509 // If Op1 is false implies Op0 is false, then Op0 is a subset of Op1.
2510 if (*Implied
== false)
2512 // If Op1 is false implies Op0 is true, then at least one is always true.
2513 if (*Implied
== true)
2514 return ConstantInt::getTrue(Op1
->getType());
2518 if (Value
*V
= simplifyByDomEq(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2524 Value
*llvm::simplifyOrInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
2525 return ::simplifyOrInst(Op0
, Op1
, Q
, RecursionLimit
);
2528 /// Given operands for a Xor, see if we can fold the result.
2529 /// If not, this returns null.
2530 static Value
*simplifyXorInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
2531 unsigned MaxRecurse
) {
2532 if (Constant
*C
= foldOrCommuteConstant(Instruction::Xor
, Op0
, Op1
, Q
))
2535 // X ^ poison -> poison
2536 if (isa
<PoisonValue
>(Op1
))
2539 // A ^ undef -> undef
2540 if (Q
.isUndefValue(Op1
))
2544 if (match(Op1
, m_Zero()))
2549 return Constant::getNullValue(Op0
->getType());
2551 // A ^ ~A = ~A ^ A = -1
2552 if (match(Op0
, m_Not(m_Specific(Op1
))) || match(Op1
, m_Not(m_Specific(Op0
))))
2553 return Constant::getAllOnesValue(Op0
->getType());
2555 auto foldAndOrNot
= [](Value
*X
, Value
*Y
) -> Value
* {
2557 // (~A & B) ^ (A | B) --> A -- There are 8 commuted variants.
2558 if (match(X
, m_c_And(m_Not(m_Value(A
)), m_Value(B
))) &&
2559 match(Y
, m_c_Or(m_Specific(A
), m_Specific(B
))))
2562 // (~A | B) ^ (A & B) --> ~A -- There are 8 commuted variants.
2563 // The 'not' op must contain a complete -1 operand (no undef elements for
2564 // vector) for the transform to be safe.
2566 if (match(X
, m_c_Or(m_CombineAnd(m_Not(m_Value(A
)), m_Value(NotA
)),
2568 match(Y
, m_c_And(m_Specific(A
), m_Specific(B
))))
2573 if (Value
*R
= foldAndOrNot(Op0
, Op1
))
2575 if (Value
*R
= foldAndOrNot(Op1
, Op0
))
2578 if (Value
*V
= simplifyLogicOfAddSub(Op0
, Op1
, Instruction::Xor
))
2581 // Try some generic simplifications for associative operations.
2583 simplifyAssociativeBinOp(Instruction::Xor
, Op0
, Op1
, Q
, MaxRecurse
))
2586 // Threading Xor over selects and phi nodes is pointless, so don't bother.
2587 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
2588 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
2589 // only if B and C are equal. If B and C are equal then (since we assume
2590 // that operands have already been simplified) "select(cond, B, C)" should
2591 // have been simplified to the common value of B and C already. Analysing
2592 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
2593 // for threading over phi nodes.
2595 if (Value
*V
= simplifyByDomEq(Instruction::Xor
, Op0
, Op1
, Q
, MaxRecurse
))
2601 Value
*llvm::simplifyXorInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
2602 return ::simplifyXorInst(Op0
, Op1
, Q
, RecursionLimit
);
2605 static Type
*getCompareTy(Value
*Op
) {
2606 return CmpInst::makeCmpResultType(Op
->getType());
2609 /// Rummage around inside V looking for something equivalent to the comparison
2610 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
2611 /// Helper function for analyzing max/min idioms.
2612 static Value
*extractEquivalentCondition(Value
*V
, CmpInst::Predicate Pred
,
2613 Value
*LHS
, Value
*RHS
) {
2614 SelectInst
*SI
= dyn_cast
<SelectInst
>(V
);
2617 CmpInst
*Cmp
= dyn_cast
<CmpInst
>(SI
->getCondition());
2620 Value
*CmpLHS
= Cmp
->getOperand(0), *CmpRHS
= Cmp
->getOperand(1);
2621 if (Pred
== Cmp
->getPredicate() && LHS
== CmpLHS
&& RHS
== CmpRHS
)
2623 if (Pred
== CmpInst::getSwappedPredicate(Cmp
->getPredicate()) &&
2624 LHS
== CmpRHS
&& RHS
== CmpLHS
)
2629 /// Return true if the underlying object (storage) must be disjoint from
2630 /// storage returned by any noalias return call.
2631 static bool isAllocDisjoint(const Value
*V
) {
2632 // For allocas, we consider only static ones (dynamic
2633 // allocas might be transformed into calls to malloc not simultaneously
2634 // live with the compared-to allocation). For globals, we exclude symbols
2635 // that might be resolve lazily to symbols in another dynamically-loaded
2636 // library (and, thus, could be malloc'ed by the implementation).
2637 if (const AllocaInst
*AI
= dyn_cast
<AllocaInst
>(V
))
2638 return AI
->isStaticAlloca();
2639 if (const GlobalValue
*GV
= dyn_cast
<GlobalValue
>(V
))
2640 return (GV
->hasLocalLinkage() || GV
->hasHiddenVisibility() ||
2641 GV
->hasProtectedVisibility() || GV
->hasGlobalUnnamedAddr()) &&
2642 !GV
->isThreadLocal();
2643 if (const Argument
*A
= dyn_cast
<Argument
>(V
))
2644 return A
->hasByValAttr();
2648 /// Return true if V1 and V2 are each the base of some distict storage region
2649 /// [V, object_size(V)] which do not overlap. Note that zero sized regions
2650 /// *are* possible, and that zero sized regions do not overlap with any other.
2651 static bool haveNonOverlappingStorage(const Value
*V1
, const Value
*V2
) {
2652 // Global variables always exist, so they always exist during the lifetime
2653 // of each other and all allocas. Global variables themselves usually have
2654 // non-overlapping storage, but since their addresses are constants, the
2655 // case involving two globals does not reach here and is instead handled in
2656 // constant folding.
2658 // Two different allocas usually have different addresses...
2660 // However, if there's an @llvm.stackrestore dynamically in between two
2661 // allocas, they may have the same address. It's tempting to reduce the
2662 // scope of the problem by only looking at *static* allocas here. That would
2663 // cover the majority of allocas while significantly reducing the likelihood
2664 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2665 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2666 // an entry block. Also, if we have a block that's not attached to a
2667 // function, we can't tell if it's "static" under the current definition.
2668 // Theoretically, this problem could be fixed by creating a new kind of
2669 // instruction kind specifically for static allocas. Such a new instruction
2670 // could be required to be at the top of the entry block, thus preventing it
2671 // from being subject to a @llvm.stackrestore. Instcombine could even
2672 // convert regular allocas into these special allocas. It'd be nifty.
2673 // However, until then, this problem remains open.
2675 // So, we'll assume that two non-empty allocas have different addresses
2677 auto isByValArg
= [](const Value
*V
) {
2678 const Argument
*A
= dyn_cast
<Argument
>(V
);
2679 return A
&& A
->hasByValAttr();
2682 // Byval args are backed by store which does not overlap with each other,
2683 // allocas, or globals.
2685 return isa
<AllocaInst
>(V2
) || isa
<GlobalVariable
>(V2
) || isByValArg(V2
);
2687 return isa
<AllocaInst
>(V1
) || isa
<GlobalVariable
>(V1
) || isByValArg(V1
);
2689 return isa
<AllocaInst
>(V1
) &&
2690 (isa
<AllocaInst
>(V2
) || isa
<GlobalVariable
>(V2
));
2693 // A significant optimization not implemented here is assuming that alloca
2694 // addresses are not equal to incoming argument values. They don't *alias*,
2695 // as we say, but that doesn't mean they aren't equal, so we take a
2696 // conservative approach.
2698 // This is inspired in part by C++11 5.10p1:
2699 // "Two pointers of the same type compare equal if and only if they are both
2700 // null, both point to the same function, or both represent the same
2703 // This is pretty permissive.
2705 // It's also partly due to C11 6.5.9p6:
2706 // "Two pointers compare equal if and only if both are null pointers, both are
2707 // pointers to the same object (including a pointer to an object and a
2708 // subobject at its beginning) or function, both are pointers to one past the
2709 // last element of the same array object, or one is a pointer to one past the
2710 // end of one array object and the other is a pointer to the start of a
2711 // different array object that happens to immediately follow the first array
2712 // object in the address space.)
2714 // C11's version is more restrictive, however there's no reason why an argument
2715 // couldn't be a one-past-the-end value for a stack object in the caller and be
2716 // equal to the beginning of a stack object in the callee.
2718 // If the C and C++ standards are ever made sufficiently restrictive in this
2719 // area, it may be possible to update LLVM's semantics accordingly and reinstate
2720 // this optimization.
2721 static Constant
*computePointerICmp(CmpInst::Predicate Pred
, Value
*LHS
,
2722 Value
*RHS
, const SimplifyQuery
&Q
) {
2723 assert(LHS
->getType() == RHS
->getType() && "Must have same types");
2724 const DataLayout
&DL
= Q
.DL
;
2725 const TargetLibraryInfo
*TLI
= Q
.TLI
;
2727 // We can only fold certain predicates on pointer comparisons.
2732 // Equality comparisons are easy to fold.
2733 case CmpInst::ICMP_EQ
:
2734 case CmpInst::ICMP_NE
:
2737 // We can only handle unsigned relational comparisons because 'inbounds' on
2738 // a GEP only protects against unsigned wrapping.
2739 case CmpInst::ICMP_UGT
:
2740 case CmpInst::ICMP_UGE
:
2741 case CmpInst::ICMP_ULT
:
2742 case CmpInst::ICMP_ULE
:
2743 // However, we have to switch them to their signed variants to handle
2744 // negative indices from the base pointer.
2745 Pred
= ICmpInst::getSignedPredicate(Pred
);
2749 // Strip off any constant offsets so that we can reason about them.
2750 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2751 // here and compare base addresses like AliasAnalysis does, however there are
2752 // numerous hazards. AliasAnalysis and its utilities rely on special rules
2753 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2754 // doesn't need to guarantee pointer inequality when it says NoAlias.
2756 // Even if an non-inbounds GEP occurs along the path we can still optimize
2757 // equality comparisons concerning the result.
2758 bool AllowNonInbounds
= ICmpInst::isEquality(Pred
);
2759 unsigned IndexSize
= DL
.getIndexTypeSizeInBits(LHS
->getType());
2760 APInt
LHSOffset(IndexSize
, 0), RHSOffset(IndexSize
, 0);
2761 LHS
= LHS
->stripAndAccumulateConstantOffsets(DL
, LHSOffset
, AllowNonInbounds
);
2762 RHS
= RHS
->stripAndAccumulateConstantOffsets(DL
, RHSOffset
, AllowNonInbounds
);
2764 // If LHS and RHS are related via constant offsets to the same base
2765 // value, we can replace it with an icmp which just compares the offsets.
2767 return ConstantInt::get(getCompareTy(LHS
),
2768 ICmpInst::compare(LHSOffset
, RHSOffset
, Pred
));
2770 // Various optimizations for (in)equality comparisons.
2771 if (Pred
== CmpInst::ICMP_EQ
|| Pred
== CmpInst::ICMP_NE
) {
2772 // Different non-empty allocations that exist at the same time have
2773 // different addresses (if the program can tell). If the offsets are
2774 // within the bounds of their allocations (and not one-past-the-end!
2775 // so we can't use inbounds!), and their allocations aren't the same,
2776 // the pointers are not equal.
2777 if (haveNonOverlappingStorage(LHS
, RHS
)) {
2778 uint64_t LHSSize
, RHSSize
;
2779 ObjectSizeOpts Opts
;
2780 Opts
.EvalMode
= ObjectSizeOpts::Mode::Min
;
2781 auto *F
= [](Value
*V
) -> Function
* {
2782 if (auto *I
= dyn_cast
<Instruction
>(V
))
2783 return I
->getFunction();
2784 if (auto *A
= dyn_cast
<Argument
>(V
))
2785 return A
->getParent();
2788 Opts
.NullIsUnknownSize
= F
? NullPointerIsDefined(F
) : true;
2789 if (getObjectSize(LHS
, LHSSize
, DL
, TLI
, Opts
) &&
2790 getObjectSize(RHS
, RHSSize
, DL
, TLI
, Opts
)) {
2791 APInt Dist
= LHSOffset
- RHSOffset
;
2792 if (Dist
.isNonNegative() ? Dist
.ult(LHSSize
) : (-Dist
).ult(RHSSize
))
2793 return ConstantInt::get(getCompareTy(LHS
),
2794 !CmpInst::isTrueWhenEqual(Pred
));
2798 // If one side of the equality comparison must come from a noalias call
2799 // (meaning a system memory allocation function), and the other side must
2800 // come from a pointer that cannot overlap with dynamically-allocated
2801 // memory within the lifetime of the current function (allocas, byval
2802 // arguments, globals), then determine the comparison result here.
2803 SmallVector
<const Value
*, 8> LHSUObjs
, RHSUObjs
;
2804 getUnderlyingObjects(LHS
, LHSUObjs
);
2805 getUnderlyingObjects(RHS
, RHSUObjs
);
2807 // Is the set of underlying objects all noalias calls?
2808 auto IsNAC
= [](ArrayRef
<const Value
*> Objects
) {
2809 return all_of(Objects
, isNoAliasCall
);
2812 // Is the set of underlying objects all things which must be disjoint from
2813 // noalias calls. We assume that indexing from such disjoint storage
2814 // into the heap is undefined, and thus offsets can be safely ignored.
2815 auto IsAllocDisjoint
= [](ArrayRef
<const Value
*> Objects
) {
2816 return all_of(Objects
, ::isAllocDisjoint
);
2819 if ((IsNAC(LHSUObjs
) && IsAllocDisjoint(RHSUObjs
)) ||
2820 (IsNAC(RHSUObjs
) && IsAllocDisjoint(LHSUObjs
)))
2821 return ConstantInt::get(getCompareTy(LHS
),
2822 !CmpInst::isTrueWhenEqual(Pred
));
2824 // Fold comparisons for non-escaping pointer even if the allocation call
2825 // cannot be elided. We cannot fold malloc comparison to null. Also, the
2826 // dynamic allocation call could be either of the operands. Note that
2827 // the other operand can not be based on the alloc - if it were, then
2828 // the cmp itself would be a capture.
2829 Value
*MI
= nullptr;
2830 if (isAllocLikeFn(LHS
, TLI
) && llvm::isKnownNonZero(RHS
, Q
))
2832 else if (isAllocLikeFn(RHS
, TLI
) && llvm::isKnownNonZero(LHS
, Q
))
2835 // FIXME: This is incorrect, see PR54002. While we can assume that the
2836 // allocation is at an address that makes the comparison false, this
2837 // requires that *all* comparisons to that address be false, which
2838 // InstSimplify cannot guarantee.
2839 struct CustomCaptureTracker
: public CaptureTracker
{
2840 bool Captured
= false;
2841 void tooManyUses() override
{ Captured
= true; }
2842 bool captured(const Use
*U
) override
{
2843 if (auto *ICmp
= dyn_cast
<ICmpInst
>(U
->getUser())) {
2844 // Comparison against value stored in global variable. Given the
2845 // pointer does not escape, its value cannot be guessed and stored
2846 // separately in a global variable.
2847 unsigned OtherIdx
= 1 - U
->getOperandNo();
2848 auto *LI
= dyn_cast
<LoadInst
>(ICmp
->getOperand(OtherIdx
));
2849 if (LI
&& isa
<GlobalVariable
>(LI
->getPointerOperand()))
2857 CustomCaptureTracker Tracker
;
2858 PointerMayBeCaptured(MI
, &Tracker
);
2859 if (!Tracker
.Captured
)
2860 return ConstantInt::get(getCompareTy(LHS
),
2861 CmpInst::isFalseWhenEqual(Pred
));
2869 /// Fold an icmp when its operands have i1 scalar type.
2870 static Value
*simplifyICmpOfBools(CmpInst::Predicate Pred
, Value
*LHS
,
2871 Value
*RHS
, const SimplifyQuery
&Q
) {
2872 Type
*ITy
= getCompareTy(LHS
); // The return type.
2873 Type
*OpTy
= LHS
->getType(); // The operand type.
2874 if (!OpTy
->isIntOrIntVectorTy(1))
2877 // A boolean compared to true/false can be reduced in 14 out of the 20
2878 // (10 predicates * 2 constants) possible combinations. The other
2879 // 6 cases require a 'not' of the LHS.
2881 auto ExtractNotLHS
= [](Value
*V
) -> Value
* {
2883 if (match(V
, m_Not(m_Value(X
))))
2888 if (match(RHS
, m_Zero())) {
2890 case CmpInst::ICMP_NE
: // X != 0 -> X
2891 case CmpInst::ICMP_UGT
: // X >u 0 -> X
2892 case CmpInst::ICMP_SLT
: // X <s 0 -> X
2895 case CmpInst::ICMP_EQ
: // not(X) == 0 -> X != 0 -> X
2896 case CmpInst::ICMP_ULE
: // not(X) <=u 0 -> X >u 0 -> X
2897 case CmpInst::ICMP_SGE
: // not(X) >=s 0 -> X <s 0 -> X
2898 if (Value
*X
= ExtractNotLHS(LHS
))
2902 case CmpInst::ICMP_ULT
: // X <u 0 -> false
2903 case CmpInst::ICMP_SGT
: // X >s 0 -> false
2904 return getFalse(ITy
);
2906 case CmpInst::ICMP_UGE
: // X >=u 0 -> true
2907 case CmpInst::ICMP_SLE
: // X <=s 0 -> true
2908 return getTrue(ITy
);
2913 } else if (match(RHS
, m_One())) {
2915 case CmpInst::ICMP_EQ
: // X == 1 -> X
2916 case CmpInst::ICMP_UGE
: // X >=u 1 -> X
2917 case CmpInst::ICMP_SLE
: // X <=s -1 -> X
2920 case CmpInst::ICMP_NE
: // not(X) != 1 -> X == 1 -> X
2921 case CmpInst::ICMP_ULT
: // not(X) <=u 1 -> X >=u 1 -> X
2922 case CmpInst::ICMP_SGT
: // not(X) >s 1 -> X <=s -1 -> X
2923 if (Value
*X
= ExtractNotLHS(LHS
))
2927 case CmpInst::ICMP_UGT
: // X >u 1 -> false
2928 case CmpInst::ICMP_SLT
: // X <s -1 -> false
2929 return getFalse(ITy
);
2931 case CmpInst::ICMP_ULE
: // X <=u 1 -> true
2932 case CmpInst::ICMP_SGE
: // X >=s -1 -> true
2933 return getTrue(ITy
);
2943 case ICmpInst::ICMP_UGE
:
2944 if (isImpliedCondition(RHS
, LHS
, Q
.DL
).value_or(false))
2945 return getTrue(ITy
);
2947 case ICmpInst::ICMP_SGE
:
2948 /// For signed comparison, the values for an i1 are 0 and -1
2949 /// respectively. This maps into a truth table of:
2950 /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2951 /// 0 | 0 | 1 (0 >= 0) | 1
2952 /// 0 | 1 | 1 (0 >= -1) | 1
2953 /// 1 | 0 | 0 (-1 >= 0) | 0
2954 /// 1 | 1 | 1 (-1 >= -1) | 1
2955 if (isImpliedCondition(LHS
, RHS
, Q
.DL
).value_or(false))
2956 return getTrue(ITy
);
2958 case ICmpInst::ICMP_ULE
:
2959 if (isImpliedCondition(LHS
, RHS
, Q
.DL
).value_or(false))
2960 return getTrue(ITy
);
2962 case ICmpInst::ICMP_SLE
:
2963 /// SLE follows the same logic as SGE with the LHS and RHS swapped.
2964 if (isImpliedCondition(RHS
, LHS
, Q
.DL
).value_or(false))
2965 return getTrue(ITy
);
2972 /// Try hard to fold icmp with zero RHS because this is a common case.
2973 static Value
*simplifyICmpWithZero(CmpInst::Predicate Pred
, Value
*LHS
,
2974 Value
*RHS
, const SimplifyQuery
&Q
) {
2975 if (!match(RHS
, m_Zero()))
2978 Type
*ITy
= getCompareTy(LHS
); // The return type.
2981 llvm_unreachable("Unknown ICmp predicate!");
2982 case ICmpInst::ICMP_ULT
:
2983 return getFalse(ITy
);
2984 case ICmpInst::ICMP_UGE
:
2985 return getTrue(ITy
);
2986 case ICmpInst::ICMP_EQ
:
2987 case ICmpInst::ICMP_ULE
:
2988 if (isKnownNonZero(LHS
, Q
))
2989 return getFalse(ITy
);
2991 case ICmpInst::ICMP_NE
:
2992 case ICmpInst::ICMP_UGT
:
2993 if (isKnownNonZero(LHS
, Q
))
2994 return getTrue(ITy
);
2996 case ICmpInst::ICMP_SLT
: {
2997 KnownBits LHSKnown
= computeKnownBits(LHS
, /* Depth */ 0, Q
);
2998 if (LHSKnown
.isNegative())
2999 return getTrue(ITy
);
3000 if (LHSKnown
.isNonNegative())
3001 return getFalse(ITy
);
3004 case ICmpInst::ICMP_SLE
: {
3005 KnownBits LHSKnown
= computeKnownBits(LHS
, /* Depth */ 0, Q
);
3006 if (LHSKnown
.isNegative())
3007 return getTrue(ITy
);
3008 if (LHSKnown
.isNonNegative() && isKnownNonZero(LHS
, Q
))
3009 return getFalse(ITy
);
3012 case ICmpInst::ICMP_SGE
: {
3013 KnownBits LHSKnown
= computeKnownBits(LHS
, /* Depth */ 0, Q
);
3014 if (LHSKnown
.isNegative())
3015 return getFalse(ITy
);
3016 if (LHSKnown
.isNonNegative())
3017 return getTrue(ITy
);
3020 case ICmpInst::ICMP_SGT
: {
3021 KnownBits LHSKnown
= computeKnownBits(LHS
, /* Depth */ 0, Q
);
3022 if (LHSKnown
.isNegative())
3023 return getFalse(ITy
);
3024 if (LHSKnown
.isNonNegative() && isKnownNonZero(LHS
, Q
))
3025 return getTrue(ITy
);
3033 static Value
*simplifyICmpWithConstant(CmpInst::Predicate Pred
, Value
*LHS
,
3034 Value
*RHS
, const InstrInfoQuery
&IIQ
) {
3035 Type
*ITy
= getCompareTy(RHS
); // The return type.
3039 if (!match(RHS
, m_APIntAllowPoison(C
)))
3042 // Sign-bit checks can be optimized to true/false after unsigned
3043 // floating-point casts:
3044 // icmp slt (bitcast (uitofp X)), 0 --> false
3045 // icmp sgt (bitcast (uitofp X)), -1 --> true
3046 if (match(LHS
, m_ElementWiseBitCast(m_UIToFP(m_Value(X
))))) {
3048 if (isSignBitCheck(Pred
, *C
, TrueIfSigned
))
3049 return ConstantInt::getBool(ITy
, !TrueIfSigned
);
3052 // Rule out tautological comparisons (eg., ult 0 or uge 0).
3053 ConstantRange RHS_CR
= ConstantRange::makeExactICmpRegion(Pred
, *C
);
3054 if (RHS_CR
.isEmptySet())
3055 return ConstantInt::getFalse(ITy
);
3056 if (RHS_CR
.isFullSet())
3057 return ConstantInt::getTrue(ITy
);
3059 ConstantRange LHS_CR
=
3060 computeConstantRange(LHS
, CmpInst::isSigned(Pred
), IIQ
.UseInstrInfo
);
3061 if (!LHS_CR
.isFullSet()) {
3062 if (RHS_CR
.contains(LHS_CR
))
3063 return ConstantInt::getTrue(ITy
);
3064 if (RHS_CR
.inverse().contains(LHS_CR
))
3065 return ConstantInt::getFalse(ITy
);
3068 // (mul nuw/nsw X, MulC) != C --> true (if C is not a multiple of MulC)
3069 // (mul nuw/nsw X, MulC) == C --> false (if C is not a multiple of MulC)
3071 if (IIQ
.UseInstrInfo
&& ICmpInst::isEquality(Pred
) &&
3072 ((match(LHS
, m_NUWMul(m_Value(), m_APIntAllowPoison(MulC
))) &&
3073 *MulC
!= 0 && C
->urem(*MulC
) != 0) ||
3074 (match(LHS
, m_NSWMul(m_Value(), m_APIntAllowPoison(MulC
))) &&
3075 *MulC
!= 0 && C
->srem(*MulC
) != 0)))
3076 return ConstantInt::get(ITy
, Pred
== ICmpInst::ICMP_NE
);
3081 static Value
*simplifyICmpWithBinOpOnLHS(CmpInst::Predicate Pred
,
3082 BinaryOperator
*LBO
, Value
*RHS
,
3083 const SimplifyQuery
&Q
,
3084 unsigned MaxRecurse
) {
3085 Type
*ITy
= getCompareTy(RHS
); // The return type.
3088 // icmp pred (or X, Y), X
3089 if (match(LBO
, m_c_Or(m_Value(Y
), m_Specific(RHS
)))) {
3090 if (Pred
== ICmpInst::ICMP_ULT
)
3091 return getFalse(ITy
);
3092 if (Pred
== ICmpInst::ICMP_UGE
)
3093 return getTrue(ITy
);
3095 if (Pred
== ICmpInst::ICMP_SLT
|| Pred
== ICmpInst::ICMP_SGE
) {
3096 KnownBits RHSKnown
= computeKnownBits(RHS
, /* Depth */ 0, Q
);
3097 KnownBits YKnown
= computeKnownBits(Y
, /* Depth */ 0, Q
);
3098 if (RHSKnown
.isNonNegative() && YKnown
.isNegative())
3099 return Pred
== ICmpInst::ICMP_SLT
? getTrue(ITy
) : getFalse(ITy
);
3100 if (RHSKnown
.isNegative() || YKnown
.isNonNegative())
3101 return Pred
== ICmpInst::ICMP_SLT
? getFalse(ITy
) : getTrue(ITy
);
3105 // icmp pred (and X, Y), X
3106 if (match(LBO
, m_c_And(m_Value(), m_Specific(RHS
)))) {
3107 if (Pred
== ICmpInst::ICMP_UGT
)
3108 return getFalse(ITy
);
3109 if (Pred
== ICmpInst::ICMP_ULE
)
3110 return getTrue(ITy
);
3113 // icmp pred (urem X, Y), Y
3114 if (match(LBO
, m_URem(m_Value(), m_Specific(RHS
)))) {
3118 case ICmpInst::ICMP_SGT
:
3119 case ICmpInst::ICMP_SGE
: {
3120 KnownBits Known
= computeKnownBits(RHS
, /* Depth */ 0, Q
);
3121 if (!Known
.isNonNegative())
3125 case ICmpInst::ICMP_EQ
:
3126 case ICmpInst::ICMP_UGT
:
3127 case ICmpInst::ICMP_UGE
:
3128 return getFalse(ITy
);
3129 case ICmpInst::ICMP_SLT
:
3130 case ICmpInst::ICMP_SLE
: {
3131 KnownBits Known
= computeKnownBits(RHS
, /* Depth */ 0, Q
);
3132 if (!Known
.isNonNegative())
3136 case ICmpInst::ICMP_NE
:
3137 case ICmpInst::ICMP_ULT
:
3138 case ICmpInst::ICMP_ULE
:
3139 return getTrue(ITy
);
3143 // icmp pred (urem X, Y), X
3144 if (match(LBO
, m_URem(m_Specific(RHS
), m_Value()))) {
3145 if (Pred
== ICmpInst::ICMP_ULE
)
3146 return getTrue(ITy
);
3147 if (Pred
== ICmpInst::ICMP_UGT
)
3148 return getFalse(ITy
);
3151 // x >>u y <=u x --> true.
3152 // x >>u y >u x --> false.
3153 // x udiv y <=u x --> true.
3154 // x udiv y >u x --> false.
3155 if (match(LBO
, m_LShr(m_Specific(RHS
), m_Value())) ||
3156 match(LBO
, m_UDiv(m_Specific(RHS
), m_Value()))) {
3157 // icmp pred (X op Y), X
3158 if (Pred
== ICmpInst::ICMP_UGT
)
3159 return getFalse(ITy
);
3160 if (Pred
== ICmpInst::ICMP_ULE
)
3161 return getTrue(ITy
);
3165 // x >>u C <u x --> true for C != 0.
3166 // x >>u C != x --> true for C != 0.
3167 // x >>u C >=u x --> false for C != 0.
3168 // x >>u C == x --> false for C != 0.
3169 // x udiv C <u x --> true for C != 1.
3170 // x udiv C != x --> true for C != 1.
3171 // x udiv C >=u x --> false for C != 1.
3172 // x udiv C == x --> false for C != 1.
3173 // TODO: allow non-constant shift amount/divisor
3175 if ((match(LBO
, m_LShr(m_Specific(RHS
), m_APInt(C
))) && *C
!= 0) ||
3176 (match(LBO
, m_UDiv(m_Specific(RHS
), m_APInt(C
))) && *C
!= 1)) {
3177 if (isKnownNonZero(RHS
, Q
)) {
3181 case ICmpInst::ICMP_EQ
:
3182 case ICmpInst::ICMP_UGE
:
3183 return getFalse(ITy
);
3184 case ICmpInst::ICMP_NE
:
3185 case ICmpInst::ICMP_ULT
:
3186 return getTrue(ITy
);
3187 case ICmpInst::ICMP_UGT
:
3188 case ICmpInst::ICMP_ULE
:
3189 // UGT/ULE are handled by the more general case just above
3190 llvm_unreachable("Unexpected UGT/ULE, should have been handled");
3195 // (x*C1)/C2 <= x for C1 <= C2.
3196 // This holds even if the multiplication overflows: Assume that x != 0 and
3197 // arithmetic is modulo M. For overflow to occur we must have C1 >= M/x and
3198 // thus C2 >= M/x. It follows that (x*C1)/C2 <= (M-1)/C2 <= ((M-1)*x)/M < x.
3200 // Additionally, either the multiplication and division might be represented
3202 // (x*C1)>>C2 <= x for C1 < 2**C2.
3203 // (x<<C1)/C2 <= x for 2**C1 < C2.
3204 const APInt
*C1
, *C2
;
3205 if ((match(LBO
, m_UDiv(m_Mul(m_Specific(RHS
), m_APInt(C1
)), m_APInt(C2
))) &&
3207 (match(LBO
, m_LShr(m_Mul(m_Specific(RHS
), m_APInt(C1
)), m_APInt(C2
))) &&
3208 C1
->ule(APInt(C2
->getBitWidth(), 1) << *C2
)) ||
3209 (match(LBO
, m_UDiv(m_Shl(m_Specific(RHS
), m_APInt(C1
)), m_APInt(C2
))) &&
3210 (APInt(C1
->getBitWidth(), 1) << *C1
).ule(*C2
))) {
3211 if (Pred
== ICmpInst::ICMP_UGT
)
3212 return getFalse(ITy
);
3213 if (Pred
== ICmpInst::ICMP_ULE
)
3214 return getTrue(ITy
);
3217 // (sub C, X) == X, C is odd --> false
3218 // (sub C, X) != X, C is odd --> true
3219 if (match(LBO
, m_Sub(m_APIntAllowPoison(C
), m_Specific(RHS
))) &&
3220 (*C
& 1) == 1 && ICmpInst::isEquality(Pred
))
3221 return (Pred
== ICmpInst::ICMP_EQ
) ? getFalse(ITy
) : getTrue(ITy
);
3226 // If only one of the icmp's operands has NSW flags, try to prove that:
3228 // icmp slt (x + C1), (x +nsw C2)
3230 // is equivalent to:
3234 // which is true if x + C2 has the NSW flags set and:
3235 // *) C1 < C2 && C1 >= 0, or
3236 // *) C2 < C1 && C1 <= 0.
3238 static bool trySimplifyICmpWithAdds(CmpInst::Predicate Pred
, Value
*LHS
,
3239 Value
*RHS
, const InstrInfoQuery
&IIQ
) {
3240 // TODO: only support icmp slt for now.
3241 if (Pred
!= CmpInst::ICMP_SLT
|| !IIQ
.UseInstrInfo
)
3244 // Canonicalize nsw add as RHS.
3245 if (!match(RHS
, m_NSWAdd(m_Value(), m_Value())))
3246 std::swap(LHS
, RHS
);
3247 if (!match(RHS
, m_NSWAdd(m_Value(), m_Value())))
3251 const APInt
*C1
, *C2
;
3252 if (!match(LHS
, m_Add(m_Value(X
), m_APInt(C1
))) ||
3253 !match(RHS
, m_Add(m_Specific(X
), m_APInt(C2
))))
3256 return (C1
->slt(*C2
) && C1
->isNonNegative()) ||
3257 (C2
->slt(*C1
) && C1
->isNonPositive());
3260 /// TODO: A large part of this logic is duplicated in InstCombine's
3261 /// foldICmpBinOp(). We should be able to share that and avoid the code
3263 static Value
*simplifyICmpWithBinOp(CmpInst::Predicate Pred
, Value
*LHS
,
3264 Value
*RHS
, const SimplifyQuery
&Q
,
3265 unsigned MaxRecurse
) {
3266 BinaryOperator
*LBO
= dyn_cast
<BinaryOperator
>(LHS
);
3267 BinaryOperator
*RBO
= dyn_cast
<BinaryOperator
>(RHS
);
3268 if (MaxRecurse
&& (LBO
|| RBO
)) {
3269 // Analyze the case when either LHS or RHS is an add instruction.
3270 Value
*A
= nullptr, *B
= nullptr, *C
= nullptr, *D
= nullptr;
3271 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
3272 bool NoLHSWrapProblem
= false, NoRHSWrapProblem
= false;
3273 if (LBO
&& LBO
->getOpcode() == Instruction::Add
) {
3274 A
= LBO
->getOperand(0);
3275 B
= LBO
->getOperand(1);
3277 ICmpInst::isEquality(Pred
) ||
3278 (CmpInst::isUnsigned(Pred
) &&
3279 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(LBO
))) ||
3280 (CmpInst::isSigned(Pred
) &&
3281 Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)));
3283 if (RBO
&& RBO
->getOpcode() == Instruction::Add
) {
3284 C
= RBO
->getOperand(0);
3285 D
= RBO
->getOperand(1);
3287 ICmpInst::isEquality(Pred
) ||
3288 (CmpInst::isUnsigned(Pred
) &&
3289 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(RBO
))) ||
3290 (CmpInst::isSigned(Pred
) &&
3291 Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(RBO
)));
3294 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
3295 if ((A
== RHS
|| B
== RHS
) && NoLHSWrapProblem
)
3296 if (Value
*V
= simplifyICmpInst(Pred
, A
== RHS
? B
: A
,
3297 Constant::getNullValue(RHS
->getType()), Q
,
3301 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
3302 if ((C
== LHS
|| D
== LHS
) && NoRHSWrapProblem
)
3304 simplifyICmpInst(Pred
, Constant::getNullValue(LHS
->getType()),
3305 C
== LHS
? D
: C
, Q
, MaxRecurse
- 1))
3308 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
3309 bool CanSimplify
= (NoLHSWrapProblem
&& NoRHSWrapProblem
) ||
3310 trySimplifyICmpWithAdds(Pred
, LHS
, RHS
, Q
.IIQ
);
3311 if (A
&& C
&& (A
== C
|| A
== D
|| B
== C
|| B
== D
) && CanSimplify
) {
3312 // Determine Y and Z in the form icmp (X+Y), (X+Z).
3315 // C + B == C + D -> B == D
3318 } else if (A
== D
) {
3319 // D + B == C + D -> B == C
3322 } else if (B
== C
) {
3323 // A + C == C + D -> A == D
3328 // A + D == C + D -> A == C
3332 if (Value
*V
= simplifyICmpInst(Pred
, Y
, Z
, Q
, MaxRecurse
- 1))
3338 if (Value
*V
= simplifyICmpWithBinOpOnLHS(Pred
, LBO
, RHS
, Q
, MaxRecurse
))
3342 if (Value
*V
= simplifyICmpWithBinOpOnLHS(
3343 ICmpInst::getSwappedPredicate(Pred
), RBO
, LHS
, Q
, MaxRecurse
))
3346 // 0 - (zext X) pred C
3347 if (!CmpInst::isUnsigned(Pred
) && match(LHS
, m_Neg(m_ZExt(m_Value())))) {
3349 if (match(RHS
, m_APInt(C
))) {
3350 if (C
->isStrictlyPositive()) {
3351 if (Pred
== ICmpInst::ICMP_SLT
|| Pred
== ICmpInst::ICMP_NE
)
3352 return ConstantInt::getTrue(getCompareTy(RHS
));
3353 if (Pred
== ICmpInst::ICMP_SGE
|| Pred
== ICmpInst::ICMP_EQ
)
3354 return ConstantInt::getFalse(getCompareTy(RHS
));
3356 if (C
->isNonNegative()) {
3357 if (Pred
== ICmpInst::ICMP_SLE
)
3358 return ConstantInt::getTrue(getCompareTy(RHS
));
3359 if (Pred
== ICmpInst::ICMP_SGT
)
3360 return ConstantInt::getFalse(getCompareTy(RHS
));
3365 // If C2 is a power-of-2 and C is not:
3366 // (C2 << X) == C --> false
3367 // (C2 << X) != C --> true
3369 if (match(LHS
, m_Shl(m_Power2(), m_Value())) &&
3370 match(RHS
, m_APIntAllowPoison(C
)) && !C
->isPowerOf2()) {
3371 // C2 << X can equal zero in some circumstances.
3372 // This simplification might be unsafe if C is zero.
3374 // We know it is safe if:
3375 // - The shift is nsw. We can't shift out the one bit.
3376 // - The shift is nuw. We can't shift out the one bit.
3379 if (Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)) ||
3380 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)) ||
3381 match(LHS
, m_Shl(m_One(), m_Value())) || !C
->isZero()) {
3382 if (Pred
== ICmpInst::ICMP_EQ
)
3383 return ConstantInt::getFalse(getCompareTy(RHS
));
3384 if (Pred
== ICmpInst::ICMP_NE
)
3385 return ConstantInt::getTrue(getCompareTy(RHS
));
3389 // If C is a power-of-2:
3390 // (C << X) >u 0x8000 --> false
3391 // (C << X) <=u 0x8000 --> true
3392 if (match(LHS
, m_Shl(m_Power2(), m_Value())) && match(RHS
, m_SignMask())) {
3393 if (Pred
== ICmpInst::ICMP_UGT
)
3394 return ConstantInt::getFalse(getCompareTy(RHS
));
3395 if (Pred
== ICmpInst::ICMP_ULE
)
3396 return ConstantInt::getTrue(getCompareTy(RHS
));
3399 if (!MaxRecurse
|| !LBO
|| !RBO
|| LBO
->getOpcode() != RBO
->getOpcode())
3402 if (LBO
->getOperand(0) == RBO
->getOperand(0)) {
3403 switch (LBO
->getOpcode()) {
3406 case Instruction::Shl
: {
3407 bool NUW
= Q
.IIQ
.hasNoUnsignedWrap(LBO
) && Q
.IIQ
.hasNoUnsignedWrap(RBO
);
3408 bool NSW
= Q
.IIQ
.hasNoSignedWrap(LBO
) && Q
.IIQ
.hasNoSignedWrap(RBO
);
3409 if (!NUW
|| (ICmpInst::isSigned(Pred
) && !NSW
) ||
3410 !isKnownNonZero(LBO
->getOperand(0), Q
))
3412 if (Value
*V
= simplifyICmpInst(Pred
, LBO
->getOperand(1),
3413 RBO
->getOperand(1), Q
, MaxRecurse
- 1))
3417 // If C1 & C2 == C1, A = X and/or C1, B = X and/or C2:
3418 // icmp ule A, B -> true
3419 // icmp ugt A, B -> false
3420 // icmp sle A, B -> true (C1 and C2 are the same sign)
3421 // icmp sgt A, B -> false (C1 and C2 are the same sign)
3422 case Instruction::And
:
3423 case Instruction::Or
: {
3424 const APInt
*C1
, *C2
;
3425 if (ICmpInst::isRelational(Pred
) &&
3426 match(LBO
->getOperand(1), m_APInt(C1
)) &&
3427 match(RBO
->getOperand(1), m_APInt(C2
))) {
3428 if (!C1
->isSubsetOf(*C2
)) {
3430 Pred
= ICmpInst::getSwappedPredicate(Pred
);
3432 if (C1
->isSubsetOf(*C2
)) {
3433 if (Pred
== ICmpInst::ICMP_ULE
)
3434 return ConstantInt::getTrue(getCompareTy(LHS
));
3435 if (Pred
== ICmpInst::ICMP_UGT
)
3436 return ConstantInt::getFalse(getCompareTy(LHS
));
3437 if (C1
->isNonNegative() == C2
->isNonNegative()) {
3438 if (Pred
== ICmpInst::ICMP_SLE
)
3439 return ConstantInt::getTrue(getCompareTy(LHS
));
3440 if (Pred
== ICmpInst::ICMP_SGT
)
3441 return ConstantInt::getFalse(getCompareTy(LHS
));
3450 if (LBO
->getOperand(1) == RBO
->getOperand(1)) {
3451 switch (LBO
->getOpcode()) {
3454 case Instruction::UDiv
:
3455 case Instruction::LShr
:
3456 if (ICmpInst::isSigned(Pred
) || !Q
.IIQ
.isExact(LBO
) ||
3457 !Q
.IIQ
.isExact(RBO
))
3459 if (Value
*V
= simplifyICmpInst(Pred
, LBO
->getOperand(0),
3460 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
3463 case Instruction::SDiv
:
3464 if (!ICmpInst::isEquality(Pred
) || !Q
.IIQ
.isExact(LBO
) ||
3465 !Q
.IIQ
.isExact(RBO
))
3467 if (Value
*V
= simplifyICmpInst(Pred
, LBO
->getOperand(0),
3468 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
3471 case Instruction::AShr
:
3472 if (!Q
.IIQ
.isExact(LBO
) || !Q
.IIQ
.isExact(RBO
))
3474 if (Value
*V
= simplifyICmpInst(Pred
, LBO
->getOperand(0),
3475 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
3478 case Instruction::Shl
: {
3479 bool NUW
= Q
.IIQ
.hasNoUnsignedWrap(LBO
) && Q
.IIQ
.hasNoUnsignedWrap(RBO
);
3480 bool NSW
= Q
.IIQ
.hasNoSignedWrap(LBO
) && Q
.IIQ
.hasNoSignedWrap(RBO
);
3483 if (!NSW
&& ICmpInst::isSigned(Pred
))
3485 if (Value
*V
= simplifyICmpInst(Pred
, LBO
->getOperand(0),
3486 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
3495 /// simplify integer comparisons where at least one operand of the compare
3496 /// matches an integer min/max idiom.
3497 static Value
*simplifyICmpWithMinMax(CmpInst::Predicate Pred
, Value
*LHS
,
3498 Value
*RHS
, const SimplifyQuery
&Q
,
3499 unsigned MaxRecurse
) {
3500 Type
*ITy
= getCompareTy(LHS
); // The return type.
3502 CmpInst::Predicate P
= CmpInst::BAD_ICMP_PREDICATE
;
3503 CmpInst::Predicate EqP
; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
3505 // Signed variants on "max(a,b)>=a -> true".
3506 if (match(LHS
, m_SMax(m_Value(A
), m_Value(B
))) && (A
== RHS
|| B
== RHS
)) {
3508 std::swap(A
, B
); // smax(A, B) pred A.
3509 EqP
= CmpInst::ICMP_SGE
; // "A == smax(A, B)" iff "A sge B".
3510 // We analyze this as smax(A, B) pred A.
3512 } else if (match(RHS
, m_SMax(m_Value(A
), m_Value(B
))) &&
3513 (A
== LHS
|| B
== LHS
)) {
3515 std::swap(A
, B
); // A pred smax(A, B).
3516 EqP
= CmpInst::ICMP_SGE
; // "A == smax(A, B)" iff "A sge B".
3517 // We analyze this as smax(A, B) swapped-pred A.
3518 P
= CmpInst::getSwappedPredicate(Pred
);
3519 } else if (match(LHS
, m_SMin(m_Value(A
), m_Value(B
))) &&
3520 (A
== RHS
|| B
== RHS
)) {
3522 std::swap(A
, B
); // smin(A, B) pred A.
3523 EqP
= CmpInst::ICMP_SLE
; // "A == smin(A, B)" iff "A sle B".
3524 // We analyze this as smax(-A, -B) swapped-pred -A.
3525 // Note that we do not need to actually form -A or -B thanks to EqP.
3526 P
= CmpInst::getSwappedPredicate(Pred
);
3527 } else if (match(RHS
, m_SMin(m_Value(A
), m_Value(B
))) &&
3528 (A
== LHS
|| B
== LHS
)) {
3530 std::swap(A
, B
); // A pred smin(A, B).
3531 EqP
= CmpInst::ICMP_SLE
; // "A == smin(A, B)" iff "A sle B".
3532 // We analyze this as smax(-A, -B) pred -A.
3533 // Note that we do not need to actually form -A or -B thanks to EqP.
3536 if (P
!= CmpInst::BAD_ICMP_PREDICATE
) {
3537 // Cases correspond to "max(A, B) p A".
3541 case CmpInst::ICMP_EQ
:
3542 case CmpInst::ICMP_SLE
:
3543 // Equivalent to "A EqP B". This may be the same as the condition tested
3544 // in the max/min; if so, we can just return that.
3545 if (Value
*V
= extractEquivalentCondition(LHS
, EqP
, A
, B
))
3547 if (Value
*V
= extractEquivalentCondition(RHS
, EqP
, A
, B
))
3549 // Otherwise, see if "A EqP B" simplifies.
3551 if (Value
*V
= simplifyICmpInst(EqP
, A
, B
, Q
, MaxRecurse
- 1))
3554 case CmpInst::ICMP_NE
:
3555 case CmpInst::ICMP_SGT
: {
3556 CmpInst::Predicate InvEqP
= CmpInst::getInversePredicate(EqP
);
3557 // Equivalent to "A InvEqP B". This may be the same as the condition
3558 // tested in the max/min; if so, we can just return that.
3559 if (Value
*V
= extractEquivalentCondition(LHS
, InvEqP
, A
, B
))
3561 if (Value
*V
= extractEquivalentCondition(RHS
, InvEqP
, A
, B
))
3563 // Otherwise, see if "A InvEqP B" simplifies.
3565 if (Value
*V
= simplifyICmpInst(InvEqP
, A
, B
, Q
, MaxRecurse
- 1))
3569 case CmpInst::ICMP_SGE
:
3571 return getTrue(ITy
);
3572 case CmpInst::ICMP_SLT
:
3574 return getFalse(ITy
);
3578 // Unsigned variants on "max(a,b)>=a -> true".
3579 P
= CmpInst::BAD_ICMP_PREDICATE
;
3580 if (match(LHS
, m_UMax(m_Value(A
), m_Value(B
))) && (A
== RHS
|| B
== RHS
)) {
3582 std::swap(A
, B
); // umax(A, B) pred A.
3583 EqP
= CmpInst::ICMP_UGE
; // "A == umax(A, B)" iff "A uge B".
3584 // We analyze this as umax(A, B) pred A.
3586 } else if (match(RHS
, m_UMax(m_Value(A
), m_Value(B
))) &&
3587 (A
== LHS
|| B
== LHS
)) {
3589 std::swap(A
, B
); // A pred umax(A, B).
3590 EqP
= CmpInst::ICMP_UGE
; // "A == umax(A, B)" iff "A uge B".
3591 // We analyze this as umax(A, B) swapped-pred A.
3592 P
= CmpInst::getSwappedPredicate(Pred
);
3593 } else if (match(LHS
, m_UMin(m_Value(A
), m_Value(B
))) &&
3594 (A
== RHS
|| B
== RHS
)) {
3596 std::swap(A
, B
); // umin(A, B) pred A.
3597 EqP
= CmpInst::ICMP_ULE
; // "A == umin(A, B)" iff "A ule B".
3598 // We analyze this as umax(-A, -B) swapped-pred -A.
3599 // Note that we do not need to actually form -A or -B thanks to EqP.
3600 P
= CmpInst::getSwappedPredicate(Pred
);
3601 } else if (match(RHS
, m_UMin(m_Value(A
), m_Value(B
))) &&
3602 (A
== LHS
|| B
== LHS
)) {
3604 std::swap(A
, B
); // A pred umin(A, B).
3605 EqP
= CmpInst::ICMP_ULE
; // "A == umin(A, B)" iff "A ule B".
3606 // We analyze this as umax(-A, -B) pred -A.
3607 // Note that we do not need to actually form -A or -B thanks to EqP.
3610 if (P
!= CmpInst::BAD_ICMP_PREDICATE
) {
3611 // Cases correspond to "max(A, B) p A".
3615 case CmpInst::ICMP_EQ
:
3616 case CmpInst::ICMP_ULE
:
3617 // Equivalent to "A EqP B". This may be the same as the condition tested
3618 // in the max/min; if so, we can just return that.
3619 if (Value
*V
= extractEquivalentCondition(LHS
, EqP
, A
, B
))
3621 if (Value
*V
= extractEquivalentCondition(RHS
, EqP
, A
, B
))
3623 // Otherwise, see if "A EqP B" simplifies.
3625 if (Value
*V
= simplifyICmpInst(EqP
, A
, B
, Q
, MaxRecurse
- 1))
3628 case CmpInst::ICMP_NE
:
3629 case CmpInst::ICMP_UGT
: {
3630 CmpInst::Predicate InvEqP
= CmpInst::getInversePredicate(EqP
);
3631 // Equivalent to "A InvEqP B". This may be the same as the condition
3632 // tested in the max/min; if so, we can just return that.
3633 if (Value
*V
= extractEquivalentCondition(LHS
, InvEqP
, A
, B
))
3635 if (Value
*V
= extractEquivalentCondition(RHS
, InvEqP
, A
, B
))
3637 // Otherwise, see if "A InvEqP B" simplifies.
3639 if (Value
*V
= simplifyICmpInst(InvEqP
, A
, B
, Q
, MaxRecurse
- 1))
3643 case CmpInst::ICMP_UGE
:
3644 return getTrue(ITy
);
3645 case CmpInst::ICMP_ULT
:
3646 return getFalse(ITy
);
3650 // Comparing 1 each of min/max with a common operand?
3651 // Canonicalize min operand to RHS.
3652 if (match(LHS
, m_UMin(m_Value(), m_Value())) ||
3653 match(LHS
, m_SMin(m_Value(), m_Value()))) {
3654 std::swap(LHS
, RHS
);
3655 Pred
= ICmpInst::getSwappedPredicate(Pred
);
3659 if (match(LHS
, m_SMax(m_Value(A
), m_Value(B
))) &&
3660 match(RHS
, m_SMin(m_Value(C
), m_Value(D
))) &&
3661 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3662 // smax(A, B) >=s smin(A, D) --> true
3663 if (Pred
== CmpInst::ICMP_SGE
)
3664 return getTrue(ITy
);
3665 // smax(A, B) <s smin(A, D) --> false
3666 if (Pred
== CmpInst::ICMP_SLT
)
3667 return getFalse(ITy
);
3668 } else if (match(LHS
, m_UMax(m_Value(A
), m_Value(B
))) &&
3669 match(RHS
, m_UMin(m_Value(C
), m_Value(D
))) &&
3670 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3671 // umax(A, B) >=u umin(A, D) --> true
3672 if (Pred
== CmpInst::ICMP_UGE
)
3673 return getTrue(ITy
);
3674 // umax(A, B) <u umin(A, D) --> false
3675 if (Pred
== CmpInst::ICMP_ULT
)
3676 return getFalse(ITy
);
3682 static Value
*simplifyICmpWithDominatingAssume(CmpInst::Predicate Predicate
,
3683 Value
*LHS
, Value
*RHS
,
3684 const SimplifyQuery
&Q
) {
3685 // Gracefully handle instructions that have not been inserted yet.
3686 if (!Q
.AC
|| !Q
.CxtI
)
3689 for (Value
*AssumeBaseOp
: {LHS
, RHS
}) {
3690 for (auto &AssumeVH
: Q
.AC
->assumptionsFor(AssumeBaseOp
)) {
3694 CallInst
*Assume
= cast
<CallInst
>(AssumeVH
);
3695 if (std::optional
<bool> Imp
= isImpliedCondition(
3696 Assume
->getArgOperand(0), Predicate
, LHS
, RHS
, Q
.DL
))
3697 if (isValidAssumeForContext(Assume
, Q
.CxtI
, Q
.DT
))
3698 return ConstantInt::get(getCompareTy(LHS
), *Imp
);
3705 static Value
*simplifyICmpWithIntrinsicOnLHS(CmpInst::Predicate Pred
,
3706 Value
*LHS
, Value
*RHS
) {
3707 auto *II
= dyn_cast
<IntrinsicInst
>(LHS
);
3711 switch (II
->getIntrinsicID()) {
3712 case Intrinsic::uadd_sat
:
3713 // uadd.sat(X, Y) uge X, uadd.sat(X, Y) uge Y
3714 if (II
->getArgOperand(0) == RHS
|| II
->getArgOperand(1) == RHS
) {
3715 if (Pred
== ICmpInst::ICMP_UGE
)
3716 return ConstantInt::getTrue(getCompareTy(II
));
3717 if (Pred
== ICmpInst::ICMP_ULT
)
3718 return ConstantInt::getFalse(getCompareTy(II
));
3721 case Intrinsic::usub_sat
:
3722 // usub.sat(X, Y) ule X
3723 if (II
->getArgOperand(0) == RHS
) {
3724 if (Pred
== ICmpInst::ICMP_ULE
)
3725 return ConstantInt::getTrue(getCompareTy(II
));
3726 if (Pred
== ICmpInst::ICMP_UGT
)
3727 return ConstantInt::getFalse(getCompareTy(II
));
3735 /// Helper method to get range from metadata or attribute.
3736 static std::optional
<ConstantRange
> getRange(Value
*V
,
3737 const InstrInfoQuery
&IIQ
) {
3738 if (Instruction
*I
= dyn_cast
<Instruction
>(V
))
3739 if (MDNode
*MD
= IIQ
.getMetadata(I
, LLVMContext::MD_range
))
3740 return getConstantRangeFromMetadata(*MD
);
3742 if (const Argument
*A
= dyn_cast
<Argument
>(V
))
3743 return A
->getRange();
3744 else if (const CallBase
*CB
= dyn_cast
<CallBase
>(V
))
3745 return CB
->getRange();
3747 return std::nullopt
;
3750 /// Given operands for an ICmpInst, see if we can fold the result.
3751 /// If not, this returns null.
3752 static Value
*simplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
3753 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
3754 CmpInst::Predicate Pred
= (CmpInst::Predicate
)Predicate
;
3755 assert(CmpInst::isIntPredicate(Pred
) && "Not an integer compare!");
3757 if (Constant
*CLHS
= dyn_cast
<Constant
>(LHS
)) {
3758 if (Constant
*CRHS
= dyn_cast
<Constant
>(RHS
))
3759 return ConstantFoldCompareInstOperands(Pred
, CLHS
, CRHS
, Q
.DL
, Q
.TLI
);
3761 // If we have a constant, make sure it is on the RHS.
3762 std::swap(LHS
, RHS
);
3763 Pred
= CmpInst::getSwappedPredicate(Pred
);
3765 assert(!isa
<UndefValue
>(LHS
) && "Unexpected icmp undef,%X");
3767 Type
*ITy
= getCompareTy(LHS
); // The return type.
3769 // icmp poison, X -> poison
3770 if (isa
<PoisonValue
>(RHS
))
3771 return PoisonValue::get(ITy
);
3773 // For EQ and NE, we can always pick a value for the undef to make the
3774 // predicate pass or fail, so we can return undef.
3775 // Matches behavior in llvm::ConstantFoldCompareInstruction.
3776 if (Q
.isUndefValue(RHS
) && ICmpInst::isEquality(Pred
))
3777 return UndefValue::get(ITy
);
3779 // icmp X, X -> true/false
3780 // icmp X, undef -> true/false because undef could be X.
3781 if (LHS
== RHS
|| Q
.isUndefValue(RHS
))
3782 return ConstantInt::get(ITy
, CmpInst::isTrueWhenEqual(Pred
));
3784 if (Value
*V
= simplifyICmpOfBools(Pred
, LHS
, RHS
, Q
))
3787 // TODO: Sink/common this with other potentially expensive calls that use
3788 // ValueTracking? See comment below for isKnownNonEqual().
3789 if (Value
*V
= simplifyICmpWithZero(Pred
, LHS
, RHS
, Q
))
3792 if (Value
*V
= simplifyICmpWithConstant(Pred
, LHS
, RHS
, Q
.IIQ
))
3795 // If both operands have range metadata, use the metadata
3796 // to simplify the comparison.
3797 if (std::optional
<ConstantRange
> RhsCr
= getRange(RHS
, Q
.IIQ
))
3798 if (std::optional
<ConstantRange
> LhsCr
= getRange(LHS
, Q
.IIQ
)) {
3799 if (LhsCr
->icmp(Pred
, *RhsCr
))
3800 return ConstantInt::getTrue(ITy
);
3802 if (LhsCr
->icmp(CmpInst::getInversePredicate(Pred
), *RhsCr
))
3803 return ConstantInt::getFalse(ITy
);
3806 // Compare of cast, for example (zext X) != 0 -> X != 0
3807 if (isa
<CastInst
>(LHS
) && (isa
<Constant
>(RHS
) || isa
<CastInst
>(RHS
))) {
3808 Instruction
*LI
= cast
<CastInst
>(LHS
);
3809 Value
*SrcOp
= LI
->getOperand(0);
3810 Type
*SrcTy
= SrcOp
->getType();
3811 Type
*DstTy
= LI
->getType();
3813 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3814 // if the integer type is the same size as the pointer type.
3815 if (MaxRecurse
&& isa
<PtrToIntInst
>(LI
) &&
3816 Q
.DL
.getTypeSizeInBits(SrcTy
) == DstTy
->getPrimitiveSizeInBits()) {
3817 if (Constant
*RHSC
= dyn_cast
<Constant
>(RHS
)) {
3818 // Transfer the cast to the constant.
3819 if (Value
*V
= simplifyICmpInst(Pred
, SrcOp
,
3820 ConstantExpr::getIntToPtr(RHSC
, SrcTy
),
3823 } else if (PtrToIntInst
*RI
= dyn_cast
<PtrToIntInst
>(RHS
)) {
3824 if (RI
->getOperand(0)->getType() == SrcTy
)
3825 // Compare without the cast.
3826 if (Value
*V
= simplifyICmpInst(Pred
, SrcOp
, RI
->getOperand(0), Q
,
3832 if (isa
<ZExtInst
>(LHS
)) {
3833 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3835 if (ZExtInst
*RI
= dyn_cast
<ZExtInst
>(RHS
)) {
3836 if (MaxRecurse
&& SrcTy
== RI
->getOperand(0)->getType())
3837 // Compare X and Y. Note that signed predicates become unsigned.
3839 simplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred
), SrcOp
,
3840 RI
->getOperand(0), Q
, MaxRecurse
- 1))
3843 // Fold (zext X) ule (sext X), (zext X) sge (sext X) to true.
3844 else if (SExtInst
*RI
= dyn_cast
<SExtInst
>(RHS
)) {
3845 if (SrcOp
== RI
->getOperand(0)) {
3846 if (Pred
== ICmpInst::ICMP_ULE
|| Pred
== ICmpInst::ICMP_SGE
)
3847 return ConstantInt::getTrue(ITy
);
3848 if (Pred
== ICmpInst::ICMP_UGT
|| Pred
== ICmpInst::ICMP_SLT
)
3849 return ConstantInt::getFalse(ITy
);
3852 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3853 // too. If not, then try to deduce the result of the comparison.
3854 else if (match(RHS
, m_ImmConstant())) {
3855 Constant
*C
= dyn_cast
<Constant
>(RHS
);
3856 assert(C
!= nullptr);
3858 // Compute the constant that would happen if we truncated to SrcTy then
3859 // reextended to DstTy.
3861 ConstantFoldCastOperand(Instruction::Trunc
, C
, SrcTy
, Q
.DL
);
3862 assert(Trunc
&& "Constant-fold of ImmConstant should not fail");
3864 ConstantFoldCastOperand(CastInst::ZExt
, Trunc
, DstTy
, Q
.DL
);
3865 assert(RExt
&& "Constant-fold of ImmConstant should not fail");
3867 ConstantFoldCompareInstOperands(ICmpInst::ICMP_EQ
, RExt
, C
, Q
.DL
);
3868 assert(AnyEq
&& "Constant-fold of ImmConstant should not fail");
3870 // If the re-extended constant didn't change any of the elements then
3871 // this is effectively also a case of comparing two zero-extended
3873 if (AnyEq
->isAllOnesValue() && MaxRecurse
)
3874 if (Value
*V
= simplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred
),
3875 SrcOp
, Trunc
, Q
, MaxRecurse
- 1))
3878 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3879 // there. Use this to work out the result of the comparison.
3880 if (AnyEq
->isNullValue()) {
3883 llvm_unreachable("Unknown ICmp predicate!");
3885 case ICmpInst::ICMP_EQ
:
3886 case ICmpInst::ICMP_UGT
:
3887 case ICmpInst::ICMP_UGE
:
3888 return Constant::getNullValue(ITy
);
3890 case ICmpInst::ICMP_NE
:
3891 case ICmpInst::ICMP_ULT
:
3892 case ICmpInst::ICMP_ULE
:
3893 return Constant::getAllOnesValue(ITy
);
3895 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3896 // is non-negative then LHS <s RHS.
3897 case ICmpInst::ICMP_SGT
:
3898 case ICmpInst::ICMP_SGE
:
3899 return ConstantFoldCompareInstOperands(
3900 ICmpInst::ICMP_SLT
, C
, Constant::getNullValue(C
->getType()),
3902 case ICmpInst::ICMP_SLT
:
3903 case ICmpInst::ICMP_SLE
:
3904 return ConstantFoldCompareInstOperands(
3905 ICmpInst::ICMP_SGE
, C
, Constant::getNullValue(C
->getType()),
3912 if (isa
<SExtInst
>(LHS
)) {
3913 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3915 if (SExtInst
*RI
= dyn_cast
<SExtInst
>(RHS
)) {
3916 if (MaxRecurse
&& SrcTy
== RI
->getOperand(0)->getType())
3917 // Compare X and Y. Note that the predicate does not change.
3918 if (Value
*V
= simplifyICmpInst(Pred
, SrcOp
, RI
->getOperand(0), Q
,
3922 // Fold (sext X) uge (zext X), (sext X) sle (zext X) to true.
3923 else if (ZExtInst
*RI
= dyn_cast
<ZExtInst
>(RHS
)) {
3924 if (SrcOp
== RI
->getOperand(0)) {
3925 if (Pred
== ICmpInst::ICMP_UGE
|| Pred
== ICmpInst::ICMP_SLE
)
3926 return ConstantInt::getTrue(ITy
);
3927 if (Pred
== ICmpInst::ICMP_ULT
|| Pred
== ICmpInst::ICMP_SGT
)
3928 return ConstantInt::getFalse(ITy
);
3931 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3932 // too. If not, then try to deduce the result of the comparison.
3933 else if (match(RHS
, m_ImmConstant())) {
3934 Constant
*C
= cast
<Constant
>(RHS
);
3936 // Compute the constant that would happen if we truncated to SrcTy then
3937 // reextended to DstTy.
3939 ConstantFoldCastOperand(Instruction::Trunc
, C
, SrcTy
, Q
.DL
);
3940 assert(Trunc
&& "Constant-fold of ImmConstant should not fail");
3942 ConstantFoldCastOperand(CastInst::SExt
, Trunc
, DstTy
, Q
.DL
);
3943 assert(RExt
&& "Constant-fold of ImmConstant should not fail");
3945 ConstantFoldCompareInstOperands(ICmpInst::ICMP_EQ
, RExt
, C
, Q
.DL
);
3946 assert(AnyEq
&& "Constant-fold of ImmConstant should not fail");
3948 // If the re-extended constant didn't change then this is effectively
3949 // also a case of comparing two sign-extended values.
3950 if (AnyEq
->isAllOnesValue() && MaxRecurse
)
3952 simplifyICmpInst(Pred
, SrcOp
, Trunc
, Q
, MaxRecurse
- 1))
3955 // Otherwise the upper bits of LHS are all equal, while RHS has varying
3956 // bits there. Use this to work out the result of the comparison.
3957 if (AnyEq
->isNullValue()) {
3960 llvm_unreachable("Unknown ICmp predicate!");
3961 case ICmpInst::ICMP_EQ
:
3962 return Constant::getNullValue(ITy
);
3963 case ICmpInst::ICMP_NE
:
3964 return Constant::getAllOnesValue(ITy
);
3966 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3968 case ICmpInst::ICMP_SGT
:
3969 case ICmpInst::ICMP_SGE
:
3970 return ConstantFoldCompareInstOperands(
3971 ICmpInst::ICMP_SLT
, C
, Constant::getNullValue(C
->getType()),
3973 case ICmpInst::ICMP_SLT
:
3974 case ICmpInst::ICMP_SLE
:
3975 return ConstantFoldCompareInstOperands(
3976 ICmpInst::ICMP_SGE
, C
, Constant::getNullValue(C
->getType()),
3979 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3981 case ICmpInst::ICMP_UGT
:
3982 case ICmpInst::ICMP_UGE
:
3983 // Comparison is true iff the LHS <s 0.
3985 if (Value
*V
= simplifyICmpInst(ICmpInst::ICMP_SLT
, SrcOp
,
3986 Constant::getNullValue(SrcTy
), Q
,
3990 case ICmpInst::ICMP_ULT
:
3991 case ICmpInst::ICMP_ULE
:
3992 // Comparison is true iff the LHS >=s 0.
3994 if (Value
*V
= simplifyICmpInst(ICmpInst::ICMP_SGE
, SrcOp
,
3995 Constant::getNullValue(SrcTy
), Q
,
4005 // icmp eq|ne X, Y -> false|true if X != Y
4006 // This is potentially expensive, and we have already computedKnownBits for
4007 // compares with 0 above here, so only try this for a non-zero compare.
4008 if (ICmpInst::isEquality(Pred
) && !match(RHS
, m_Zero()) &&
4009 isKnownNonEqual(LHS
, RHS
, Q
.DL
, Q
.AC
, Q
.CxtI
, Q
.DT
, Q
.IIQ
.UseInstrInfo
)) {
4010 return Pred
== ICmpInst::ICMP_NE
? getTrue(ITy
) : getFalse(ITy
);
4013 if (Value
*V
= simplifyICmpWithBinOp(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4016 if (Value
*V
= simplifyICmpWithMinMax(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4019 if (Value
*V
= simplifyICmpWithIntrinsicOnLHS(Pred
, LHS
, RHS
))
4021 if (Value
*V
= simplifyICmpWithIntrinsicOnLHS(
4022 ICmpInst::getSwappedPredicate(Pred
), RHS
, LHS
))
4025 if (Value
*V
= simplifyICmpWithDominatingAssume(Pred
, LHS
, RHS
, Q
))
4028 if (std::optional
<bool> Res
=
4029 isImpliedByDomCondition(Pred
, LHS
, RHS
, Q
.CxtI
, Q
.DL
))
4030 return ConstantInt::getBool(ITy
, *Res
);
4032 // Simplify comparisons of related pointers using a powerful, recursive
4033 // GEP-walk when we have target data available..
4034 if (LHS
->getType()->isPointerTy())
4035 if (auto *C
= computePointerICmp(Pred
, LHS
, RHS
, Q
))
4037 if (auto *CLHS
= dyn_cast
<PtrToIntOperator
>(LHS
))
4038 if (auto *CRHS
= dyn_cast
<PtrToIntOperator
>(RHS
))
4039 if (CLHS
->getPointerOperandType() == CRHS
->getPointerOperandType() &&
4040 Q
.DL
.getTypeSizeInBits(CLHS
->getPointerOperandType()) ==
4041 Q
.DL
.getTypeSizeInBits(CLHS
->getType()))
4042 if (auto *C
= computePointerICmp(Pred
, CLHS
->getPointerOperand(),
4043 CRHS
->getPointerOperand(), Q
))
4046 // If the comparison is with the result of a select instruction, check whether
4047 // comparing with either branch of the select always yields the same value.
4048 if (isa
<SelectInst
>(LHS
) || isa
<SelectInst
>(RHS
))
4049 if (Value
*V
= threadCmpOverSelect(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4052 // If the comparison is with the result of a phi instruction, check whether
4053 // doing the compare with each incoming phi value yields a common result.
4054 if (isa
<PHINode
>(LHS
) || isa
<PHINode
>(RHS
))
4055 if (Value
*V
= threadCmpOverPHI(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4061 Value
*llvm::simplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
4062 const SimplifyQuery
&Q
) {
4063 return ::simplifyICmpInst(Predicate
, LHS
, RHS
, Q
, RecursionLimit
);
4066 /// Given operands for an FCmpInst, see if we can fold the result.
4067 /// If not, this returns null.
4068 static Value
*simplifyFCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
4069 FastMathFlags FMF
, const SimplifyQuery
&Q
,
4070 unsigned MaxRecurse
) {
4071 CmpInst::Predicate Pred
= (CmpInst::Predicate
)Predicate
;
4072 assert(CmpInst::isFPPredicate(Pred
) && "Not an FP compare!");
4074 if (Constant
*CLHS
= dyn_cast
<Constant
>(LHS
)) {
4075 if (Constant
*CRHS
= dyn_cast
<Constant
>(RHS
))
4076 return ConstantFoldCompareInstOperands(Pred
, CLHS
, CRHS
, Q
.DL
, Q
.TLI
,
4079 // If we have a constant, make sure it is on the RHS.
4080 std::swap(LHS
, RHS
);
4081 Pred
= CmpInst::getSwappedPredicate(Pred
);
4084 // Fold trivial predicates.
4085 Type
*RetTy
= getCompareTy(LHS
);
4086 if (Pred
== FCmpInst::FCMP_FALSE
)
4087 return getFalse(RetTy
);
4088 if (Pred
== FCmpInst::FCMP_TRUE
)
4089 return getTrue(RetTy
);
4091 // fcmp pred x, poison and fcmp pred poison, x
4093 if (isa
<PoisonValue
>(LHS
) || isa
<PoisonValue
>(RHS
))
4094 return PoisonValue::get(RetTy
);
4096 // fcmp pred x, undef and fcmp pred undef, x
4097 // fold to true if unordered, false if ordered
4098 if (Q
.isUndefValue(LHS
) || Q
.isUndefValue(RHS
)) {
4099 // Choosing NaN for the undef will always make unordered comparison succeed
4100 // and ordered comparison fail.
4101 return ConstantInt::get(RetTy
, CmpInst::isUnordered(Pred
));
4104 // fcmp x,x -> true/false. Not all compares are foldable.
4106 if (CmpInst::isTrueWhenEqual(Pred
))
4107 return getTrue(RetTy
);
4108 if (CmpInst::isFalseWhenEqual(Pred
))
4109 return getFalse(RetTy
);
4112 // Fold (un)ordered comparison if we can determine there are no NaNs.
4114 // This catches the 2 variable input case, constants are handled below as a
4115 // class-like compare.
4116 if (Pred
== FCmpInst::FCMP_ORD
|| Pred
== FCmpInst::FCMP_UNO
) {
4117 KnownFPClass RHSClass
=
4118 computeKnownFPClass(RHS
, fcAllFlags
, /*Depth=*/0, Q
);
4119 KnownFPClass LHSClass
=
4120 computeKnownFPClass(LHS
, fcAllFlags
, /*Depth=*/0, Q
);
4123 (RHSClass
.isKnownNeverNaN() && LHSClass
.isKnownNeverNaN()))
4124 return ConstantInt::get(RetTy
, Pred
== FCmpInst::FCMP_ORD
);
4126 if (RHSClass
.isKnownAlwaysNaN() || LHSClass
.isKnownAlwaysNaN())
4127 return ConstantInt::get(RetTy
, Pred
== CmpInst::FCMP_UNO
);
4130 const APFloat
*C
= nullptr;
4131 match(RHS
, m_APFloatAllowPoison(C
));
4132 std::optional
<KnownFPClass
> FullKnownClassLHS
;
4134 // Lazily compute the possible classes for LHS. Avoid computing it twice if
4136 auto computeLHSClass
= [=, &FullKnownClassLHS
](FPClassTest InterestedFlags
=
4138 if (FullKnownClassLHS
)
4139 return *FullKnownClassLHS
;
4140 return computeKnownFPClass(LHS
, FMF
, InterestedFlags
, 0, Q
);
4144 // Fold out compares that express a class test.
4146 // FIXME: Should be able to perform folds without context
4147 // instruction. Always pass in the context function?
4149 const Function
*ParentF
= Q
.CxtI
->getFunction();
4150 auto [ClassVal
, ClassTest
] = fcmpToClassTest(Pred
, *ParentF
, LHS
, C
);
4152 FullKnownClassLHS
= computeLHSClass();
4153 if ((FullKnownClassLHS
->KnownFPClasses
& ClassTest
) == fcNone
)
4154 return getFalse(RetTy
);
4155 if ((FullKnownClassLHS
->KnownFPClasses
& ~ClassTest
) == fcNone
)
4156 return getTrue(RetTy
);
4160 // Handle fcmp with constant RHS.
4162 // TODO: If we always required a context function, we wouldn't need to
4163 // special case nans.
4165 return ConstantInt::get(RetTy
, CmpInst::isUnordered(Pred
));
4167 // TODO: Need version fcmpToClassTest which returns implied class when the
4168 // compare isn't a complete class test. e.g. > 1.0 implies fcPositive, but
4169 // isn't implementable as a class call.
4170 if (C
->isNegative() && !C
->isNegZero()) {
4171 FPClassTest Interested
= KnownFPClass::OrderedLessThanZeroMask
;
4173 // TODO: We can catch more cases by using a range check rather than
4174 // relying on CannotBeOrderedLessThanZero.
4176 case FCmpInst::FCMP_UGE
:
4177 case FCmpInst::FCMP_UGT
:
4178 case FCmpInst::FCMP_UNE
: {
4179 KnownFPClass KnownClass
= computeLHSClass(Interested
);
4181 // (X >= 0) implies (X > C) when (C < 0)
4182 if (KnownClass
.cannotBeOrderedLessThanZero())
4183 return getTrue(RetTy
);
4186 case FCmpInst::FCMP_OEQ
:
4187 case FCmpInst::FCMP_OLE
:
4188 case FCmpInst::FCMP_OLT
: {
4189 KnownFPClass KnownClass
= computeLHSClass(Interested
);
4191 // (X >= 0) implies !(X < C) when (C < 0)
4192 if (KnownClass
.cannotBeOrderedLessThanZero())
4193 return getFalse(RetTy
);
4200 // Check comparison of [minnum/maxnum with constant] with other constant.
4202 if ((match(LHS
, m_Intrinsic
<Intrinsic::minnum
>(m_Value(), m_APFloat(C2
))) &&
4204 (match(LHS
, m_Intrinsic
<Intrinsic::maxnum
>(m_Value(), m_APFloat(C2
))) &&
4207 cast
<IntrinsicInst
>(LHS
)->getIntrinsicID() == Intrinsic::maxnum
;
4208 // The ordered relationship and minnum/maxnum guarantee that we do not
4209 // have NaN constants, so ordered/unordered preds are handled the same.
4211 case FCmpInst::FCMP_OEQ
:
4212 case FCmpInst::FCMP_UEQ
:
4213 // minnum(X, LesserC) == C --> false
4214 // maxnum(X, GreaterC) == C --> false
4215 return getFalse(RetTy
);
4216 case FCmpInst::FCMP_ONE
:
4217 case FCmpInst::FCMP_UNE
:
4218 // minnum(X, LesserC) != C --> true
4219 // maxnum(X, GreaterC) != C --> true
4220 return getTrue(RetTy
);
4221 case FCmpInst::FCMP_OGE
:
4222 case FCmpInst::FCMP_UGE
:
4223 case FCmpInst::FCMP_OGT
:
4224 case FCmpInst::FCMP_UGT
:
4225 // minnum(X, LesserC) >= C --> false
4226 // minnum(X, LesserC) > C --> false
4227 // maxnum(X, GreaterC) >= C --> true
4228 // maxnum(X, GreaterC) > C --> true
4229 return ConstantInt::get(RetTy
, IsMaxNum
);
4230 case FCmpInst::FCMP_OLE
:
4231 case FCmpInst::FCMP_ULE
:
4232 case FCmpInst::FCMP_OLT
:
4233 case FCmpInst::FCMP_ULT
:
4234 // minnum(X, LesserC) <= C --> true
4235 // minnum(X, LesserC) < C --> true
4236 // maxnum(X, GreaterC) <= C --> false
4237 // maxnum(X, GreaterC) < C --> false
4238 return ConstantInt::get(RetTy
, !IsMaxNum
);
4240 // TRUE/FALSE/ORD/UNO should be handled before this.
4241 llvm_unreachable("Unexpected fcmp predicate");
4246 // TODO: Could fold this with above if there were a matcher which returned all
4247 // classes in a non-splat vector.
4248 if (match(RHS
, m_AnyZeroFP())) {
4250 case FCmpInst::FCMP_OGE
:
4251 case FCmpInst::FCMP_ULT
: {
4252 FPClassTest Interested
= KnownFPClass::OrderedLessThanZeroMask
;
4254 Interested
|= fcNan
;
4256 KnownFPClass Known
= computeLHSClass(Interested
);
4258 // Positive or zero X >= 0.0 --> true
4259 // Positive or zero X < 0.0 --> false
4260 if ((FMF
.noNaNs() || Known
.isKnownNeverNaN()) &&
4261 Known
.cannotBeOrderedLessThanZero())
4262 return Pred
== FCmpInst::FCMP_OGE
? getTrue(RetTy
) : getFalse(RetTy
);
4265 case FCmpInst::FCMP_UGE
:
4266 case FCmpInst::FCMP_OLT
: {
4267 FPClassTest Interested
= KnownFPClass::OrderedLessThanZeroMask
;
4268 KnownFPClass Known
= computeLHSClass(Interested
);
4270 // Positive or zero or nan X >= 0.0 --> true
4271 // Positive or zero or nan X < 0.0 --> false
4272 if (Known
.cannotBeOrderedLessThanZero())
4273 return Pred
== FCmpInst::FCMP_UGE
? getTrue(RetTy
) : getFalse(RetTy
);
4281 // If the comparison is with the result of a select instruction, check whether
4282 // comparing with either branch of the select always yields the same value.
4283 if (isa
<SelectInst
>(LHS
) || isa
<SelectInst
>(RHS
))
4284 if (Value
*V
= threadCmpOverSelect(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4287 // If the comparison is with the result of a phi instruction, check whether
4288 // doing the compare with each incoming phi value yields a common result.
4289 if (isa
<PHINode
>(LHS
) || isa
<PHINode
>(RHS
))
4290 if (Value
*V
= threadCmpOverPHI(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
4296 Value
*llvm::simplifyFCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
4297 FastMathFlags FMF
, const SimplifyQuery
&Q
) {
4298 return ::simplifyFCmpInst(Predicate
, LHS
, RHS
, FMF
, Q
, RecursionLimit
);
4301 static Value
*simplifyWithOpReplaced(Value
*V
, Value
*Op
, Value
*RepOp
,
4302 const SimplifyQuery
&Q
,
4303 bool AllowRefinement
,
4304 SmallVectorImpl
<Instruction
*> *DropFlags
,
4305 unsigned MaxRecurse
) {
4306 assert((AllowRefinement
|| !Q
.CanUseUndef
) &&
4307 "If AllowRefinement=false then CanUseUndef=false");
4309 // Trivial replacement.
4316 // We cannot replace a constant, and shouldn't even try.
4317 if (isa
<Constant
>(Op
))
4320 auto *I
= dyn_cast
<Instruction
>(V
);
4324 // The arguments of a phi node might refer to a value from a previous
4326 if (isa
<PHINode
>(I
))
4329 if (Op
->getType()->isVectorTy()) {
4330 // For vector types, the simplification must hold per-lane, so forbid
4331 // potentially cross-lane operations like shufflevector.
4332 if (!I
->getType()->isVectorTy() || isa
<ShuffleVectorInst
>(I
) ||
4333 isa
<CallBase
>(I
) || isa
<BitCastInst
>(I
))
4337 // Don't fold away llvm.is.constant checks based on assumptions.
4338 if (match(I
, m_Intrinsic
<Intrinsic::is_constant
>()))
4341 // Don't simplify freeze.
4342 if (isa
<FreezeInst
>(I
))
4345 // Replace Op with RepOp in instruction operands.
4346 SmallVector
<Value
*, 8> NewOps
;
4347 bool AnyReplaced
= false;
4348 for (Value
*InstOp
: I
->operands()) {
4349 if (Value
*NewInstOp
= simplifyWithOpReplaced(
4350 InstOp
, Op
, RepOp
, Q
, AllowRefinement
, DropFlags
, MaxRecurse
)) {
4351 NewOps
.push_back(NewInstOp
);
4352 AnyReplaced
= InstOp
!= NewInstOp
;
4354 NewOps
.push_back(InstOp
);
4357 // Bail out if any operand is undef and SimplifyQuery disables undef
4358 // simplification. Constant folding currently doesn't respect this option.
4359 if (isa
<UndefValue
>(NewOps
.back()) && !Q
.CanUseUndef
)
4366 if (!AllowRefinement
) {
4367 // General InstSimplify functions may refine the result, e.g. by returning
4368 // a constant for a potentially poison value. To avoid this, implement only
4369 // a few non-refining but profitable transforms here.
4371 if (auto *BO
= dyn_cast
<BinaryOperator
>(I
)) {
4372 unsigned Opcode
= BO
->getOpcode();
4373 // id op x -> x, x op id -> x
4374 if (NewOps
[0] == ConstantExpr::getBinOpIdentity(Opcode
, I
->getType()))
4376 if (NewOps
[1] == ConstantExpr::getBinOpIdentity(Opcode
, I
->getType(),
4380 // x & x -> x, x | x -> x
4381 if ((Opcode
== Instruction::And
|| Opcode
== Instruction::Or
) &&
4382 NewOps
[0] == NewOps
[1]) {
4383 // or disjoint x, x results in poison.
4384 if (auto *PDI
= dyn_cast
<PossiblyDisjointInst
>(BO
)) {
4385 if (PDI
->isDisjoint()) {
4388 DropFlags
->push_back(BO
);
4394 // x - x -> 0, x ^ x -> 0. This is non-refining, because x is non-poison
4395 // by assumption and this case never wraps, so nowrap flags can be
4397 if ((Opcode
== Instruction::Sub
|| Opcode
== Instruction::Xor
) &&
4398 NewOps
[0] == RepOp
&& NewOps
[1] == RepOp
)
4399 return Constant::getNullValue(I
->getType());
4401 // If we are substituting an absorber constant into a binop and extra
4402 // poison can't leak if we remove the select -- because both operands of
4403 // the binop are based on the same value -- then it may be safe to replace
4404 // the value with the absorber constant. Examples:
4405 // (Op == 0) ? 0 : (Op & -Op) --> Op & -Op
4406 // (Op == 0) ? 0 : (Op * (binop Op, C)) --> Op * (binop Op, C)
4407 // (Op == -1) ? -1 : (Op | (binop C, Op) --> Op | (binop C, Op)
4408 Constant
*Absorber
=
4409 ConstantExpr::getBinOpAbsorber(Opcode
, I
->getType());
4410 if ((NewOps
[0] == Absorber
|| NewOps
[1] == Absorber
) &&
4411 impliesPoison(BO
, Op
))
4415 if (isa
<GetElementPtrInst
>(I
)) {
4416 // getelementptr x, 0 -> x.
4417 // This never returns poison, even if inbounds is set.
4418 if (NewOps
.size() == 2 && match(NewOps
[1], m_Zero()))
4422 // The simplification queries below may return the original value. Consider:
4423 // %div = udiv i32 %arg, %arg2
4424 // %mul = mul nsw i32 %div, %arg2
4425 // %cmp = icmp eq i32 %mul, %arg
4426 // %sel = select i1 %cmp, i32 %div, i32 undef
4427 // Replacing %arg by %mul, %div becomes "udiv i32 %mul, %arg2", which
4428 // simplifies back to %arg. This can only happen because %mul does not
4429 // dominate %div. To ensure a consistent return value contract, we make sure
4430 // that this case returns nullptr as well.
4431 auto PreventSelfSimplify
= [V
](Value
*Simplified
) {
4432 return Simplified
!= V
? Simplified
: nullptr;
4435 return PreventSelfSimplify(
4436 ::simplifyInstructionWithOperands(I
, NewOps
, Q
, MaxRecurse
));
4439 // If all operands are constant after substituting Op for RepOp then we can
4440 // constant fold the instruction.
4441 SmallVector
<Constant
*, 8> ConstOps
;
4442 for (Value
*NewOp
: NewOps
) {
4443 if (Constant
*ConstOp
= dyn_cast
<Constant
>(NewOp
))
4444 ConstOps
.push_back(ConstOp
);
4450 // %cmp = icmp eq i32 %x, 2147483647
4451 // %add = add nsw i32 %x, 1
4452 // %sel = select i1 %cmp, i32 -2147483648, i32 %add
4454 // We can't replace %sel with %add unless we strip away the flags (which
4455 // will be done in InstCombine).
4456 // TODO: This may be unsound, because it only catches some forms of
4458 if (!AllowRefinement
) {
4459 if (canCreatePoison(cast
<Operator
>(I
), !DropFlags
)) {
4460 // abs cannot create poison if the value is known to never be int_min.
4461 if (auto *II
= dyn_cast
<IntrinsicInst
>(I
);
4462 II
&& II
->getIntrinsicID() == Intrinsic::abs
) {
4463 if (!ConstOps
[0]->isNotMinSignedValue())
4468 Constant
*Res
= ConstantFoldInstOperands(I
, ConstOps
, Q
.DL
, Q
.TLI
);
4469 if (DropFlags
&& Res
&& I
->hasPoisonGeneratingAnnotations())
4470 DropFlags
->push_back(I
);
4474 return ConstantFoldInstOperands(I
, ConstOps
, Q
.DL
, Q
.TLI
);
4477 Value
*llvm::simplifyWithOpReplaced(Value
*V
, Value
*Op
, Value
*RepOp
,
4478 const SimplifyQuery
&Q
,
4479 bool AllowRefinement
,
4480 SmallVectorImpl
<Instruction
*> *DropFlags
) {
4481 // If refinement is disabled, also disable undef simplifications (which are
4482 // always refinements) in SimplifyQuery.
4483 if (!AllowRefinement
)
4484 return ::simplifyWithOpReplaced(V
, Op
, RepOp
, Q
.getWithoutUndef(),
4485 AllowRefinement
, DropFlags
, RecursionLimit
);
4486 return ::simplifyWithOpReplaced(V
, Op
, RepOp
, Q
, AllowRefinement
, DropFlags
,
4490 /// Try to simplify a select instruction when its condition operand is an
4491 /// integer comparison where one operand of the compare is a constant.
4492 static Value
*simplifySelectBitTest(Value
*TrueVal
, Value
*FalseVal
, Value
*X
,
4493 const APInt
*Y
, bool TrueWhenUnset
) {
4496 // (X & Y) == 0 ? X & ~Y : X --> X
4497 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
4498 if (FalseVal
== X
&& match(TrueVal
, m_And(m_Specific(X
), m_APInt(C
))) &&
4500 return TrueWhenUnset
? FalseVal
: TrueVal
;
4502 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
4503 // (X & Y) != 0 ? X : X & ~Y --> X
4504 if (TrueVal
== X
&& match(FalseVal
, m_And(m_Specific(X
), m_APInt(C
))) &&
4506 return TrueWhenUnset
? FalseVal
: TrueVal
;
4508 if (Y
->isPowerOf2()) {
4509 // (X & Y) == 0 ? X | Y : X --> X | Y
4510 // (X & Y) != 0 ? X | Y : X --> X
4511 if (FalseVal
== X
&& match(TrueVal
, m_Or(m_Specific(X
), m_APInt(C
))) &&
4513 // We can't return the or if it has the disjoint flag.
4514 if (TrueWhenUnset
&& cast
<PossiblyDisjointInst
>(TrueVal
)->isDisjoint())
4516 return TrueWhenUnset
? TrueVal
: FalseVal
;
4519 // (X & Y) == 0 ? X : X | Y --> X
4520 // (X & Y) != 0 ? X : X | Y --> X | Y
4521 if (TrueVal
== X
&& match(FalseVal
, m_Or(m_Specific(X
), m_APInt(C
))) &&
4523 // We can't return the or if it has the disjoint flag.
4524 if (!TrueWhenUnset
&& cast
<PossiblyDisjointInst
>(FalseVal
)->isDisjoint())
4526 return TrueWhenUnset
? TrueVal
: FalseVal
;
4533 static Value
*simplifyCmpSelOfMaxMin(Value
*CmpLHS
, Value
*CmpRHS
,
4534 ICmpInst::Predicate Pred
, Value
*TVal
,
4536 // Canonicalize common cmp+sel operand as CmpLHS.
4537 if (CmpRHS
== TVal
|| CmpRHS
== FVal
) {
4538 std::swap(CmpLHS
, CmpRHS
);
4539 Pred
= ICmpInst::getSwappedPredicate(Pred
);
4542 // Canonicalize common cmp+sel operand as TVal.
4543 if (CmpLHS
== FVal
) {
4544 std::swap(TVal
, FVal
);
4545 Pred
= ICmpInst::getInversePredicate(Pred
);
4548 // A vector select may be shuffling together elements that are equivalent
4549 // based on the max/min/select relationship.
4550 Value
*X
= CmpLHS
, *Y
= CmpRHS
;
4551 bool PeekedThroughSelectShuffle
= false;
4552 auto *Shuf
= dyn_cast
<ShuffleVectorInst
>(FVal
);
4553 if (Shuf
&& Shuf
->isSelect()) {
4554 if (Shuf
->getOperand(0) == Y
)
4555 FVal
= Shuf
->getOperand(1);
4556 else if (Shuf
->getOperand(1) == Y
)
4557 FVal
= Shuf
->getOperand(0);
4560 PeekedThroughSelectShuffle
= true;
4563 // (X pred Y) ? X : max/min(X, Y)
4564 auto *MMI
= dyn_cast
<MinMaxIntrinsic
>(FVal
);
4565 if (!MMI
|| TVal
!= X
||
4566 !match(FVal
, m_c_MaxOrMin(m_Specific(X
), m_Specific(Y
))))
4569 // (X > Y) ? X : max(X, Y) --> max(X, Y)
4570 // (X >= Y) ? X : max(X, Y) --> max(X, Y)
4571 // (X < Y) ? X : min(X, Y) --> min(X, Y)
4572 // (X <= Y) ? X : min(X, Y) --> min(X, Y)
4574 // The equivalence allows a vector select (shuffle) of max/min and Y. Ex:
4575 // (X > Y) ? X : (Z ? max(X, Y) : Y)
4576 // If Z is true, this reduces as above, and if Z is false:
4577 // (X > Y) ? X : Y --> max(X, Y)
4578 ICmpInst::Predicate MMPred
= MMI
->getPredicate();
4579 if (MMPred
== CmpInst::getStrictPredicate(Pred
))
4582 // Other transforms are not valid with a shuffle.
4583 if (PeekedThroughSelectShuffle
)
4586 // (X == Y) ? X : max/min(X, Y) --> max/min(X, Y)
4587 if (Pred
== CmpInst::ICMP_EQ
)
4590 // (X != Y) ? X : max/min(X, Y) --> X
4591 if (Pred
== CmpInst::ICMP_NE
)
4594 // (X < Y) ? X : max(X, Y) --> X
4595 // (X <= Y) ? X : max(X, Y) --> X
4596 // (X > Y) ? X : min(X, Y) --> X
4597 // (X >= Y) ? X : min(X, Y) --> X
4598 ICmpInst::Predicate InvPred
= CmpInst::getInversePredicate(Pred
);
4599 if (MMPred
== CmpInst::getStrictPredicate(InvPred
))
4605 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
4607 static Value
*simplifySelectWithFakeICmpEq(Value
*CmpLHS
, Value
*CmpRHS
,
4608 ICmpInst::Predicate Pred
,
4609 Value
*TrueVal
, Value
*FalseVal
) {
4612 if (!decomposeBitTestICmp(CmpLHS
, CmpRHS
, Pred
, X
, Mask
))
4615 return simplifySelectBitTest(TrueVal
, FalseVal
, X
, &Mask
,
4616 Pred
== ICmpInst::ICMP_EQ
);
4619 /// Try to simplify a select instruction when its condition operand is an
4620 /// integer equality comparison.
4621 static Value
*simplifySelectWithICmpEq(Value
*CmpLHS
, Value
*CmpRHS
,
4622 Value
*TrueVal
, Value
*FalseVal
,
4623 const SimplifyQuery
&Q
,
4624 unsigned MaxRecurse
) {
4625 if (simplifyWithOpReplaced(FalseVal
, CmpLHS
, CmpRHS
, Q
.getWithoutUndef(),
4626 /* AllowRefinement */ false,
4627 /* DropFlags */ nullptr, MaxRecurse
) == TrueVal
)
4629 if (simplifyWithOpReplaced(TrueVal
, CmpLHS
, CmpRHS
, Q
,
4630 /* AllowRefinement */ true,
4631 /* DropFlags */ nullptr, MaxRecurse
) == FalseVal
)
4637 /// Try to simplify a select instruction when its condition operand is an
4638 /// integer comparison.
4639 static Value
*simplifySelectWithICmpCond(Value
*CondVal
, Value
*TrueVal
,
4641 const SimplifyQuery
&Q
,
4642 unsigned MaxRecurse
) {
4643 ICmpInst::Predicate Pred
;
4644 Value
*CmpLHS
, *CmpRHS
;
4645 if (!match(CondVal
, m_ICmp(Pred
, m_Value(CmpLHS
), m_Value(CmpRHS
))))
4648 if (Value
*V
= simplifyCmpSelOfMaxMin(CmpLHS
, CmpRHS
, Pred
, TrueVal
, FalseVal
))
4651 // Canonicalize ne to eq predicate.
4652 if (Pred
== ICmpInst::ICMP_NE
) {
4653 Pred
= ICmpInst::ICMP_EQ
;
4654 std::swap(TrueVal
, FalseVal
);
4657 // Check for integer min/max with a limit constant:
4658 // X > MIN_INT ? X : MIN_INT --> X
4659 // X < MAX_INT ? X : MAX_INT --> X
4660 if (TrueVal
->getType()->isIntOrIntVectorTy()) {
4662 SelectPatternFlavor SPF
=
4663 matchDecomposedSelectPattern(cast
<ICmpInst
>(CondVal
), TrueVal
, FalseVal
,
4666 if (SelectPatternResult::isMinOrMax(SPF
) && Pred
== getMinMaxPred(SPF
)) {
4667 APInt LimitC
= getMinMaxLimit(getInverseMinMaxFlavor(SPF
),
4668 X
->getType()->getScalarSizeInBits());
4669 if (match(Y
, m_SpecificInt(LimitC
)))
4674 if (Pred
== ICmpInst::ICMP_EQ
&& match(CmpRHS
, m_Zero())) {
4677 if (match(CmpLHS
, m_And(m_Value(X
), m_APInt(Y
))))
4678 if (Value
*V
= simplifySelectBitTest(TrueVal
, FalseVal
, X
, Y
,
4679 /*TrueWhenUnset=*/true))
4682 // Test for a bogus zero-shift-guard-op around funnel-shift or rotate.
4684 auto isFsh
= m_CombineOr(m_FShl(m_Value(X
), m_Value(), m_Value(ShAmt
)),
4685 m_FShr(m_Value(), m_Value(X
), m_Value(ShAmt
)));
4686 // (ShAmt == 0) ? fshl(X, *, ShAmt) : X --> X
4687 // (ShAmt == 0) ? fshr(*, X, ShAmt) : X --> X
4688 if (match(TrueVal
, isFsh
) && FalseVal
== X
&& CmpLHS
== ShAmt
)
4691 // Test for a zero-shift-guard-op around rotates. These are used to
4692 // avoid UB from oversized shifts in raw IR rotate patterns, but the
4693 // intrinsics do not have that problem.
4694 // We do not allow this transform for the general funnel shift case because
4695 // that would not preserve the poison safety of the original code.
4697 m_CombineOr(m_FShl(m_Value(X
), m_Deferred(X
), m_Value(ShAmt
)),
4698 m_FShr(m_Value(X
), m_Deferred(X
), m_Value(ShAmt
)));
4699 // (ShAmt == 0) ? X : fshl(X, X, ShAmt) --> fshl(X, X, ShAmt)
4700 // (ShAmt == 0) ? X : fshr(X, X, ShAmt) --> fshr(X, X, ShAmt)
4701 if (match(FalseVal
, isRotate
) && TrueVal
== X
&& CmpLHS
== ShAmt
&&
4702 Pred
== ICmpInst::ICMP_EQ
)
4705 // X == 0 ? abs(X) : -abs(X) --> -abs(X)
4706 // X == 0 ? -abs(X) : abs(X) --> abs(X)
4707 if (match(TrueVal
, m_Intrinsic
<Intrinsic::abs
>(m_Specific(CmpLHS
))) &&
4708 match(FalseVal
, m_Neg(m_Intrinsic
<Intrinsic::abs
>(m_Specific(CmpLHS
)))))
4711 m_Neg(m_Intrinsic
<Intrinsic::abs
>(m_Specific(CmpLHS
)))) &&
4712 match(FalseVal
, m_Intrinsic
<Intrinsic::abs
>(m_Specific(CmpLHS
))))
4716 // Check for other compares that behave like bit test.
4718 simplifySelectWithFakeICmpEq(CmpLHS
, CmpRHS
, Pred
, TrueVal
, FalseVal
))
4721 // If we have a scalar equality comparison, then we know the value in one of
4722 // the arms of the select. See if substituting this value into the arm and
4723 // simplifying the result yields the same value as the other arm.
4724 if (Pred
== ICmpInst::ICMP_EQ
) {
4725 if (Value
*V
= simplifySelectWithICmpEq(CmpLHS
, CmpRHS
, TrueVal
, FalseVal
,
4728 if (Value
*V
= simplifySelectWithICmpEq(CmpRHS
, CmpLHS
, TrueVal
, FalseVal
,
4734 // select((X | Y) == 0 ? X : 0) --> 0 (commuted 2 ways)
4735 if (match(CmpLHS
, m_Or(m_Value(X
), m_Value(Y
))) &&
4736 match(CmpRHS
, m_Zero())) {
4737 // (X | Y) == 0 implies X == 0 and Y == 0.
4738 if (Value
*V
= simplifySelectWithICmpEq(X
, CmpRHS
, TrueVal
, FalseVal
, Q
,
4741 if (Value
*V
= simplifySelectWithICmpEq(Y
, CmpRHS
, TrueVal
, FalseVal
, Q
,
4746 // select((X & Y) == -1 ? X : -1) --> -1 (commuted 2 ways)
4747 if (match(CmpLHS
, m_And(m_Value(X
), m_Value(Y
))) &&
4748 match(CmpRHS
, m_AllOnes())) {
4749 // (X & Y) == -1 implies X == -1 and Y == -1.
4750 if (Value
*V
= simplifySelectWithICmpEq(X
, CmpRHS
, TrueVal
, FalseVal
, Q
,
4753 if (Value
*V
= simplifySelectWithICmpEq(Y
, CmpRHS
, TrueVal
, FalseVal
, Q
,
4762 /// Try to simplify a select instruction when its condition operand is a
4763 /// floating-point comparison.
4764 static Value
*simplifySelectWithFCmp(Value
*Cond
, Value
*T
, Value
*F
,
4765 const SimplifyQuery
&Q
) {
4766 FCmpInst::Predicate Pred
;
4767 if (!match(Cond
, m_FCmp(Pred
, m_Specific(T
), m_Specific(F
))) &&
4768 !match(Cond
, m_FCmp(Pred
, m_Specific(F
), m_Specific(T
))))
4771 // This transform is safe if we do not have (do not care about) -0.0 or if
4772 // at least one operand is known to not be -0.0. Otherwise, the select can
4773 // change the sign of a zero operand.
4774 bool HasNoSignedZeros
=
4775 Q
.CxtI
&& isa
<FPMathOperator
>(Q
.CxtI
) && Q
.CxtI
->hasNoSignedZeros();
4777 if (HasNoSignedZeros
|| (match(T
, m_APFloat(C
)) && C
->isNonZero()) ||
4778 (match(F
, m_APFloat(C
)) && C
->isNonZero())) {
4779 // (T == F) ? T : F --> F
4780 // (F == T) ? T : F --> F
4781 if (Pred
== FCmpInst::FCMP_OEQ
)
4784 // (T != F) ? T : F --> T
4785 // (F != T) ? T : F --> T
4786 if (Pred
== FCmpInst::FCMP_UNE
)
4793 /// Given operands for a SelectInst, see if we can fold the result.
4794 /// If not, this returns null.
4795 static Value
*simplifySelectInst(Value
*Cond
, Value
*TrueVal
, Value
*FalseVal
,
4796 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4797 if (auto *CondC
= dyn_cast
<Constant
>(Cond
)) {
4798 if (auto *TrueC
= dyn_cast
<Constant
>(TrueVal
))
4799 if (auto *FalseC
= dyn_cast
<Constant
>(FalseVal
))
4800 if (Constant
*C
= ConstantFoldSelectInstruction(CondC
, TrueC
, FalseC
))
4803 // select poison, X, Y -> poison
4804 if (isa
<PoisonValue
>(CondC
))
4805 return PoisonValue::get(TrueVal
->getType());
4807 // select undef, X, Y -> X or Y
4808 if (Q
.isUndefValue(CondC
))
4809 return isa
<Constant
>(FalseVal
) ? FalseVal
: TrueVal
;
4811 // select true, X, Y --> X
4812 // select false, X, Y --> Y
4813 // For vectors, allow undef/poison elements in the condition to match the
4814 // defined elements, so we can eliminate the select.
4815 if (match(CondC
, m_One()))
4817 if (match(CondC
, m_Zero()))
4821 assert(Cond
->getType()->isIntOrIntVectorTy(1) &&
4822 "Select must have bool or bool vector condition");
4823 assert(TrueVal
->getType() == FalseVal
->getType() &&
4824 "Select must have same types for true/false ops");
4826 if (Cond
->getType() == TrueVal
->getType()) {
4827 // select i1 Cond, i1 true, i1 false --> i1 Cond
4828 if (match(TrueVal
, m_One()) && match(FalseVal
, m_ZeroInt()))
4831 // (X && Y) ? X : Y --> Y (commuted 2 ways)
4832 if (match(Cond
, m_c_LogicalAnd(m_Specific(TrueVal
), m_Specific(FalseVal
))))
4835 // (X || Y) ? X : Y --> X (commuted 2 ways)
4836 if (match(Cond
, m_c_LogicalOr(m_Specific(TrueVal
), m_Specific(FalseVal
))))
4839 // (X || Y) ? false : X --> false (commuted 2 ways)
4840 if (match(Cond
, m_c_LogicalOr(m_Specific(FalseVal
), m_Value())) &&
4841 match(TrueVal
, m_ZeroInt()))
4842 return ConstantInt::getFalse(Cond
->getType());
4844 // Match patterns that end in logical-and.
4845 if (match(FalseVal
, m_ZeroInt())) {
4846 // !(X || Y) && X --> false (commuted 2 ways)
4847 if (match(Cond
, m_Not(m_c_LogicalOr(m_Specific(TrueVal
), m_Value()))))
4848 return ConstantInt::getFalse(Cond
->getType());
4849 // X && !(X || Y) --> false (commuted 2 ways)
4850 if (match(TrueVal
, m_Not(m_c_LogicalOr(m_Specific(Cond
), m_Value()))))
4851 return ConstantInt::getFalse(Cond
->getType());
4853 // (X || Y) && Y --> Y (commuted 2 ways)
4854 if (match(Cond
, m_c_LogicalOr(m_Specific(TrueVal
), m_Value())))
4856 // Y && (X || Y) --> Y (commuted 2 ways)
4857 if (match(TrueVal
, m_c_LogicalOr(m_Specific(Cond
), m_Value())))
4860 // (X || Y) && (X || !Y) --> X (commuted 8 ways)
4862 if (match(Cond
, m_c_LogicalOr(m_Value(X
), m_Not(m_Value(Y
)))) &&
4863 match(TrueVal
, m_c_LogicalOr(m_Specific(X
), m_Specific(Y
))))
4865 if (match(TrueVal
, m_c_LogicalOr(m_Value(X
), m_Not(m_Value(Y
)))) &&
4866 match(Cond
, m_c_LogicalOr(m_Specific(X
), m_Specific(Y
))))
4870 // Match patterns that end in logical-or.
4871 if (match(TrueVal
, m_One())) {
4872 // !(X && Y) || X --> true (commuted 2 ways)
4873 if (match(Cond
, m_Not(m_c_LogicalAnd(m_Specific(FalseVal
), m_Value()))))
4874 return ConstantInt::getTrue(Cond
->getType());
4875 // X || !(X && Y) --> true (commuted 2 ways)
4876 if (match(FalseVal
, m_Not(m_c_LogicalAnd(m_Specific(Cond
), m_Value()))))
4877 return ConstantInt::getTrue(Cond
->getType());
4879 // (X && Y) || Y --> Y (commuted 2 ways)
4880 if (match(Cond
, m_c_LogicalAnd(m_Specific(FalseVal
), m_Value())))
4882 // Y || (X && Y) --> Y (commuted 2 ways)
4883 if (match(FalseVal
, m_c_LogicalAnd(m_Specific(Cond
), m_Value())))
4888 // select ?, X, X -> X
4889 if (TrueVal
== FalseVal
)
4892 if (Cond
== TrueVal
) {
4893 // select i1 X, i1 X, i1 false --> X (logical-and)
4894 if (match(FalseVal
, m_ZeroInt()))
4896 // select i1 X, i1 X, i1 true --> true
4897 if (match(FalseVal
, m_One()))
4898 return ConstantInt::getTrue(Cond
->getType());
4900 if (Cond
== FalseVal
) {
4901 // select i1 X, i1 true, i1 X --> X (logical-or)
4902 if (match(TrueVal
, m_One()))
4904 // select i1 X, i1 false, i1 X --> false
4905 if (match(TrueVal
, m_ZeroInt()))
4906 return ConstantInt::getFalse(Cond
->getType());
4909 // If the true or false value is poison, we can fold to the other value.
4910 // If the true or false value is undef, we can fold to the other value as
4911 // long as the other value isn't poison.
4912 // select ?, poison, X -> X
4913 // select ?, undef, X -> X
4914 if (isa
<PoisonValue
>(TrueVal
) ||
4915 (Q
.isUndefValue(TrueVal
) && impliesPoison(FalseVal
, Cond
)))
4917 // select ?, X, poison -> X
4918 // select ?, X, undef -> X
4919 if (isa
<PoisonValue
>(FalseVal
) ||
4920 (Q
.isUndefValue(FalseVal
) && impliesPoison(TrueVal
, Cond
)))
4923 // Deal with partial undef vector constants: select ?, VecC, VecC' --> VecC''
4924 Constant
*TrueC
, *FalseC
;
4925 if (isa
<FixedVectorType
>(TrueVal
->getType()) &&
4926 match(TrueVal
, m_Constant(TrueC
)) &&
4927 match(FalseVal
, m_Constant(FalseC
))) {
4929 cast
<FixedVectorType
>(TrueC
->getType())->getNumElements();
4930 SmallVector
<Constant
*, 16> NewC
;
4931 for (unsigned i
= 0; i
!= NumElts
; ++i
) {
4932 // Bail out on incomplete vector constants.
4933 Constant
*TEltC
= TrueC
->getAggregateElement(i
);
4934 Constant
*FEltC
= FalseC
->getAggregateElement(i
);
4935 if (!TEltC
|| !FEltC
)
4938 // If the elements match (undef or not), that value is the result. If only
4939 // one element is undef, choose the defined element as the safe result.
4941 NewC
.push_back(TEltC
);
4942 else if (isa
<PoisonValue
>(TEltC
) ||
4943 (Q
.isUndefValue(TEltC
) && isGuaranteedNotToBePoison(FEltC
)))
4944 NewC
.push_back(FEltC
);
4945 else if (isa
<PoisonValue
>(FEltC
) ||
4946 (Q
.isUndefValue(FEltC
) && isGuaranteedNotToBePoison(TEltC
)))
4947 NewC
.push_back(TEltC
);
4951 if (NewC
.size() == NumElts
)
4952 return ConstantVector::get(NewC
);
4956 simplifySelectWithICmpCond(Cond
, TrueVal
, FalseVal
, Q
, MaxRecurse
))
4959 if (Value
*V
= simplifySelectWithFCmp(Cond
, TrueVal
, FalseVal
, Q
))
4962 if (Value
*V
= foldSelectWithBinaryOp(Cond
, TrueVal
, FalseVal
))
4965 std::optional
<bool> Imp
= isImpliedByDomCondition(Cond
, Q
.CxtI
, Q
.DL
);
4967 return *Imp
? TrueVal
: FalseVal
;
4972 Value
*llvm::simplifySelectInst(Value
*Cond
, Value
*TrueVal
, Value
*FalseVal
,
4973 const SimplifyQuery
&Q
) {
4974 return ::simplifySelectInst(Cond
, TrueVal
, FalseVal
, Q
, RecursionLimit
);
4977 /// Given operands for an GetElementPtrInst, see if we can fold the result.
4978 /// If not, this returns null.
4979 static Value
*simplifyGEPInst(Type
*SrcTy
, Value
*Ptr
,
4980 ArrayRef
<Value
*> Indices
, GEPNoWrapFlags NW
,
4981 const SimplifyQuery
&Q
, unsigned) {
4982 // The type of the GEP pointer operand.
4984 cast
<PointerType
>(Ptr
->getType()->getScalarType())->getAddressSpace();
4986 // getelementptr P -> P.
4987 if (Indices
.empty())
4990 // Compute the (pointer) type returned by the GEP instruction.
4991 Type
*LastType
= GetElementPtrInst::getIndexedType(SrcTy
, Indices
);
4992 Type
*GEPTy
= Ptr
->getType();
4993 if (!GEPTy
->isVectorTy()) {
4994 for (Value
*Op
: Indices
) {
4995 // If one of the operands is a vector, the result type is a vector of
4996 // pointers. All vector operands must have the same number of elements.
4997 if (VectorType
*VT
= dyn_cast
<VectorType
>(Op
->getType())) {
4998 GEPTy
= VectorType::get(GEPTy
, VT
->getElementCount());
5004 // All-zero GEP is a no-op, unless it performs a vector splat.
5005 if (Ptr
->getType() == GEPTy
&&
5006 all_of(Indices
, [](const auto *V
) { return match(V
, m_Zero()); }))
5009 // getelementptr poison, idx -> poison
5010 // getelementptr baseptr, poison -> poison
5011 if (isa
<PoisonValue
>(Ptr
) ||
5012 any_of(Indices
, [](const auto *V
) { return isa
<PoisonValue
>(V
); }))
5013 return PoisonValue::get(GEPTy
);
5015 // getelementptr undef, idx -> undef
5016 if (Q
.isUndefValue(Ptr
))
5017 return UndefValue::get(GEPTy
);
5019 bool IsScalableVec
=
5020 SrcTy
->isScalableTy() || any_of(Indices
, [](const Value
*V
) {
5021 return isa
<ScalableVectorType
>(V
->getType());
5024 if (Indices
.size() == 1) {
5026 if (!IsScalableVec
&& Ty
->isSized()) {
5029 uint64_t TyAllocSize
= Q
.DL
.getTypeAllocSize(Ty
);
5030 // getelementptr P, N -> P if P points to a type of zero size.
5031 if (TyAllocSize
== 0 && Ptr
->getType() == GEPTy
)
5034 // The following transforms are only safe if the ptrtoint cast
5035 // doesn't truncate the pointers.
5036 if (Indices
[0]->getType()->getScalarSizeInBits() ==
5037 Q
.DL
.getPointerSizeInBits(AS
)) {
5038 auto CanSimplify
= [GEPTy
, &P
, Ptr
]() -> bool {
5039 return P
->getType() == GEPTy
&&
5040 getUnderlyingObject(P
) == getUnderlyingObject(Ptr
);
5042 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
5043 if (TyAllocSize
== 1 &&
5045 m_Sub(m_PtrToInt(m_Value(P
)), m_PtrToInt(m_Specific(Ptr
)))) &&
5049 // getelementptr V, (ashr (sub P, V), C) -> P if P points to a type of
5051 if (match(Indices
[0], m_AShr(m_Sub(m_PtrToInt(m_Value(P
)),
5052 m_PtrToInt(m_Specific(Ptr
))),
5053 m_ConstantInt(C
))) &&
5054 TyAllocSize
== 1ULL << C
&& CanSimplify())
5057 // getelementptr V, (sdiv (sub P, V), C) -> P if P points to a type of
5059 if (match(Indices
[0], m_SDiv(m_Sub(m_PtrToInt(m_Value(P
)),
5060 m_PtrToInt(m_Specific(Ptr
))),
5061 m_SpecificInt(TyAllocSize
))) &&
5068 if (!IsScalableVec
&& Q
.DL
.getTypeAllocSize(LastType
) == 1 &&
5069 all_of(Indices
.drop_back(1),
5070 [](Value
*Idx
) { return match(Idx
, m_Zero()); })) {
5072 Q
.DL
.getIndexSizeInBits(Ptr
->getType()->getPointerAddressSpace());
5073 if (Q
.DL
.getTypeSizeInBits(Indices
.back()->getType()) == IdxWidth
) {
5074 APInt
BasePtrOffset(IdxWidth
, 0);
5075 Value
*StrippedBasePtr
=
5076 Ptr
->stripAndAccumulateInBoundsConstantOffsets(Q
.DL
, BasePtrOffset
);
5078 // Avoid creating inttoptr of zero here: While LLVMs treatment of
5079 // inttoptr is generally conservative, this particular case is folded to
5080 // a null pointer, which will have incorrect provenance.
5082 // gep (gep V, C), (sub 0, V) -> C
5083 if (match(Indices
.back(),
5084 m_Neg(m_PtrToInt(m_Specific(StrippedBasePtr
)))) &&
5085 !BasePtrOffset
.isZero()) {
5086 auto *CI
= ConstantInt::get(GEPTy
->getContext(), BasePtrOffset
);
5087 return ConstantExpr::getIntToPtr(CI
, GEPTy
);
5089 // gep (gep V, C), (xor V, -1) -> C-1
5090 if (match(Indices
.back(),
5091 m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr
)), m_AllOnes())) &&
5092 !BasePtrOffset
.isOne()) {
5093 auto *CI
= ConstantInt::get(GEPTy
->getContext(), BasePtrOffset
- 1);
5094 return ConstantExpr::getIntToPtr(CI
, GEPTy
);
5099 // Check to see if this is constant foldable.
5100 if (!isa
<Constant
>(Ptr
) ||
5101 !all_of(Indices
, [](Value
*V
) { return isa
<Constant
>(V
); }))
5104 if (!ConstantExpr::isSupportedGetElementPtr(SrcTy
))
5105 return ConstantFoldGetElementPtr(SrcTy
, cast
<Constant
>(Ptr
), std::nullopt
,
5109 ConstantExpr::getGetElementPtr(SrcTy
, cast
<Constant
>(Ptr
), Indices
, NW
);
5110 return ConstantFoldConstant(CE
, Q
.DL
);
5113 Value
*llvm::simplifyGEPInst(Type
*SrcTy
, Value
*Ptr
, ArrayRef
<Value
*> Indices
,
5114 GEPNoWrapFlags NW
, const SimplifyQuery
&Q
) {
5115 return ::simplifyGEPInst(SrcTy
, Ptr
, Indices
, NW
, Q
, RecursionLimit
);
5118 /// Given operands for an InsertValueInst, see if we can fold the result.
5119 /// If not, this returns null.
5120 static Value
*simplifyInsertValueInst(Value
*Agg
, Value
*Val
,
5121 ArrayRef
<unsigned> Idxs
,
5122 const SimplifyQuery
&Q
, unsigned) {
5123 if (Constant
*CAgg
= dyn_cast
<Constant
>(Agg
))
5124 if (Constant
*CVal
= dyn_cast
<Constant
>(Val
))
5125 return ConstantFoldInsertValueInstruction(CAgg
, CVal
, Idxs
);
5127 // insertvalue x, poison, n -> x
5128 // insertvalue x, undef, n -> x if x cannot be poison
5129 if (isa
<PoisonValue
>(Val
) ||
5130 (Q
.isUndefValue(Val
) && isGuaranteedNotToBePoison(Agg
)))
5133 // insertvalue x, (extractvalue y, n), n
5134 if (ExtractValueInst
*EV
= dyn_cast
<ExtractValueInst
>(Val
))
5135 if (EV
->getAggregateOperand()->getType() == Agg
->getType() &&
5136 EV
->getIndices() == Idxs
) {
5137 // insertvalue poison, (extractvalue y, n), n -> y
5138 // insertvalue undef, (extractvalue y, n), n -> y if y cannot be poison
5139 if (isa
<PoisonValue
>(Agg
) ||
5140 (Q
.isUndefValue(Agg
) &&
5141 isGuaranteedNotToBePoison(EV
->getAggregateOperand())))
5142 return EV
->getAggregateOperand();
5144 // insertvalue y, (extractvalue y, n), n -> y
5145 if (Agg
== EV
->getAggregateOperand())
5152 Value
*llvm::simplifyInsertValueInst(Value
*Agg
, Value
*Val
,
5153 ArrayRef
<unsigned> Idxs
,
5154 const SimplifyQuery
&Q
) {
5155 return ::simplifyInsertValueInst(Agg
, Val
, Idxs
, Q
, RecursionLimit
);
5158 Value
*llvm::simplifyInsertElementInst(Value
*Vec
, Value
*Val
, Value
*Idx
,
5159 const SimplifyQuery
&Q
) {
5160 // Try to constant fold.
5161 auto *VecC
= dyn_cast
<Constant
>(Vec
);
5162 auto *ValC
= dyn_cast
<Constant
>(Val
);
5163 auto *IdxC
= dyn_cast
<Constant
>(Idx
);
5164 if (VecC
&& ValC
&& IdxC
)
5165 return ConstantExpr::getInsertElement(VecC
, ValC
, IdxC
);
5167 // For fixed-length vector, fold into poison if index is out of bounds.
5168 if (auto *CI
= dyn_cast
<ConstantInt
>(Idx
)) {
5169 if (isa
<FixedVectorType
>(Vec
->getType()) &&
5170 CI
->uge(cast
<FixedVectorType
>(Vec
->getType())->getNumElements()))
5171 return PoisonValue::get(Vec
->getType());
5174 // If index is undef, it might be out of bounds (see above case)
5175 if (Q
.isUndefValue(Idx
))
5176 return PoisonValue::get(Vec
->getType());
5178 // If the scalar is poison, or it is undef and there is no risk of
5179 // propagating poison from the vector value, simplify to the vector value.
5180 if (isa
<PoisonValue
>(Val
) ||
5181 (Q
.isUndefValue(Val
) && isGuaranteedNotToBePoison(Vec
)))
5184 // If we are extracting a value from a vector, then inserting it into the same
5185 // place, that's the input vector:
5186 // insertelt Vec, (extractelt Vec, Idx), Idx --> Vec
5187 if (match(Val
, m_ExtractElt(m_Specific(Vec
), m_Specific(Idx
))))
5193 /// Given operands for an ExtractValueInst, see if we can fold the result.
5194 /// If not, this returns null.
5195 static Value
*simplifyExtractValueInst(Value
*Agg
, ArrayRef
<unsigned> Idxs
,
5196 const SimplifyQuery
&, unsigned) {
5197 if (auto *CAgg
= dyn_cast
<Constant
>(Agg
))
5198 return ConstantFoldExtractValueInstruction(CAgg
, Idxs
);
5200 // extractvalue x, (insertvalue y, elt, n), n -> elt
5201 unsigned NumIdxs
= Idxs
.size();
5202 for (auto *IVI
= dyn_cast
<InsertValueInst
>(Agg
); IVI
!= nullptr;
5203 IVI
= dyn_cast
<InsertValueInst
>(IVI
->getAggregateOperand())) {
5204 ArrayRef
<unsigned> InsertValueIdxs
= IVI
->getIndices();
5205 unsigned NumInsertValueIdxs
= InsertValueIdxs
.size();
5206 unsigned NumCommonIdxs
= std::min(NumInsertValueIdxs
, NumIdxs
);
5207 if (InsertValueIdxs
.slice(0, NumCommonIdxs
) ==
5208 Idxs
.slice(0, NumCommonIdxs
)) {
5209 if (NumIdxs
== NumInsertValueIdxs
)
5210 return IVI
->getInsertedValueOperand();
5218 Value
*llvm::simplifyExtractValueInst(Value
*Agg
, ArrayRef
<unsigned> Idxs
,
5219 const SimplifyQuery
&Q
) {
5220 return ::simplifyExtractValueInst(Agg
, Idxs
, Q
, RecursionLimit
);
5223 /// Given operands for an ExtractElementInst, see if we can fold the result.
5224 /// If not, this returns null.
5225 static Value
*simplifyExtractElementInst(Value
*Vec
, Value
*Idx
,
5226 const SimplifyQuery
&Q
, unsigned) {
5227 auto *VecVTy
= cast
<VectorType
>(Vec
->getType());
5228 if (auto *CVec
= dyn_cast
<Constant
>(Vec
)) {
5229 if (auto *CIdx
= dyn_cast
<Constant
>(Idx
))
5230 return ConstantExpr::getExtractElement(CVec
, CIdx
);
5232 if (Q
.isUndefValue(Vec
))
5233 return UndefValue::get(VecVTy
->getElementType());
5236 // An undef extract index can be arbitrarily chosen to be an out-of-range
5237 // index value, which would result in the instruction being poison.
5238 if (Q
.isUndefValue(Idx
))
5239 return PoisonValue::get(VecVTy
->getElementType());
5241 // If extracting a specified index from the vector, see if we can recursively
5242 // find a previously computed scalar that was inserted into the vector.
5243 if (auto *IdxC
= dyn_cast
<ConstantInt
>(Idx
)) {
5244 // For fixed-length vector, fold into undef if index is out of bounds.
5245 unsigned MinNumElts
= VecVTy
->getElementCount().getKnownMinValue();
5246 if (isa
<FixedVectorType
>(VecVTy
) && IdxC
->getValue().uge(MinNumElts
))
5247 return PoisonValue::get(VecVTy
->getElementType());
5248 // Handle case where an element is extracted from a splat.
5249 if (IdxC
->getValue().ult(MinNumElts
))
5250 if (auto *Splat
= getSplatValue(Vec
))
5252 if (Value
*Elt
= findScalarElement(Vec
, IdxC
->getZExtValue()))
5255 // extractelt x, (insertelt y, elt, n), n -> elt
5256 // If the possibly-variable indices are trivially known to be equal
5257 // (because they are the same operand) then use the value that was
5258 // inserted directly.
5259 auto *IE
= dyn_cast
<InsertElementInst
>(Vec
);
5260 if (IE
&& IE
->getOperand(2) == Idx
)
5261 return IE
->getOperand(1);
5263 // The index is not relevant if our vector is a splat.
5264 if (Value
*Splat
= getSplatValue(Vec
))
5270 Value
*llvm::simplifyExtractElementInst(Value
*Vec
, Value
*Idx
,
5271 const SimplifyQuery
&Q
) {
5272 return ::simplifyExtractElementInst(Vec
, Idx
, Q
, RecursionLimit
);
5275 /// See if we can fold the given phi. If not, returns null.
5276 static Value
*simplifyPHINode(PHINode
*PN
, ArrayRef
<Value
*> IncomingValues
,
5277 const SimplifyQuery
&Q
) {
5278 // WARNING: no matter how worthwhile it may seem, we can not perform PHI CSE
5279 // here, because the PHI we may succeed simplifying to was not
5280 // def-reachable from the original PHI!
5282 // If all of the PHI's incoming values are the same then replace the PHI node
5283 // with the common value.
5284 Value
*CommonValue
= nullptr;
5285 bool HasPoisonInput
= false;
5286 bool HasUndefInput
= false;
5287 for (Value
*Incoming
: IncomingValues
) {
5288 // If the incoming value is the phi node itself, it can safely be skipped.
5291 if (isa
<PoisonValue
>(Incoming
)) {
5292 HasPoisonInput
= true;
5295 if (Q
.isUndefValue(Incoming
)) {
5296 // Remember that we saw an undef value, but otherwise ignore them.
5297 HasUndefInput
= true;
5300 if (CommonValue
&& Incoming
!= CommonValue
)
5301 return nullptr; // Not the same, bail out.
5302 CommonValue
= Incoming
;
5305 // If CommonValue is null then all of the incoming values were either undef,
5306 // poison or equal to the phi node itself.
5308 return HasUndefInput
? UndefValue::get(PN
->getType())
5309 : PoisonValue::get(PN
->getType());
5311 if (HasPoisonInput
|| HasUndefInput
) {
5312 // If we have a PHI node like phi(X, undef, X), where X is defined by some
5313 // instruction, we cannot return X as the result of the PHI node unless it
5314 // dominates the PHI block.
5315 return valueDominatesPHI(CommonValue
, PN
, Q
.DT
) ? CommonValue
: nullptr;
5321 static Value
*simplifyCastInst(unsigned CastOpc
, Value
*Op
, Type
*Ty
,
5322 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
5323 if (auto *C
= dyn_cast
<Constant
>(Op
))
5324 return ConstantFoldCastOperand(CastOpc
, C
, Ty
, Q
.DL
);
5326 if (auto *CI
= dyn_cast
<CastInst
>(Op
)) {
5327 auto *Src
= CI
->getOperand(0);
5328 Type
*SrcTy
= Src
->getType();
5329 Type
*MidTy
= CI
->getType();
5331 if (Src
->getType() == Ty
) {
5332 auto FirstOp
= static_cast<Instruction::CastOps
>(CI
->getOpcode());
5333 auto SecondOp
= static_cast<Instruction::CastOps
>(CastOpc
);
5335 SrcTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(SrcTy
) : nullptr;
5337 MidTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(MidTy
) : nullptr;
5339 DstTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(DstTy
) : nullptr;
5340 if (CastInst::isEliminableCastPair(FirstOp
, SecondOp
, SrcTy
, MidTy
, DstTy
,
5341 SrcIntPtrTy
, MidIntPtrTy
,
5342 DstIntPtrTy
) == Instruction::BitCast
)
5348 if (CastOpc
== Instruction::BitCast
)
5349 if (Op
->getType() == Ty
)
5352 // ptrtoint (ptradd (Ptr, X - ptrtoint(Ptr))) -> X
5354 if (CastOpc
== Instruction::PtrToInt
&&
5355 match(Op
, m_PtrAdd(m_Value(Ptr
),
5356 m_Sub(m_Value(X
), m_PtrToInt(m_Deferred(Ptr
))))) &&
5357 X
->getType() == Ty
&& Ty
== Q
.DL
.getIndexType(Ptr
->getType()))
5363 Value
*llvm::simplifyCastInst(unsigned CastOpc
, Value
*Op
, Type
*Ty
,
5364 const SimplifyQuery
&Q
) {
5365 return ::simplifyCastInst(CastOpc
, Op
, Ty
, Q
, RecursionLimit
);
5368 /// For the given destination element of a shuffle, peek through shuffles to
5369 /// match a root vector source operand that contains that element in the same
5370 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
5371 static Value
*foldIdentityShuffles(int DestElt
, Value
*Op0
, Value
*Op1
,
5372 int MaskVal
, Value
*RootVec
,
5373 unsigned MaxRecurse
) {
5377 // Bail out if any mask value is undefined. That kind of shuffle may be
5378 // simplified further based on demanded bits or other folds.
5382 // The mask value chooses which source operand we need to look at next.
5383 int InVecNumElts
= cast
<FixedVectorType
>(Op0
->getType())->getNumElements();
5384 int RootElt
= MaskVal
;
5385 Value
*SourceOp
= Op0
;
5386 if (MaskVal
>= InVecNumElts
) {
5387 RootElt
= MaskVal
- InVecNumElts
;
5391 // If the source operand is a shuffle itself, look through it to find the
5392 // matching root vector.
5393 if (auto *SourceShuf
= dyn_cast
<ShuffleVectorInst
>(SourceOp
)) {
5394 return foldIdentityShuffles(
5395 DestElt
, SourceShuf
->getOperand(0), SourceShuf
->getOperand(1),
5396 SourceShuf
->getMaskValue(RootElt
), RootVec
, MaxRecurse
);
5399 // The source operand is not a shuffle. Initialize the root vector value for
5400 // this shuffle if that has not been done yet.
5404 // Give up as soon as a source operand does not match the existing root value.
5405 if (RootVec
!= SourceOp
)
5408 // The element must be coming from the same lane in the source vector
5409 // (although it may have crossed lanes in intermediate shuffles).
5410 if (RootElt
!= DestElt
)
5416 static Value
*simplifyShuffleVectorInst(Value
*Op0
, Value
*Op1
,
5417 ArrayRef
<int> Mask
, Type
*RetTy
,
5418 const SimplifyQuery
&Q
,
5419 unsigned MaxRecurse
) {
5420 if (all_of(Mask
, [](int Elem
) { return Elem
== PoisonMaskElem
; }))
5421 return PoisonValue::get(RetTy
);
5423 auto *InVecTy
= cast
<VectorType
>(Op0
->getType());
5424 unsigned MaskNumElts
= Mask
.size();
5425 ElementCount InVecEltCount
= InVecTy
->getElementCount();
5427 bool Scalable
= InVecEltCount
.isScalable();
5429 SmallVector
<int, 32> Indices
;
5430 Indices
.assign(Mask
.begin(), Mask
.end());
5432 // Canonicalization: If mask does not select elements from an input vector,
5433 // replace that input vector with poison.
5435 bool MaskSelects0
= false, MaskSelects1
= false;
5436 unsigned InVecNumElts
= InVecEltCount
.getKnownMinValue();
5437 for (unsigned i
= 0; i
!= MaskNumElts
; ++i
) {
5438 if (Indices
[i
] == -1)
5440 if ((unsigned)Indices
[i
] < InVecNumElts
)
5441 MaskSelects0
= true;
5443 MaskSelects1
= true;
5446 Op0
= PoisonValue::get(InVecTy
);
5448 Op1
= PoisonValue::get(InVecTy
);
5451 auto *Op0Const
= dyn_cast
<Constant
>(Op0
);
5452 auto *Op1Const
= dyn_cast
<Constant
>(Op1
);
5454 // If all operands are constant, constant fold the shuffle. This
5455 // transformation depends on the value of the mask which is not known at
5456 // compile time for scalable vectors
5457 if (Op0Const
&& Op1Const
)
5458 return ConstantExpr::getShuffleVector(Op0Const
, Op1Const
, Mask
);
5460 // Canonicalization: if only one input vector is constant, it shall be the
5461 // second one. This transformation depends on the value of the mask which
5462 // is not known at compile time for scalable vectors
5463 if (!Scalable
&& Op0Const
&& !Op1Const
) {
5464 std::swap(Op0
, Op1
);
5465 ShuffleVectorInst::commuteShuffleMask(Indices
,
5466 InVecEltCount
.getKnownMinValue());
5469 // A splat of an inserted scalar constant becomes a vector constant:
5470 // shuf (inselt ?, C, IndexC), undef, <IndexC, IndexC...> --> <C, C...>
5471 // NOTE: We may have commuted above, so analyze the updated Indices, not the
5472 // original mask constant.
5473 // NOTE: This transformation depends on the value of the mask which is not
5474 // known at compile time for scalable vectors
5476 ConstantInt
*IndexC
;
5477 if (!Scalable
&& match(Op0
, m_InsertElt(m_Value(), m_Constant(C
),
5478 m_ConstantInt(IndexC
)))) {
5479 // Match a splat shuffle mask of the insert index allowing undef elements.
5480 int InsertIndex
= IndexC
->getZExtValue();
5481 if (all_of(Indices
, [InsertIndex
](int MaskElt
) {
5482 return MaskElt
== InsertIndex
|| MaskElt
== -1;
5484 assert(isa
<UndefValue
>(Op1
) && "Expected undef operand 1 for splat");
5486 // Shuffle mask poisons become poison constant result elements.
5487 SmallVector
<Constant
*, 16> VecC(MaskNumElts
, C
);
5488 for (unsigned i
= 0; i
!= MaskNumElts
; ++i
)
5489 if (Indices
[i
] == -1)
5490 VecC
[i
] = PoisonValue::get(C
->getType());
5491 return ConstantVector::get(VecC
);
5495 // A shuffle of a splat is always the splat itself. Legal if the shuffle's
5496 // value type is same as the input vectors' type.
5497 if (auto *OpShuf
= dyn_cast
<ShuffleVectorInst
>(Op0
))
5498 if (Q
.isUndefValue(Op1
) && RetTy
== InVecTy
&&
5499 all_equal(OpShuf
->getShuffleMask()))
5502 // All remaining transformation depend on the value of the mask, which is
5503 // not known at compile time for scalable vectors.
5507 // Don't fold a shuffle with undef mask elements. This may get folded in a
5508 // better way using demanded bits or other analysis.
5509 // TODO: Should we allow this?
5510 if (is_contained(Indices
, -1))
5513 // Check if every element of this shuffle can be mapped back to the
5514 // corresponding element of a single root vector. If so, we don't need this
5515 // shuffle. This handles simple identity shuffles as well as chains of
5516 // shuffles that may widen/narrow and/or move elements across lanes and back.
5517 Value
*RootVec
= nullptr;
5518 for (unsigned i
= 0; i
!= MaskNumElts
; ++i
) {
5519 // Note that recursion is limited for each vector element, so if any element
5520 // exceeds the limit, this will fail to simplify.
5522 foldIdentityShuffles(i
, Op0
, Op1
, Indices
[i
], RootVec
, MaxRecurse
);
5524 // We can't replace a widening/narrowing shuffle with one of its operands.
5525 if (!RootVec
|| RootVec
->getType() != RetTy
)
5531 /// Given operands for a ShuffleVectorInst, fold the result or return null.
5532 Value
*llvm::simplifyShuffleVectorInst(Value
*Op0
, Value
*Op1
,
5533 ArrayRef
<int> Mask
, Type
*RetTy
,
5534 const SimplifyQuery
&Q
) {
5535 return ::simplifyShuffleVectorInst(Op0
, Op1
, Mask
, RetTy
, Q
, RecursionLimit
);
5538 static Constant
*foldConstant(Instruction::UnaryOps Opcode
, Value
*&Op
,
5539 const SimplifyQuery
&Q
) {
5540 if (auto *C
= dyn_cast
<Constant
>(Op
))
5541 return ConstantFoldUnaryOpOperand(Opcode
, C
, Q
.DL
);
5545 /// Given the operand for an FNeg, see if we can fold the result. If not, this
5547 static Value
*simplifyFNegInst(Value
*Op
, FastMathFlags FMF
,
5548 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
5549 if (Constant
*C
= foldConstant(Instruction::FNeg
, Op
, Q
))
5553 // fneg (fneg X) ==> X
5554 if (match(Op
, m_FNeg(m_Value(X
))))
5560 Value
*llvm::simplifyFNegInst(Value
*Op
, FastMathFlags FMF
,
5561 const SimplifyQuery
&Q
) {
5562 return ::simplifyFNegInst(Op
, FMF
, Q
, RecursionLimit
);
5565 /// Try to propagate existing NaN values when possible. If not, replace the
5566 /// constant or elements in the constant with a canonical NaN.
5567 static Constant
*propagateNaN(Constant
*In
) {
5568 Type
*Ty
= In
->getType();
5569 if (auto *VecTy
= dyn_cast
<FixedVectorType
>(Ty
)) {
5570 unsigned NumElts
= VecTy
->getNumElements();
5571 SmallVector
<Constant
*, 32> NewC(NumElts
);
5572 for (unsigned i
= 0; i
!= NumElts
; ++i
) {
5573 Constant
*EltC
= In
->getAggregateElement(i
);
5574 // Poison elements propagate. NaN propagates except signaling is quieted.
5575 // Replace unknown or undef elements with canonical NaN.
5576 if (EltC
&& isa
<PoisonValue
>(EltC
))
5578 else if (EltC
&& EltC
->isNaN())
5579 NewC
[i
] = ConstantFP::get(
5580 EltC
->getType(), cast
<ConstantFP
>(EltC
)->getValue().makeQuiet());
5582 NewC
[i
] = ConstantFP::getNaN(VecTy
->getElementType());
5584 return ConstantVector::get(NewC
);
5587 // If it is not a fixed vector, but not a simple NaN either, return a
5590 return ConstantFP::getNaN(Ty
);
5592 // If we known this is a NaN, and it's scalable vector, we must have a splat
5593 // on our hands. Grab that before splatting a QNaN constant.
5594 if (isa
<ScalableVectorType
>(Ty
)) {
5595 auto *Splat
= In
->getSplatValue();
5596 assert(Splat
&& Splat
->isNaN() &&
5597 "Found a scalable-vector NaN but not a splat");
5601 // Propagate an existing QNaN constant. If it is an SNaN, make it quiet, but
5602 // preserve the sign/payload.
5603 return ConstantFP::get(Ty
, cast
<ConstantFP
>(In
)->getValue().makeQuiet());
5606 /// Perform folds that are common to any floating-point operation. This implies
5607 /// transforms based on poison/undef/NaN because the operation itself makes no
5608 /// difference to the result.
5609 static Constant
*simplifyFPOp(ArrayRef
<Value
*> Ops
, FastMathFlags FMF
,
5610 const SimplifyQuery
&Q
,
5611 fp::ExceptionBehavior ExBehavior
,
5612 RoundingMode Rounding
) {
5613 // Poison is independent of anything else. It always propagates from an
5614 // operand to a math result.
5615 if (any_of(Ops
, [](Value
*V
) { return match(V
, m_Poison()); }))
5616 return PoisonValue::get(Ops
[0]->getType());
5618 for (Value
*V
: Ops
) {
5619 bool IsNan
= match(V
, m_NaN());
5620 bool IsInf
= match(V
, m_Inf());
5621 bool IsUndef
= Q
.isUndefValue(V
);
5623 // If this operation has 'nnan' or 'ninf' and at least 1 disallowed operand
5624 // (an undef operand can be chosen to be Nan/Inf), then the result of
5625 // this operation is poison.
5626 if (FMF
.noNaNs() && (IsNan
|| IsUndef
))
5627 return PoisonValue::get(V
->getType());
5628 if (FMF
.noInfs() && (IsInf
|| IsUndef
))
5629 return PoisonValue::get(V
->getType());
5631 if (isDefaultFPEnvironment(ExBehavior
, Rounding
)) {
5632 // Undef does not propagate because undef means that all bits can take on
5633 // any value. If this is undef * NaN for example, then the result values
5634 // (at least the exponent bits) are limited. Assume the undef is a
5635 // canonical NaN and propagate that.
5637 return ConstantFP::getNaN(V
->getType());
5639 return propagateNaN(cast
<Constant
>(V
));
5640 } else if (ExBehavior
!= fp::ebStrict
) {
5642 return propagateNaN(cast
<Constant
>(V
));
5648 /// Given operands for an FAdd, see if we can fold the result. If not, this
5651 simplifyFAddInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5652 const SimplifyQuery
&Q
, unsigned MaxRecurse
,
5653 fp::ExceptionBehavior ExBehavior
= fp::ebIgnore
,
5654 RoundingMode Rounding
= RoundingMode::NearestTiesToEven
) {
5655 if (isDefaultFPEnvironment(ExBehavior
, Rounding
))
5656 if (Constant
*C
= foldOrCommuteConstant(Instruction::FAdd
, Op0
, Op1
, Q
))
5659 if (Constant
*C
= simplifyFPOp({Op0
, Op1
}, FMF
, Q
, ExBehavior
, Rounding
))
5663 // With strict/constrained FP, we have these possible edge cases that do
5664 // not simplify to Op0:
5665 // fadd SNaN, -0.0 --> QNaN
5666 // fadd +0.0, -0.0 --> -0.0 (but only with round toward negative)
5667 if (canIgnoreSNaN(ExBehavior
, FMF
) &&
5668 (!canRoundingModeBe(Rounding
, RoundingMode::TowardNegative
) ||
5669 FMF
.noSignedZeros()))
5670 if (match(Op1
, m_NegZeroFP()))
5673 // fadd X, 0 ==> X, when we know X is not -0
5674 if (canIgnoreSNaN(ExBehavior
, FMF
))
5675 if (match(Op1
, m_PosZeroFP()) &&
5676 (FMF
.noSignedZeros() || cannotBeNegativeZero(Op0
, /*Depth=*/0, Q
)))
5679 if (!isDefaultFPEnvironment(ExBehavior
, Rounding
))
5683 // With nnan: X + {+/-}Inf --> {+/-}Inf
5684 if (match(Op1
, m_Inf()))
5687 // With nnan: -X + X --> 0.0 (and commuted variant)
5688 // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
5689 // Negative zeros are allowed because we always end up with positive zero:
5690 // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
5691 // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
5692 // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
5693 // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
5694 if (match(Op0
, m_FSub(m_AnyZeroFP(), m_Specific(Op1
))) ||
5695 match(Op1
, m_FSub(m_AnyZeroFP(), m_Specific(Op0
))))
5696 return ConstantFP::getZero(Op0
->getType());
5698 if (match(Op0
, m_FNeg(m_Specific(Op1
))) ||
5699 match(Op1
, m_FNeg(m_Specific(Op0
))))
5700 return ConstantFP::getZero(Op0
->getType());
5703 // (X - Y) + Y --> X
5704 // Y + (X - Y) --> X
5706 if (FMF
.noSignedZeros() && FMF
.allowReassoc() &&
5707 (match(Op0
, m_FSub(m_Value(X
), m_Specific(Op1
))) ||
5708 match(Op1
, m_FSub(m_Value(X
), m_Specific(Op0
)))))
5714 /// Given operands for an FSub, see if we can fold the result. If not, this
5717 simplifyFSubInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5718 const SimplifyQuery
&Q
, unsigned MaxRecurse
,
5719 fp::ExceptionBehavior ExBehavior
= fp::ebIgnore
,
5720 RoundingMode Rounding
= RoundingMode::NearestTiesToEven
) {
5721 if (isDefaultFPEnvironment(ExBehavior
, Rounding
))
5722 if (Constant
*C
= foldOrCommuteConstant(Instruction::FSub
, Op0
, Op1
, Q
))
5725 if (Constant
*C
= simplifyFPOp({Op0
, Op1
}, FMF
, Q
, ExBehavior
, Rounding
))
5729 if (canIgnoreSNaN(ExBehavior
, FMF
) &&
5730 (!canRoundingModeBe(Rounding
, RoundingMode::TowardNegative
) ||
5731 FMF
.noSignedZeros()))
5732 if (match(Op1
, m_PosZeroFP()))
5735 // fsub X, -0 ==> X, when we know X is not -0
5736 if (canIgnoreSNaN(ExBehavior
, FMF
))
5737 if (match(Op1
, m_NegZeroFP()) &&
5738 (FMF
.noSignedZeros() || cannotBeNegativeZero(Op0
, /*Depth=*/0, Q
)))
5741 // fsub -0.0, (fsub -0.0, X) ==> X
5742 // fsub -0.0, (fneg X) ==> X
5744 if (canIgnoreSNaN(ExBehavior
, FMF
))
5745 if (match(Op0
, m_NegZeroFP()) && match(Op1
, m_FNeg(m_Value(X
))))
5748 // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
5749 // fsub 0.0, (fneg X) ==> X if signed zeros are ignored.
5750 if (canIgnoreSNaN(ExBehavior
, FMF
))
5751 if (FMF
.noSignedZeros() && match(Op0
, m_AnyZeroFP()) &&
5752 (match(Op1
, m_FSub(m_AnyZeroFP(), m_Value(X
))) ||
5753 match(Op1
, m_FNeg(m_Value(X
)))))
5756 if (!isDefaultFPEnvironment(ExBehavior
, Rounding
))
5760 // fsub nnan x, x ==> 0.0
5762 return Constant::getNullValue(Op0
->getType());
5764 // With nnan: {+/-}Inf - X --> {+/-}Inf
5765 if (match(Op0
, m_Inf()))
5768 // With nnan: X - {+/-}Inf --> {-/+}Inf
5769 if (match(Op1
, m_Inf()))
5770 return foldConstant(Instruction::FNeg
, Op1
, Q
);
5773 // Y - (Y - X) --> X
5774 // (X + Y) - Y --> X
5775 if (FMF
.noSignedZeros() && FMF
.allowReassoc() &&
5776 (match(Op1
, m_FSub(m_Specific(Op0
), m_Value(X
))) ||
5777 match(Op0
, m_c_FAdd(m_Specific(Op1
), m_Value(X
)))))
5783 static Value
*simplifyFMAFMul(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5784 const SimplifyQuery
&Q
, unsigned MaxRecurse
,
5785 fp::ExceptionBehavior ExBehavior
,
5786 RoundingMode Rounding
) {
5787 if (Constant
*C
= simplifyFPOp({Op0
, Op1
}, FMF
, Q
, ExBehavior
, Rounding
))
5790 if (!isDefaultFPEnvironment(ExBehavior
, Rounding
))
5793 // Canonicalize special constants as operand 1.
5794 if (match(Op0
, m_FPOne()) || match(Op0
, m_AnyZeroFP()))
5795 std::swap(Op0
, Op1
);
5798 if (match(Op1
, m_FPOne()))
5801 if (match(Op1
, m_AnyZeroFP())) {
5802 // X * 0.0 --> 0.0 (with nnan and nsz)
5803 if (FMF
.noNaNs() && FMF
.noSignedZeros())
5804 return ConstantFP::getZero(Op0
->getType());
5806 KnownFPClass Known
=
5807 computeKnownFPClass(Op0
, FMF
, fcInf
| fcNan
, /*Depth=*/0, Q
);
5808 if (Known
.isKnownNever(fcInf
| fcNan
)) {
5809 // +normal number * (-)0.0 --> (-)0.0
5810 if (Known
.SignBit
== false)
5812 // -normal number * (-)0.0 --> -(-)0.0
5813 if (Known
.SignBit
== true)
5814 return foldConstant(Instruction::FNeg
, Op1
, Q
);
5818 // sqrt(X) * sqrt(X) --> X, if we can:
5819 // 1. Remove the intermediate rounding (reassociate).
5820 // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
5821 // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
5823 if (Op0
== Op1
&& match(Op0
, m_Sqrt(m_Value(X
))) && FMF
.allowReassoc() &&
5824 FMF
.noNaNs() && FMF
.noSignedZeros())
5830 /// Given the operands for an FMul, see if we can fold the result
5832 simplifyFMulInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5833 const SimplifyQuery
&Q
, unsigned MaxRecurse
,
5834 fp::ExceptionBehavior ExBehavior
= fp::ebIgnore
,
5835 RoundingMode Rounding
= RoundingMode::NearestTiesToEven
) {
5836 if (isDefaultFPEnvironment(ExBehavior
, Rounding
))
5837 if (Constant
*C
= foldOrCommuteConstant(Instruction::FMul
, Op0
, Op1
, Q
))
5840 // Now apply simplifications that do not require rounding.
5841 return simplifyFMAFMul(Op0
, Op1
, FMF
, Q
, MaxRecurse
, ExBehavior
, Rounding
);
5844 Value
*llvm::simplifyFAddInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5845 const SimplifyQuery
&Q
,
5846 fp::ExceptionBehavior ExBehavior
,
5847 RoundingMode Rounding
) {
5848 return ::simplifyFAddInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5852 Value
*llvm::simplifyFSubInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5853 const SimplifyQuery
&Q
,
5854 fp::ExceptionBehavior ExBehavior
,
5855 RoundingMode Rounding
) {
5856 return ::simplifyFSubInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5860 Value
*llvm::simplifyFMulInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5861 const SimplifyQuery
&Q
,
5862 fp::ExceptionBehavior ExBehavior
,
5863 RoundingMode Rounding
) {
5864 return ::simplifyFMulInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5868 Value
*llvm::simplifyFMAFMul(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5869 const SimplifyQuery
&Q
,
5870 fp::ExceptionBehavior ExBehavior
,
5871 RoundingMode Rounding
) {
5872 return ::simplifyFMAFMul(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5877 simplifyFDivInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5878 const SimplifyQuery
&Q
, unsigned,
5879 fp::ExceptionBehavior ExBehavior
= fp::ebIgnore
,
5880 RoundingMode Rounding
= RoundingMode::NearestTiesToEven
) {
5881 if (isDefaultFPEnvironment(ExBehavior
, Rounding
))
5882 if (Constant
*C
= foldOrCommuteConstant(Instruction::FDiv
, Op0
, Op1
, Q
))
5885 if (Constant
*C
= simplifyFPOp({Op0
, Op1
}, FMF
, Q
, ExBehavior
, Rounding
))
5888 if (!isDefaultFPEnvironment(ExBehavior
, Rounding
))
5892 if (match(Op1
, m_FPOne()))
5896 // Requires that NaNs are off (X could be zero) and signed zeroes are
5897 // ignored (X could be positive or negative, so the output sign is unknown).
5898 if (FMF
.noNaNs() && FMF
.noSignedZeros() && match(Op0
, m_AnyZeroFP()))
5899 return ConstantFP::getZero(Op0
->getType());
5902 // X / X -> 1.0 is legal when NaNs are ignored.
5903 // We can ignore infinities because INF/INF is NaN.
5905 return ConstantFP::get(Op0
->getType(), 1.0);
5907 // (X * Y) / Y --> X if we can reassociate to the above form.
5909 if (FMF
.allowReassoc() && match(Op0
, m_c_FMul(m_Value(X
), m_Specific(Op1
))))
5912 // -X / X -> -1.0 and
5913 // X / -X -> -1.0 are legal when NaNs are ignored.
5914 // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
5915 if (match(Op0
, m_FNegNSZ(m_Specific(Op1
))) ||
5916 match(Op1
, m_FNegNSZ(m_Specific(Op0
))))
5917 return ConstantFP::get(Op0
->getType(), -1.0);
5919 // nnan ninf X / [-]0.0 -> poison
5920 if (FMF
.noInfs() && match(Op1
, m_AnyZeroFP()))
5921 return PoisonValue::get(Op1
->getType());
5927 Value
*llvm::simplifyFDivInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5928 const SimplifyQuery
&Q
,
5929 fp::ExceptionBehavior ExBehavior
,
5930 RoundingMode Rounding
) {
5931 return ::simplifyFDivInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5936 simplifyFRemInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5937 const SimplifyQuery
&Q
, unsigned,
5938 fp::ExceptionBehavior ExBehavior
= fp::ebIgnore
,
5939 RoundingMode Rounding
= RoundingMode::NearestTiesToEven
) {
5940 if (isDefaultFPEnvironment(ExBehavior
, Rounding
))
5941 if (Constant
*C
= foldOrCommuteConstant(Instruction::FRem
, Op0
, Op1
, Q
))
5944 if (Constant
*C
= simplifyFPOp({Op0
, Op1
}, FMF
, Q
, ExBehavior
, Rounding
))
5947 if (!isDefaultFPEnvironment(ExBehavior
, Rounding
))
5950 // Unlike fdiv, the result of frem always matches the sign of the dividend.
5951 // The constant match may include undef elements in a vector, so return a full
5952 // zero constant as the result.
5955 if (match(Op0
, m_PosZeroFP()))
5956 return ConstantFP::getZero(Op0
->getType());
5958 if (match(Op0
, m_NegZeroFP()))
5959 return ConstantFP::getNegativeZero(Op0
->getType());
5965 Value
*llvm::simplifyFRemInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
5966 const SimplifyQuery
&Q
,
5967 fp::ExceptionBehavior ExBehavior
,
5968 RoundingMode Rounding
) {
5969 return ::simplifyFRemInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
, ExBehavior
,
5973 //=== Helper functions for higher up the class hierarchy.
5975 /// Given the operand for a UnaryOperator, see if we can fold the result.
5976 /// If not, this returns null.
5977 static Value
*simplifyUnOp(unsigned Opcode
, Value
*Op
, const SimplifyQuery
&Q
,
5978 unsigned MaxRecurse
) {
5980 case Instruction::FNeg
:
5981 return simplifyFNegInst(Op
, FastMathFlags(), Q
, MaxRecurse
);
5983 llvm_unreachable("Unexpected opcode");
5987 /// Given the operand for a UnaryOperator, see if we can fold the result.
5988 /// If not, this returns null.
5989 /// Try to use FastMathFlags when folding the result.
5990 static Value
*simplifyFPUnOp(unsigned Opcode
, Value
*Op
,
5991 const FastMathFlags
&FMF
, const SimplifyQuery
&Q
,
5992 unsigned MaxRecurse
) {
5994 case Instruction::FNeg
:
5995 return simplifyFNegInst(Op
, FMF
, Q
, MaxRecurse
);
5997 return simplifyUnOp(Opcode
, Op
, Q
, MaxRecurse
);
6001 Value
*llvm::simplifyUnOp(unsigned Opcode
, Value
*Op
, const SimplifyQuery
&Q
) {
6002 return ::simplifyUnOp(Opcode
, Op
, Q
, RecursionLimit
);
6005 Value
*llvm::simplifyUnOp(unsigned Opcode
, Value
*Op
, FastMathFlags FMF
,
6006 const SimplifyQuery
&Q
) {
6007 return ::simplifyFPUnOp(Opcode
, Op
, FMF
, Q
, RecursionLimit
);
6010 /// Given operands for a BinaryOperator, see if we can fold the result.
6011 /// If not, this returns null.
6012 static Value
*simplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
6013 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
6015 case Instruction::Add
:
6016 return simplifyAddInst(LHS
, RHS
, /* IsNSW */ false, /* IsNUW */ false, Q
,
6018 case Instruction::Sub
:
6019 return simplifySubInst(LHS
, RHS
, /* IsNSW */ false, /* IsNUW */ false, Q
,
6021 case Instruction::Mul
:
6022 return simplifyMulInst(LHS
, RHS
, /* IsNSW */ false, /* IsNUW */ false, Q
,
6024 case Instruction::SDiv
:
6025 return simplifySDivInst(LHS
, RHS
, /* IsExact */ false, Q
, MaxRecurse
);
6026 case Instruction::UDiv
:
6027 return simplifyUDivInst(LHS
, RHS
, /* IsExact */ false, Q
, MaxRecurse
);
6028 case Instruction::SRem
:
6029 return simplifySRemInst(LHS
, RHS
, Q
, MaxRecurse
);
6030 case Instruction::URem
:
6031 return simplifyURemInst(LHS
, RHS
, Q
, MaxRecurse
);
6032 case Instruction::Shl
:
6033 return simplifyShlInst(LHS
, RHS
, /* IsNSW */ false, /* IsNUW */ false, Q
,
6035 case Instruction::LShr
:
6036 return simplifyLShrInst(LHS
, RHS
, /* IsExact */ false, Q
, MaxRecurse
);
6037 case Instruction::AShr
:
6038 return simplifyAShrInst(LHS
, RHS
, /* IsExact */ false, Q
, MaxRecurse
);
6039 case Instruction::And
:
6040 return simplifyAndInst(LHS
, RHS
, Q
, MaxRecurse
);
6041 case Instruction::Or
:
6042 return simplifyOrInst(LHS
, RHS
, Q
, MaxRecurse
);
6043 case Instruction::Xor
:
6044 return simplifyXorInst(LHS
, RHS
, Q
, MaxRecurse
);
6045 case Instruction::FAdd
:
6046 return simplifyFAddInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6047 case Instruction::FSub
:
6048 return simplifyFSubInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6049 case Instruction::FMul
:
6050 return simplifyFMulInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6051 case Instruction::FDiv
:
6052 return simplifyFDivInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6053 case Instruction::FRem
:
6054 return simplifyFRemInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6056 llvm_unreachable("Unexpected opcode");
6060 /// Given operands for a BinaryOperator, see if we can fold the result.
6061 /// If not, this returns null.
6062 /// Try to use FastMathFlags when folding the result.
6063 static Value
*simplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
6064 const FastMathFlags
&FMF
, const SimplifyQuery
&Q
,
6065 unsigned MaxRecurse
) {
6067 case Instruction::FAdd
:
6068 return simplifyFAddInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
6069 case Instruction::FSub
:
6070 return simplifyFSubInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
6071 case Instruction::FMul
:
6072 return simplifyFMulInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
6073 case Instruction::FDiv
:
6074 return simplifyFDivInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
6076 return simplifyBinOp(Opcode
, LHS
, RHS
, Q
, MaxRecurse
);
6080 Value
*llvm::simplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
6081 const SimplifyQuery
&Q
) {
6082 return ::simplifyBinOp(Opcode
, LHS
, RHS
, Q
, RecursionLimit
);
6085 Value
*llvm::simplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
6086 FastMathFlags FMF
, const SimplifyQuery
&Q
) {
6087 return ::simplifyBinOp(Opcode
, LHS
, RHS
, FMF
, Q
, RecursionLimit
);
6090 /// Given operands for a CmpInst, see if we can fold the result.
6091 static Value
*simplifyCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
6092 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
6093 if (CmpInst::isIntPredicate((CmpInst::Predicate
)Predicate
))
6094 return simplifyICmpInst(Predicate
, LHS
, RHS
, Q
, MaxRecurse
);
6095 return simplifyFCmpInst(Predicate
, LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
6098 Value
*llvm::simplifyCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
6099 const SimplifyQuery
&Q
) {
6100 return ::simplifyCmpInst(Predicate
, LHS
, RHS
, Q
, RecursionLimit
);
6103 static bool isIdempotent(Intrinsic::ID ID
) {
6108 // Unary idempotent: f(f(x)) = f(x)
6109 case Intrinsic::fabs
:
6110 case Intrinsic::floor
:
6111 case Intrinsic::ceil
:
6112 case Intrinsic::trunc
:
6113 case Intrinsic::rint
:
6114 case Intrinsic::nearbyint
:
6115 case Intrinsic::round
:
6116 case Intrinsic::roundeven
:
6117 case Intrinsic::canonicalize
:
6118 case Intrinsic::arithmetic_fence
:
6123 /// Return true if the intrinsic rounds a floating-point value to an integral
6124 /// floating-point value (not an integer type).
6125 static bool removesFPFraction(Intrinsic::ID ID
) {
6130 case Intrinsic::floor
:
6131 case Intrinsic::ceil
:
6132 case Intrinsic::trunc
:
6133 case Intrinsic::rint
:
6134 case Intrinsic::nearbyint
:
6135 case Intrinsic::round
:
6136 case Intrinsic::roundeven
:
6141 static Value
*simplifyRelativeLoad(Constant
*Ptr
, Constant
*Offset
,
6142 const DataLayout
&DL
) {
6143 GlobalValue
*PtrSym
;
6145 if (!IsConstantOffsetFromGlobal(Ptr
, PtrSym
, PtrOffset
, DL
))
6148 Type
*Int32Ty
= Type::getInt32Ty(Ptr
->getContext());
6150 auto *OffsetConstInt
= dyn_cast
<ConstantInt
>(Offset
);
6151 if (!OffsetConstInt
|| OffsetConstInt
->getBitWidth() > 64)
6154 APInt OffsetInt
= OffsetConstInt
->getValue().sextOrTrunc(
6155 DL
.getIndexTypeSizeInBits(Ptr
->getType()));
6156 if (OffsetInt
.srem(4) != 0)
6160 ConstantFoldLoadFromConstPtr(Ptr
, Int32Ty
, std::move(OffsetInt
), DL
);
6164 auto *LoadedCE
= dyn_cast
<ConstantExpr
>(Loaded
);
6168 if (LoadedCE
->getOpcode() == Instruction::Trunc
) {
6169 LoadedCE
= dyn_cast
<ConstantExpr
>(LoadedCE
->getOperand(0));
6174 if (LoadedCE
->getOpcode() != Instruction::Sub
)
6177 auto *LoadedLHS
= dyn_cast
<ConstantExpr
>(LoadedCE
->getOperand(0));
6178 if (!LoadedLHS
|| LoadedLHS
->getOpcode() != Instruction::PtrToInt
)
6180 auto *LoadedLHSPtr
= LoadedLHS
->getOperand(0);
6182 Constant
*LoadedRHS
= LoadedCE
->getOperand(1);
6183 GlobalValue
*LoadedRHSSym
;
6184 APInt LoadedRHSOffset
;
6185 if (!IsConstantOffsetFromGlobal(LoadedRHS
, LoadedRHSSym
, LoadedRHSOffset
,
6187 PtrSym
!= LoadedRHSSym
|| PtrOffset
!= LoadedRHSOffset
)
6190 return LoadedLHSPtr
;
6193 // TODO: Need to pass in FastMathFlags
6194 static Value
*simplifyLdexp(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
6196 // ldexp(poison, x) -> poison
6197 // ldexp(x, poison) -> poison
6198 if (isa
<PoisonValue
>(Op0
) || isa
<PoisonValue
>(Op1
))
6201 // ldexp(undef, x) -> nan
6202 if (Q
.isUndefValue(Op0
))
6203 return ConstantFP::getNaN(Op0
->getType());
6206 // TODO: Could insert a canonicalize for strict
6208 // ldexp(x, undef) -> x
6209 if (Q
.isUndefValue(Op1
))
6213 const APFloat
*C
= nullptr;
6214 match(Op0
, PatternMatch::m_APFloat(C
));
6216 // These cases should be safe, even with strictfp.
6217 // ldexp(0.0, x) -> 0.0
6218 // ldexp(-0.0, x) -> -0.0
6219 // ldexp(inf, x) -> inf
6220 // ldexp(-inf, x) -> -inf
6221 if (C
&& (C
->isZero() || C
->isInfinity()))
6224 // These are canonicalization dropping, could do it if we knew how we could
6225 // ignore denormal flushes and target handling of nan payload bits.
6229 // TODO: Could quiet this with strictfp if the exception mode isn't strict.
6230 if (C
&& C
->isNaN())
6231 return ConstantFP::get(Op0
->getType(), C
->makeQuiet());
6235 // TODO: Could fold this if we know the exception mode isn't
6236 // strict, we know the denormal mode and other target modes.
6237 if (match(Op1
, PatternMatch::m_ZeroInt()))
6243 static Value
*simplifyUnaryIntrinsic(Function
*F
, Value
*Op0
,
6244 const SimplifyQuery
&Q
,
6245 const CallBase
*Call
) {
6246 // Idempotent functions return the same result when called repeatedly.
6247 Intrinsic::ID IID
= F
->getIntrinsicID();
6248 if (isIdempotent(IID
))
6249 if (auto *II
= dyn_cast
<IntrinsicInst
>(Op0
))
6250 if (II
->getIntrinsicID() == IID
)
6253 if (removesFPFraction(IID
)) {
6254 // Converting from int or calling a rounding function always results in a
6255 // finite integral number or infinity. For those inputs, rounding functions
6256 // always return the same value, so the (2nd) rounding is eliminated. Ex:
6257 // floor (sitofp x) -> sitofp x
6258 // round (ceil x) -> ceil x
6259 auto *II
= dyn_cast
<IntrinsicInst
>(Op0
);
6260 if ((II
&& removesFPFraction(II
->getIntrinsicID())) ||
6261 match(Op0
, m_SIToFP(m_Value())) || match(Op0
, m_UIToFP(m_Value())))
6267 case Intrinsic::fabs
:
6268 if (computeKnownFPSignBit(Op0
, /*Depth=*/0, Q
) == false)
6271 case Intrinsic::bswap
:
6272 // bswap(bswap(x)) -> x
6273 if (match(Op0
, m_BSwap(m_Value(X
))))
6276 case Intrinsic::bitreverse
:
6277 // bitreverse(bitreverse(x)) -> x
6278 if (match(Op0
, m_BitReverse(m_Value(X
))))
6281 case Intrinsic::ctpop
: {
6282 // ctpop(X) -> 1 iff X is non-zero power of 2.
6283 if (isKnownToBeAPowerOfTwo(Op0
, Q
.DL
, /*OrZero*/ false, 0, Q
.AC
, Q
.CxtI
,
6285 return ConstantInt::get(Op0
->getType(), 1);
6286 // If everything but the lowest bit is zero, that bit is the pop-count. Ex:
6287 // ctpop(and X, 1) --> and X, 1
6288 unsigned BitWidth
= Op0
->getType()->getScalarSizeInBits();
6289 if (MaskedValueIsZero(Op0
, APInt::getHighBitsSet(BitWidth
, BitWidth
- 1),
6294 case Intrinsic::exp
:
6296 if (Call
->hasAllowReassoc() &&
6297 match(Op0
, m_Intrinsic
<Intrinsic::log
>(m_Value(X
))))
6300 case Intrinsic::exp2
:
6301 // exp2(log2(x)) -> x
6302 if (Call
->hasAllowReassoc() &&
6303 match(Op0
, m_Intrinsic
<Intrinsic::log2
>(m_Value(X
))))
6306 case Intrinsic::exp10
:
6307 // exp10(log10(x)) -> x
6308 if (Call
->hasAllowReassoc() &&
6309 match(Op0
, m_Intrinsic
<Intrinsic::log10
>(m_Value(X
))))
6312 case Intrinsic::log
:
6314 if (Call
->hasAllowReassoc() &&
6315 match(Op0
, m_Intrinsic
<Intrinsic::exp
>(m_Value(X
))))
6318 case Intrinsic::log2
:
6319 // log2(exp2(x)) -> x
6320 if (Call
->hasAllowReassoc() &&
6321 (match(Op0
, m_Intrinsic
<Intrinsic::exp2
>(m_Value(X
))) ||
6323 m_Intrinsic
<Intrinsic::pow
>(m_SpecificFP(2.0), m_Value(X
)))))
6326 case Intrinsic::log10
:
6327 // log10(pow(10.0, x)) -> x
6328 // log10(exp10(x)) -> x
6329 if (Call
->hasAllowReassoc() &&
6330 (match(Op0
, m_Intrinsic
<Intrinsic::exp10
>(m_Value(X
))) ||
6332 m_Intrinsic
<Intrinsic::pow
>(m_SpecificFP(10.0), m_Value(X
)))))
6335 case Intrinsic::vector_reverse
:
6336 // vector.reverse(vector.reverse(x)) -> x
6337 if (match(Op0
, m_VecReverse(m_Value(X
))))
6339 // vector.reverse(splat(X)) -> splat(X)
6340 if (isSplatValue(Op0
))
6343 case Intrinsic::frexp
: {
6344 // Frexp is idempotent with the added complication of the struct return.
6345 if (match(Op0
, m_ExtractValue
<0>(m_Value(X
)))) {
6346 if (match(X
, m_Intrinsic
<Intrinsic::frexp
>(m_Value())))
6359 /// Given a min/max intrinsic, see if it can be removed based on having an
6360 /// operand that is another min/max intrinsic with shared operand(s). The caller
6361 /// is expected to swap the operand arguments to handle commutation.
6362 static Value
*foldMinMaxSharedOp(Intrinsic::ID IID
, Value
*Op0
, Value
*Op1
) {
6364 if (!match(Op0
, m_MaxOrMin(m_Value(X
), m_Value(Y
))))
6367 auto *MM0
= dyn_cast
<IntrinsicInst
>(Op0
);
6370 Intrinsic::ID IID0
= MM0
->getIntrinsicID();
6372 if (Op1
== X
|| Op1
== Y
||
6373 match(Op1
, m_c_MaxOrMin(m_Specific(X
), m_Specific(Y
)))) {
6374 // max (max X, Y), X --> max X, Y
6377 // max (min X, Y), X --> X
6378 if (IID0
== getInverseMinMaxIntrinsic(IID
))
6384 /// Given a min/max intrinsic, see if it can be removed based on having an
6385 /// operand that is another min/max intrinsic with shared operand(s). The caller
6386 /// is expected to swap the operand arguments to handle commutation.
6387 static Value
*foldMinimumMaximumSharedOp(Intrinsic::ID IID
, Value
*Op0
,
6389 assert((IID
== Intrinsic::maxnum
|| IID
== Intrinsic::minnum
||
6390 IID
== Intrinsic::maximum
|| IID
== Intrinsic::minimum
) &&
6391 "Unsupported intrinsic");
6393 auto *M0
= dyn_cast
<IntrinsicInst
>(Op0
);
6394 // If Op0 is not the same intrinsic as IID, do not process.
6395 // This is a difference with integer min/max handling. We do not process the
6396 // case like max(min(X,Y),min(X,Y)) => min(X,Y). But it can be handled by GVN.
6397 if (!M0
|| M0
->getIntrinsicID() != IID
)
6399 Value
*X0
= M0
->getOperand(0);
6400 Value
*Y0
= M0
->getOperand(1);
6401 // Simple case, m(m(X,Y), X) => m(X, Y)
6402 // m(m(X,Y), Y) => m(X, Y)
6403 // For minimum/maximum, X is NaN => m(NaN, Y) == NaN and m(NaN, NaN) == NaN.
6404 // For minimum/maximum, Y is NaN => m(X, NaN) == NaN and m(NaN, NaN) == NaN.
6405 // For minnum/maxnum, X is NaN => m(NaN, Y) == Y and m(Y, Y) == Y.
6406 // For minnum/maxnum, Y is NaN => m(X, NaN) == X and m(X, NaN) == X.
6407 if (X0
== Op1
|| Y0
== Op1
)
6410 auto *M1
= dyn_cast
<IntrinsicInst
>(Op1
);
6413 Value
*X1
= M1
->getOperand(0);
6414 Value
*Y1
= M1
->getOperand(1);
6415 Intrinsic::ID IID1
= M1
->getIntrinsicID();
6416 // we have a case m(m(X,Y),m'(X,Y)) taking into account m' is commutative.
6417 // if m' is m or inversion of m => m(m(X,Y),m'(X,Y)) == m(X,Y).
6418 // For minimum/maximum, X is NaN => m(NaN,Y) == m'(NaN, Y) == NaN.
6419 // For minimum/maximum, Y is NaN => m(X,NaN) == m'(X, NaN) == NaN.
6420 // For minnum/maxnum, X is NaN => m(NaN,Y) == m'(NaN, Y) == Y.
6421 // For minnum/maxnum, Y is NaN => m(X,NaN) == m'(X, NaN) == X.
6422 if ((X0
== X1
&& Y0
== Y1
) || (X0
== Y1
&& Y0
== X1
))
6423 if (IID1
== IID
|| getInverseMinMaxIntrinsic(IID1
) == IID
)
6429 Value
*llvm::simplifyBinaryIntrinsic(Intrinsic::ID IID
, Type
*ReturnType
,
6430 Value
*Op0
, Value
*Op1
,
6431 const SimplifyQuery
&Q
,
6432 const CallBase
*Call
) {
6433 unsigned BitWidth
= ReturnType
->getScalarSizeInBits();
6435 case Intrinsic::abs
:
6436 // abs(abs(x)) -> abs(x). We don't need to worry about the nsw arg here.
6437 // It is always ok to pick the earlier abs. We'll just lose nsw if its only
6438 // on the outer abs.
6439 if (match(Op0
, m_Intrinsic
<Intrinsic::abs
>(m_Value(), m_Value())))
6443 case Intrinsic::cttz
: {
6445 if (match(Op0
, m_Shl(m_One(), m_Value(X
))))
6449 case Intrinsic::ctlz
: {
6451 if (match(Op0
, m_LShr(m_Negative(), m_Value(X
))))
6453 if (match(Op0
, m_AShr(m_Negative(), m_Value())))
6454 return Constant::getNullValue(ReturnType
);
6457 case Intrinsic::ptrmask
: {
6458 if (isa
<PoisonValue
>(Op0
) || isa
<PoisonValue
>(Op1
))
6459 return PoisonValue::get(Op0
->getType());
6461 // NOTE: We can't apply this simplifications based on the value of Op1
6462 // because we need to preserve provenance.
6463 if (Q
.isUndefValue(Op0
) || match(Op0
, m_Zero()))
6464 return Constant::getNullValue(Op0
->getType());
6466 assert(Op1
->getType()->getScalarSizeInBits() ==
6467 Q
.DL
.getIndexTypeSizeInBits(Op0
->getType()) &&
6468 "Invalid mask width");
6469 // If index-width (mask size) is less than pointer-size then mask is
6471 if (match(Op1
, m_PtrToInt(m_Specific(Op0
))))
6474 // NOTE: We may have attributes associated with the return value of the
6475 // llvm.ptrmask intrinsic that will be lost when we just return the
6476 // operand. We should try to preserve them.
6477 if (match(Op1
, m_AllOnes()) || Q
.isUndefValue(Op1
))
6481 if (match(Op1
, m_ImmConstant(C
))) {
6482 KnownBits PtrKnown
= computeKnownBits(Op0
, /*Depth=*/0, Q
);
6483 // See if we only masking off bits we know are already zero due to
6485 APInt IrrelevantPtrBits
=
6486 PtrKnown
.Zero
.zextOrTrunc(C
->getType()->getScalarSizeInBits());
6487 C
= ConstantFoldBinaryOpOperands(
6488 Instruction::Or
, C
, ConstantInt::get(C
->getType(), IrrelevantPtrBits
),
6490 if (C
!= nullptr && C
->isAllOnesValue())
6495 case Intrinsic::smax
:
6496 case Intrinsic::smin
:
6497 case Intrinsic::umax
:
6498 case Intrinsic::umin
: {
6499 // If the arguments are the same, this is a no-op.
6503 // Canonicalize immediate constant operand as Op1.
6504 if (match(Op0
, m_ImmConstant()))
6505 std::swap(Op0
, Op1
);
6507 // Assume undef is the limit value.
6508 if (Q
.isUndefValue(Op1
))
6509 return ConstantInt::get(
6510 ReturnType
, MinMaxIntrinsic::getSaturationPoint(IID
, BitWidth
));
6513 if (match(Op1
, m_APIntAllowPoison(C
))) {
6514 // Clamp to limit value. For example:
6515 // umax(i8 %x, i8 255) --> 255
6516 if (*C
== MinMaxIntrinsic::getSaturationPoint(IID
, BitWidth
))
6517 return ConstantInt::get(ReturnType
, *C
);
6519 // If the constant op is the opposite of the limit value, the other must
6520 // be larger/smaller or equal. For example:
6521 // umin(i8 %x, i8 255) --> %x
6522 if (*C
== MinMaxIntrinsic::getSaturationPoint(
6523 getInverseMinMaxIntrinsic(IID
), BitWidth
))
6526 // Remove nested call if constant operands allow it. Example:
6527 // max (max X, 7), 5 -> max X, 7
6528 auto *MinMax0
= dyn_cast
<IntrinsicInst
>(Op0
);
6529 if (MinMax0
&& MinMax0
->getIntrinsicID() == IID
) {
6530 // TODO: loosen undef/splat restrictions for vector constants.
6531 Value
*M00
= MinMax0
->getOperand(0), *M01
= MinMax0
->getOperand(1);
6532 const APInt
*InnerC
;
6533 if ((match(M00
, m_APInt(InnerC
)) || match(M01
, m_APInt(InnerC
))) &&
6534 ICmpInst::compare(*InnerC
, *C
,
6535 ICmpInst::getNonStrictPredicate(
6536 MinMaxIntrinsic::getPredicate(IID
))))
6541 if (Value
*V
= foldMinMaxSharedOp(IID
, Op0
, Op1
))
6543 if (Value
*V
= foldMinMaxSharedOp(IID
, Op1
, Op0
))
6546 ICmpInst::Predicate Pred
=
6547 ICmpInst::getNonStrictPredicate(MinMaxIntrinsic::getPredicate(IID
));
6548 if (isICmpTrue(Pred
, Op0
, Op1
, Q
.getWithoutUndef(), RecursionLimit
))
6550 if (isICmpTrue(Pred
, Op1
, Op0
, Q
.getWithoutUndef(), RecursionLimit
))
6555 case Intrinsic::scmp
:
6556 case Intrinsic::ucmp
: {
6557 // Fold to a constant if the relationship between operands can be
6558 // established with certainty
6559 if (isICmpTrue(CmpInst::ICMP_EQ
, Op0
, Op1
, Q
, RecursionLimit
))
6560 return Constant::getNullValue(ReturnType
);
6562 ICmpInst::Predicate PredGT
=
6563 IID
== Intrinsic::scmp
? ICmpInst::ICMP_SGT
: ICmpInst::ICMP_UGT
;
6564 if (isICmpTrue(PredGT
, Op0
, Op1
, Q
, RecursionLimit
))
6565 return ConstantInt::get(ReturnType
, 1);
6567 ICmpInst::Predicate PredLT
=
6568 IID
== Intrinsic::scmp
? ICmpInst::ICMP_SLT
: ICmpInst::ICMP_ULT
;
6569 if (isICmpTrue(PredLT
, Op0
, Op1
, Q
, RecursionLimit
))
6570 return ConstantInt::getSigned(ReturnType
, -1);
6574 case Intrinsic::usub_with_overflow
:
6575 case Intrinsic::ssub_with_overflow
:
6576 // X - X -> { 0, false }
6577 // X - undef -> { 0, false }
6578 // undef - X -> { 0, false }
6579 if (Op0
== Op1
|| Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
))
6580 return Constant::getNullValue(ReturnType
);
6582 case Intrinsic::uadd_with_overflow
:
6583 case Intrinsic::sadd_with_overflow
:
6584 // X + undef -> { -1, false }
6585 // undef + x -> { -1, false }
6586 if (Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
)) {
6587 return ConstantStruct::get(
6588 cast
<StructType
>(ReturnType
),
6589 {Constant::getAllOnesValue(ReturnType
->getStructElementType(0)),
6590 Constant::getNullValue(ReturnType
->getStructElementType(1))});
6593 case Intrinsic::umul_with_overflow
:
6594 case Intrinsic::smul_with_overflow
:
6595 // 0 * X -> { 0, false }
6596 // X * 0 -> { 0, false }
6597 if (match(Op0
, m_Zero()) || match(Op1
, m_Zero()))
6598 return Constant::getNullValue(ReturnType
);
6599 // undef * X -> { 0, false }
6600 // X * undef -> { 0, false }
6601 if (Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
))
6602 return Constant::getNullValue(ReturnType
);
6604 case Intrinsic::uadd_sat
:
6605 // sat(MAX + X) -> MAX
6606 // sat(X + MAX) -> MAX
6607 if (match(Op0
, m_AllOnes()) || match(Op1
, m_AllOnes()))
6608 return Constant::getAllOnesValue(ReturnType
);
6610 case Intrinsic::sadd_sat
:
6611 // sat(X + undef) -> -1
6612 // sat(undef + X) -> -1
6613 // For unsigned: Assume undef is MAX, thus we saturate to MAX (-1).
6614 // For signed: Assume undef is ~X, in which case X + ~X = -1.
6615 if (Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
))
6616 return Constant::getAllOnesValue(ReturnType
);
6619 if (match(Op1
, m_Zero()))
6622 if (match(Op0
, m_Zero()))
6625 case Intrinsic::usub_sat
:
6626 // sat(0 - X) -> 0, sat(X - MAX) -> 0
6627 if (match(Op0
, m_Zero()) || match(Op1
, m_AllOnes()))
6628 return Constant::getNullValue(ReturnType
);
6630 case Intrinsic::ssub_sat
:
6631 // X - X -> 0, X - undef -> 0, undef - X -> 0
6632 if (Op0
== Op1
|| Q
.isUndefValue(Op0
) || Q
.isUndefValue(Op1
))
6633 return Constant::getNullValue(ReturnType
);
6635 if (match(Op1
, m_Zero()))
6638 case Intrinsic::load_relative
:
6639 if (auto *C0
= dyn_cast
<Constant
>(Op0
))
6640 if (auto *C1
= dyn_cast
<Constant
>(Op1
))
6641 return simplifyRelativeLoad(C0
, C1
, Q
.DL
);
6643 case Intrinsic::powi
:
6644 if (auto *Power
= dyn_cast
<ConstantInt
>(Op1
)) {
6645 // powi(x, 0) -> 1.0
6646 if (Power
->isZero())
6647 return ConstantFP::get(Op0
->getType(), 1.0);
6653 case Intrinsic::ldexp
:
6654 return simplifyLdexp(Op0
, Op1
, Q
, false);
6655 case Intrinsic::copysign
:
6656 // copysign X, X --> X
6659 // copysign -X, X --> X
6660 // copysign X, -X --> -X
6661 if (match(Op0
, m_FNeg(m_Specific(Op1
))) ||
6662 match(Op1
, m_FNeg(m_Specific(Op0
))))
6665 case Intrinsic::is_fpclass
: {
6666 if (isa
<PoisonValue
>(Op0
))
6667 return PoisonValue::get(ReturnType
);
6669 uint64_t Mask
= cast
<ConstantInt
>(Op1
)->getZExtValue();
6670 // If all tests are made, it doesn't matter what the value is.
6671 if ((Mask
& fcAllFlags
) == fcAllFlags
)
6672 return ConstantInt::get(ReturnType
, true);
6673 if ((Mask
& fcAllFlags
) == 0)
6674 return ConstantInt::get(ReturnType
, false);
6675 if (Q
.isUndefValue(Op0
))
6676 return UndefValue::get(ReturnType
);
6679 case Intrinsic::maxnum
:
6680 case Intrinsic::minnum
:
6681 case Intrinsic::maximum
:
6682 case Intrinsic::minimum
: {
6683 // If the arguments are the same, this is a no-op.
6687 // Canonicalize constant operand as Op1.
6688 if (isa
<Constant
>(Op0
))
6689 std::swap(Op0
, Op1
);
6691 // If an argument is undef, return the other argument.
6692 if (Q
.isUndefValue(Op1
))
6695 bool PropagateNaN
= IID
== Intrinsic::minimum
|| IID
== Intrinsic::maximum
;
6696 bool IsMin
= IID
== Intrinsic::minimum
|| IID
== Intrinsic::minnum
;
6698 // minnum(X, nan) -> X
6699 // maxnum(X, nan) -> X
6700 // minimum(X, nan) -> nan
6701 // maximum(X, nan) -> nan
6702 if (match(Op1
, m_NaN()))
6703 return PropagateNaN
? propagateNaN(cast
<Constant
>(Op1
)) : Op0
;
6705 // In the following folds, inf can be replaced with the largest finite
6706 // float, if the ninf flag is set.
6708 if (match(Op1
, m_APFloat(C
)) &&
6709 (C
->isInfinity() || (Call
&& Call
->hasNoInfs() && C
->isLargest()))) {
6710 // minnum(X, -inf) -> -inf
6711 // maxnum(X, +inf) -> +inf
6712 // minimum(X, -inf) -> -inf if nnan
6713 // maximum(X, +inf) -> +inf if nnan
6714 if (C
->isNegative() == IsMin
&&
6715 (!PropagateNaN
|| (Call
&& Call
->hasNoNaNs())))
6716 return ConstantFP::get(ReturnType
, *C
);
6718 // minnum(X, +inf) -> X if nnan
6719 // maxnum(X, -inf) -> X if nnan
6720 // minimum(X, +inf) -> X
6721 // maximum(X, -inf) -> X
6722 if (C
->isNegative() != IsMin
&&
6723 (PropagateNaN
|| (Call
&& Call
->hasNoNaNs())))
6727 // Min/max of the same operation with common operand:
6728 // m(m(X, Y)), X --> m(X, Y) (4 commuted variants)
6729 if (Value
*V
= foldMinimumMaximumSharedOp(IID
, Op0
, Op1
))
6731 if (Value
*V
= foldMinimumMaximumSharedOp(IID
, Op1
, Op0
))
6736 case Intrinsic::vector_extract
: {
6737 // (extract_vector (insert_vector _, X, 0), 0) -> X
6738 unsigned IdxN
= cast
<ConstantInt
>(Op1
)->getZExtValue();
6740 if (match(Op0
, m_Intrinsic
<Intrinsic::vector_insert
>(m_Value(), m_Value(X
),
6742 IdxN
== 0 && X
->getType() == ReturnType
)
6754 static Value
*simplifyIntrinsic(CallBase
*Call
, Value
*Callee
,
6755 ArrayRef
<Value
*> Args
,
6756 const SimplifyQuery
&Q
) {
6757 // Operand bundles should not be in Args.
6758 assert(Call
->arg_size() == Args
.size());
6759 unsigned NumOperands
= Args
.size();
6760 Function
*F
= cast
<Function
>(Callee
);
6761 Intrinsic::ID IID
= F
->getIntrinsicID();
6763 // Most of the intrinsics with no operands have some kind of side effect.
6767 case Intrinsic::vscale
: {
6768 Type
*RetTy
= F
->getReturnType();
6769 ConstantRange CR
= getVScaleRange(Call
->getFunction(), 64);
6770 if (const APInt
*C
= CR
.getSingleElement())
6771 return ConstantInt::get(RetTy
, C
->getZExtValue());
6779 if (NumOperands
== 1)
6780 return simplifyUnaryIntrinsic(F
, Args
[0], Q
, Call
);
6782 if (NumOperands
== 2)
6783 return simplifyBinaryIntrinsic(IID
, F
->getReturnType(), Args
[0], Args
[1], Q
,
6786 // Handle intrinsics with 3 or more arguments.
6788 case Intrinsic::masked_load
:
6789 case Intrinsic::masked_gather
: {
6790 Value
*MaskArg
= Args
[2];
6791 Value
*PassthruArg
= Args
[3];
6792 // If the mask is all zeros or undef, the "passthru" argument is the result.
6793 if (maskIsAllZeroOrUndef(MaskArg
))
6797 case Intrinsic::fshl
:
6798 case Intrinsic::fshr
: {
6799 Value
*Op0
= Args
[0], *Op1
= Args
[1], *ShAmtArg
= Args
[2];
6801 // If both operands are undef, the result is undef.
6802 if (Q
.isUndefValue(Op0
) && Q
.isUndefValue(Op1
))
6803 return UndefValue::get(F
->getReturnType());
6805 // If shift amount is undef, assume it is zero.
6806 if (Q
.isUndefValue(ShAmtArg
))
6807 return Args
[IID
== Intrinsic::fshl
? 0 : 1];
6809 const APInt
*ShAmtC
;
6810 if (match(ShAmtArg
, m_APInt(ShAmtC
))) {
6811 // If there's effectively no shift, return the 1st arg or 2nd arg.
6812 APInt BitWidth
= APInt(ShAmtC
->getBitWidth(), ShAmtC
->getBitWidth());
6813 if (ShAmtC
->urem(BitWidth
).isZero())
6814 return Args
[IID
== Intrinsic::fshl
? 0 : 1];
6817 // Rotating zero by anything is zero.
6818 if (match(Op0
, m_Zero()) && match(Op1
, m_Zero()))
6819 return ConstantInt::getNullValue(F
->getReturnType());
6821 // Rotating -1 by anything is -1.
6822 if (match(Op0
, m_AllOnes()) && match(Op1
, m_AllOnes()))
6823 return ConstantInt::getAllOnesValue(F
->getReturnType());
6827 case Intrinsic::experimental_constrained_fma
: {
6828 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6829 if (Value
*V
= simplifyFPOp(Args
, {}, Q
, *FPI
->getExceptionBehavior(),
6830 *FPI
->getRoundingMode()))
6834 case Intrinsic::fma
:
6835 case Intrinsic::fmuladd
: {
6836 if (Value
*V
= simplifyFPOp(Args
, {}, Q
, fp::ebIgnore
,
6837 RoundingMode::NearestTiesToEven
))
6841 case Intrinsic::smul_fix
:
6842 case Intrinsic::smul_fix_sat
: {
6843 Value
*Op0
= Args
[0];
6844 Value
*Op1
= Args
[1];
6845 Value
*Op2
= Args
[2];
6846 Type
*ReturnType
= F
->getReturnType();
6848 // Canonicalize constant operand as Op1 (ConstantFolding handles the case
6849 // when both Op0 and Op1 are constant so we do not care about that special
6851 if (isa
<Constant
>(Op0
))
6852 std::swap(Op0
, Op1
);
6855 if (match(Op1
, m_Zero()))
6856 return Constant::getNullValue(ReturnType
);
6859 if (Q
.isUndefValue(Op1
))
6860 return Constant::getNullValue(ReturnType
);
6862 // X * (1 << Scale) -> X
6864 APInt::getOneBitSet(ReturnType
->getScalarSizeInBits(),
6865 cast
<ConstantInt
>(Op2
)->getZExtValue());
6866 if (ScaledOne
.isNonNegative() && match(Op1
, m_SpecificInt(ScaledOne
)))
6871 case Intrinsic::vector_insert
: {
6872 Value
*Vec
= Args
[0];
6873 Value
*SubVec
= Args
[1];
6874 Value
*Idx
= Args
[2];
6875 Type
*ReturnType
= F
->getReturnType();
6877 // (insert_vector Y, (extract_vector X, 0), 0) -> X
6878 // where: Y is X, or Y is undef
6879 unsigned IdxN
= cast
<ConstantInt
>(Idx
)->getZExtValue();
6882 m_Intrinsic
<Intrinsic::vector_extract
>(m_Value(X
), m_Zero())) &&
6883 (Q
.isUndefValue(Vec
) || Vec
== X
) && IdxN
== 0 &&
6884 X
->getType() == ReturnType
)
6889 case Intrinsic::experimental_constrained_fadd
: {
6890 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6891 return simplifyFAddInst(Args
[0], Args
[1], FPI
->getFastMathFlags(), Q
,
6892 *FPI
->getExceptionBehavior(),
6893 *FPI
->getRoundingMode());
6895 case Intrinsic::experimental_constrained_fsub
: {
6896 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6897 return simplifyFSubInst(Args
[0], Args
[1], FPI
->getFastMathFlags(), Q
,
6898 *FPI
->getExceptionBehavior(),
6899 *FPI
->getRoundingMode());
6901 case Intrinsic::experimental_constrained_fmul
: {
6902 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6903 return simplifyFMulInst(Args
[0], Args
[1], FPI
->getFastMathFlags(), Q
,
6904 *FPI
->getExceptionBehavior(),
6905 *FPI
->getRoundingMode());
6907 case Intrinsic::experimental_constrained_fdiv
: {
6908 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6909 return simplifyFDivInst(Args
[0], Args
[1], FPI
->getFastMathFlags(), Q
,
6910 *FPI
->getExceptionBehavior(),
6911 *FPI
->getRoundingMode());
6913 case Intrinsic::experimental_constrained_frem
: {
6914 auto *FPI
= cast
<ConstrainedFPIntrinsic
>(Call
);
6915 return simplifyFRemInst(Args
[0], Args
[1], FPI
->getFastMathFlags(), Q
,
6916 *FPI
->getExceptionBehavior(),
6917 *FPI
->getRoundingMode());
6919 case Intrinsic::experimental_constrained_ldexp
:
6920 return simplifyLdexp(Args
[0], Args
[1], Q
, true);
6921 case Intrinsic::experimental_gc_relocate
: {
6922 GCRelocateInst
&GCR
= *cast
<GCRelocateInst
>(Call
);
6923 Value
*DerivedPtr
= GCR
.getDerivedPtr();
6924 Value
*BasePtr
= GCR
.getBasePtr();
6926 // Undef is undef, even after relocation.
6927 if (isa
<UndefValue
>(DerivedPtr
) || isa
<UndefValue
>(BasePtr
)) {
6928 return UndefValue::get(GCR
.getType());
6931 if (auto *PT
= dyn_cast
<PointerType
>(GCR
.getType())) {
6932 // For now, the assumption is that the relocation of null will be null
6933 // for most any collector. If this ever changes, a corresponding hook
6934 // should be added to GCStrategy and this code should check it first.
6935 if (isa
<ConstantPointerNull
>(DerivedPtr
)) {
6936 // Use null-pointer of gc_relocate's type to replace it.
6937 return ConstantPointerNull::get(PT
);
6947 static Value
*tryConstantFoldCall(CallBase
*Call
, Value
*Callee
,
6948 ArrayRef
<Value
*> Args
,
6949 const SimplifyQuery
&Q
) {
6950 auto *F
= dyn_cast
<Function
>(Callee
);
6951 if (!F
|| !canConstantFoldCallTo(Call
, F
))
6954 SmallVector
<Constant
*, 4> ConstantArgs
;
6955 ConstantArgs
.reserve(Args
.size());
6956 for (Value
*Arg
: Args
) {
6957 Constant
*C
= dyn_cast
<Constant
>(Arg
);
6959 if (isa
<MetadataAsValue
>(Arg
))
6963 ConstantArgs
.push_back(C
);
6966 return ConstantFoldCall(Call
, F
, ConstantArgs
, Q
.TLI
);
6969 Value
*llvm::simplifyCall(CallBase
*Call
, Value
*Callee
, ArrayRef
<Value
*> Args
,
6970 const SimplifyQuery
&Q
) {
6971 // Args should not contain operand bundle operands.
6972 assert(Call
->arg_size() == Args
.size());
6974 // musttail calls can only be simplified if they are also DCEd.
6975 // As we can't guarantee this here, don't simplify them.
6976 if (Call
->isMustTailCall())
6979 // call undef -> poison
6980 // call null -> poison
6981 if (isa
<UndefValue
>(Callee
) || isa
<ConstantPointerNull
>(Callee
))
6982 return PoisonValue::get(Call
->getType());
6984 if (Value
*V
= tryConstantFoldCall(Call
, Callee
, Args
, Q
))
6987 auto *F
= dyn_cast
<Function
>(Callee
);
6988 if (F
&& F
->isIntrinsic())
6989 if (Value
*Ret
= simplifyIntrinsic(Call
, Callee
, Args
, Q
))
6995 Value
*llvm::simplifyConstrainedFPCall(CallBase
*Call
, const SimplifyQuery
&Q
) {
6996 assert(isa
<ConstrainedFPIntrinsic
>(Call
));
6997 SmallVector
<Value
*, 4> Args(Call
->args());
6998 if (Value
*V
= tryConstantFoldCall(Call
, Call
->getCalledOperand(), Args
, Q
))
7000 if (Value
*Ret
= simplifyIntrinsic(Call
, Call
->getCalledOperand(), Args
, Q
))
7005 /// Given operands for a Freeze, see if we can fold the result.
7006 static Value
*simplifyFreezeInst(Value
*Op0
, const SimplifyQuery
&Q
) {
7007 // Use a utility function defined in ValueTracking.
7008 if (llvm::isGuaranteedNotToBeUndefOrPoison(Op0
, Q
.AC
, Q
.CxtI
, Q
.DT
))
7010 // We have room for improvement.
7014 Value
*llvm::simplifyFreezeInst(Value
*Op0
, const SimplifyQuery
&Q
) {
7015 return ::simplifyFreezeInst(Op0
, Q
);
7018 Value
*llvm::simplifyLoadInst(LoadInst
*LI
, Value
*PtrOp
,
7019 const SimplifyQuery
&Q
) {
7020 if (LI
->isVolatile())
7023 if (auto *PtrOpC
= dyn_cast
<Constant
>(PtrOp
))
7024 return ConstantFoldLoadFromConstPtr(PtrOpC
, LI
->getType(), Q
.DL
);
7026 // We can only fold the load if it is from a constant global with definitive
7027 // initializer. Skip expensive logic if this is not the case.
7028 auto *GV
= dyn_cast
<GlobalVariable
>(getUnderlyingObject(PtrOp
));
7029 if (!GV
|| !GV
->isConstant() || !GV
->hasDefinitiveInitializer())
7032 // If GlobalVariable's initializer is uniform, then return the constant
7033 // regardless of its offset.
7034 if (Constant
*C
= ConstantFoldLoadFromUniformValue(GV
->getInitializer(),
7035 LI
->getType(), Q
.DL
))
7038 // Try to convert operand into a constant by stripping offsets while looking
7039 // through invariant.group intrinsics.
7040 APInt
Offset(Q
.DL
.getIndexTypeSizeInBits(PtrOp
->getType()), 0);
7041 PtrOp
= PtrOp
->stripAndAccumulateConstantOffsets(
7042 Q
.DL
, Offset
, /* AllowNonInbounts */ true,
7043 /* AllowInvariantGroup */ true);
7045 // Index size may have changed due to address space casts.
7046 Offset
= Offset
.sextOrTrunc(Q
.DL
.getIndexTypeSizeInBits(PtrOp
->getType()));
7047 return ConstantFoldLoadFromConstPtr(GV
, LI
->getType(), std::move(Offset
),
7054 /// See if we can compute a simplified version of this instruction.
7055 /// If not, this returns null.
7057 static Value
*simplifyInstructionWithOperands(Instruction
*I
,
7058 ArrayRef
<Value
*> NewOps
,
7059 const SimplifyQuery
&SQ
,
7060 unsigned MaxRecurse
) {
7061 assert(I
->getFunction() && "instruction should be inserted in a function");
7062 assert((!SQ
.CxtI
|| SQ
.CxtI
->getFunction() == I
->getFunction()) &&
7063 "context instruction should be in the same function");
7065 const SimplifyQuery Q
= SQ
.CxtI
? SQ
: SQ
.getWithInstruction(I
);
7067 switch (I
->getOpcode()) {
7069 if (llvm::all_of(NewOps
, [](Value
*V
) { return isa
<Constant
>(V
); })) {
7070 SmallVector
<Constant
*, 8> NewConstOps(NewOps
.size());
7071 transform(NewOps
, NewConstOps
.begin(),
7072 [](Value
*V
) { return cast
<Constant
>(V
); });
7073 return ConstantFoldInstOperands(I
, NewConstOps
, Q
.DL
, Q
.TLI
);
7076 case Instruction::FNeg
:
7077 return simplifyFNegInst(NewOps
[0], I
->getFastMathFlags(), Q
, MaxRecurse
);
7078 case Instruction::FAdd
:
7079 return simplifyFAddInst(NewOps
[0], NewOps
[1], I
->getFastMathFlags(), Q
,
7081 case Instruction::Add
:
7082 return simplifyAddInst(
7083 NewOps
[0], NewOps
[1], Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
7084 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
, MaxRecurse
);
7085 case Instruction::FSub
:
7086 return simplifyFSubInst(NewOps
[0], NewOps
[1], I
->getFastMathFlags(), Q
,
7088 case Instruction::Sub
:
7089 return simplifySubInst(
7090 NewOps
[0], NewOps
[1], Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
7091 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
, MaxRecurse
);
7092 case Instruction::FMul
:
7093 return simplifyFMulInst(NewOps
[0], NewOps
[1], I
->getFastMathFlags(), Q
,
7095 case Instruction::Mul
:
7096 return simplifyMulInst(
7097 NewOps
[0], NewOps
[1], Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
7098 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
, MaxRecurse
);
7099 case Instruction::SDiv
:
7100 return simplifySDivInst(NewOps
[0], NewOps
[1],
7101 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
,
7103 case Instruction::UDiv
:
7104 return simplifyUDivInst(NewOps
[0], NewOps
[1],
7105 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
,
7107 case Instruction::FDiv
:
7108 return simplifyFDivInst(NewOps
[0], NewOps
[1], I
->getFastMathFlags(), Q
,
7110 case Instruction::SRem
:
7111 return simplifySRemInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7112 case Instruction::URem
:
7113 return simplifyURemInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7114 case Instruction::FRem
:
7115 return simplifyFRemInst(NewOps
[0], NewOps
[1], I
->getFastMathFlags(), Q
,
7117 case Instruction::Shl
:
7118 return simplifyShlInst(
7119 NewOps
[0], NewOps
[1], Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
7120 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
, MaxRecurse
);
7121 case Instruction::LShr
:
7122 return simplifyLShrInst(NewOps
[0], NewOps
[1],
7123 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
,
7125 case Instruction::AShr
:
7126 return simplifyAShrInst(NewOps
[0], NewOps
[1],
7127 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
,
7129 case Instruction::And
:
7130 return simplifyAndInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7131 case Instruction::Or
:
7132 return simplifyOrInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7133 case Instruction::Xor
:
7134 return simplifyXorInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7135 case Instruction::ICmp
:
7136 return simplifyICmpInst(cast
<ICmpInst
>(I
)->getPredicate(), NewOps
[0],
7137 NewOps
[1], Q
, MaxRecurse
);
7138 case Instruction::FCmp
:
7139 return simplifyFCmpInst(cast
<FCmpInst
>(I
)->getPredicate(), NewOps
[0],
7140 NewOps
[1], I
->getFastMathFlags(), Q
, MaxRecurse
);
7141 case Instruction::Select
:
7142 return simplifySelectInst(NewOps
[0], NewOps
[1], NewOps
[2], Q
, MaxRecurse
);
7144 case Instruction::GetElementPtr
: {
7145 auto *GEPI
= cast
<GetElementPtrInst
>(I
);
7146 return simplifyGEPInst(GEPI
->getSourceElementType(), NewOps
[0],
7147 ArrayRef(NewOps
).slice(1), GEPI
->getNoWrapFlags(), Q
,
7150 case Instruction::InsertValue
: {
7151 InsertValueInst
*IV
= cast
<InsertValueInst
>(I
);
7152 return simplifyInsertValueInst(NewOps
[0], NewOps
[1], IV
->getIndices(), Q
,
7155 case Instruction::InsertElement
:
7156 return simplifyInsertElementInst(NewOps
[0], NewOps
[1], NewOps
[2], Q
);
7157 case Instruction::ExtractValue
: {
7158 auto *EVI
= cast
<ExtractValueInst
>(I
);
7159 return simplifyExtractValueInst(NewOps
[0], EVI
->getIndices(), Q
,
7162 case Instruction::ExtractElement
:
7163 return simplifyExtractElementInst(NewOps
[0], NewOps
[1], Q
, MaxRecurse
);
7164 case Instruction::ShuffleVector
: {
7165 auto *SVI
= cast
<ShuffleVectorInst
>(I
);
7166 return simplifyShuffleVectorInst(NewOps
[0], NewOps
[1],
7167 SVI
->getShuffleMask(), SVI
->getType(), Q
,
7170 case Instruction::PHI
:
7171 return simplifyPHINode(cast
<PHINode
>(I
), NewOps
, Q
);
7172 case Instruction::Call
:
7173 return simplifyCall(
7174 cast
<CallInst
>(I
), NewOps
.back(),
7175 NewOps
.drop_back(1 + cast
<CallInst
>(I
)->getNumTotalBundleOperands()), Q
);
7176 case Instruction::Freeze
:
7177 return llvm::simplifyFreezeInst(NewOps
[0], Q
);
7178 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
7179 #include "llvm/IR/Instruction.def"
7180 #undef HANDLE_CAST_INST
7181 return simplifyCastInst(I
->getOpcode(), NewOps
[0], I
->getType(), Q
,
7183 case Instruction::Alloca
:
7184 // No simplifications for Alloca and it can't be constant folded.
7186 case Instruction::Load
:
7187 return simplifyLoadInst(cast
<LoadInst
>(I
), NewOps
[0], Q
);
7191 Value
*llvm::simplifyInstructionWithOperands(Instruction
*I
,
7192 ArrayRef
<Value
*> NewOps
,
7193 const SimplifyQuery
&SQ
) {
7194 assert(NewOps
.size() == I
->getNumOperands() &&
7195 "Number of operands should match the instruction!");
7196 return ::simplifyInstructionWithOperands(I
, NewOps
, SQ
, RecursionLimit
);
7199 Value
*llvm::simplifyInstruction(Instruction
*I
, const SimplifyQuery
&SQ
) {
7200 SmallVector
<Value
*, 8> Ops(I
->operands());
7201 Value
*Result
= ::simplifyInstructionWithOperands(I
, Ops
, SQ
, RecursionLimit
);
7203 /// If called on unreachable code, the instruction may simplify to itself.
7204 /// Make life easier for users by detecting that case here, and returning a
7205 /// safe value instead.
7206 return Result
== I
? PoisonValue::get(I
->getType()) : Result
;
7209 /// Implementation of recursive simplification through an instruction's
7212 /// This is the common implementation of the recursive simplification routines.
7213 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
7214 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
7215 /// instructions to process and attempt to simplify it using
7216 /// InstructionSimplify. Recursively visited users which could not be
7217 /// simplified themselves are to the optional UnsimplifiedUsers set for
7218 /// further processing by the caller.
7220 /// This routine returns 'true' only when *it* simplifies something. The passed
7221 /// in simplified value does not count toward this.
7222 static bool replaceAndRecursivelySimplifyImpl(
7223 Instruction
*I
, Value
*SimpleV
, const TargetLibraryInfo
*TLI
,
7224 const DominatorTree
*DT
, AssumptionCache
*AC
,
7225 SmallSetVector
<Instruction
*, 8> *UnsimplifiedUsers
= nullptr) {
7226 bool Simplified
= false;
7227 SmallSetVector
<Instruction
*, 8> Worklist
;
7228 const DataLayout
&DL
= I
->getDataLayout();
7230 // If we have an explicit value to collapse to, do that round of the
7231 // simplification loop by hand initially.
7233 for (User
*U
: I
->users())
7235 Worklist
.insert(cast
<Instruction
>(U
));
7237 // Replace the instruction with its simplified value.
7238 I
->replaceAllUsesWith(SimpleV
);
7240 if (!I
->isEHPad() && !I
->isTerminator() && !I
->mayHaveSideEffects())
7241 I
->eraseFromParent();
7246 // Note that we must test the size on each iteration, the worklist can grow.
7247 for (unsigned Idx
= 0; Idx
!= Worklist
.size(); ++Idx
) {
7250 // See if this instruction simplifies.
7251 SimpleV
= simplifyInstruction(I
, {DL
, TLI
, DT
, AC
});
7253 if (UnsimplifiedUsers
)
7254 UnsimplifiedUsers
->insert(I
);
7260 // Stash away all the uses of the old instruction so we can check them for
7261 // recursive simplifications after a RAUW. This is cheaper than checking all
7262 // uses of To on the recursive step in most cases.
7263 for (User
*U
: I
->users())
7264 Worklist
.insert(cast
<Instruction
>(U
));
7266 // Replace the instruction with its simplified value.
7267 I
->replaceAllUsesWith(SimpleV
);
7269 if (!I
->isEHPad() && !I
->isTerminator() && !I
->mayHaveSideEffects())
7270 I
->eraseFromParent();
7275 bool llvm::replaceAndRecursivelySimplify(
7276 Instruction
*I
, Value
*SimpleV
, const TargetLibraryInfo
*TLI
,
7277 const DominatorTree
*DT
, AssumptionCache
*AC
,
7278 SmallSetVector
<Instruction
*, 8> *UnsimplifiedUsers
) {
7279 assert(I
!= SimpleV
&& "replaceAndRecursivelySimplify(X,X) is not valid!");
7280 assert(SimpleV
&& "Must provide a simplified value.");
7281 return replaceAndRecursivelySimplifyImpl(I
, SimpleV
, TLI
, DT
, AC
,
7286 const SimplifyQuery
getBestSimplifyQuery(Pass
&P
, Function
&F
) {
7287 auto *DTWP
= P
.getAnalysisIfAvailable
<DominatorTreeWrapperPass
>();
7288 auto *DT
= DTWP
? &DTWP
->getDomTree() : nullptr;
7289 auto *TLIWP
= P
.getAnalysisIfAvailable
<TargetLibraryInfoWrapperPass
>();
7290 auto *TLI
= TLIWP
? &TLIWP
->getTLI(F
) : nullptr;
7291 auto *ACWP
= P
.getAnalysisIfAvailable
<AssumptionCacheTracker
>();
7292 auto *AC
= ACWP
? &ACWP
->getAssumptionCache(F
) : nullptr;
7293 return {F
.getDataLayout(), TLI
, DT
, AC
};
7296 const SimplifyQuery
getBestSimplifyQuery(LoopStandardAnalysisResults
&AR
,
7297 const DataLayout
&DL
) {
7298 return {DL
, &AR
.TLI
, &AR
.DT
, &AR
.AC
};
7301 template <class T
, class... TArgs
>
7302 const SimplifyQuery
getBestSimplifyQuery(AnalysisManager
<T
, TArgs
...> &AM
,
7304 auto *DT
= AM
.template getCachedResult
<DominatorTreeAnalysis
>(F
);
7305 auto *TLI
= AM
.template getCachedResult
<TargetLibraryAnalysis
>(F
);
7306 auto *AC
= AM
.template getCachedResult
<AssumptionAnalysis
>(F
);
7307 return {F
.getDataLayout(), TLI
, DT
, AC
};
7309 template const SimplifyQuery
getBestSimplifyQuery(AnalysisManager
<Function
> &,
7312 bool SimplifyQuery::isUndefValue(Value
*V
) const {
7316 return match(V
, m_Undef());
7321 void InstSimplifyFolder::anchor() {}