1 //===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements routines for folding instructions into simpler forms
11 // that do not require creating new instructions. This does constant folding
12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14 // ("and i32 %x, %x" -> "%x"). All operands are assumed to have already been
15 // simplified: This is usually true and assuming it simplifies the logic (if
16 // they have not been simplified then results are correct but maybe suboptimal).
18 //===----------------------------------------------------------------------===//
20 #include "llvm/Analysis/InstructionSimplify.h"
21 #include "llvm/ADT/SetVector.h"
22 #include "llvm/ADT/Statistic.h"
23 #include "llvm/Analysis/AliasAnalysis.h"
24 #include "llvm/Analysis/AssumptionCache.h"
25 #include "llvm/Analysis/CaptureTracking.h"
26 #include "llvm/Analysis/CmpInstAnalysis.h"
27 #include "llvm/Analysis/ConstantFolding.h"
28 #include "llvm/Analysis/LoopAnalysisManager.h"
29 #include "llvm/Analysis/MemoryBuiltins.h"
30 #include "llvm/Analysis/ValueTracking.h"
31 #include "llvm/Analysis/VectorUtils.h"
32 #include "llvm/IR/ConstantRange.h"
33 #include "llvm/IR/DataLayout.h"
34 #include "llvm/IR/Dominators.h"
35 #include "llvm/IR/GetElementPtrTypeIterator.h"
36 #include "llvm/IR/GlobalAlias.h"
37 #include "llvm/IR/Operator.h"
38 #include "llvm/IR/PatternMatch.h"
39 #include "llvm/IR/ValueHandle.h"
40 #include "llvm/Support/KnownBits.h"
43 using namespace llvm::PatternMatch
;
45 #define DEBUG_TYPE "instsimplify"
47 enum { RecursionLimit
= 3 };
49 STATISTIC(NumExpand
, "Number of expansions");
50 STATISTIC(NumReassoc
, "Number of reassociations");
52 static Value
*SimplifyAndInst(Value
*, Value
*, const SimplifyQuery
&, unsigned);
53 static Value
*SimplifyBinOp(unsigned, Value
*, Value
*, const SimplifyQuery
&,
55 static Value
*SimplifyFPBinOp(unsigned, Value
*, Value
*, const FastMathFlags
&,
56 const SimplifyQuery
&, unsigned);
57 static Value
*SimplifyCmpInst(unsigned, Value
*, Value
*, const SimplifyQuery
&,
59 static Value
*SimplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
60 const SimplifyQuery
&Q
, unsigned MaxRecurse
);
61 static Value
*SimplifyOrInst(Value
*, Value
*, const SimplifyQuery
&, unsigned);
62 static Value
*SimplifyXorInst(Value
*, Value
*, const SimplifyQuery
&, unsigned);
63 static Value
*SimplifyCastInst(unsigned, Value
*, Type
*,
64 const SimplifyQuery
&, unsigned);
65 static Value
*SimplifyGEPInst(Type
*, ArrayRef
<Value
*>, const SimplifyQuery
&,
68 static Value
*foldSelectWithBinaryOp(Value
*Cond
, Value
*TrueVal
,
70 BinaryOperator::BinaryOps BinOpCode
;
71 if (auto *BO
= dyn_cast
<BinaryOperator
>(Cond
))
72 BinOpCode
= BO
->getOpcode();
76 CmpInst::Predicate ExpectedPred
, Pred1
, Pred2
;
77 if (BinOpCode
== BinaryOperator::Or
) {
78 ExpectedPred
= ICmpInst::ICMP_NE
;
79 } else if (BinOpCode
== BinaryOperator::And
) {
80 ExpectedPred
= ICmpInst::ICMP_EQ
;
84 // %A = icmp eq %TV, %FV
85 // %B = icmp eq %X, %Y (and one of these is a select operand)
87 // %D = select %C, %TV, %FV
91 // %A = icmp ne %TV, %FV
92 // %B = icmp ne %X, %Y (and one of these is a select operand)
94 // %D = select %C, %TV, %FV
98 if (!match(Cond
, m_c_BinOp(m_c_ICmp(Pred1
, m_Specific(TrueVal
),
99 m_Specific(FalseVal
)),
100 m_ICmp(Pred2
, m_Value(X
), m_Value(Y
)))) ||
101 Pred1
!= Pred2
|| Pred1
!= ExpectedPred
)
104 if (X
== TrueVal
|| X
== FalseVal
|| Y
== TrueVal
|| Y
== FalseVal
)
105 return BinOpCode
== BinaryOperator::Or
? TrueVal
: FalseVal
;
110 /// For a boolean type or a vector of boolean type, return false or a vector
111 /// with every element false.
112 static Constant
*getFalse(Type
*Ty
) {
113 return ConstantInt::getFalse(Ty
);
116 /// For a boolean type or a vector of boolean type, return true or a vector
117 /// with every element true.
118 static Constant
*getTrue(Type
*Ty
) {
119 return ConstantInt::getTrue(Ty
);
122 /// isSameCompare - Is V equivalent to the comparison "LHS Pred RHS"?
123 static bool isSameCompare(Value
*V
, CmpInst::Predicate Pred
, Value
*LHS
,
125 CmpInst
*Cmp
= dyn_cast
<CmpInst
>(V
);
128 CmpInst::Predicate CPred
= Cmp
->getPredicate();
129 Value
*CLHS
= Cmp
->getOperand(0), *CRHS
= Cmp
->getOperand(1);
130 if (CPred
== Pred
&& CLHS
== LHS
&& CRHS
== RHS
)
132 return CPred
== CmpInst::getSwappedPredicate(Pred
) && CLHS
== RHS
&&
136 /// Does the given value dominate the specified phi node?
137 static bool valueDominatesPHI(Value
*V
, PHINode
*P
, const DominatorTree
*DT
) {
138 Instruction
*I
= dyn_cast
<Instruction
>(V
);
140 // Arguments and constants dominate all instructions.
143 // If we are processing instructions (and/or basic blocks) that have not been
144 // fully added to a function, the parent nodes may still be null. Simply
145 // return the conservative answer in these cases.
146 if (!I
->getParent() || !P
->getParent() || !I
->getFunction())
149 // If we have a DominatorTree then do a precise test.
151 return DT
->dominates(I
, P
);
153 // Otherwise, if the instruction is in the entry block and is not an invoke,
154 // then it obviously dominates all phi nodes.
155 if (I
->getParent() == &I
->getFunction()->getEntryBlock() &&
162 /// Simplify "A op (B op' C)" by distributing op over op', turning it into
163 /// "(A op B) op' (A op C)". Here "op" is given by Opcode and "op'" is
164 /// given by OpcodeToExpand, while "A" corresponds to LHS and "B op' C" to RHS.
165 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
166 /// Returns the simplified value, or null if no simplification was performed.
167 static Value
*ExpandBinOp(Instruction::BinaryOps Opcode
, Value
*LHS
, Value
*RHS
,
168 Instruction::BinaryOps OpcodeToExpand
,
169 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
170 // Recursion is always used, so bail out at once if we already hit the limit.
174 // Check whether the expression has the form "(A op' B) op C".
175 if (BinaryOperator
*Op0
= dyn_cast
<BinaryOperator
>(LHS
))
176 if (Op0
->getOpcode() == OpcodeToExpand
) {
177 // It does! Try turning it into "(A op C) op' (B op C)".
178 Value
*A
= Op0
->getOperand(0), *B
= Op0
->getOperand(1), *C
= RHS
;
179 // Do "A op C" and "B op C" both simplify?
180 if (Value
*L
= SimplifyBinOp(Opcode
, A
, C
, Q
, MaxRecurse
))
181 if (Value
*R
= SimplifyBinOp(Opcode
, B
, C
, Q
, MaxRecurse
)) {
182 // They do! Return "L op' R" if it simplifies or is already available.
183 // If "L op' R" equals "A op' B" then "L op' R" is just the LHS.
184 if ((L
== A
&& R
== B
) || (Instruction::isCommutative(OpcodeToExpand
)
185 && L
== B
&& R
== A
)) {
189 // Otherwise return "L op' R" if it simplifies.
190 if (Value
*V
= SimplifyBinOp(OpcodeToExpand
, L
, R
, Q
, MaxRecurse
)) {
197 // Check whether the expression has the form "A op (B op' C)".
198 if (BinaryOperator
*Op1
= dyn_cast
<BinaryOperator
>(RHS
))
199 if (Op1
->getOpcode() == OpcodeToExpand
) {
200 // It does! Try turning it into "(A op B) op' (A op C)".
201 Value
*A
= LHS
, *B
= Op1
->getOperand(0), *C
= Op1
->getOperand(1);
202 // Do "A op B" and "A op C" both simplify?
203 if (Value
*L
= SimplifyBinOp(Opcode
, A
, B
, Q
, MaxRecurse
))
204 if (Value
*R
= SimplifyBinOp(Opcode
, A
, C
, Q
, MaxRecurse
)) {
205 // They do! Return "L op' R" if it simplifies or is already available.
206 // If "L op' R" equals "B op' C" then "L op' R" is just the RHS.
207 if ((L
== B
&& R
== C
) || (Instruction::isCommutative(OpcodeToExpand
)
208 && L
== C
&& R
== B
)) {
212 // Otherwise return "L op' R" if it simplifies.
213 if (Value
*V
= SimplifyBinOp(OpcodeToExpand
, L
, R
, Q
, MaxRecurse
)) {
223 /// Generic simplifications for associative binary operations.
224 /// Returns the simpler value, or null if none was found.
225 static Value
*SimplifyAssociativeBinOp(Instruction::BinaryOps Opcode
,
226 Value
*LHS
, Value
*RHS
,
227 const SimplifyQuery
&Q
,
228 unsigned MaxRecurse
) {
229 assert(Instruction::isAssociative(Opcode
) && "Not an associative operation!");
231 // Recursion is always used, so bail out at once if we already hit the limit.
235 BinaryOperator
*Op0
= dyn_cast
<BinaryOperator
>(LHS
);
236 BinaryOperator
*Op1
= dyn_cast
<BinaryOperator
>(RHS
);
238 // Transform: "(A op B) op C" ==> "A op (B op C)" if it simplifies completely.
239 if (Op0
&& Op0
->getOpcode() == Opcode
) {
240 Value
*A
= Op0
->getOperand(0);
241 Value
*B
= Op0
->getOperand(1);
244 // Does "B op C" simplify?
245 if (Value
*V
= SimplifyBinOp(Opcode
, B
, C
, Q
, MaxRecurse
)) {
246 // It does! Return "A op V" if it simplifies or is already available.
247 // If V equals B then "A op V" is just the LHS.
248 if (V
== B
) return LHS
;
249 // Otherwise return "A op V" if it simplifies.
250 if (Value
*W
= SimplifyBinOp(Opcode
, A
, V
, Q
, MaxRecurse
)) {
257 // Transform: "A op (B op C)" ==> "(A op B) op C" if it simplifies completely.
258 if (Op1
&& Op1
->getOpcode() == Opcode
) {
260 Value
*B
= Op1
->getOperand(0);
261 Value
*C
= Op1
->getOperand(1);
263 // Does "A op B" simplify?
264 if (Value
*V
= SimplifyBinOp(Opcode
, A
, B
, Q
, MaxRecurse
)) {
265 // It does! Return "V op C" if it simplifies or is already available.
266 // If V equals B then "V op C" is just the RHS.
267 if (V
== B
) return RHS
;
268 // Otherwise return "V op C" if it simplifies.
269 if (Value
*W
= SimplifyBinOp(Opcode
, V
, C
, Q
, MaxRecurse
)) {
276 // The remaining transforms require commutativity as well as associativity.
277 if (!Instruction::isCommutative(Opcode
))
280 // Transform: "(A op B) op C" ==> "(C op A) op B" if it simplifies completely.
281 if (Op0
&& Op0
->getOpcode() == Opcode
) {
282 Value
*A
= Op0
->getOperand(0);
283 Value
*B
= Op0
->getOperand(1);
286 // Does "C op A" simplify?
287 if (Value
*V
= SimplifyBinOp(Opcode
, C
, A
, Q
, MaxRecurse
)) {
288 // It does! Return "V op B" if it simplifies or is already available.
289 // If V equals A then "V op B" is just the LHS.
290 if (V
== A
) return LHS
;
291 // Otherwise return "V op B" if it simplifies.
292 if (Value
*W
= SimplifyBinOp(Opcode
, V
, B
, Q
, MaxRecurse
)) {
299 // Transform: "A op (B op C)" ==> "B op (C op A)" if it simplifies completely.
300 if (Op1
&& Op1
->getOpcode() == Opcode
) {
302 Value
*B
= Op1
->getOperand(0);
303 Value
*C
= Op1
->getOperand(1);
305 // Does "C op A" simplify?
306 if (Value
*V
= SimplifyBinOp(Opcode
, C
, A
, Q
, MaxRecurse
)) {
307 // It does! Return "B op V" if it simplifies or is already available.
308 // If V equals C then "B op V" is just the RHS.
309 if (V
== C
) return RHS
;
310 // Otherwise return "B op V" if it simplifies.
311 if (Value
*W
= SimplifyBinOp(Opcode
, B
, V
, Q
, MaxRecurse
)) {
321 /// In the case of a binary operation with a select instruction as an operand,
322 /// try to simplify the binop by seeing whether evaluating it on both branches
323 /// of the select results in the same value. Returns the common value if so,
324 /// otherwise returns null.
325 static Value
*ThreadBinOpOverSelect(Instruction::BinaryOps Opcode
, Value
*LHS
,
326 Value
*RHS
, const SimplifyQuery
&Q
,
327 unsigned MaxRecurse
) {
328 // Recursion is always used, so bail out at once if we already hit the limit.
333 if (isa
<SelectInst
>(LHS
)) {
334 SI
= cast
<SelectInst
>(LHS
);
336 assert(isa
<SelectInst
>(RHS
) && "No select instruction operand!");
337 SI
= cast
<SelectInst
>(RHS
);
340 // Evaluate the BinOp on the true and false branches of the select.
344 TV
= SimplifyBinOp(Opcode
, SI
->getTrueValue(), RHS
, Q
, MaxRecurse
);
345 FV
= SimplifyBinOp(Opcode
, SI
->getFalseValue(), RHS
, Q
, MaxRecurse
);
347 TV
= SimplifyBinOp(Opcode
, LHS
, SI
->getTrueValue(), Q
, MaxRecurse
);
348 FV
= SimplifyBinOp(Opcode
, LHS
, SI
->getFalseValue(), Q
, MaxRecurse
);
351 // If they simplified to the same value, then return the common value.
352 // If they both failed to simplify then return null.
356 // If one branch simplified to undef, return the other one.
357 if (TV
&& isa
<UndefValue
>(TV
))
359 if (FV
&& isa
<UndefValue
>(FV
))
362 // If applying the operation did not change the true and false select values,
363 // then the result of the binop is the select itself.
364 if (TV
== SI
->getTrueValue() && FV
== SI
->getFalseValue())
367 // If one branch simplified and the other did not, and the simplified
368 // value is equal to the unsimplified one, return the simplified value.
369 // For example, select (cond, X, X & Z) & Z -> X & Z.
370 if ((FV
&& !TV
) || (TV
&& !FV
)) {
371 // Check that the simplified value has the form "X op Y" where "op" is the
372 // same as the original operation.
373 Instruction
*Simplified
= dyn_cast
<Instruction
>(FV
? FV
: TV
);
374 if (Simplified
&& Simplified
->getOpcode() == unsigned(Opcode
)) {
375 // The value that didn't simplify is "UnsimplifiedLHS op UnsimplifiedRHS".
376 // We already know that "op" is the same as for the simplified value. See
377 // if the operands match too. If so, return the simplified value.
378 Value
*UnsimplifiedBranch
= FV
? SI
->getTrueValue() : SI
->getFalseValue();
379 Value
*UnsimplifiedLHS
= SI
== LHS
? UnsimplifiedBranch
: LHS
;
380 Value
*UnsimplifiedRHS
= SI
== LHS
? RHS
: UnsimplifiedBranch
;
381 if (Simplified
->getOperand(0) == UnsimplifiedLHS
&&
382 Simplified
->getOperand(1) == UnsimplifiedRHS
)
384 if (Simplified
->isCommutative() &&
385 Simplified
->getOperand(1) == UnsimplifiedLHS
&&
386 Simplified
->getOperand(0) == UnsimplifiedRHS
)
394 /// In the case of a comparison with a select instruction, try to simplify the
395 /// comparison by seeing whether both branches of the select result in the same
396 /// value. Returns the common value if so, otherwise returns null.
397 static Value
*ThreadCmpOverSelect(CmpInst::Predicate Pred
, Value
*LHS
,
398 Value
*RHS
, const SimplifyQuery
&Q
,
399 unsigned MaxRecurse
) {
400 // Recursion is always used, so bail out at once if we already hit the limit.
404 // Make sure the select is on the LHS.
405 if (!isa
<SelectInst
>(LHS
)) {
407 Pred
= CmpInst::getSwappedPredicate(Pred
);
409 assert(isa
<SelectInst
>(LHS
) && "Not comparing with a select instruction!");
410 SelectInst
*SI
= cast
<SelectInst
>(LHS
);
411 Value
*Cond
= SI
->getCondition();
412 Value
*TV
= SI
->getTrueValue();
413 Value
*FV
= SI
->getFalseValue();
415 // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
416 // Does "cmp TV, RHS" simplify?
417 Value
*TCmp
= SimplifyCmpInst(Pred
, TV
, RHS
, Q
, MaxRecurse
);
419 // It not only simplified, it simplified to the select condition. Replace
421 TCmp
= getTrue(Cond
->getType());
423 // It didn't simplify. However if "cmp TV, RHS" is equal to the select
424 // condition then we can replace it with 'true'. Otherwise give up.
425 if (!isSameCompare(Cond
, Pred
, TV
, RHS
))
427 TCmp
= getTrue(Cond
->getType());
430 // Does "cmp FV, RHS" simplify?
431 Value
*FCmp
= SimplifyCmpInst(Pred
, FV
, RHS
, Q
, MaxRecurse
);
433 // It not only simplified, it simplified to the select condition. Replace
435 FCmp
= getFalse(Cond
->getType());
437 // It didn't simplify. However if "cmp FV, RHS" is equal to the select
438 // condition then we can replace it with 'false'. Otherwise give up.
439 if (!isSameCompare(Cond
, Pred
, FV
, RHS
))
441 FCmp
= getFalse(Cond
->getType());
444 // If both sides simplified to the same value, then use it as the result of
445 // the original comparison.
449 // The remaining cases only make sense if the select condition has the same
450 // type as the result of the comparison, so bail out if this is not so.
451 if (Cond
->getType()->isVectorTy() != RHS
->getType()->isVectorTy())
453 // If the false value simplified to false, then the result of the compare
454 // is equal to "Cond && TCmp". This also catches the case when the false
455 // value simplified to false and the true value to true, returning "Cond".
456 if (match(FCmp
, m_Zero()))
457 if (Value
*V
= SimplifyAndInst(Cond
, TCmp
, Q
, MaxRecurse
))
459 // If the true value simplified to true, then the result of the compare
460 // is equal to "Cond || FCmp".
461 if (match(TCmp
, m_One()))
462 if (Value
*V
= SimplifyOrInst(Cond
, FCmp
, Q
, MaxRecurse
))
464 // Finally, if the false value simplified to true and the true value to
465 // false, then the result of the compare is equal to "!Cond".
466 if (match(FCmp
, m_One()) && match(TCmp
, m_Zero()))
468 SimplifyXorInst(Cond
, Constant::getAllOnesValue(Cond
->getType()),
475 /// In the case of a binary operation with an operand that is a PHI instruction,
476 /// try to simplify the binop by seeing whether evaluating it on the incoming
477 /// phi values yields the same result for every value. If so returns the common
478 /// value, otherwise returns null.
479 static Value
*ThreadBinOpOverPHI(Instruction::BinaryOps Opcode
, Value
*LHS
,
480 Value
*RHS
, const SimplifyQuery
&Q
,
481 unsigned MaxRecurse
) {
482 // Recursion is always used, so bail out at once if we already hit the limit.
487 if (isa
<PHINode
>(LHS
)) {
488 PI
= cast
<PHINode
>(LHS
);
489 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
490 if (!valueDominatesPHI(RHS
, PI
, Q
.DT
))
493 assert(isa
<PHINode
>(RHS
) && "No PHI instruction operand!");
494 PI
= cast
<PHINode
>(RHS
);
495 // Bail out if LHS and the phi may be mutually interdependent due to a loop.
496 if (!valueDominatesPHI(LHS
, PI
, Q
.DT
))
500 // Evaluate the BinOp on the incoming phi values.
501 Value
*CommonValue
= nullptr;
502 for (Value
*Incoming
: PI
->incoming_values()) {
503 // If the incoming value is the phi node itself, it can safely be skipped.
504 if (Incoming
== PI
) continue;
505 Value
*V
= PI
== LHS
?
506 SimplifyBinOp(Opcode
, Incoming
, RHS
, Q
, MaxRecurse
) :
507 SimplifyBinOp(Opcode
, LHS
, Incoming
, Q
, MaxRecurse
);
508 // If the operation failed to simplify, or simplified to a different value
509 // to previously, then give up.
510 if (!V
|| (CommonValue
&& V
!= CommonValue
))
518 /// In the case of a comparison with a PHI instruction, try to simplify the
519 /// comparison by seeing whether comparing with all of the incoming phi values
520 /// yields the same result every time. If so returns the common result,
521 /// otherwise returns null.
522 static Value
*ThreadCmpOverPHI(CmpInst::Predicate Pred
, Value
*LHS
, Value
*RHS
,
523 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
524 // Recursion is always used, so bail out at once if we already hit the limit.
528 // Make sure the phi is on the LHS.
529 if (!isa
<PHINode
>(LHS
)) {
531 Pred
= CmpInst::getSwappedPredicate(Pred
);
533 assert(isa
<PHINode
>(LHS
) && "Not comparing with a phi instruction!");
534 PHINode
*PI
= cast
<PHINode
>(LHS
);
536 // Bail out if RHS and the phi may be mutually interdependent due to a loop.
537 if (!valueDominatesPHI(RHS
, PI
, Q
.DT
))
540 // Evaluate the BinOp on the incoming phi values.
541 Value
*CommonValue
= nullptr;
542 for (Value
*Incoming
: PI
->incoming_values()) {
543 // If the incoming value is the phi node itself, it can safely be skipped.
544 if (Incoming
== PI
) continue;
545 Value
*V
= SimplifyCmpInst(Pred
, Incoming
, RHS
, Q
, MaxRecurse
);
546 // If the operation failed to simplify, or simplified to a different value
547 // to previously, then give up.
548 if (!V
|| (CommonValue
&& V
!= CommonValue
))
556 static Constant
*foldOrCommuteConstant(Instruction::BinaryOps Opcode
,
557 Value
*&Op0
, Value
*&Op1
,
558 const SimplifyQuery
&Q
) {
559 if (auto *CLHS
= dyn_cast
<Constant
>(Op0
)) {
560 if (auto *CRHS
= dyn_cast
<Constant
>(Op1
))
561 return ConstantFoldBinaryOpOperands(Opcode
, CLHS
, CRHS
, Q
.DL
);
563 // Canonicalize the constant to the RHS if this is a commutative operation.
564 if (Instruction::isCommutative(Opcode
))
570 /// Given operands for an Add, see if we can fold the result.
571 /// If not, this returns null.
572 static Value
*SimplifyAddInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
573 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
574 if (Constant
*C
= foldOrCommuteConstant(Instruction::Add
, Op0
, Op1
, Q
))
577 // X + undef -> undef
578 if (match(Op1
, m_Undef()))
582 if (match(Op1
, m_Zero()))
585 // If two operands are negative, return 0.
586 if (isKnownNegation(Op0
, Op1
))
587 return Constant::getNullValue(Op0
->getType());
593 if (match(Op1
, m_Sub(m_Value(Y
), m_Specific(Op0
))) ||
594 match(Op0
, m_Sub(m_Value(Y
), m_Specific(Op1
))))
597 // X + ~X -> -1 since ~X = -X-1
598 Type
*Ty
= Op0
->getType();
599 if (match(Op0
, m_Not(m_Specific(Op1
))) ||
600 match(Op1
, m_Not(m_Specific(Op0
))))
601 return Constant::getAllOnesValue(Ty
);
603 // add nsw/nuw (xor Y, signmask), signmask --> Y
604 // The no-wrapping add guarantees that the top bit will be set by the add.
605 // Therefore, the xor must be clearing the already set sign bit of Y.
606 if ((IsNSW
|| IsNUW
) && match(Op1
, m_SignMask()) &&
607 match(Op0
, m_Xor(m_Value(Y
), m_SignMask())))
610 // add nuw %x, -1 -> -1, because %x can only be 0.
611 if (IsNUW
&& match(Op1
, m_AllOnes()))
612 return Op1
; // Which is -1.
615 if (MaxRecurse
&& Op0
->getType()->isIntOrIntVectorTy(1))
616 if (Value
*V
= SimplifyXorInst(Op0
, Op1
, Q
, MaxRecurse
-1))
619 // Try some generic simplifications for associative operations.
620 if (Value
*V
= SimplifyAssociativeBinOp(Instruction::Add
, Op0
, Op1
, Q
,
624 // Threading Add over selects and phi nodes is pointless, so don't bother.
625 // Threading over the select in "A + select(cond, B, C)" means evaluating
626 // "A+B" and "A+C" and seeing if they are equal; but they are equal if and
627 // only if B and C are equal. If B and C are equal then (since we assume
628 // that operands have already been simplified) "select(cond, B, C)" should
629 // have been simplified to the common value of B and C already. Analysing
630 // "A+B" and "A+C" thus gains nothing, but costs compile time. Similarly
631 // for threading over phi nodes.
636 Value
*llvm::SimplifyAddInst(Value
*Op0
, Value
*Op1
, bool IsNSW
, bool IsNUW
,
637 const SimplifyQuery
&Query
) {
638 return ::SimplifyAddInst(Op0
, Op1
, IsNSW
, IsNUW
, Query
, RecursionLimit
);
641 /// Compute the base pointer and cumulative constant offsets for V.
643 /// This strips all constant offsets off of V, leaving it the base pointer, and
644 /// accumulates the total constant offset applied in the returned constant. It
645 /// returns 0 if V is not a pointer, and returns the constant '0' if there are
646 /// no constant offsets applied.
648 /// This is very similar to GetPointerBaseWithConstantOffset except it doesn't
649 /// follow non-inbounds geps. This allows it to remain usable for icmp ult/etc.
651 static Constant
*stripAndComputeConstantOffsets(const DataLayout
&DL
, Value
*&V
,
652 bool AllowNonInbounds
= false) {
653 assert(V
->getType()->isPtrOrPtrVectorTy());
655 Type
*IntPtrTy
= DL
.getIntPtrType(V
->getType())->getScalarType();
656 APInt Offset
= APInt::getNullValue(IntPtrTy
->getIntegerBitWidth());
658 // Even though we don't look through PHI nodes, we could be called on an
659 // instruction in an unreachable block, which may be on a cycle.
660 SmallPtrSet
<Value
*, 4> Visited
;
663 if (GEPOperator
*GEP
= dyn_cast
<GEPOperator
>(V
)) {
664 if ((!AllowNonInbounds
&& !GEP
->isInBounds()) ||
665 !GEP
->accumulateConstantOffset(DL
, Offset
))
667 V
= GEP
->getPointerOperand();
668 } else if (Operator::getOpcode(V
) == Instruction::BitCast
) {
669 V
= cast
<Operator
>(V
)->getOperand(0);
670 } else if (GlobalAlias
*GA
= dyn_cast
<GlobalAlias
>(V
)) {
671 if (GA
->isInterposable())
673 V
= GA
->getAliasee();
675 if (auto CS
= CallSite(V
))
676 if (Value
*RV
= CS
.getReturnedArgOperand()) {
682 assert(V
->getType()->isPtrOrPtrVectorTy() && "Unexpected operand type!");
683 } while (Visited
.insert(V
).second
);
685 Constant
*OffsetIntPtr
= ConstantInt::get(IntPtrTy
, Offset
);
686 if (V
->getType()->isVectorTy())
687 return ConstantVector::getSplat(V
->getType()->getVectorNumElements(),
692 /// Compute the constant difference between two pointer values.
693 /// If the difference is not a constant, returns zero.
694 static Constant
*computePointerDifference(const DataLayout
&DL
, Value
*LHS
,
696 Constant
*LHSOffset
= stripAndComputeConstantOffsets(DL
, LHS
);
697 Constant
*RHSOffset
= stripAndComputeConstantOffsets(DL
, RHS
);
699 // If LHS and RHS are not related via constant offsets to the same base
700 // value, there is nothing we can do here.
704 // Otherwise, the difference of LHS - RHS can be computed as:
706 // = (LHSOffset + Base) - (RHSOffset + Base)
707 // = LHSOffset - RHSOffset
708 return ConstantExpr::getSub(LHSOffset
, RHSOffset
);
711 /// Given operands for a Sub, see if we can fold the result.
712 /// If not, this returns null.
713 static Value
*SimplifySubInst(Value
*Op0
, Value
*Op1
, bool isNSW
, bool isNUW
,
714 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
715 if (Constant
*C
= foldOrCommuteConstant(Instruction::Sub
, Op0
, Op1
, Q
))
718 // X - undef -> undef
719 // undef - X -> undef
720 if (match(Op0
, m_Undef()) || match(Op1
, m_Undef()))
721 return UndefValue::get(Op0
->getType());
724 if (match(Op1
, m_Zero()))
729 return Constant::getNullValue(Op0
->getType());
731 // Is this a negation?
732 if (match(Op0
, m_Zero())) {
733 // 0 - X -> 0 if the sub is NUW.
735 return Constant::getNullValue(Op0
->getType());
737 KnownBits Known
= computeKnownBits(Op1
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
738 if (Known
.Zero
.isMaxSignedValue()) {
739 // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
740 // Op1 must be 0 because negating the minimum signed value is undefined.
742 return Constant::getNullValue(Op0
->getType());
744 // 0 - X -> X if X is 0 or the minimum signed value.
749 // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
750 // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
751 Value
*X
= nullptr, *Y
= nullptr, *Z
= Op1
;
752 if (MaxRecurse
&& match(Op0
, m_Add(m_Value(X
), m_Value(Y
)))) { // (X + Y) - Z
753 // See if "V === Y - Z" simplifies.
754 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, Y
, Z
, Q
, MaxRecurse
-1))
755 // It does! Now see if "X + V" simplifies.
756 if (Value
*W
= SimplifyBinOp(Instruction::Add
, X
, V
, Q
, MaxRecurse
-1)) {
757 // It does, we successfully reassociated!
761 // See if "V === X - Z" simplifies.
762 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, X
, Z
, Q
, MaxRecurse
-1))
763 // It does! Now see if "Y + V" simplifies.
764 if (Value
*W
= SimplifyBinOp(Instruction::Add
, Y
, V
, Q
, MaxRecurse
-1)) {
765 // It does, we successfully reassociated!
771 // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
772 // For example, X - (X + 1) -> -1
774 if (MaxRecurse
&& match(Op1
, m_Add(m_Value(Y
), m_Value(Z
)))) { // X - (Y + Z)
775 // See if "V === X - Y" simplifies.
776 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, X
, Y
, Q
, MaxRecurse
-1))
777 // It does! Now see if "V - Z" simplifies.
778 if (Value
*W
= SimplifyBinOp(Instruction::Sub
, V
, Z
, Q
, MaxRecurse
-1)) {
779 // It does, we successfully reassociated!
783 // See if "V === X - Z" simplifies.
784 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, X
, Z
, Q
, MaxRecurse
-1))
785 // It does! Now see if "V - Y" simplifies.
786 if (Value
*W
= SimplifyBinOp(Instruction::Sub
, V
, Y
, Q
, MaxRecurse
-1)) {
787 // It does, we successfully reassociated!
793 // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
794 // For example, X - (X - Y) -> Y.
796 if (MaxRecurse
&& match(Op1
, m_Sub(m_Value(X
), m_Value(Y
)))) // Z - (X - Y)
797 // See if "V === Z - X" simplifies.
798 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, Z
, X
, Q
, MaxRecurse
-1))
799 // It does! Now see if "V + Y" simplifies.
800 if (Value
*W
= SimplifyBinOp(Instruction::Add
, V
, Y
, Q
, MaxRecurse
-1)) {
801 // It does, we successfully reassociated!
806 // trunc(X) - trunc(Y) -> trunc(X - Y) if everything simplifies.
807 if (MaxRecurse
&& match(Op0
, m_Trunc(m_Value(X
))) &&
808 match(Op1
, m_Trunc(m_Value(Y
))))
809 if (X
->getType() == Y
->getType())
810 // See if "V === X - Y" simplifies.
811 if (Value
*V
= SimplifyBinOp(Instruction::Sub
, X
, Y
, Q
, MaxRecurse
-1))
812 // It does! Now see if "trunc V" simplifies.
813 if (Value
*W
= SimplifyCastInst(Instruction::Trunc
, V
, Op0
->getType(),
815 // It does, return the simplified "trunc V".
818 // Variations on GEP(base, I, ...) - GEP(base, i, ...) -> GEP(null, I-i, ...).
819 if (match(Op0
, m_PtrToInt(m_Value(X
))) &&
820 match(Op1
, m_PtrToInt(m_Value(Y
))))
821 if (Constant
*Result
= computePointerDifference(Q
.DL
, X
, Y
))
822 return ConstantExpr::getIntegerCast(Result
, Op0
->getType(), true);
825 if (MaxRecurse
&& Op0
->getType()->isIntOrIntVectorTy(1))
826 if (Value
*V
= SimplifyXorInst(Op0
, Op1
, Q
, MaxRecurse
-1))
829 // Threading Sub over selects and phi nodes is pointless, so don't bother.
830 // Threading over the select in "A - select(cond, B, C)" means evaluating
831 // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
832 // only if B and C are equal. If B and C are equal then (since we assume
833 // that operands have already been simplified) "select(cond, B, C)" should
834 // have been simplified to the common value of B and C already. Analysing
835 // "A-B" and "A-C" thus gains nothing, but costs compile time. Similarly
836 // for threading over phi nodes.
841 Value
*llvm::SimplifySubInst(Value
*Op0
, Value
*Op1
, bool isNSW
, bool isNUW
,
842 const SimplifyQuery
&Q
) {
843 return ::SimplifySubInst(Op0
, Op1
, isNSW
, isNUW
, Q
, RecursionLimit
);
846 /// Given operands for a Mul, see if we can fold the result.
847 /// If not, this returns null.
848 static Value
*SimplifyMulInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
849 unsigned MaxRecurse
) {
850 if (Constant
*C
= foldOrCommuteConstant(Instruction::Mul
, Op0
, Op1
, Q
))
855 if (match(Op1
, m_CombineOr(m_Undef(), m_Zero())))
856 return Constant::getNullValue(Op0
->getType());
859 if (match(Op1
, m_One()))
862 // (X / Y) * Y -> X if the division is exact.
864 if (Q
.IIQ
.UseInstrInfo
&&
866 m_Exact(m_IDiv(m_Value(X
), m_Specific(Op1
)))) || // (X / Y) * Y
867 match(Op1
, m_Exact(m_IDiv(m_Value(X
), m_Specific(Op0
)))))) // Y * (X / Y)
871 if (MaxRecurse
&& Op0
->getType()->isIntOrIntVectorTy(1))
872 if (Value
*V
= SimplifyAndInst(Op0
, Op1
, Q
, MaxRecurse
-1))
875 // Try some generic simplifications for associative operations.
876 if (Value
*V
= SimplifyAssociativeBinOp(Instruction::Mul
, Op0
, Op1
, Q
,
880 // Mul distributes over Add. Try some generic simplifications based on this.
881 if (Value
*V
= ExpandBinOp(Instruction::Mul
, Op0
, Op1
, Instruction::Add
,
885 // If the operation is with the result of a select instruction, check whether
886 // operating on either branch of the select always yields the same value.
887 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
888 if (Value
*V
= ThreadBinOpOverSelect(Instruction::Mul
, Op0
, Op1
, Q
,
892 // If the operation is with the result of a phi instruction, check whether
893 // operating on all incoming values of the phi always yields the same value.
894 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
895 if (Value
*V
= ThreadBinOpOverPHI(Instruction::Mul
, Op0
, Op1
, Q
,
902 Value
*llvm::SimplifyMulInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
903 return ::SimplifyMulInst(Op0
, Op1
, Q
, RecursionLimit
);
906 /// Check for common or similar folds of integer division or integer remainder.
907 /// This applies to all 4 opcodes (sdiv/udiv/srem/urem).
908 static Value
*simplifyDivRem(Value
*Op0
, Value
*Op1
, bool IsDiv
) {
909 Type
*Ty
= Op0
->getType();
911 // X / undef -> undef
912 // X % undef -> undef
913 if (match(Op1
, m_Undef()))
918 // We don't need to preserve faults!
919 if (match(Op1
, m_Zero()))
920 return UndefValue::get(Ty
);
922 // If any element of a constant divisor vector is zero or undef, the whole op
924 auto *Op1C
= dyn_cast
<Constant
>(Op1
);
925 if (Op1C
&& Ty
->isVectorTy()) {
926 unsigned NumElts
= Ty
->getVectorNumElements();
927 for (unsigned i
= 0; i
!= NumElts
; ++i
) {
928 Constant
*Elt
= Op1C
->getAggregateElement(i
);
929 if (Elt
&& (Elt
->isNullValue() || isa
<UndefValue
>(Elt
)))
930 return UndefValue::get(Ty
);
936 if (match(Op0
, m_Undef()))
937 return Constant::getNullValue(Ty
);
941 if (match(Op0
, m_Zero()))
942 return Constant::getNullValue(Op0
->getType());
947 return IsDiv
? ConstantInt::get(Ty
, 1) : Constant::getNullValue(Ty
);
951 // If this is a boolean op (single-bit element type), we can't have
952 // division-by-zero or remainder-by-zero, so assume the divisor is 1.
953 // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
955 if (match(Op1
, m_One()) || Ty
->isIntOrIntVectorTy(1) ||
956 (match(Op1
, m_ZExt(m_Value(X
))) && X
->getType()->isIntOrIntVectorTy(1)))
957 return IsDiv
? Op0
: Constant::getNullValue(Ty
);
962 /// Given a predicate and two operands, return true if the comparison is true.
963 /// This is a helper for div/rem simplification where we return some other value
964 /// when we can prove a relationship between the operands.
965 static bool isICmpTrue(ICmpInst::Predicate Pred
, Value
*LHS
, Value
*RHS
,
966 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
967 Value
*V
= SimplifyICmpInst(Pred
, LHS
, RHS
, Q
, MaxRecurse
);
968 Constant
*C
= dyn_cast_or_null
<Constant
>(V
);
969 return (C
&& C
->isAllOnesValue());
972 /// Return true if we can simplify X / Y to 0. Remainder can adapt that answer
973 /// to simplify X % Y to X.
974 static bool isDivZero(Value
*X
, Value
*Y
, const SimplifyQuery
&Q
,
975 unsigned MaxRecurse
, bool IsSigned
) {
976 // Recursion is always used, so bail out at once if we already hit the limit.
983 // We require that 1 operand is a simple constant. That could be extended to
984 // 2 variables if we computed the sign bit for each.
986 // Make sure that a constant is not the minimum signed value because taking
987 // the abs() of that is undefined.
988 Type
*Ty
= X
->getType();
990 if (match(X
, m_APInt(C
)) && !C
->isMinSignedValue()) {
991 // Is the variable divisor magnitude always greater than the constant
992 // dividend magnitude?
993 // |Y| > |C| --> Y < -abs(C) or Y > abs(C)
994 Constant
*PosDividendC
= ConstantInt::get(Ty
, C
->abs());
995 Constant
*NegDividendC
= ConstantInt::get(Ty
, -C
->abs());
996 if (isICmpTrue(CmpInst::ICMP_SLT
, Y
, NegDividendC
, Q
, MaxRecurse
) ||
997 isICmpTrue(CmpInst::ICMP_SGT
, Y
, PosDividendC
, Q
, MaxRecurse
))
1000 if (match(Y
, m_APInt(C
))) {
1001 // Special-case: we can't take the abs() of a minimum signed value. If
1002 // that's the divisor, then all we have to do is prove that the dividend
1003 // is also not the minimum signed value.
1004 if (C
->isMinSignedValue())
1005 return isICmpTrue(CmpInst::ICMP_NE
, X
, Y
, Q
, MaxRecurse
);
1007 // Is the variable dividend magnitude always less than the constant
1008 // divisor magnitude?
1009 // |X| < |C| --> X > -abs(C) and X < abs(C)
1010 Constant
*PosDivisorC
= ConstantInt::get(Ty
, C
->abs());
1011 Constant
*NegDivisorC
= ConstantInt::get(Ty
, -C
->abs());
1012 if (isICmpTrue(CmpInst::ICMP_SGT
, X
, NegDivisorC
, Q
, MaxRecurse
) &&
1013 isICmpTrue(CmpInst::ICMP_SLT
, X
, PosDivisorC
, Q
, MaxRecurse
))
1019 // IsSigned == false.
1020 // Is the dividend unsigned less than the divisor?
1021 return isICmpTrue(ICmpInst::ICMP_ULT
, X
, Y
, Q
, MaxRecurse
);
1024 /// These are simplifications common to SDiv and UDiv.
1025 static Value
*simplifyDiv(Instruction::BinaryOps Opcode
, Value
*Op0
, Value
*Op1
,
1026 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1027 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1030 if (Value
*V
= simplifyDivRem(Op0
, Op1
, true))
1033 bool IsSigned
= Opcode
== Instruction::SDiv
;
1035 // (X * Y) / Y -> X if the multiplication does not overflow.
1037 if (match(Op0
, m_c_Mul(m_Value(X
), m_Specific(Op1
)))) {
1038 auto *Mul
= cast
<OverflowingBinaryOperator
>(Op0
);
1039 // If the Mul does not overflow, then we are good to go.
1040 if ((IsSigned
&& Q
.IIQ
.hasNoSignedWrap(Mul
)) ||
1041 (!IsSigned
&& Q
.IIQ
.hasNoUnsignedWrap(Mul
)))
1043 // If X has the form X = A / Y, then X * Y cannot overflow.
1044 if ((IsSigned
&& match(X
, m_SDiv(m_Value(), m_Specific(Op1
)))) ||
1045 (!IsSigned
&& match(X
, m_UDiv(m_Value(), m_Specific(Op1
)))))
1049 // (X rem Y) / Y -> 0
1050 if ((IsSigned
&& match(Op0
, m_SRem(m_Value(), m_Specific(Op1
)))) ||
1051 (!IsSigned
&& match(Op0
, m_URem(m_Value(), m_Specific(Op1
)))))
1052 return Constant::getNullValue(Op0
->getType());
1054 // (X /u C1) /u C2 -> 0 if C1 * C2 overflow
1055 ConstantInt
*C1
, *C2
;
1056 if (!IsSigned
&& match(Op0
, m_UDiv(m_Value(X
), m_ConstantInt(C1
))) &&
1057 match(Op1
, m_ConstantInt(C2
))) {
1059 (void)C1
->getValue().umul_ov(C2
->getValue(), Overflow
);
1061 return Constant::getNullValue(Op0
->getType());
1064 // If the operation is with the result of a select instruction, check whether
1065 // operating on either branch of the select always yields the same value.
1066 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1067 if (Value
*V
= ThreadBinOpOverSelect(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1070 // If the operation is with the result of a phi instruction, check whether
1071 // operating on all incoming values of the phi always yields the same value.
1072 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1073 if (Value
*V
= ThreadBinOpOverPHI(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1076 if (isDivZero(Op0
, Op1
, Q
, MaxRecurse
, IsSigned
))
1077 return Constant::getNullValue(Op0
->getType());
1082 /// These are simplifications common to SRem and URem.
1083 static Value
*simplifyRem(Instruction::BinaryOps Opcode
, Value
*Op0
, Value
*Op1
,
1084 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1085 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1088 if (Value
*V
= simplifyDivRem(Op0
, Op1
, false))
1091 // (X % Y) % Y -> X % Y
1092 if ((Opcode
== Instruction::SRem
&&
1093 match(Op0
, m_SRem(m_Value(), m_Specific(Op1
)))) ||
1094 (Opcode
== Instruction::URem
&&
1095 match(Op0
, m_URem(m_Value(), m_Specific(Op1
)))))
1098 // (X << Y) % X -> 0
1099 if (Q
.IIQ
.UseInstrInfo
&&
1100 ((Opcode
== Instruction::SRem
&&
1101 match(Op0
, m_NSWShl(m_Specific(Op1
), m_Value()))) ||
1102 (Opcode
== Instruction::URem
&&
1103 match(Op0
, m_NUWShl(m_Specific(Op1
), m_Value())))))
1104 return Constant::getNullValue(Op0
->getType());
1106 // If the operation is with the result of a select instruction, check whether
1107 // operating on either branch of the select always yields the same value.
1108 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1109 if (Value
*V
= ThreadBinOpOverSelect(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1112 // If the operation is with the result of a phi instruction, check whether
1113 // operating on all incoming values of the phi always yields the same value.
1114 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1115 if (Value
*V
= ThreadBinOpOverPHI(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1118 // If X / Y == 0, then X % Y == X.
1119 if (isDivZero(Op0
, Op1
, Q
, MaxRecurse
, Opcode
== Instruction::SRem
))
1125 /// Given operands for an SDiv, see if we can fold the result.
1126 /// If not, this returns null.
1127 static Value
*SimplifySDivInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1128 unsigned MaxRecurse
) {
1129 // If two operands are negated and no signed overflow, return -1.
1130 if (isKnownNegation(Op0
, Op1
, /*NeedNSW=*/true))
1131 return Constant::getAllOnesValue(Op0
->getType());
1133 return simplifyDiv(Instruction::SDiv
, Op0
, Op1
, Q
, MaxRecurse
);
1136 Value
*llvm::SimplifySDivInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1137 return ::SimplifySDivInst(Op0
, Op1
, Q
, RecursionLimit
);
1140 /// Given operands for a UDiv, see if we can fold the result.
1141 /// If not, this returns null.
1142 static Value
*SimplifyUDivInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1143 unsigned MaxRecurse
) {
1144 return simplifyDiv(Instruction::UDiv
, Op0
, Op1
, Q
, MaxRecurse
);
1147 Value
*llvm::SimplifyUDivInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1148 return ::SimplifyUDivInst(Op0
, Op1
, Q
, RecursionLimit
);
1151 /// Given operands for an SRem, see if we can fold the result.
1152 /// If not, this returns null.
1153 static Value
*SimplifySRemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1154 unsigned MaxRecurse
) {
1155 // If the divisor is 0, the result is undefined, so assume the divisor is -1.
1156 // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
1158 if (match(Op1
, m_SExt(m_Value(X
))) && X
->getType()->isIntOrIntVectorTy(1))
1159 return ConstantInt::getNullValue(Op0
->getType());
1161 // If the two operands are negated, return 0.
1162 if (isKnownNegation(Op0
, Op1
))
1163 return ConstantInt::getNullValue(Op0
->getType());
1165 return simplifyRem(Instruction::SRem
, Op0
, Op1
, Q
, MaxRecurse
);
1168 Value
*llvm::SimplifySRemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1169 return ::SimplifySRemInst(Op0
, Op1
, Q
, RecursionLimit
);
1172 /// Given operands for a URem, see if we can fold the result.
1173 /// If not, this returns null.
1174 static Value
*SimplifyURemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1175 unsigned MaxRecurse
) {
1176 return simplifyRem(Instruction::URem
, Op0
, Op1
, Q
, MaxRecurse
);
1179 Value
*llvm::SimplifyURemInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1180 return ::SimplifyURemInst(Op0
, Op1
, Q
, RecursionLimit
);
1183 /// Returns true if a shift by \c Amount always yields undef.
1184 static bool isUndefShift(Value
*Amount
) {
1185 Constant
*C
= dyn_cast
<Constant
>(Amount
);
1189 // X shift by undef -> undef because it may shift by the bitwidth.
1190 if (isa
<UndefValue
>(C
))
1193 // Shifting by the bitwidth or more is undefined.
1194 if (ConstantInt
*CI
= dyn_cast
<ConstantInt
>(C
))
1195 if (CI
->getValue().getLimitedValue() >=
1196 CI
->getType()->getScalarSizeInBits())
1199 // If all lanes of a vector shift are undefined the whole shift is.
1200 if (isa
<ConstantVector
>(C
) || isa
<ConstantDataVector
>(C
)) {
1201 for (unsigned I
= 0, E
= C
->getType()->getVectorNumElements(); I
!= E
; ++I
)
1202 if (!isUndefShift(C
->getAggregateElement(I
)))
1210 /// Given operands for an Shl, LShr or AShr, see if we can fold the result.
1211 /// If not, this returns null.
1212 static Value
*SimplifyShift(Instruction::BinaryOps Opcode
, Value
*Op0
,
1213 Value
*Op1
, const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1214 if (Constant
*C
= foldOrCommuteConstant(Opcode
, Op0
, Op1
, Q
))
1217 // 0 shift by X -> 0
1218 if (match(Op0
, m_Zero()))
1219 return Constant::getNullValue(Op0
->getType());
1221 // X shift by 0 -> X
1222 // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
1225 if (match(Op1
, m_Zero()) ||
1226 (match(Op1
, m_SExt(m_Value(X
))) && X
->getType()->isIntOrIntVectorTy(1)))
1229 // Fold undefined shifts.
1230 if (isUndefShift(Op1
))
1231 return UndefValue::get(Op0
->getType());
1233 // If the operation is with the result of a select instruction, check whether
1234 // operating on either branch of the select always yields the same value.
1235 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1236 if (Value
*V
= ThreadBinOpOverSelect(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1239 // If the operation is with the result of a phi instruction, check whether
1240 // operating on all incoming values of the phi always yields the same value.
1241 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1242 if (Value
*V
= ThreadBinOpOverPHI(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1245 // If any bits in the shift amount make that value greater than or equal to
1246 // the number of bits in the type, the shift is undefined.
1247 KnownBits Known
= computeKnownBits(Op1
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1248 if (Known
.One
.getLimitedValue() >= Known
.getBitWidth())
1249 return UndefValue::get(Op0
->getType());
1251 // If all valid bits in the shift amount are known zero, the first operand is
1253 unsigned NumValidShiftBits
= Log2_32_Ceil(Known
.getBitWidth());
1254 if (Known
.countMinTrailingZeros() >= NumValidShiftBits
)
1260 /// Given operands for an Shl, LShr or AShr, see if we can
1261 /// fold the result. If not, this returns null.
1262 static Value
*SimplifyRightShift(Instruction::BinaryOps Opcode
, Value
*Op0
,
1263 Value
*Op1
, bool isExact
, const SimplifyQuery
&Q
,
1264 unsigned MaxRecurse
) {
1265 if (Value
*V
= SimplifyShift(Opcode
, Op0
, Op1
, Q
, MaxRecurse
))
1270 return Constant::getNullValue(Op0
->getType());
1273 // undef >> X -> undef (if it's exact)
1274 if (match(Op0
, m_Undef()))
1275 return isExact
? Op0
: Constant::getNullValue(Op0
->getType());
1277 // The low bit cannot be shifted out of an exact shift if it is set.
1279 KnownBits Op0Known
= computeKnownBits(Op0
, Q
.DL
, /*Depth=*/0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1280 if (Op0Known
.One
[0])
1287 /// Given operands for an Shl, see if we can fold the result.
1288 /// If not, this returns null.
1289 static Value
*SimplifyShlInst(Value
*Op0
, Value
*Op1
, bool isNSW
, bool isNUW
,
1290 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1291 if (Value
*V
= SimplifyShift(Instruction::Shl
, Op0
, Op1
, Q
, MaxRecurse
))
1295 // undef << X -> undef if (if it's NSW/NUW)
1296 if (match(Op0
, m_Undef()))
1297 return isNSW
|| isNUW
? Op0
: Constant::getNullValue(Op0
->getType());
1299 // (X >> A) << A -> X
1301 if (Q
.IIQ
.UseInstrInfo
&&
1302 match(Op0
, m_Exact(m_Shr(m_Value(X
), m_Specific(Op1
)))))
1305 // shl nuw i8 C, %x -> C iff C has sign bit set.
1306 if (isNUW
&& match(Op0
, m_Negative()))
1308 // NOTE: could use computeKnownBits() / LazyValueInfo,
1309 // but the cost-benefit analysis suggests it isn't worth it.
1314 Value
*llvm::SimplifyShlInst(Value
*Op0
, Value
*Op1
, bool isNSW
, bool isNUW
,
1315 const SimplifyQuery
&Q
) {
1316 return ::SimplifyShlInst(Op0
, Op1
, isNSW
, isNUW
, Q
, RecursionLimit
);
1319 /// Given operands for an LShr, see if we can fold the result.
1320 /// If not, this returns null.
1321 static Value
*SimplifyLShrInst(Value
*Op0
, Value
*Op1
, bool isExact
,
1322 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1323 if (Value
*V
= SimplifyRightShift(Instruction::LShr
, Op0
, Op1
, isExact
, Q
,
1327 // (X << A) >> A -> X
1329 if (match(Op0
, m_NUWShl(m_Value(X
), m_Specific(Op1
))))
1332 // ((X << A) | Y) >> A -> X if effective width of Y is not larger than A.
1333 // We can return X as we do in the above case since OR alters no bits in X.
1334 // SimplifyDemandedBits in InstCombine can do more general optimization for
1335 // bit manipulation. This pattern aims to provide opportunities for other
1336 // optimizers by supporting a simple but common case in InstSimplify.
1338 const APInt
*ShRAmt
, *ShLAmt
;
1339 if (match(Op1
, m_APInt(ShRAmt
)) &&
1340 match(Op0
, m_c_Or(m_NUWShl(m_Value(X
), m_APInt(ShLAmt
)), m_Value(Y
))) &&
1341 *ShRAmt
== *ShLAmt
) {
1342 const KnownBits YKnown
= computeKnownBits(Y
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1343 const unsigned Width
= Op0
->getType()->getScalarSizeInBits();
1344 const unsigned EffWidthY
= Width
- YKnown
.countMinLeadingZeros();
1345 if (ShRAmt
->uge(EffWidthY
))
1352 Value
*llvm::SimplifyLShrInst(Value
*Op0
, Value
*Op1
, bool isExact
,
1353 const SimplifyQuery
&Q
) {
1354 return ::SimplifyLShrInst(Op0
, Op1
, isExact
, Q
, RecursionLimit
);
1357 /// Given operands for an AShr, see if we can fold the result.
1358 /// If not, this returns null.
1359 static Value
*SimplifyAShrInst(Value
*Op0
, Value
*Op1
, bool isExact
,
1360 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
1361 if (Value
*V
= SimplifyRightShift(Instruction::AShr
, Op0
, Op1
, isExact
, Q
,
1365 // all ones >>a X -> -1
1366 // Do not return Op0 because it may contain undef elements if it's a vector.
1367 if (match(Op0
, m_AllOnes()))
1368 return Constant::getAllOnesValue(Op0
->getType());
1370 // (X << A) >> A -> X
1372 if (Q
.IIQ
.UseInstrInfo
&& match(Op0
, m_NSWShl(m_Value(X
), m_Specific(Op1
))))
1375 // Arithmetic shifting an all-sign-bit value is a no-op.
1376 unsigned NumSignBits
= ComputeNumSignBits(Op0
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1377 if (NumSignBits
== Op0
->getType()->getScalarSizeInBits())
1383 Value
*llvm::SimplifyAShrInst(Value
*Op0
, Value
*Op1
, bool isExact
,
1384 const SimplifyQuery
&Q
) {
1385 return ::SimplifyAShrInst(Op0
, Op1
, isExact
, Q
, RecursionLimit
);
1388 /// Commuted variants are assumed to be handled by calling this function again
1389 /// with the parameters swapped.
1390 static Value
*simplifyUnsignedRangeCheck(ICmpInst
*ZeroICmp
,
1391 ICmpInst
*UnsignedICmp
, bool IsAnd
) {
1394 ICmpInst::Predicate EqPred
;
1395 if (!match(ZeroICmp
, m_ICmp(EqPred
, m_Value(Y
), m_Zero())) ||
1396 !ICmpInst::isEquality(EqPred
))
1399 ICmpInst::Predicate UnsignedPred
;
1400 if (match(UnsignedICmp
, m_ICmp(UnsignedPred
, m_Value(X
), m_Specific(Y
))) &&
1401 ICmpInst::isUnsigned(UnsignedPred
))
1403 else if (match(UnsignedICmp
,
1404 m_ICmp(UnsignedPred
, m_Specific(Y
), m_Value(X
))) &&
1405 ICmpInst::isUnsigned(UnsignedPred
))
1406 UnsignedPred
= ICmpInst::getSwappedPredicate(UnsignedPred
);
1410 // X < Y && Y != 0 --> X < Y
1411 // X < Y || Y != 0 --> Y != 0
1412 if (UnsignedPred
== ICmpInst::ICMP_ULT
&& EqPred
== ICmpInst::ICMP_NE
)
1413 return IsAnd
? UnsignedICmp
: ZeroICmp
;
1415 // X >= Y || Y != 0 --> true
1416 // X >= Y || Y == 0 --> X >= Y
1417 if (UnsignedPred
== ICmpInst::ICMP_UGE
&& !IsAnd
) {
1418 if (EqPred
== ICmpInst::ICMP_NE
)
1419 return getTrue(UnsignedICmp
->getType());
1420 return UnsignedICmp
;
1423 // X < Y && Y == 0 --> false
1424 if (UnsignedPred
== ICmpInst::ICMP_ULT
&& EqPred
== ICmpInst::ICMP_EQ
&&
1426 return getFalse(UnsignedICmp
->getType());
1431 /// Commuted variants are assumed to be handled by calling this function again
1432 /// with the parameters swapped.
1433 static Value
*simplifyAndOfICmpsWithSameOperands(ICmpInst
*Op0
, ICmpInst
*Op1
) {
1434 ICmpInst::Predicate Pred0
, Pred1
;
1436 if (!match(Op0
, m_ICmp(Pred0
, m_Value(A
), m_Value(B
))) ||
1437 !match(Op1
, m_ICmp(Pred1
, m_Specific(A
), m_Specific(B
))))
1440 // We have (icmp Pred0, A, B) & (icmp Pred1, A, B).
1441 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1442 // can eliminate Op1 from this 'and'.
1443 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0
, Pred1
))
1446 // Check for any combination of predicates that are guaranteed to be disjoint.
1447 if ((Pred0
== ICmpInst::getInversePredicate(Pred1
)) ||
1448 (Pred0
== ICmpInst::ICMP_EQ
&& ICmpInst::isFalseWhenEqual(Pred1
)) ||
1449 (Pred0
== ICmpInst::ICMP_SLT
&& Pred1
== ICmpInst::ICMP_SGT
) ||
1450 (Pred0
== ICmpInst::ICMP_ULT
&& Pred1
== ICmpInst::ICMP_UGT
))
1451 return getFalse(Op0
->getType());
1456 /// Commuted variants are assumed to be handled by calling this function again
1457 /// with the parameters swapped.
1458 static Value
*simplifyOrOfICmpsWithSameOperands(ICmpInst
*Op0
, ICmpInst
*Op1
) {
1459 ICmpInst::Predicate Pred0
, Pred1
;
1461 if (!match(Op0
, m_ICmp(Pred0
, m_Value(A
), m_Value(B
))) ||
1462 !match(Op1
, m_ICmp(Pred1
, m_Specific(A
), m_Specific(B
))))
1465 // We have (icmp Pred0, A, B) | (icmp Pred1, A, B).
1466 // If Op1 is always implied true by Op0, then Op0 is a subset of Op1, and we
1467 // can eliminate Op0 from this 'or'.
1468 if (ICmpInst::isImpliedTrueByMatchingCmp(Pred0
, Pred1
))
1471 // Check for any combination of predicates that cover the entire range of
1473 if ((Pred0
== ICmpInst::getInversePredicate(Pred1
)) ||
1474 (Pred0
== ICmpInst::ICMP_NE
&& ICmpInst::isTrueWhenEqual(Pred1
)) ||
1475 (Pred0
== ICmpInst::ICMP_SLE
&& Pred1
== ICmpInst::ICMP_SGE
) ||
1476 (Pred0
== ICmpInst::ICMP_ULE
&& Pred1
== ICmpInst::ICMP_UGE
))
1477 return getTrue(Op0
->getType());
1482 /// Test if a pair of compares with a shared operand and 2 constants has an
1483 /// empty set intersection, full set union, or if one compare is a superset of
1485 static Value
*simplifyAndOrOfICmpsWithConstants(ICmpInst
*Cmp0
, ICmpInst
*Cmp1
,
1487 // Look for this pattern: {and/or} (icmp X, C0), (icmp X, C1)).
1488 if (Cmp0
->getOperand(0) != Cmp1
->getOperand(0))
1491 const APInt
*C0
, *C1
;
1492 if (!match(Cmp0
->getOperand(1), m_APInt(C0
)) ||
1493 !match(Cmp1
->getOperand(1), m_APInt(C1
)))
1496 auto Range0
= ConstantRange::makeExactICmpRegion(Cmp0
->getPredicate(), *C0
);
1497 auto Range1
= ConstantRange::makeExactICmpRegion(Cmp1
->getPredicate(), *C1
);
1499 // For and-of-compares, check if the intersection is empty:
1500 // (icmp X, C0) && (icmp X, C1) --> empty set --> false
1501 if (IsAnd
&& Range0
.intersectWith(Range1
).isEmptySet())
1502 return getFalse(Cmp0
->getType());
1504 // For or-of-compares, check if the union is full:
1505 // (icmp X, C0) || (icmp X, C1) --> full set --> true
1506 if (!IsAnd
&& Range0
.unionWith(Range1
).isFullSet())
1507 return getTrue(Cmp0
->getType());
1509 // Is one range a superset of the other?
1510 // If this is and-of-compares, take the smaller set:
1511 // (icmp sgt X, 4) && (icmp sgt X, 42) --> icmp sgt X, 42
1512 // If this is or-of-compares, take the larger set:
1513 // (icmp sgt X, 4) || (icmp sgt X, 42) --> icmp sgt X, 4
1514 if (Range0
.contains(Range1
))
1515 return IsAnd
? Cmp1
: Cmp0
;
1516 if (Range1
.contains(Range0
))
1517 return IsAnd
? Cmp0
: Cmp1
;
1522 static Value
*simplifyAndOrOfICmpsWithZero(ICmpInst
*Cmp0
, ICmpInst
*Cmp1
,
1524 ICmpInst::Predicate P0
= Cmp0
->getPredicate(), P1
= Cmp1
->getPredicate();
1525 if (!match(Cmp0
->getOperand(1), m_Zero()) ||
1526 !match(Cmp1
->getOperand(1), m_Zero()) || P0
!= P1
)
1529 if ((IsAnd
&& P0
!= ICmpInst::ICMP_NE
) || (!IsAnd
&& P1
!= ICmpInst::ICMP_EQ
))
1532 // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
1533 Value
*X
= Cmp0
->getOperand(0);
1534 Value
*Y
= Cmp1
->getOperand(0);
1536 // If one of the compares is a masked version of a (not) null check, then
1537 // that compare implies the other, so we eliminate the other. Optionally, look
1538 // through a pointer-to-int cast to match a null check of a pointer type.
1540 // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
1541 // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
1542 // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
1543 // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
1544 if (match(Y
, m_c_And(m_Specific(X
), m_Value())) ||
1545 match(Y
, m_c_And(m_PtrToInt(m_Specific(X
)), m_Value())))
1548 // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
1549 // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
1550 // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
1551 // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
1552 if (match(X
, m_c_And(m_Specific(Y
), m_Value())) ||
1553 match(X
, m_c_And(m_PtrToInt(m_Specific(Y
)), m_Value())))
1559 static Value
*simplifyAndOfICmpsWithAdd(ICmpInst
*Op0
, ICmpInst
*Op1
,
1560 const InstrInfoQuery
&IIQ
) {
1561 // (icmp (add V, C0), C1) & (icmp V, C0)
1562 ICmpInst::Predicate Pred0
, Pred1
;
1563 const APInt
*C0
, *C1
;
1565 if (!match(Op0
, m_ICmp(Pred0
, m_Add(m_Value(V
), m_APInt(C0
)), m_APInt(C1
))))
1568 if (!match(Op1
, m_ICmp(Pred1
, m_Specific(V
), m_Value())))
1571 auto *AddInst
= cast
<OverflowingBinaryOperator
>(Op0
->getOperand(0));
1572 if (AddInst
->getOperand(1) != Op1
->getOperand(1))
1575 Type
*ITy
= Op0
->getType();
1576 bool isNSW
= IIQ
.hasNoSignedWrap(AddInst
);
1577 bool isNUW
= IIQ
.hasNoUnsignedWrap(AddInst
);
1579 const APInt Delta
= *C1
- *C0
;
1580 if (C0
->isStrictlyPositive()) {
1582 if (Pred0
== ICmpInst::ICMP_ULT
&& Pred1
== ICmpInst::ICMP_SGT
)
1583 return getFalse(ITy
);
1584 if (Pred0
== ICmpInst::ICMP_SLT
&& Pred1
== ICmpInst::ICMP_SGT
&& isNSW
)
1585 return getFalse(ITy
);
1588 if (Pred0
== ICmpInst::ICMP_ULE
&& Pred1
== ICmpInst::ICMP_SGT
)
1589 return getFalse(ITy
);
1590 if (Pred0
== ICmpInst::ICMP_SLE
&& Pred1
== ICmpInst::ICMP_SGT
&& isNSW
)
1591 return getFalse(ITy
);
1594 if (C0
->getBoolValue() && isNUW
) {
1596 if (Pred0
== ICmpInst::ICMP_ULT
&& Pred1
== ICmpInst::ICMP_UGT
)
1597 return getFalse(ITy
);
1599 if (Pred0
== ICmpInst::ICMP_ULE
&& Pred1
== ICmpInst::ICMP_UGT
)
1600 return getFalse(ITy
);
1606 static Value
*simplifyAndOfICmps(ICmpInst
*Op0
, ICmpInst
*Op1
,
1607 const InstrInfoQuery
&IIQ
) {
1608 if (Value
*X
= simplifyUnsignedRangeCheck(Op0
, Op1
, /*IsAnd=*/true))
1610 if (Value
*X
= simplifyUnsignedRangeCheck(Op1
, Op0
, /*IsAnd=*/true))
1613 if (Value
*X
= simplifyAndOfICmpsWithSameOperands(Op0
, Op1
))
1615 if (Value
*X
= simplifyAndOfICmpsWithSameOperands(Op1
, Op0
))
1618 if (Value
*X
= simplifyAndOrOfICmpsWithConstants(Op0
, Op1
, true))
1621 if (Value
*X
= simplifyAndOrOfICmpsWithZero(Op0
, Op1
, true))
1624 if (Value
*X
= simplifyAndOfICmpsWithAdd(Op0
, Op1
, IIQ
))
1626 if (Value
*X
= simplifyAndOfICmpsWithAdd(Op1
, Op0
, IIQ
))
1632 static Value
*simplifyOrOfICmpsWithAdd(ICmpInst
*Op0
, ICmpInst
*Op1
,
1633 const InstrInfoQuery
&IIQ
) {
1634 // (icmp (add V, C0), C1) | (icmp V, C0)
1635 ICmpInst::Predicate Pred0
, Pred1
;
1636 const APInt
*C0
, *C1
;
1638 if (!match(Op0
, m_ICmp(Pred0
, m_Add(m_Value(V
), m_APInt(C0
)), m_APInt(C1
))))
1641 if (!match(Op1
, m_ICmp(Pred1
, m_Specific(V
), m_Value())))
1644 auto *AddInst
= cast
<BinaryOperator
>(Op0
->getOperand(0));
1645 if (AddInst
->getOperand(1) != Op1
->getOperand(1))
1648 Type
*ITy
= Op0
->getType();
1649 bool isNSW
= IIQ
.hasNoSignedWrap(AddInst
);
1650 bool isNUW
= IIQ
.hasNoUnsignedWrap(AddInst
);
1652 const APInt Delta
= *C1
- *C0
;
1653 if (C0
->isStrictlyPositive()) {
1655 if (Pred0
== ICmpInst::ICMP_UGE
&& Pred1
== ICmpInst::ICMP_SLE
)
1656 return getTrue(ITy
);
1657 if (Pred0
== ICmpInst::ICMP_SGE
&& Pred1
== ICmpInst::ICMP_SLE
&& isNSW
)
1658 return getTrue(ITy
);
1661 if (Pred0
== ICmpInst::ICMP_UGT
&& Pred1
== ICmpInst::ICMP_SLE
)
1662 return getTrue(ITy
);
1663 if (Pred0
== ICmpInst::ICMP_SGT
&& Pred1
== ICmpInst::ICMP_SLE
&& isNSW
)
1664 return getTrue(ITy
);
1667 if (C0
->getBoolValue() && isNUW
) {
1669 if (Pred0
== ICmpInst::ICMP_UGE
&& Pred1
== ICmpInst::ICMP_ULE
)
1670 return getTrue(ITy
);
1672 if (Pred0
== ICmpInst::ICMP_UGT
&& Pred1
== ICmpInst::ICMP_ULE
)
1673 return getTrue(ITy
);
1679 static Value
*simplifyOrOfICmps(ICmpInst
*Op0
, ICmpInst
*Op1
,
1680 const InstrInfoQuery
&IIQ
) {
1681 if (Value
*X
= simplifyUnsignedRangeCheck(Op0
, Op1
, /*IsAnd=*/false))
1683 if (Value
*X
= simplifyUnsignedRangeCheck(Op1
, Op0
, /*IsAnd=*/false))
1686 if (Value
*X
= simplifyOrOfICmpsWithSameOperands(Op0
, Op1
))
1688 if (Value
*X
= simplifyOrOfICmpsWithSameOperands(Op1
, Op0
))
1691 if (Value
*X
= simplifyAndOrOfICmpsWithConstants(Op0
, Op1
, false))
1694 if (Value
*X
= simplifyAndOrOfICmpsWithZero(Op0
, Op1
, false))
1697 if (Value
*X
= simplifyOrOfICmpsWithAdd(Op0
, Op1
, IIQ
))
1699 if (Value
*X
= simplifyOrOfICmpsWithAdd(Op1
, Op0
, IIQ
))
1705 static Value
*simplifyAndOrOfFCmps(const TargetLibraryInfo
*TLI
,
1706 FCmpInst
*LHS
, FCmpInst
*RHS
, bool IsAnd
) {
1707 Value
*LHS0
= LHS
->getOperand(0), *LHS1
= LHS
->getOperand(1);
1708 Value
*RHS0
= RHS
->getOperand(0), *RHS1
= RHS
->getOperand(1);
1709 if (LHS0
->getType() != RHS0
->getType())
1712 FCmpInst::Predicate PredL
= LHS
->getPredicate(), PredR
= RHS
->getPredicate();
1713 if ((PredL
== FCmpInst::FCMP_ORD
&& PredR
== FCmpInst::FCMP_ORD
&& IsAnd
) ||
1714 (PredL
== FCmpInst::FCMP_UNO
&& PredR
== FCmpInst::FCMP_UNO
&& !IsAnd
)) {
1715 // (fcmp ord NNAN, X) & (fcmp ord X, Y) --> fcmp ord X, Y
1716 // (fcmp ord NNAN, X) & (fcmp ord Y, X) --> fcmp ord Y, X
1717 // (fcmp ord X, NNAN) & (fcmp ord X, Y) --> fcmp ord X, Y
1718 // (fcmp ord X, NNAN) & (fcmp ord Y, X) --> fcmp ord Y, X
1719 // (fcmp uno NNAN, X) | (fcmp uno X, Y) --> fcmp uno X, Y
1720 // (fcmp uno NNAN, X) | (fcmp uno Y, X) --> fcmp uno Y, X
1721 // (fcmp uno X, NNAN) | (fcmp uno X, Y) --> fcmp uno X, Y
1722 // (fcmp uno X, NNAN) | (fcmp uno Y, X) --> fcmp uno Y, X
1723 if ((isKnownNeverNaN(LHS0
, TLI
) && (LHS1
== RHS0
|| LHS1
== RHS1
)) ||
1724 (isKnownNeverNaN(LHS1
, TLI
) && (LHS0
== RHS0
|| LHS0
== RHS1
)))
1727 // (fcmp ord X, Y) & (fcmp ord NNAN, X) --> fcmp ord X, Y
1728 // (fcmp ord Y, X) & (fcmp ord NNAN, X) --> fcmp ord Y, X
1729 // (fcmp ord X, Y) & (fcmp ord X, NNAN) --> fcmp ord X, Y
1730 // (fcmp ord Y, X) & (fcmp ord X, NNAN) --> fcmp ord Y, X
1731 // (fcmp uno X, Y) | (fcmp uno NNAN, X) --> fcmp uno X, Y
1732 // (fcmp uno Y, X) | (fcmp uno NNAN, X) --> fcmp uno Y, X
1733 // (fcmp uno X, Y) | (fcmp uno X, NNAN) --> fcmp uno X, Y
1734 // (fcmp uno Y, X) | (fcmp uno X, NNAN) --> fcmp uno Y, X
1735 if ((isKnownNeverNaN(RHS0
, TLI
) && (RHS1
== LHS0
|| RHS1
== LHS1
)) ||
1736 (isKnownNeverNaN(RHS1
, TLI
) && (RHS0
== LHS0
|| RHS0
== LHS1
)))
1743 static Value
*simplifyAndOrOfCmps(const SimplifyQuery
&Q
,
1744 Value
*Op0
, Value
*Op1
, bool IsAnd
) {
1745 // Look through casts of the 'and' operands to find compares.
1746 auto *Cast0
= dyn_cast
<CastInst
>(Op0
);
1747 auto *Cast1
= dyn_cast
<CastInst
>(Op1
);
1748 if (Cast0
&& Cast1
&& Cast0
->getOpcode() == Cast1
->getOpcode() &&
1749 Cast0
->getSrcTy() == Cast1
->getSrcTy()) {
1750 Op0
= Cast0
->getOperand(0);
1751 Op1
= Cast1
->getOperand(0);
1755 auto *ICmp0
= dyn_cast
<ICmpInst
>(Op0
);
1756 auto *ICmp1
= dyn_cast
<ICmpInst
>(Op1
);
1758 V
= IsAnd
? simplifyAndOfICmps(ICmp0
, ICmp1
, Q
.IIQ
)
1759 : simplifyOrOfICmps(ICmp0
, ICmp1
, Q
.IIQ
);
1761 auto *FCmp0
= dyn_cast
<FCmpInst
>(Op0
);
1762 auto *FCmp1
= dyn_cast
<FCmpInst
>(Op1
);
1764 V
= simplifyAndOrOfFCmps(Q
.TLI
, FCmp0
, FCmp1
, IsAnd
);
1771 // If we looked through casts, we can only handle a constant simplification
1772 // because we are not allowed to create a cast instruction here.
1773 if (auto *C
= dyn_cast
<Constant
>(V
))
1774 return ConstantExpr::getCast(Cast0
->getOpcode(), C
, Cast0
->getType());
1779 /// Given operands for an And, see if we can fold the result.
1780 /// If not, this returns null.
1781 static Value
*SimplifyAndInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1782 unsigned MaxRecurse
) {
1783 if (Constant
*C
= foldOrCommuteConstant(Instruction::And
, Op0
, Op1
, Q
))
1787 if (match(Op1
, m_Undef()))
1788 return Constant::getNullValue(Op0
->getType());
1795 if (match(Op1
, m_Zero()))
1796 return Constant::getNullValue(Op0
->getType());
1799 if (match(Op1
, m_AllOnes()))
1802 // A & ~A = ~A & A = 0
1803 if (match(Op0
, m_Not(m_Specific(Op1
))) ||
1804 match(Op1
, m_Not(m_Specific(Op0
))))
1805 return Constant::getNullValue(Op0
->getType());
1808 if (match(Op0
, m_c_Or(m_Specific(Op1
), m_Value())))
1812 if (match(Op1
, m_c_Or(m_Specific(Op0
), m_Value())))
1815 // A mask that only clears known zeros of a shifted value is a no-op.
1819 if (match(Op1
, m_APInt(Mask
))) {
1820 // If all bits in the inverted and shifted mask are clear:
1821 // and (shl X, ShAmt), Mask --> shl X, ShAmt
1822 if (match(Op0
, m_Shl(m_Value(X
), m_APInt(ShAmt
))) &&
1823 (~(*Mask
)).lshr(*ShAmt
).isNullValue())
1826 // If all bits in the inverted and shifted mask are clear:
1827 // and (lshr X, ShAmt), Mask --> lshr X, ShAmt
1828 if (match(Op0
, m_LShr(m_Value(X
), m_APInt(ShAmt
))) &&
1829 (~(*Mask
)).shl(*ShAmt
).isNullValue())
1833 // A & (-A) = A if A is a power of two or zero.
1834 if (match(Op0
, m_Neg(m_Specific(Op1
))) ||
1835 match(Op1
, m_Neg(m_Specific(Op0
)))) {
1836 if (isKnownToBeAPowerOfTwo(Op0
, Q
.DL
, /*OrZero*/ true, 0, Q
.AC
, Q
.CxtI
,
1839 if (isKnownToBeAPowerOfTwo(Op1
, Q
.DL
, /*OrZero*/ true, 0, Q
.AC
, Q
.CxtI
,
1844 if (Value
*V
= simplifyAndOrOfCmps(Q
, Op0
, Op1
, true))
1847 // Try some generic simplifications for associative operations.
1848 if (Value
*V
= SimplifyAssociativeBinOp(Instruction::And
, Op0
, Op1
, Q
,
1852 // And distributes over Or. Try some generic simplifications based on this.
1853 if (Value
*V
= ExpandBinOp(Instruction::And
, Op0
, Op1
, Instruction::Or
,
1857 // And distributes over Xor. Try some generic simplifications based on this.
1858 if (Value
*V
= ExpandBinOp(Instruction::And
, Op0
, Op1
, Instruction::Xor
,
1862 // If the operation is with the result of a select instruction, check whether
1863 // operating on either branch of the select always yields the same value.
1864 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
1865 if (Value
*V
= ThreadBinOpOverSelect(Instruction::And
, Op0
, Op1
, Q
,
1869 // If the operation is with the result of a phi instruction, check whether
1870 // operating on all incoming values of the phi always yields the same value.
1871 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
1872 if (Value
*V
= ThreadBinOpOverPHI(Instruction::And
, Op0
, Op1
, Q
,
1876 // Assuming the effective width of Y is not larger than A, i.e. all bits
1877 // from X and Y are disjoint in (X << A) | Y,
1878 // if the mask of this AND op covers all bits of X or Y, while it covers
1879 // no bits from the other, we can bypass this AND op. E.g.,
1880 // ((X << A) | Y) & Mask -> Y,
1881 // if Mask = ((1 << effective_width_of(Y)) - 1)
1882 // ((X << A) | Y) & Mask -> X << A,
1883 // if Mask = ((1 << effective_width_of(X)) - 1) << A
1884 // SimplifyDemandedBits in InstCombine can optimize the general case.
1885 // This pattern aims to help other passes for a common case.
1886 Value
*Y
, *XShifted
;
1887 if (match(Op1
, m_APInt(Mask
)) &&
1888 match(Op0
, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X
), m_APInt(ShAmt
)),
1891 const unsigned Width
= Op0
->getType()->getScalarSizeInBits();
1892 const unsigned ShftCnt
= ShAmt
->getLimitedValue(Width
);
1893 const KnownBits YKnown
= computeKnownBits(Y
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
1894 const unsigned EffWidthY
= Width
- YKnown
.countMinLeadingZeros();
1895 if (EffWidthY
<= ShftCnt
) {
1896 const KnownBits XKnown
= computeKnownBits(X
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
,
1898 const unsigned EffWidthX
= Width
- XKnown
.countMinLeadingZeros();
1899 const APInt EffBitsY
= APInt::getLowBitsSet(Width
, EffWidthY
);
1900 const APInt EffBitsX
= APInt::getLowBitsSet(Width
, EffWidthX
) << ShftCnt
;
1901 // If the mask is extracting all bits from X or Y as is, we can skip
1903 if (EffBitsY
.isSubsetOf(*Mask
) && !EffBitsX
.intersects(*Mask
))
1905 if (EffBitsX
.isSubsetOf(*Mask
) && !EffBitsY
.intersects(*Mask
))
1913 Value
*llvm::SimplifyAndInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
1914 return ::SimplifyAndInst(Op0
, Op1
, Q
, RecursionLimit
);
1917 /// Given operands for an Or, see if we can fold the result.
1918 /// If not, this returns null.
1919 static Value
*SimplifyOrInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
1920 unsigned MaxRecurse
) {
1921 if (Constant
*C
= foldOrCommuteConstant(Instruction::Or
, Op0
, Op1
, Q
))
1926 // Do not return Op1 because it may contain undef elements if it's a vector.
1927 if (match(Op1
, m_Undef()) || match(Op1
, m_AllOnes()))
1928 return Constant::getAllOnesValue(Op0
->getType());
1932 if (Op0
== Op1
|| match(Op1
, m_Zero()))
1935 // A | ~A = ~A | A = -1
1936 if (match(Op0
, m_Not(m_Specific(Op1
))) ||
1937 match(Op1
, m_Not(m_Specific(Op0
))))
1938 return Constant::getAllOnesValue(Op0
->getType());
1941 if (match(Op0
, m_c_And(m_Specific(Op1
), m_Value())))
1945 if (match(Op1
, m_c_And(m_Specific(Op0
), m_Value())))
1948 // ~(A & ?) | A = -1
1949 if (match(Op0
, m_Not(m_c_And(m_Specific(Op1
), m_Value()))))
1950 return Constant::getAllOnesValue(Op1
->getType());
1952 // A | ~(A & ?) = -1
1953 if (match(Op1
, m_Not(m_c_And(m_Specific(Op1
), m_Value()))))
1954 return Constant::getAllOnesValue(Op0
->getType());
1957 // (A & ~B) | (A ^ B) -> (A ^ B)
1958 // (~B & A) | (A ^ B) -> (A ^ B)
1959 // (A & ~B) | (B ^ A) -> (B ^ A)
1960 // (~B & A) | (B ^ A) -> (B ^ A)
1961 if (match(Op1
, m_Xor(m_Value(A
), m_Value(B
))) &&
1962 (match(Op0
, m_c_And(m_Specific(A
), m_Not(m_Specific(B
)))) ||
1963 match(Op0
, m_c_And(m_Not(m_Specific(A
)), m_Specific(B
)))))
1966 // Commute the 'or' operands.
1967 // (A ^ B) | (A & ~B) -> (A ^ B)
1968 // (A ^ B) | (~B & A) -> (A ^ B)
1969 // (B ^ A) | (A & ~B) -> (B ^ A)
1970 // (B ^ A) | (~B & A) -> (B ^ A)
1971 if (match(Op0
, m_Xor(m_Value(A
), m_Value(B
))) &&
1972 (match(Op1
, m_c_And(m_Specific(A
), m_Not(m_Specific(B
)))) ||
1973 match(Op1
, m_c_And(m_Not(m_Specific(A
)), m_Specific(B
)))))
1976 // (A & B) | (~A ^ B) -> (~A ^ B)
1977 // (B & A) | (~A ^ B) -> (~A ^ B)
1978 // (A & B) | (B ^ ~A) -> (B ^ ~A)
1979 // (B & A) | (B ^ ~A) -> (B ^ ~A)
1980 if (match(Op0
, m_And(m_Value(A
), m_Value(B
))) &&
1981 (match(Op1
, m_c_Xor(m_Specific(A
), m_Not(m_Specific(B
)))) ||
1982 match(Op1
, m_c_Xor(m_Not(m_Specific(A
)), m_Specific(B
)))))
1985 // (~A ^ B) | (A & B) -> (~A ^ B)
1986 // (~A ^ B) | (B & A) -> (~A ^ B)
1987 // (B ^ ~A) | (A & B) -> (B ^ ~A)
1988 // (B ^ ~A) | (B & A) -> (B ^ ~A)
1989 if (match(Op1
, m_And(m_Value(A
), m_Value(B
))) &&
1990 (match(Op0
, m_c_Xor(m_Specific(A
), m_Not(m_Specific(B
)))) ||
1991 match(Op0
, m_c_Xor(m_Not(m_Specific(A
)), m_Specific(B
)))))
1994 if (Value
*V
= simplifyAndOrOfCmps(Q
, Op0
, Op1
, false))
1997 // Try some generic simplifications for associative operations.
1998 if (Value
*V
= SimplifyAssociativeBinOp(Instruction::Or
, Op0
, Op1
, Q
,
2002 // Or distributes over And. Try some generic simplifications based on this.
2003 if (Value
*V
= ExpandBinOp(Instruction::Or
, Op0
, Op1
, Instruction::And
, Q
,
2007 // If the operation is with the result of a select instruction, check whether
2008 // operating on either branch of the select always yields the same value.
2009 if (isa
<SelectInst
>(Op0
) || isa
<SelectInst
>(Op1
))
2010 if (Value
*V
= ThreadBinOpOverSelect(Instruction::Or
, Op0
, Op1
, Q
,
2014 // (A & C1)|(B & C2)
2015 const APInt
*C1
, *C2
;
2016 if (match(Op0
, m_And(m_Value(A
), m_APInt(C1
))) &&
2017 match(Op1
, m_And(m_Value(B
), m_APInt(C2
)))) {
2019 // (A & C1)|(B & C2)
2020 // If we have: ((V + N) & C1) | (V & C2)
2021 // .. and C2 = ~C1 and C2 is 0+1+ and (N & C2) == 0
2022 // replace with V+N.
2024 if (C2
->isMask() && // C2 == 0+1+
2025 match(A
, m_c_Add(m_Specific(B
), m_Value(N
)))) {
2026 // Add commutes, try both ways.
2027 if (MaskedValueIsZero(N
, *C2
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2030 // Or commutes, try both ways.
2032 match(B
, m_c_Add(m_Specific(A
), m_Value(N
)))) {
2033 // Add commutes, try both ways.
2034 if (MaskedValueIsZero(N
, *C1
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2040 // If the operation is with the result of a phi instruction, check whether
2041 // operating on all incoming values of the phi always yields the same value.
2042 if (isa
<PHINode
>(Op0
) || isa
<PHINode
>(Op1
))
2043 if (Value
*V
= ThreadBinOpOverPHI(Instruction::Or
, Op0
, Op1
, Q
, MaxRecurse
))
2049 Value
*llvm::SimplifyOrInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
2050 return ::SimplifyOrInst(Op0
, Op1
, Q
, RecursionLimit
);
2053 /// Given operands for a Xor, see if we can fold the result.
2054 /// If not, this returns null.
2055 static Value
*SimplifyXorInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
,
2056 unsigned MaxRecurse
) {
2057 if (Constant
*C
= foldOrCommuteConstant(Instruction::Xor
, Op0
, Op1
, Q
))
2060 // A ^ undef -> undef
2061 if (match(Op1
, m_Undef()))
2065 if (match(Op1
, m_Zero()))
2070 return Constant::getNullValue(Op0
->getType());
2072 // A ^ ~A = ~A ^ A = -1
2073 if (match(Op0
, m_Not(m_Specific(Op1
))) ||
2074 match(Op1
, m_Not(m_Specific(Op0
))))
2075 return Constant::getAllOnesValue(Op0
->getType());
2077 // Try some generic simplifications for associative operations.
2078 if (Value
*V
= SimplifyAssociativeBinOp(Instruction::Xor
, Op0
, Op1
, Q
,
2082 // Threading Xor over selects and phi nodes is pointless, so don't bother.
2083 // Threading over the select in "A ^ select(cond, B, C)" means evaluating
2084 // "A^B" and "A^C" and seeing if they are equal; but they are equal if and
2085 // only if B and C are equal. If B and C are equal then (since we assume
2086 // that operands have already been simplified) "select(cond, B, C)" should
2087 // have been simplified to the common value of B and C already. Analysing
2088 // "A^B" and "A^C" thus gains nothing, but costs compile time. Similarly
2089 // for threading over phi nodes.
2094 Value
*llvm::SimplifyXorInst(Value
*Op0
, Value
*Op1
, const SimplifyQuery
&Q
) {
2095 return ::SimplifyXorInst(Op0
, Op1
, Q
, RecursionLimit
);
2099 static Type
*GetCompareTy(Value
*Op
) {
2100 return CmpInst::makeCmpResultType(Op
->getType());
2103 /// Rummage around inside V looking for something equivalent to the comparison
2104 /// "LHS Pred RHS". Return such a value if found, otherwise return null.
2105 /// Helper function for analyzing max/min idioms.
2106 static Value
*ExtractEquivalentCondition(Value
*V
, CmpInst::Predicate Pred
,
2107 Value
*LHS
, Value
*RHS
) {
2108 SelectInst
*SI
= dyn_cast
<SelectInst
>(V
);
2111 CmpInst
*Cmp
= dyn_cast
<CmpInst
>(SI
->getCondition());
2114 Value
*CmpLHS
= Cmp
->getOperand(0), *CmpRHS
= Cmp
->getOperand(1);
2115 if (Pred
== Cmp
->getPredicate() && LHS
== CmpLHS
&& RHS
== CmpRHS
)
2117 if (Pred
== CmpInst::getSwappedPredicate(Cmp
->getPredicate()) &&
2118 LHS
== CmpRHS
&& RHS
== CmpLHS
)
2123 // A significant optimization not implemented here is assuming that alloca
2124 // addresses are not equal to incoming argument values. They don't *alias*,
2125 // as we say, but that doesn't mean they aren't equal, so we take a
2126 // conservative approach.
2128 // This is inspired in part by C++11 5.10p1:
2129 // "Two pointers of the same type compare equal if and only if they are both
2130 // null, both point to the same function, or both represent the same
2133 // This is pretty permissive.
2135 // It's also partly due to C11 6.5.9p6:
2136 // "Two pointers compare equal if and only if both are null pointers, both are
2137 // pointers to the same object (including a pointer to an object and a
2138 // subobject at its beginning) or function, both are pointers to one past the
2139 // last element of the same array object, or one is a pointer to one past the
2140 // end of one array object and the other is a pointer to the start of a
2141 // different array object that happens to immediately follow the first array
2142 // object in the address space.)
2144 // C11's version is more restrictive, however there's no reason why an argument
2145 // couldn't be a one-past-the-end value for a stack object in the caller and be
2146 // equal to the beginning of a stack object in the callee.
2148 // If the C and C++ standards are ever made sufficiently restrictive in this
2149 // area, it may be possible to update LLVM's semantics accordingly and reinstate
2150 // this optimization.
2152 computePointerICmp(const DataLayout
&DL
, const TargetLibraryInfo
*TLI
,
2153 const DominatorTree
*DT
, CmpInst::Predicate Pred
,
2154 AssumptionCache
*AC
, const Instruction
*CxtI
,
2155 const InstrInfoQuery
&IIQ
, Value
*LHS
, Value
*RHS
) {
2156 // First, skip past any trivial no-ops.
2157 LHS
= LHS
->stripPointerCasts();
2158 RHS
= RHS
->stripPointerCasts();
2160 // A non-null pointer is not equal to a null pointer.
2161 if (llvm::isKnownNonZero(LHS
, DL
, 0, nullptr, nullptr, nullptr,
2162 IIQ
.UseInstrInfo
) &&
2163 isa
<ConstantPointerNull
>(RHS
) &&
2164 (Pred
== CmpInst::ICMP_EQ
|| Pred
== CmpInst::ICMP_NE
))
2165 return ConstantInt::get(GetCompareTy(LHS
),
2166 !CmpInst::isTrueWhenEqual(Pred
));
2168 // We can only fold certain predicates on pointer comparisons.
2173 // Equality comaprisons are easy to fold.
2174 case CmpInst::ICMP_EQ
:
2175 case CmpInst::ICMP_NE
:
2178 // We can only handle unsigned relational comparisons because 'inbounds' on
2179 // a GEP only protects against unsigned wrapping.
2180 case CmpInst::ICMP_UGT
:
2181 case CmpInst::ICMP_UGE
:
2182 case CmpInst::ICMP_ULT
:
2183 case CmpInst::ICMP_ULE
:
2184 // However, we have to switch them to their signed variants to handle
2185 // negative indices from the base pointer.
2186 Pred
= ICmpInst::getSignedPredicate(Pred
);
2190 // Strip off any constant offsets so that we can reason about them.
2191 // It's tempting to use getUnderlyingObject or even just stripInBoundsOffsets
2192 // here and compare base addresses like AliasAnalysis does, however there are
2193 // numerous hazards. AliasAnalysis and its utilities rely on special rules
2194 // governing loads and stores which don't apply to icmps. Also, AliasAnalysis
2195 // doesn't need to guarantee pointer inequality when it says NoAlias.
2196 Constant
*LHSOffset
= stripAndComputeConstantOffsets(DL
, LHS
);
2197 Constant
*RHSOffset
= stripAndComputeConstantOffsets(DL
, RHS
);
2199 // If LHS and RHS are related via constant offsets to the same base
2200 // value, we can replace it with an icmp which just compares the offsets.
2202 return ConstantExpr::getICmp(Pred
, LHSOffset
, RHSOffset
);
2204 // Various optimizations for (in)equality comparisons.
2205 if (Pred
== CmpInst::ICMP_EQ
|| Pred
== CmpInst::ICMP_NE
) {
2206 // Different non-empty allocations that exist at the same time have
2207 // different addresses (if the program can tell). Global variables always
2208 // exist, so they always exist during the lifetime of each other and all
2209 // allocas. Two different allocas usually have different addresses...
2211 // However, if there's an @llvm.stackrestore dynamically in between two
2212 // allocas, they may have the same address. It's tempting to reduce the
2213 // scope of the problem by only looking at *static* allocas here. That would
2214 // cover the majority of allocas while significantly reducing the likelihood
2215 // of having an @llvm.stackrestore pop up in the middle. However, it's not
2216 // actually impossible for an @llvm.stackrestore to pop up in the middle of
2217 // an entry block. Also, if we have a block that's not attached to a
2218 // function, we can't tell if it's "static" under the current definition.
2219 // Theoretically, this problem could be fixed by creating a new kind of
2220 // instruction kind specifically for static allocas. Such a new instruction
2221 // could be required to be at the top of the entry block, thus preventing it
2222 // from being subject to a @llvm.stackrestore. Instcombine could even
2223 // convert regular allocas into these special allocas. It'd be nifty.
2224 // However, until then, this problem remains open.
2226 // So, we'll assume that two non-empty allocas have different addresses
2229 // With all that, if the offsets are within the bounds of their allocations
2230 // (and not one-past-the-end! so we can't use inbounds!), and their
2231 // allocations aren't the same, the pointers are not equal.
2233 // Note that it's not necessary to check for LHS being a global variable
2234 // address, due to canonicalization and constant folding.
2235 if (isa
<AllocaInst
>(LHS
) &&
2236 (isa
<AllocaInst
>(RHS
) || isa
<GlobalVariable
>(RHS
))) {
2237 ConstantInt
*LHSOffsetCI
= dyn_cast
<ConstantInt
>(LHSOffset
);
2238 ConstantInt
*RHSOffsetCI
= dyn_cast
<ConstantInt
>(RHSOffset
);
2239 uint64_t LHSSize
, RHSSize
;
2240 ObjectSizeOpts Opts
;
2241 Opts
.NullIsUnknownSize
=
2242 NullPointerIsDefined(cast
<AllocaInst
>(LHS
)->getFunction());
2243 if (LHSOffsetCI
&& RHSOffsetCI
&&
2244 getObjectSize(LHS
, LHSSize
, DL
, TLI
, Opts
) &&
2245 getObjectSize(RHS
, RHSSize
, DL
, TLI
, Opts
)) {
2246 const APInt
&LHSOffsetValue
= LHSOffsetCI
->getValue();
2247 const APInt
&RHSOffsetValue
= RHSOffsetCI
->getValue();
2248 if (!LHSOffsetValue
.isNegative() &&
2249 !RHSOffsetValue
.isNegative() &&
2250 LHSOffsetValue
.ult(LHSSize
) &&
2251 RHSOffsetValue
.ult(RHSSize
)) {
2252 return ConstantInt::get(GetCompareTy(LHS
),
2253 !CmpInst::isTrueWhenEqual(Pred
));
2257 // Repeat the above check but this time without depending on DataLayout
2258 // or being able to compute a precise size.
2259 if (!cast
<PointerType
>(LHS
->getType())->isEmptyTy() &&
2260 !cast
<PointerType
>(RHS
->getType())->isEmptyTy() &&
2261 LHSOffset
->isNullValue() &&
2262 RHSOffset
->isNullValue())
2263 return ConstantInt::get(GetCompareTy(LHS
),
2264 !CmpInst::isTrueWhenEqual(Pred
));
2267 // Even if an non-inbounds GEP occurs along the path we can still optimize
2268 // equality comparisons concerning the result. We avoid walking the whole
2269 // chain again by starting where the last calls to
2270 // stripAndComputeConstantOffsets left off and accumulate the offsets.
2271 Constant
*LHSNoBound
= stripAndComputeConstantOffsets(DL
, LHS
, true);
2272 Constant
*RHSNoBound
= stripAndComputeConstantOffsets(DL
, RHS
, true);
2274 return ConstantExpr::getICmp(Pred
,
2275 ConstantExpr::getAdd(LHSOffset
, LHSNoBound
),
2276 ConstantExpr::getAdd(RHSOffset
, RHSNoBound
));
2278 // If one side of the equality comparison must come from a noalias call
2279 // (meaning a system memory allocation function), and the other side must
2280 // come from a pointer that cannot overlap with dynamically-allocated
2281 // memory within the lifetime of the current function (allocas, byval
2282 // arguments, globals), then determine the comparison result here.
2283 SmallVector
<Value
*, 8> LHSUObjs
, RHSUObjs
;
2284 GetUnderlyingObjects(LHS
, LHSUObjs
, DL
);
2285 GetUnderlyingObjects(RHS
, RHSUObjs
, DL
);
2287 // Is the set of underlying objects all noalias calls?
2288 auto IsNAC
= [](ArrayRef
<Value
*> Objects
) {
2289 return all_of(Objects
, isNoAliasCall
);
2292 // Is the set of underlying objects all things which must be disjoint from
2293 // noalias calls. For allocas, we consider only static ones (dynamic
2294 // allocas might be transformed into calls to malloc not simultaneously
2295 // live with the compared-to allocation). For globals, we exclude symbols
2296 // that might be resolve lazily to symbols in another dynamically-loaded
2297 // library (and, thus, could be malloc'ed by the implementation).
2298 auto IsAllocDisjoint
= [](ArrayRef
<Value
*> Objects
) {
2299 return all_of(Objects
, [](Value
*V
) {
2300 if (const AllocaInst
*AI
= dyn_cast
<AllocaInst
>(V
))
2301 return AI
->getParent() && AI
->getFunction() && AI
->isStaticAlloca();
2302 if (const GlobalValue
*GV
= dyn_cast
<GlobalValue
>(V
))
2303 return (GV
->hasLocalLinkage() || GV
->hasHiddenVisibility() ||
2304 GV
->hasProtectedVisibility() || GV
->hasGlobalUnnamedAddr()) &&
2305 !GV
->isThreadLocal();
2306 if (const Argument
*A
= dyn_cast
<Argument
>(V
))
2307 return A
->hasByValAttr();
2312 if ((IsNAC(LHSUObjs
) && IsAllocDisjoint(RHSUObjs
)) ||
2313 (IsNAC(RHSUObjs
) && IsAllocDisjoint(LHSUObjs
)))
2314 return ConstantInt::get(GetCompareTy(LHS
),
2315 !CmpInst::isTrueWhenEqual(Pred
));
2317 // Fold comparisons for non-escaping pointer even if the allocation call
2318 // cannot be elided. We cannot fold malloc comparison to null. Also, the
2319 // dynamic allocation call could be either of the operands.
2320 Value
*MI
= nullptr;
2321 if (isAllocLikeFn(LHS
, TLI
) &&
2322 llvm::isKnownNonZero(RHS
, DL
, 0, nullptr, CxtI
, DT
))
2324 else if (isAllocLikeFn(RHS
, TLI
) &&
2325 llvm::isKnownNonZero(LHS
, DL
, 0, nullptr, CxtI
, DT
))
2327 // FIXME: We should also fold the compare when the pointer escapes, but the
2328 // compare dominates the pointer escape
2329 if (MI
&& !PointerMayBeCaptured(MI
, true, true))
2330 return ConstantInt::get(GetCompareTy(LHS
),
2331 CmpInst::isFalseWhenEqual(Pred
));
2338 /// Fold an icmp when its operands have i1 scalar type.
2339 static Value
*simplifyICmpOfBools(CmpInst::Predicate Pred
, Value
*LHS
,
2340 Value
*RHS
, const SimplifyQuery
&Q
) {
2341 Type
*ITy
= GetCompareTy(LHS
); // The return type.
2342 Type
*OpTy
= LHS
->getType(); // The operand type.
2343 if (!OpTy
->isIntOrIntVectorTy(1))
2346 // A boolean compared to true/false can be simplified in 14 out of the 20
2347 // (10 predicates * 2 constants) possible combinations. Cases not handled here
2348 // require a 'not' of the LHS, so those must be transformed in InstCombine.
2349 if (match(RHS
, m_Zero())) {
2351 case CmpInst::ICMP_NE
: // X != 0 -> X
2352 case CmpInst::ICMP_UGT
: // X >u 0 -> X
2353 case CmpInst::ICMP_SLT
: // X <s 0 -> X
2356 case CmpInst::ICMP_ULT
: // X <u 0 -> false
2357 case CmpInst::ICMP_SGT
: // X >s 0 -> false
2358 return getFalse(ITy
);
2360 case CmpInst::ICMP_UGE
: // X >=u 0 -> true
2361 case CmpInst::ICMP_SLE
: // X <=s 0 -> true
2362 return getTrue(ITy
);
2366 } else if (match(RHS
, m_One())) {
2368 case CmpInst::ICMP_EQ
: // X == 1 -> X
2369 case CmpInst::ICMP_UGE
: // X >=u 1 -> X
2370 case CmpInst::ICMP_SLE
: // X <=s -1 -> X
2373 case CmpInst::ICMP_UGT
: // X >u 1 -> false
2374 case CmpInst::ICMP_SLT
: // X <s -1 -> false
2375 return getFalse(ITy
);
2377 case CmpInst::ICMP_ULE
: // X <=u 1 -> true
2378 case CmpInst::ICMP_SGE
: // X >=s -1 -> true
2379 return getTrue(ITy
);
2388 case ICmpInst::ICMP_UGE
:
2389 if (isImpliedCondition(RHS
, LHS
, Q
.DL
).getValueOr(false))
2390 return getTrue(ITy
);
2392 case ICmpInst::ICMP_SGE
:
2393 /// For signed comparison, the values for an i1 are 0 and -1
2394 /// respectively. This maps into a truth table of:
2395 /// LHS | RHS | LHS >=s RHS | LHS implies RHS
2396 /// 0 | 0 | 1 (0 >= 0) | 1
2397 /// 0 | 1 | 1 (0 >= -1) | 1
2398 /// 1 | 0 | 0 (-1 >= 0) | 0
2399 /// 1 | 1 | 1 (-1 >= -1) | 1
2400 if (isImpliedCondition(LHS
, RHS
, Q
.DL
).getValueOr(false))
2401 return getTrue(ITy
);
2403 case ICmpInst::ICMP_ULE
:
2404 if (isImpliedCondition(LHS
, RHS
, Q
.DL
).getValueOr(false))
2405 return getTrue(ITy
);
2412 /// Try hard to fold icmp with zero RHS because this is a common case.
2413 static Value
*simplifyICmpWithZero(CmpInst::Predicate Pred
, Value
*LHS
,
2414 Value
*RHS
, const SimplifyQuery
&Q
) {
2415 if (!match(RHS
, m_Zero()))
2418 Type
*ITy
= GetCompareTy(LHS
); // The return type.
2421 llvm_unreachable("Unknown ICmp predicate!");
2422 case ICmpInst::ICMP_ULT
:
2423 return getFalse(ITy
);
2424 case ICmpInst::ICMP_UGE
:
2425 return getTrue(ITy
);
2426 case ICmpInst::ICMP_EQ
:
2427 case ICmpInst::ICMP_ULE
:
2428 if (isKnownNonZero(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
, Q
.IIQ
.UseInstrInfo
))
2429 return getFalse(ITy
);
2431 case ICmpInst::ICMP_NE
:
2432 case ICmpInst::ICMP_UGT
:
2433 if (isKnownNonZero(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
, Q
.IIQ
.UseInstrInfo
))
2434 return getTrue(ITy
);
2436 case ICmpInst::ICMP_SLT
: {
2437 KnownBits LHSKnown
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2438 if (LHSKnown
.isNegative())
2439 return getTrue(ITy
);
2440 if (LHSKnown
.isNonNegative())
2441 return getFalse(ITy
);
2444 case ICmpInst::ICMP_SLE
: {
2445 KnownBits LHSKnown
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2446 if (LHSKnown
.isNegative())
2447 return getTrue(ITy
);
2448 if (LHSKnown
.isNonNegative() &&
2449 isKnownNonZero(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2450 return getFalse(ITy
);
2453 case ICmpInst::ICMP_SGE
: {
2454 KnownBits LHSKnown
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2455 if (LHSKnown
.isNegative())
2456 return getFalse(ITy
);
2457 if (LHSKnown
.isNonNegative())
2458 return getTrue(ITy
);
2461 case ICmpInst::ICMP_SGT
: {
2462 KnownBits LHSKnown
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2463 if (LHSKnown
.isNegative())
2464 return getFalse(ITy
);
2465 if (LHSKnown
.isNonNegative() &&
2466 isKnownNonZero(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
))
2467 return getTrue(ITy
);
2475 /// Many binary operators with a constant operand have an easy-to-compute
2476 /// range of outputs. This can be used to fold a comparison to always true or
2478 static void setLimitsForBinOp(BinaryOperator
&BO
, APInt
&Lower
, APInt
&Upper
,
2479 const InstrInfoQuery
&IIQ
) {
2480 unsigned Width
= Lower
.getBitWidth();
2482 switch (BO
.getOpcode()) {
2483 case Instruction::Add
:
2484 if (match(BO
.getOperand(1), m_APInt(C
)) && !C
->isNullValue()) {
2485 // FIXME: If we have both nuw and nsw, we should reduce the range further.
2486 if (IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(&BO
))) {
2487 // 'add nuw x, C' produces [C, UINT_MAX].
2489 } else if (IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(&BO
))) {
2490 if (C
->isNegative()) {
2491 // 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
2492 Lower
= APInt::getSignedMinValue(Width
);
2493 Upper
= APInt::getSignedMaxValue(Width
) + *C
+ 1;
2495 // 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
2496 Lower
= APInt::getSignedMinValue(Width
) + *C
;
2497 Upper
= APInt::getSignedMaxValue(Width
) + 1;
2503 case Instruction::And
:
2504 if (match(BO
.getOperand(1), m_APInt(C
)))
2505 // 'and x, C' produces [0, C].
2509 case Instruction::Or
:
2510 if (match(BO
.getOperand(1), m_APInt(C
)))
2511 // 'or x, C' produces [C, UINT_MAX].
2515 case Instruction::AShr
:
2516 if (match(BO
.getOperand(1), m_APInt(C
)) && C
->ult(Width
)) {
2517 // 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
2518 Lower
= APInt::getSignedMinValue(Width
).ashr(*C
);
2519 Upper
= APInt::getSignedMaxValue(Width
).ashr(*C
) + 1;
2520 } else if (match(BO
.getOperand(0), m_APInt(C
))) {
2521 unsigned ShiftAmount
= Width
- 1;
2522 if (!C
->isNullValue() && IIQ
.isExact(&BO
))
2523 ShiftAmount
= C
->countTrailingZeros();
2524 if (C
->isNegative()) {
2525 // 'ashr C, x' produces [C, C >> (Width-1)]
2527 Upper
= C
->ashr(ShiftAmount
) + 1;
2529 // 'ashr C, x' produces [C >> (Width-1), C]
2530 Lower
= C
->ashr(ShiftAmount
);
2536 case Instruction::LShr
:
2537 if (match(BO
.getOperand(1), m_APInt(C
)) && C
->ult(Width
)) {
2538 // 'lshr x, C' produces [0, UINT_MAX >> C].
2539 Upper
= APInt::getAllOnesValue(Width
).lshr(*C
) + 1;
2540 } else if (match(BO
.getOperand(0), m_APInt(C
))) {
2541 // 'lshr C, x' produces [C >> (Width-1), C].
2542 unsigned ShiftAmount
= Width
- 1;
2543 if (!C
->isNullValue() && IIQ
.isExact(&BO
))
2544 ShiftAmount
= C
->countTrailingZeros();
2545 Lower
= C
->lshr(ShiftAmount
);
2550 case Instruction::Shl
:
2551 if (match(BO
.getOperand(0), m_APInt(C
))) {
2552 if (IIQ
.hasNoUnsignedWrap(&BO
)) {
2553 // 'shl nuw C, x' produces [C, C << CLZ(C)]
2555 Upper
= Lower
.shl(Lower
.countLeadingZeros()) + 1;
2556 } else if (BO
.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
2557 if (C
->isNegative()) {
2558 // 'shl nsw C, x' produces [C << CLO(C)-1, C]
2559 unsigned ShiftAmount
= C
->countLeadingOnes() - 1;
2560 Lower
= C
->shl(ShiftAmount
);
2563 // 'shl nsw C, x' produces [C, C << CLZ(C)-1]
2564 unsigned ShiftAmount
= C
->countLeadingZeros() - 1;
2566 Upper
= C
->shl(ShiftAmount
) + 1;
2572 case Instruction::SDiv
:
2573 if (match(BO
.getOperand(1), m_APInt(C
))) {
2574 APInt IntMin
= APInt::getSignedMinValue(Width
);
2575 APInt IntMax
= APInt::getSignedMaxValue(Width
);
2576 if (C
->isAllOnesValue()) {
2577 // 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
2578 // where C != -1 and C != 0 and C != 1
2581 } else if (C
->countLeadingZeros() < Width
- 1) {
2582 // 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
2583 // where C != -1 and C != 0 and C != 1
2584 Lower
= IntMin
.sdiv(*C
);
2585 Upper
= IntMax
.sdiv(*C
);
2586 if (Lower
.sgt(Upper
))
2587 std::swap(Lower
, Upper
);
2589 assert(Upper
!= Lower
&& "Upper part of range has wrapped!");
2591 } else if (match(BO
.getOperand(0), m_APInt(C
))) {
2592 if (C
->isMinSignedValue()) {
2593 // 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
2595 Upper
= Lower
.lshr(1) + 1;
2597 // 'sdiv C, x' produces [-|C|, |C|].
2598 Upper
= C
->abs() + 1;
2599 Lower
= (-Upper
) + 1;
2604 case Instruction::UDiv
:
2605 if (match(BO
.getOperand(1), m_APInt(C
)) && !C
->isNullValue()) {
2606 // 'udiv x, C' produces [0, UINT_MAX / C].
2607 Upper
= APInt::getMaxValue(Width
).udiv(*C
) + 1;
2608 } else if (match(BO
.getOperand(0), m_APInt(C
))) {
2609 // 'udiv C, x' produces [0, C].
2614 case Instruction::SRem
:
2615 if (match(BO
.getOperand(1), m_APInt(C
))) {
2616 // 'srem x, C' produces (-|C|, |C|).
2618 Lower
= (-Upper
) + 1;
2622 case Instruction::URem
:
2623 if (match(BO
.getOperand(1), m_APInt(C
)))
2624 // 'urem x, C' produces [0, C).
2633 static Value
*simplifyICmpWithConstant(CmpInst::Predicate Pred
, Value
*LHS
,
2634 Value
*RHS
, const InstrInfoQuery
&IIQ
) {
2635 Type
*ITy
= GetCompareTy(RHS
); // The return type.
2638 // Sign-bit checks can be optimized to true/false after unsigned
2639 // floating-point casts:
2640 // icmp slt (bitcast (uitofp X)), 0 --> false
2641 // icmp sgt (bitcast (uitofp X)), -1 --> true
2642 if (match(LHS
, m_BitCast(m_UIToFP(m_Value(X
))))) {
2643 if (Pred
== ICmpInst::ICMP_SLT
&& match(RHS
, m_Zero()))
2644 return ConstantInt::getFalse(ITy
);
2645 if (Pred
== ICmpInst::ICMP_SGT
&& match(RHS
, m_AllOnes()))
2646 return ConstantInt::getTrue(ITy
);
2650 if (!match(RHS
, m_APInt(C
)))
2653 // Rule out tautological comparisons (eg., ult 0 or uge 0).
2654 ConstantRange RHS_CR
= ConstantRange::makeExactICmpRegion(Pred
, *C
);
2655 if (RHS_CR
.isEmptySet())
2656 return ConstantInt::getFalse(ITy
);
2657 if (RHS_CR
.isFullSet())
2658 return ConstantInt::getTrue(ITy
);
2660 // Find the range of possible values for binary operators.
2661 unsigned Width
= C
->getBitWidth();
2662 APInt Lower
= APInt(Width
, 0);
2663 APInt Upper
= APInt(Width
, 0);
2664 if (auto *BO
= dyn_cast
<BinaryOperator
>(LHS
))
2665 setLimitsForBinOp(*BO
, Lower
, Upper
, IIQ
);
2667 ConstantRange LHS_CR
=
2668 Lower
!= Upper
? ConstantRange(Lower
, Upper
) : ConstantRange(Width
, true);
2670 if (auto *I
= dyn_cast
<Instruction
>(LHS
))
2671 if (auto *Ranges
= IIQ
.getMetadata(I
, LLVMContext::MD_range
))
2672 LHS_CR
= LHS_CR
.intersectWith(getConstantRangeFromMetadata(*Ranges
));
2674 if (!LHS_CR
.isFullSet()) {
2675 if (RHS_CR
.contains(LHS_CR
))
2676 return ConstantInt::getTrue(ITy
);
2677 if (RHS_CR
.inverse().contains(LHS_CR
))
2678 return ConstantInt::getFalse(ITy
);
2684 /// TODO: A large part of this logic is duplicated in InstCombine's
2685 /// foldICmpBinOp(). We should be able to share that and avoid the code
2687 static Value
*simplifyICmpWithBinOp(CmpInst::Predicate Pred
, Value
*LHS
,
2688 Value
*RHS
, const SimplifyQuery
&Q
,
2689 unsigned MaxRecurse
) {
2690 Type
*ITy
= GetCompareTy(LHS
); // The return type.
2692 BinaryOperator
*LBO
= dyn_cast
<BinaryOperator
>(LHS
);
2693 BinaryOperator
*RBO
= dyn_cast
<BinaryOperator
>(RHS
);
2694 if (MaxRecurse
&& (LBO
|| RBO
)) {
2695 // Analyze the case when either LHS or RHS is an add instruction.
2696 Value
*A
= nullptr, *B
= nullptr, *C
= nullptr, *D
= nullptr;
2697 // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
2698 bool NoLHSWrapProblem
= false, NoRHSWrapProblem
= false;
2699 if (LBO
&& LBO
->getOpcode() == Instruction::Add
) {
2700 A
= LBO
->getOperand(0);
2701 B
= LBO
->getOperand(1);
2703 ICmpInst::isEquality(Pred
) ||
2704 (CmpInst::isUnsigned(Pred
) &&
2705 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(LBO
))) ||
2706 (CmpInst::isSigned(Pred
) &&
2707 Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)));
2709 if (RBO
&& RBO
->getOpcode() == Instruction::Add
) {
2710 C
= RBO
->getOperand(0);
2711 D
= RBO
->getOperand(1);
2713 ICmpInst::isEquality(Pred
) ||
2714 (CmpInst::isUnsigned(Pred
) &&
2715 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(RBO
))) ||
2716 (CmpInst::isSigned(Pred
) &&
2717 Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(RBO
)));
2720 // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
2721 if ((A
== RHS
|| B
== RHS
) && NoLHSWrapProblem
)
2722 if (Value
*V
= SimplifyICmpInst(Pred
, A
== RHS
? B
: A
,
2723 Constant::getNullValue(RHS
->getType()), Q
,
2727 // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
2728 if ((C
== LHS
|| D
== LHS
) && NoRHSWrapProblem
)
2730 SimplifyICmpInst(Pred
, Constant::getNullValue(LHS
->getType()),
2731 C
== LHS
? D
: C
, Q
, MaxRecurse
- 1))
2734 // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
2735 if (A
&& C
&& (A
== C
|| A
== D
|| B
== C
|| B
== D
) && NoLHSWrapProblem
&&
2737 // Determine Y and Z in the form icmp (X+Y), (X+Z).
2740 // C + B == C + D -> B == D
2743 } else if (A
== D
) {
2744 // D + B == C + D -> B == C
2747 } else if (B
== C
) {
2748 // A + C == C + D -> A == D
2753 // A + D == C + D -> A == C
2757 if (Value
*V
= SimplifyICmpInst(Pred
, Y
, Z
, Q
, MaxRecurse
- 1))
2764 // icmp pred (or X, Y), X
2765 if (LBO
&& match(LBO
, m_c_Or(m_Value(Y
), m_Specific(RHS
)))) {
2766 if (Pred
== ICmpInst::ICMP_ULT
)
2767 return getFalse(ITy
);
2768 if (Pred
== ICmpInst::ICMP_UGE
)
2769 return getTrue(ITy
);
2771 if (Pred
== ICmpInst::ICMP_SLT
|| Pred
== ICmpInst::ICMP_SGE
) {
2772 KnownBits RHSKnown
= computeKnownBits(RHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2773 KnownBits YKnown
= computeKnownBits(Y
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2774 if (RHSKnown
.isNonNegative() && YKnown
.isNegative())
2775 return Pred
== ICmpInst::ICMP_SLT
? getTrue(ITy
) : getFalse(ITy
);
2776 if (RHSKnown
.isNegative() || YKnown
.isNonNegative())
2777 return Pred
== ICmpInst::ICMP_SLT
? getFalse(ITy
) : getTrue(ITy
);
2780 // icmp pred X, (or X, Y)
2781 if (RBO
&& match(RBO
, m_c_Or(m_Value(Y
), m_Specific(LHS
)))) {
2782 if (Pred
== ICmpInst::ICMP_ULE
)
2783 return getTrue(ITy
);
2784 if (Pred
== ICmpInst::ICMP_UGT
)
2785 return getFalse(ITy
);
2787 if (Pred
== ICmpInst::ICMP_SGT
|| Pred
== ICmpInst::ICMP_SLE
) {
2788 KnownBits LHSKnown
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2789 KnownBits YKnown
= computeKnownBits(Y
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2790 if (LHSKnown
.isNonNegative() && YKnown
.isNegative())
2791 return Pred
== ICmpInst::ICMP_SGT
? getTrue(ITy
) : getFalse(ITy
);
2792 if (LHSKnown
.isNegative() || YKnown
.isNonNegative())
2793 return Pred
== ICmpInst::ICMP_SGT
? getFalse(ITy
) : getTrue(ITy
);
2798 // icmp pred (and X, Y), X
2799 if (LBO
&& match(LBO
, m_c_And(m_Value(), m_Specific(RHS
)))) {
2800 if (Pred
== ICmpInst::ICMP_UGT
)
2801 return getFalse(ITy
);
2802 if (Pred
== ICmpInst::ICMP_ULE
)
2803 return getTrue(ITy
);
2805 // icmp pred X, (and X, Y)
2806 if (RBO
&& match(RBO
, m_c_And(m_Value(), m_Specific(LHS
)))) {
2807 if (Pred
== ICmpInst::ICMP_UGE
)
2808 return getTrue(ITy
);
2809 if (Pred
== ICmpInst::ICMP_ULT
)
2810 return getFalse(ITy
);
2813 // 0 - (zext X) pred C
2814 if (!CmpInst::isUnsigned(Pred
) && match(LHS
, m_Neg(m_ZExt(m_Value())))) {
2815 if (ConstantInt
*RHSC
= dyn_cast
<ConstantInt
>(RHS
)) {
2816 if (RHSC
->getValue().isStrictlyPositive()) {
2817 if (Pred
== ICmpInst::ICMP_SLT
)
2818 return ConstantInt::getTrue(RHSC
->getContext());
2819 if (Pred
== ICmpInst::ICMP_SGE
)
2820 return ConstantInt::getFalse(RHSC
->getContext());
2821 if (Pred
== ICmpInst::ICMP_EQ
)
2822 return ConstantInt::getFalse(RHSC
->getContext());
2823 if (Pred
== ICmpInst::ICMP_NE
)
2824 return ConstantInt::getTrue(RHSC
->getContext());
2826 if (RHSC
->getValue().isNonNegative()) {
2827 if (Pred
== ICmpInst::ICMP_SLE
)
2828 return ConstantInt::getTrue(RHSC
->getContext());
2829 if (Pred
== ICmpInst::ICMP_SGT
)
2830 return ConstantInt::getFalse(RHSC
->getContext());
2835 // icmp pred (urem X, Y), Y
2836 if (LBO
&& match(LBO
, m_URem(m_Value(), m_Specific(RHS
)))) {
2840 case ICmpInst::ICMP_SGT
:
2841 case ICmpInst::ICMP_SGE
: {
2842 KnownBits Known
= computeKnownBits(RHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2843 if (!Known
.isNonNegative())
2847 case ICmpInst::ICMP_EQ
:
2848 case ICmpInst::ICMP_UGT
:
2849 case ICmpInst::ICMP_UGE
:
2850 return getFalse(ITy
);
2851 case ICmpInst::ICMP_SLT
:
2852 case ICmpInst::ICMP_SLE
: {
2853 KnownBits Known
= computeKnownBits(RHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2854 if (!Known
.isNonNegative())
2858 case ICmpInst::ICMP_NE
:
2859 case ICmpInst::ICMP_ULT
:
2860 case ICmpInst::ICMP_ULE
:
2861 return getTrue(ITy
);
2865 // icmp pred X, (urem Y, X)
2866 if (RBO
&& match(RBO
, m_URem(m_Value(), m_Specific(LHS
)))) {
2870 case ICmpInst::ICMP_SGT
:
2871 case ICmpInst::ICMP_SGE
: {
2872 KnownBits Known
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2873 if (!Known
.isNonNegative())
2877 case ICmpInst::ICMP_NE
:
2878 case ICmpInst::ICMP_UGT
:
2879 case ICmpInst::ICMP_UGE
:
2880 return getTrue(ITy
);
2881 case ICmpInst::ICMP_SLT
:
2882 case ICmpInst::ICMP_SLE
: {
2883 KnownBits Known
= computeKnownBits(LHS
, Q
.DL
, 0, Q
.AC
, Q
.CxtI
, Q
.DT
);
2884 if (!Known
.isNonNegative())
2888 case ICmpInst::ICMP_EQ
:
2889 case ICmpInst::ICMP_ULT
:
2890 case ICmpInst::ICMP_ULE
:
2891 return getFalse(ITy
);
2897 if (LBO
&& (match(LBO
, m_LShr(m_Specific(RHS
), m_Value())) ||
2898 match(LBO
, m_UDiv(m_Specific(RHS
), m_Value())))) {
2899 // icmp pred (X op Y), X
2900 if (Pred
== ICmpInst::ICMP_UGT
)
2901 return getFalse(ITy
);
2902 if (Pred
== ICmpInst::ICMP_ULE
)
2903 return getTrue(ITy
);
2908 if (RBO
&& (match(RBO
, m_LShr(m_Specific(LHS
), m_Value())) ||
2909 match(RBO
, m_UDiv(m_Specific(LHS
), m_Value())))) {
2910 // icmp pred X, (X op Y)
2911 if (Pred
== ICmpInst::ICMP_ULT
)
2912 return getFalse(ITy
);
2913 if (Pred
== ICmpInst::ICMP_UGE
)
2914 return getTrue(ITy
);
2921 // where CI2 is a power of 2 and CI isn't
2922 if (auto *CI
= dyn_cast
<ConstantInt
>(RHS
)) {
2923 const APInt
*CI2Val
, *CIVal
= &CI
->getValue();
2924 if (LBO
&& match(LBO
, m_Shl(m_APInt(CI2Val
), m_Value())) &&
2925 CI2Val
->isPowerOf2()) {
2926 if (!CIVal
->isPowerOf2()) {
2927 // CI2 << X can equal zero in some circumstances,
2928 // this simplification is unsafe if CI is zero.
2930 // We know it is safe if:
2931 // - The shift is nsw, we can't shift out the one bit.
2932 // - The shift is nuw, we can't shift out the one bit.
2935 if (Q
.IIQ
.hasNoSignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)) ||
2936 Q
.IIQ
.hasNoUnsignedWrap(cast
<OverflowingBinaryOperator
>(LBO
)) ||
2937 CI2Val
->isOneValue() || !CI
->isZero()) {
2938 if (Pred
== ICmpInst::ICMP_EQ
)
2939 return ConstantInt::getFalse(RHS
->getContext());
2940 if (Pred
== ICmpInst::ICMP_NE
)
2941 return ConstantInt::getTrue(RHS
->getContext());
2944 if (CIVal
->isSignMask() && CI2Val
->isOneValue()) {
2945 if (Pred
== ICmpInst::ICMP_UGT
)
2946 return ConstantInt::getFalse(RHS
->getContext());
2947 if (Pred
== ICmpInst::ICMP_ULE
)
2948 return ConstantInt::getTrue(RHS
->getContext());
2953 if (MaxRecurse
&& LBO
&& RBO
&& LBO
->getOpcode() == RBO
->getOpcode() &&
2954 LBO
->getOperand(1) == RBO
->getOperand(1)) {
2955 switch (LBO
->getOpcode()) {
2958 case Instruction::UDiv
:
2959 case Instruction::LShr
:
2960 if (ICmpInst::isSigned(Pred
) || !Q
.IIQ
.isExact(LBO
) ||
2961 !Q
.IIQ
.isExact(RBO
))
2963 if (Value
*V
= SimplifyICmpInst(Pred
, LBO
->getOperand(0),
2964 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
2967 case Instruction::SDiv
:
2968 if (!ICmpInst::isEquality(Pred
) || !Q
.IIQ
.isExact(LBO
) ||
2969 !Q
.IIQ
.isExact(RBO
))
2971 if (Value
*V
= SimplifyICmpInst(Pred
, LBO
->getOperand(0),
2972 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
2975 case Instruction::AShr
:
2976 if (!Q
.IIQ
.isExact(LBO
) || !Q
.IIQ
.isExact(RBO
))
2978 if (Value
*V
= SimplifyICmpInst(Pred
, LBO
->getOperand(0),
2979 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
2982 case Instruction::Shl
: {
2983 bool NUW
= Q
.IIQ
.hasNoUnsignedWrap(LBO
) && Q
.IIQ
.hasNoUnsignedWrap(RBO
);
2984 bool NSW
= Q
.IIQ
.hasNoSignedWrap(LBO
) && Q
.IIQ
.hasNoSignedWrap(RBO
);
2987 if (!NSW
&& ICmpInst::isSigned(Pred
))
2989 if (Value
*V
= SimplifyICmpInst(Pred
, LBO
->getOperand(0),
2990 RBO
->getOperand(0), Q
, MaxRecurse
- 1))
2999 /// Simplify integer comparisons where at least one operand of the compare
3000 /// matches an integer min/max idiom.
3001 static Value
*simplifyICmpWithMinMax(CmpInst::Predicate Pred
, Value
*LHS
,
3002 Value
*RHS
, const SimplifyQuery
&Q
,
3003 unsigned MaxRecurse
) {
3004 Type
*ITy
= GetCompareTy(LHS
); // The return type.
3006 CmpInst::Predicate P
= CmpInst::BAD_ICMP_PREDICATE
;
3007 CmpInst::Predicate EqP
; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
3009 // Signed variants on "max(a,b)>=a -> true".
3010 if (match(LHS
, m_SMax(m_Value(A
), m_Value(B
))) && (A
== RHS
|| B
== RHS
)) {
3012 std::swap(A
, B
); // smax(A, B) pred A.
3013 EqP
= CmpInst::ICMP_SGE
; // "A == smax(A, B)" iff "A sge B".
3014 // We analyze this as smax(A, B) pred A.
3016 } else if (match(RHS
, m_SMax(m_Value(A
), m_Value(B
))) &&
3017 (A
== LHS
|| B
== LHS
)) {
3019 std::swap(A
, B
); // A pred smax(A, B).
3020 EqP
= CmpInst::ICMP_SGE
; // "A == smax(A, B)" iff "A sge B".
3021 // We analyze this as smax(A, B) swapped-pred A.
3022 P
= CmpInst::getSwappedPredicate(Pred
);
3023 } else if (match(LHS
, m_SMin(m_Value(A
), m_Value(B
))) &&
3024 (A
== RHS
|| B
== RHS
)) {
3026 std::swap(A
, B
); // smin(A, B) pred A.
3027 EqP
= CmpInst::ICMP_SLE
; // "A == smin(A, B)" iff "A sle B".
3028 // We analyze this as smax(-A, -B) swapped-pred -A.
3029 // Note that we do not need to actually form -A or -B thanks to EqP.
3030 P
= CmpInst::getSwappedPredicate(Pred
);
3031 } else if (match(RHS
, m_SMin(m_Value(A
), m_Value(B
))) &&
3032 (A
== LHS
|| B
== LHS
)) {
3034 std::swap(A
, B
); // A pred smin(A, B).
3035 EqP
= CmpInst::ICMP_SLE
; // "A == smin(A, B)" iff "A sle B".
3036 // We analyze this as smax(-A, -B) pred -A.
3037 // Note that we do not need to actually form -A or -B thanks to EqP.
3040 if (P
!= CmpInst::BAD_ICMP_PREDICATE
) {
3041 // Cases correspond to "max(A, B) p A".
3045 case CmpInst::ICMP_EQ
:
3046 case CmpInst::ICMP_SLE
:
3047 // Equivalent to "A EqP B". This may be the same as the condition tested
3048 // in the max/min; if so, we can just return that.
3049 if (Value
*V
= ExtractEquivalentCondition(LHS
, EqP
, A
, B
))
3051 if (Value
*V
= ExtractEquivalentCondition(RHS
, EqP
, A
, B
))
3053 // Otherwise, see if "A EqP B" simplifies.
3055 if (Value
*V
= SimplifyICmpInst(EqP
, A
, B
, Q
, MaxRecurse
- 1))
3058 case CmpInst::ICMP_NE
:
3059 case CmpInst::ICMP_SGT
: {
3060 CmpInst::Predicate InvEqP
= CmpInst::getInversePredicate(EqP
);
3061 // Equivalent to "A InvEqP B". This may be the same as the condition
3062 // tested in the max/min; if so, we can just return that.
3063 if (Value
*V
= ExtractEquivalentCondition(LHS
, InvEqP
, A
, B
))
3065 if (Value
*V
= ExtractEquivalentCondition(RHS
, InvEqP
, A
, B
))
3067 // Otherwise, see if "A InvEqP B" simplifies.
3069 if (Value
*V
= SimplifyICmpInst(InvEqP
, A
, B
, Q
, MaxRecurse
- 1))
3073 case CmpInst::ICMP_SGE
:
3075 return getTrue(ITy
);
3076 case CmpInst::ICMP_SLT
:
3078 return getFalse(ITy
);
3082 // Unsigned variants on "max(a,b)>=a -> true".
3083 P
= CmpInst::BAD_ICMP_PREDICATE
;
3084 if (match(LHS
, m_UMax(m_Value(A
), m_Value(B
))) && (A
== RHS
|| B
== RHS
)) {
3086 std::swap(A
, B
); // umax(A, B) pred A.
3087 EqP
= CmpInst::ICMP_UGE
; // "A == umax(A, B)" iff "A uge B".
3088 // We analyze this as umax(A, B) pred A.
3090 } else if (match(RHS
, m_UMax(m_Value(A
), m_Value(B
))) &&
3091 (A
== LHS
|| B
== LHS
)) {
3093 std::swap(A
, B
); // A pred umax(A, B).
3094 EqP
= CmpInst::ICMP_UGE
; // "A == umax(A, B)" iff "A uge B".
3095 // We analyze this as umax(A, B) swapped-pred A.
3096 P
= CmpInst::getSwappedPredicate(Pred
);
3097 } else if (match(LHS
, m_UMin(m_Value(A
), m_Value(B
))) &&
3098 (A
== RHS
|| B
== RHS
)) {
3100 std::swap(A
, B
); // umin(A, B) pred A.
3101 EqP
= CmpInst::ICMP_ULE
; // "A == umin(A, B)" iff "A ule B".
3102 // We analyze this as umax(-A, -B) swapped-pred -A.
3103 // Note that we do not need to actually form -A or -B thanks to EqP.
3104 P
= CmpInst::getSwappedPredicate(Pred
);
3105 } else if (match(RHS
, m_UMin(m_Value(A
), m_Value(B
))) &&
3106 (A
== LHS
|| B
== LHS
)) {
3108 std::swap(A
, B
); // A pred umin(A, B).
3109 EqP
= CmpInst::ICMP_ULE
; // "A == umin(A, B)" iff "A ule B".
3110 // We analyze this as umax(-A, -B) pred -A.
3111 // Note that we do not need to actually form -A or -B thanks to EqP.
3114 if (P
!= CmpInst::BAD_ICMP_PREDICATE
) {
3115 // Cases correspond to "max(A, B) p A".
3119 case CmpInst::ICMP_EQ
:
3120 case CmpInst::ICMP_ULE
:
3121 // Equivalent to "A EqP B". This may be the same as the condition tested
3122 // in the max/min; if so, we can just return that.
3123 if (Value
*V
= ExtractEquivalentCondition(LHS
, EqP
, A
, B
))
3125 if (Value
*V
= ExtractEquivalentCondition(RHS
, EqP
, A
, B
))
3127 // Otherwise, see if "A EqP B" simplifies.
3129 if (Value
*V
= SimplifyICmpInst(EqP
, A
, B
, Q
, MaxRecurse
- 1))
3132 case CmpInst::ICMP_NE
:
3133 case CmpInst::ICMP_UGT
: {
3134 CmpInst::Predicate InvEqP
= CmpInst::getInversePredicate(EqP
);
3135 // Equivalent to "A InvEqP B". This may be the same as the condition
3136 // tested in the max/min; if so, we can just return that.
3137 if (Value
*V
= ExtractEquivalentCondition(LHS
, InvEqP
, A
, B
))
3139 if (Value
*V
= ExtractEquivalentCondition(RHS
, InvEqP
, A
, B
))
3141 // Otherwise, see if "A InvEqP B" simplifies.
3143 if (Value
*V
= SimplifyICmpInst(InvEqP
, A
, B
, Q
, MaxRecurse
- 1))
3147 case CmpInst::ICMP_UGE
:
3149 return getTrue(ITy
);
3150 case CmpInst::ICMP_ULT
:
3152 return getFalse(ITy
);
3156 // Variants on "max(x,y) >= min(x,z)".
3158 if (match(LHS
, m_SMax(m_Value(A
), m_Value(B
))) &&
3159 match(RHS
, m_SMin(m_Value(C
), m_Value(D
))) &&
3160 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3161 // max(x, ?) pred min(x, ?).
3162 if (Pred
== CmpInst::ICMP_SGE
)
3164 return getTrue(ITy
);
3165 if (Pred
== CmpInst::ICMP_SLT
)
3167 return getFalse(ITy
);
3168 } else if (match(LHS
, m_SMin(m_Value(A
), m_Value(B
))) &&
3169 match(RHS
, m_SMax(m_Value(C
), m_Value(D
))) &&
3170 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3171 // min(x, ?) pred max(x, ?).
3172 if (Pred
== CmpInst::ICMP_SLE
)
3174 return getTrue(ITy
);
3175 if (Pred
== CmpInst::ICMP_SGT
)
3177 return getFalse(ITy
);
3178 } else if (match(LHS
, m_UMax(m_Value(A
), m_Value(B
))) &&
3179 match(RHS
, m_UMin(m_Value(C
), m_Value(D
))) &&
3180 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3181 // max(x, ?) pred min(x, ?).
3182 if (Pred
== CmpInst::ICMP_UGE
)
3184 return getTrue(ITy
);
3185 if (Pred
== CmpInst::ICMP_ULT
)
3187 return getFalse(ITy
);
3188 } else if (match(LHS
, m_UMin(m_Value(A
), m_Value(B
))) &&
3189 match(RHS
, m_UMax(m_Value(C
), m_Value(D
))) &&
3190 (A
== C
|| A
== D
|| B
== C
|| B
== D
)) {
3191 // min(x, ?) pred max(x, ?).
3192 if (Pred
== CmpInst::ICMP_ULE
)
3194 return getTrue(ITy
);
3195 if (Pred
== CmpInst::ICMP_UGT
)
3197 return getFalse(ITy
);
3203 /// Given operands for an ICmpInst, see if we can fold the result.
3204 /// If not, this returns null.
3205 static Value
*SimplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
3206 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
3207 CmpInst::Predicate Pred
= (CmpInst::Predicate
)Predicate
;
3208 assert(CmpInst::isIntPredicate(Pred
) && "Not an integer compare!");
3210 if (Constant
*CLHS
= dyn_cast
<Constant
>(LHS
)) {
3211 if (Constant
*CRHS
= dyn_cast
<Constant
>(RHS
))
3212 return ConstantFoldCompareInstOperands(Pred
, CLHS
, CRHS
, Q
.DL
, Q
.TLI
);
3214 // If we have a constant, make sure it is on the RHS.
3215 std::swap(LHS
, RHS
);
3216 Pred
= CmpInst::getSwappedPredicate(Pred
);
3219 Type
*ITy
= GetCompareTy(LHS
); // The return type.
3221 // icmp X, X -> true/false
3222 // icmp X, undef -> true/false because undef could be X.
3223 if (LHS
== RHS
|| isa
<UndefValue
>(RHS
))
3224 return ConstantInt::get(ITy
, CmpInst::isTrueWhenEqual(Pred
));
3226 if (Value
*V
= simplifyICmpOfBools(Pred
, LHS
, RHS
, Q
))
3229 if (Value
*V
= simplifyICmpWithZero(Pred
, LHS
, RHS
, Q
))
3232 if (Value
*V
= simplifyICmpWithConstant(Pred
, LHS
, RHS
, Q
.IIQ
))
3235 // If both operands have range metadata, use the metadata
3236 // to simplify the comparison.
3237 if (isa
<Instruction
>(RHS
) && isa
<Instruction
>(LHS
)) {
3238 auto RHS_Instr
= cast
<Instruction
>(RHS
);
3239 auto LHS_Instr
= cast
<Instruction
>(LHS
);
3241 if (Q
.IIQ
.getMetadata(RHS_Instr
, LLVMContext::MD_range
) &&
3242 Q
.IIQ
.getMetadata(LHS_Instr
, LLVMContext::MD_range
)) {
3243 auto RHS_CR
= getConstantRangeFromMetadata(
3244 *RHS_Instr
->getMetadata(LLVMContext::MD_range
));
3245 auto LHS_CR
= getConstantRangeFromMetadata(
3246 *LHS_Instr
->getMetadata(LLVMContext::MD_range
));
3248 auto Satisfied_CR
= ConstantRange::makeSatisfyingICmpRegion(Pred
, RHS_CR
);
3249 if (Satisfied_CR
.contains(LHS_CR
))
3250 return ConstantInt::getTrue(RHS
->getContext());
3252 auto InversedSatisfied_CR
= ConstantRange::makeSatisfyingICmpRegion(
3253 CmpInst::getInversePredicate(Pred
), RHS_CR
);
3254 if (InversedSatisfied_CR
.contains(LHS_CR
))
3255 return ConstantInt::getFalse(RHS
->getContext());
3259 // Compare of cast, for example (zext X) != 0 -> X != 0
3260 if (isa
<CastInst
>(LHS
) && (isa
<Constant
>(RHS
) || isa
<CastInst
>(RHS
))) {
3261 Instruction
*LI
= cast
<CastInst
>(LHS
);
3262 Value
*SrcOp
= LI
->getOperand(0);
3263 Type
*SrcTy
= SrcOp
->getType();
3264 Type
*DstTy
= LI
->getType();
3266 // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
3267 // if the integer type is the same size as the pointer type.
3268 if (MaxRecurse
&& isa
<PtrToIntInst
>(LI
) &&
3269 Q
.DL
.getTypeSizeInBits(SrcTy
) == DstTy
->getPrimitiveSizeInBits()) {
3270 if (Constant
*RHSC
= dyn_cast
<Constant
>(RHS
)) {
3271 // Transfer the cast to the constant.
3272 if (Value
*V
= SimplifyICmpInst(Pred
, SrcOp
,
3273 ConstantExpr::getIntToPtr(RHSC
, SrcTy
),
3276 } else if (PtrToIntInst
*RI
= dyn_cast
<PtrToIntInst
>(RHS
)) {
3277 if (RI
->getOperand(0)->getType() == SrcTy
)
3278 // Compare without the cast.
3279 if (Value
*V
= SimplifyICmpInst(Pred
, SrcOp
, RI
->getOperand(0),
3285 if (isa
<ZExtInst
>(LHS
)) {
3286 // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
3288 if (ZExtInst
*RI
= dyn_cast
<ZExtInst
>(RHS
)) {
3289 if (MaxRecurse
&& SrcTy
== RI
->getOperand(0)->getType())
3290 // Compare X and Y. Note that signed predicates become unsigned.
3291 if (Value
*V
= SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred
),
3292 SrcOp
, RI
->getOperand(0), Q
,
3296 // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
3297 // too. If not, then try to deduce the result of the comparison.
3298 else if (ConstantInt
*CI
= dyn_cast
<ConstantInt
>(RHS
)) {
3299 // Compute the constant that would happen if we truncated to SrcTy then
3300 // reextended to DstTy.
3301 Constant
*Trunc
= ConstantExpr::getTrunc(CI
, SrcTy
);
3302 Constant
*RExt
= ConstantExpr::getCast(CastInst::ZExt
, Trunc
, DstTy
);
3304 // If the re-extended constant didn't change then this is effectively
3305 // also a case of comparing two zero-extended values.
3306 if (RExt
== CI
&& MaxRecurse
)
3307 if (Value
*V
= SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred
),
3308 SrcOp
, Trunc
, Q
, MaxRecurse
-1))
3311 // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
3312 // there. Use this to work out the result of the comparison.
3315 default: llvm_unreachable("Unknown ICmp predicate!");
3317 case ICmpInst::ICMP_EQ
:
3318 case ICmpInst::ICMP_UGT
:
3319 case ICmpInst::ICMP_UGE
:
3320 return ConstantInt::getFalse(CI
->getContext());
3322 case ICmpInst::ICMP_NE
:
3323 case ICmpInst::ICMP_ULT
:
3324 case ICmpInst::ICMP_ULE
:
3325 return ConstantInt::getTrue(CI
->getContext());
3327 // LHS is non-negative. If RHS is negative then LHS >s LHS. If RHS
3328 // is non-negative then LHS <s RHS.
3329 case ICmpInst::ICMP_SGT
:
3330 case ICmpInst::ICMP_SGE
:
3331 return CI
->getValue().isNegative() ?
3332 ConstantInt::getTrue(CI
->getContext()) :
3333 ConstantInt::getFalse(CI
->getContext());
3335 case ICmpInst::ICMP_SLT
:
3336 case ICmpInst::ICMP_SLE
:
3337 return CI
->getValue().isNegative() ?
3338 ConstantInt::getFalse(CI
->getContext()) :
3339 ConstantInt::getTrue(CI
->getContext());
3345 if (isa
<SExtInst
>(LHS
)) {
3346 // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
3348 if (SExtInst
*RI
= dyn_cast
<SExtInst
>(RHS
)) {
3349 if (MaxRecurse
&& SrcTy
== RI
->getOperand(0)->getType())
3350 // Compare X and Y. Note that the predicate does not change.
3351 if (Value
*V
= SimplifyICmpInst(Pred
, SrcOp
, RI
->getOperand(0),
3355 // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
3356 // too. If not, then try to deduce the result of the comparison.
3357 else if (ConstantInt
*CI
= dyn_cast
<ConstantInt
>(RHS
)) {
3358 // Compute the constant that would happen if we truncated to SrcTy then
3359 // reextended to DstTy.
3360 Constant
*Trunc
= ConstantExpr::getTrunc(CI
, SrcTy
);
3361 Constant
*RExt
= ConstantExpr::getCast(CastInst::SExt
, Trunc
, DstTy
);
3363 // If the re-extended constant didn't change then this is effectively
3364 // also a case of comparing two sign-extended values.
3365 if (RExt
== CI
&& MaxRecurse
)
3366 if (Value
*V
= SimplifyICmpInst(Pred
, SrcOp
, Trunc
, Q
, MaxRecurse
-1))
3369 // Otherwise the upper bits of LHS are all equal, while RHS has varying
3370 // bits there. Use this to work out the result of the comparison.
3373 default: llvm_unreachable("Unknown ICmp predicate!");
3374 case ICmpInst::ICMP_EQ
:
3375 return ConstantInt::getFalse(CI
->getContext());
3376 case ICmpInst::ICMP_NE
:
3377 return ConstantInt::getTrue(CI
->getContext());
3379 // If RHS is non-negative then LHS <s RHS. If RHS is negative then
3381 case ICmpInst::ICMP_SGT
:
3382 case ICmpInst::ICMP_SGE
:
3383 return CI
->getValue().isNegative() ?
3384 ConstantInt::getTrue(CI
->getContext()) :
3385 ConstantInt::getFalse(CI
->getContext());
3386 case ICmpInst::ICMP_SLT
:
3387 case ICmpInst::ICMP_SLE
:
3388 return CI
->getValue().isNegative() ?
3389 ConstantInt::getFalse(CI
->getContext()) :
3390 ConstantInt::getTrue(CI
->getContext());
3392 // If LHS is non-negative then LHS <u RHS. If LHS is negative then
3394 case ICmpInst::ICMP_UGT
:
3395 case ICmpInst::ICMP_UGE
:
3396 // Comparison is true iff the LHS <s 0.
3398 if (Value
*V
= SimplifyICmpInst(ICmpInst::ICMP_SLT
, SrcOp
,
3399 Constant::getNullValue(SrcTy
),
3403 case ICmpInst::ICMP_ULT
:
3404 case ICmpInst::ICMP_ULE
:
3405 // Comparison is true iff the LHS >=s 0.
3407 if (Value
*V
= SimplifyICmpInst(ICmpInst::ICMP_SGE
, SrcOp
,
3408 Constant::getNullValue(SrcTy
),
3418 // icmp eq|ne X, Y -> false|true if X != Y
3419 if (ICmpInst::isEquality(Pred
) &&
3420 isKnownNonEqual(LHS
, RHS
, Q
.DL
, Q
.AC
, Q
.CxtI
, Q
.DT
, Q
.IIQ
.UseInstrInfo
)) {
3421 return Pred
== ICmpInst::ICMP_NE
? getTrue(ITy
) : getFalse(ITy
);
3424 if (Value
*V
= simplifyICmpWithBinOp(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3427 if (Value
*V
= simplifyICmpWithMinMax(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3430 // Simplify comparisons of related pointers using a powerful, recursive
3431 // GEP-walk when we have target data available..
3432 if (LHS
->getType()->isPointerTy())
3433 if (auto *C
= computePointerICmp(Q
.DL
, Q
.TLI
, Q
.DT
, Pred
, Q
.AC
, Q
.CxtI
,
3436 if (auto *CLHS
= dyn_cast
<PtrToIntOperator
>(LHS
))
3437 if (auto *CRHS
= dyn_cast
<PtrToIntOperator
>(RHS
))
3438 if (Q
.DL
.getTypeSizeInBits(CLHS
->getPointerOperandType()) ==
3439 Q
.DL
.getTypeSizeInBits(CLHS
->getType()) &&
3440 Q
.DL
.getTypeSizeInBits(CRHS
->getPointerOperandType()) ==
3441 Q
.DL
.getTypeSizeInBits(CRHS
->getType()))
3442 if (auto *C
= computePointerICmp(Q
.DL
, Q
.TLI
, Q
.DT
, Pred
, Q
.AC
, Q
.CxtI
,
3443 Q
.IIQ
, CLHS
->getPointerOperand(),
3444 CRHS
->getPointerOperand()))
3447 if (GetElementPtrInst
*GLHS
= dyn_cast
<GetElementPtrInst
>(LHS
)) {
3448 if (GEPOperator
*GRHS
= dyn_cast
<GEPOperator
>(RHS
)) {
3449 if (GLHS
->getPointerOperand() == GRHS
->getPointerOperand() &&
3450 GLHS
->hasAllConstantIndices() && GRHS
->hasAllConstantIndices() &&
3451 (ICmpInst::isEquality(Pred
) ||
3452 (GLHS
->isInBounds() && GRHS
->isInBounds() &&
3453 Pred
== ICmpInst::getSignedPredicate(Pred
)))) {
3454 // The bases are equal and the indices are constant. Build a constant
3455 // expression GEP with the same indices and a null base pointer to see
3456 // what constant folding can make out of it.
3457 Constant
*Null
= Constant::getNullValue(GLHS
->getPointerOperandType());
3458 SmallVector
<Value
*, 4> IndicesLHS(GLHS
->idx_begin(), GLHS
->idx_end());
3459 Constant
*NewLHS
= ConstantExpr::getGetElementPtr(
3460 GLHS
->getSourceElementType(), Null
, IndicesLHS
);
3462 SmallVector
<Value
*, 4> IndicesRHS(GRHS
->idx_begin(), GRHS
->idx_end());
3463 Constant
*NewRHS
= ConstantExpr::getGetElementPtr(
3464 GLHS
->getSourceElementType(), Null
, IndicesRHS
);
3465 return ConstantExpr::getICmp(Pred
, NewLHS
, NewRHS
);
3470 // If the comparison is with the result of a select instruction, check whether
3471 // comparing with either branch of the select always yields the same value.
3472 if (isa
<SelectInst
>(LHS
) || isa
<SelectInst
>(RHS
))
3473 if (Value
*V
= ThreadCmpOverSelect(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3476 // If the comparison is with the result of a phi instruction, check whether
3477 // doing the compare with each incoming phi value yields a common result.
3478 if (isa
<PHINode
>(LHS
) || isa
<PHINode
>(RHS
))
3479 if (Value
*V
= ThreadCmpOverPHI(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3485 Value
*llvm::SimplifyICmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
3486 const SimplifyQuery
&Q
) {
3487 return ::SimplifyICmpInst(Predicate
, LHS
, RHS
, Q
, RecursionLimit
);
3490 /// Given operands for an FCmpInst, see if we can fold the result.
3491 /// If not, this returns null.
3492 static Value
*SimplifyFCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
3493 FastMathFlags FMF
, const SimplifyQuery
&Q
,
3494 unsigned MaxRecurse
) {
3495 CmpInst::Predicate Pred
= (CmpInst::Predicate
)Predicate
;
3496 assert(CmpInst::isFPPredicate(Pred
) && "Not an FP compare!");
3498 if (Constant
*CLHS
= dyn_cast
<Constant
>(LHS
)) {
3499 if (Constant
*CRHS
= dyn_cast
<Constant
>(RHS
))
3500 return ConstantFoldCompareInstOperands(Pred
, CLHS
, CRHS
, Q
.DL
, Q
.TLI
);
3502 // If we have a constant, make sure it is on the RHS.
3503 std::swap(LHS
, RHS
);
3504 Pred
= CmpInst::getSwappedPredicate(Pred
);
3507 // Fold trivial predicates.
3508 Type
*RetTy
= GetCompareTy(LHS
);
3509 if (Pred
== FCmpInst::FCMP_FALSE
)
3510 return getFalse(RetTy
);
3511 if (Pred
== FCmpInst::FCMP_TRUE
)
3512 return getTrue(RetTy
);
3514 // Fold (un)ordered comparison if we can determine there are no NaNs.
3515 if (Pred
== FCmpInst::FCMP_UNO
|| Pred
== FCmpInst::FCMP_ORD
)
3517 (isKnownNeverNaN(LHS
, Q
.TLI
) && isKnownNeverNaN(RHS
, Q
.TLI
)))
3518 return ConstantInt::get(RetTy
, Pred
== FCmpInst::FCMP_ORD
);
3520 // NaN is unordered; NaN is not ordered.
3521 assert((FCmpInst::isOrdered(Pred
) || FCmpInst::isUnordered(Pred
)) &&
3522 "Comparison must be either ordered or unordered");
3523 if (match(RHS
, m_NaN()))
3524 return ConstantInt::get(RetTy
, CmpInst::isUnordered(Pred
));
3526 // fcmp pred x, undef and fcmp pred undef, x
3527 // fold to true if unordered, false if ordered
3528 if (isa
<UndefValue
>(LHS
) || isa
<UndefValue
>(RHS
)) {
3529 // Choosing NaN for the undef will always make unordered comparison succeed
3530 // and ordered comparison fail.
3531 return ConstantInt::get(RetTy
, CmpInst::isUnordered(Pred
));
3534 // fcmp x,x -> true/false. Not all compares are foldable.
3536 if (CmpInst::isTrueWhenEqual(Pred
))
3537 return getTrue(RetTy
);
3538 if (CmpInst::isFalseWhenEqual(Pred
))
3539 return getFalse(RetTy
);
3542 // Handle fcmp with constant RHS.
3544 if (match(RHS
, m_APFloat(C
))) {
3545 // Check whether the constant is an infinity.
3546 if (C
->isInfinity()) {
3547 if (C
->isNegative()) {
3549 case FCmpInst::FCMP_OLT
:
3550 // No value is ordered and less than negative infinity.
3551 return getFalse(RetTy
);
3552 case FCmpInst::FCMP_UGE
:
3553 // All values are unordered with or at least negative infinity.
3554 return getTrue(RetTy
);
3560 case FCmpInst::FCMP_OGT
:
3561 // No value is ordered and greater than infinity.
3562 return getFalse(RetTy
);
3563 case FCmpInst::FCMP_ULE
:
3564 // All values are unordered with and at most infinity.
3565 return getTrue(RetTy
);
3573 case FCmpInst::FCMP_UGE
:
3574 if (CannotBeOrderedLessThanZero(LHS
, Q
.TLI
))
3575 return getTrue(RetTy
);
3577 case FCmpInst::FCMP_OLT
:
3579 if (CannotBeOrderedLessThanZero(LHS
, Q
.TLI
))
3580 return getFalse(RetTy
);
3585 } else if (C
->isNegative()) {
3586 assert(!C
->isNaN() && "Unexpected NaN constant!");
3587 // TODO: We can catch more cases by using a range check rather than
3588 // relying on CannotBeOrderedLessThanZero.
3590 case FCmpInst::FCMP_UGE
:
3591 case FCmpInst::FCMP_UGT
:
3592 case FCmpInst::FCMP_UNE
:
3593 // (X >= 0) implies (X > C) when (C < 0)
3594 if (CannotBeOrderedLessThanZero(LHS
, Q
.TLI
))
3595 return getTrue(RetTy
);
3597 case FCmpInst::FCMP_OEQ
:
3598 case FCmpInst::FCMP_OLE
:
3599 case FCmpInst::FCMP_OLT
:
3600 // (X >= 0) implies !(X < C) when (C < 0)
3601 if (CannotBeOrderedLessThanZero(LHS
, Q
.TLI
))
3602 return getFalse(RetTy
);
3610 // If the comparison is with the result of a select instruction, check whether
3611 // comparing with either branch of the select always yields the same value.
3612 if (isa
<SelectInst
>(LHS
) || isa
<SelectInst
>(RHS
))
3613 if (Value
*V
= ThreadCmpOverSelect(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3616 // If the comparison is with the result of a phi instruction, check whether
3617 // doing the compare with each incoming phi value yields a common result.
3618 if (isa
<PHINode
>(LHS
) || isa
<PHINode
>(RHS
))
3619 if (Value
*V
= ThreadCmpOverPHI(Pred
, LHS
, RHS
, Q
, MaxRecurse
))
3625 Value
*llvm::SimplifyFCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
3626 FastMathFlags FMF
, const SimplifyQuery
&Q
) {
3627 return ::SimplifyFCmpInst(Predicate
, LHS
, RHS
, FMF
, Q
, RecursionLimit
);
3630 /// See if V simplifies when its operand Op is replaced with RepOp.
3631 static const Value
*SimplifyWithOpReplaced(Value
*V
, Value
*Op
, Value
*RepOp
,
3632 const SimplifyQuery
&Q
,
3633 unsigned MaxRecurse
) {
3634 // Trivial replacement.
3638 // We cannot replace a constant, and shouldn't even try.
3639 if (isa
<Constant
>(Op
))
3642 auto *I
= dyn_cast
<Instruction
>(V
);
3646 // If this is a binary operator, try to simplify it with the replaced op.
3647 if (auto *B
= dyn_cast
<BinaryOperator
>(I
)) {
3649 // %cmp = icmp eq i32 %x, 2147483647
3650 // %add = add nsw i32 %x, 1
3651 // %sel = select i1 %cmp, i32 -2147483648, i32 %add
3653 // We can't replace %sel with %add unless we strip away the flags.
3654 if (isa
<OverflowingBinaryOperator
>(B
))
3655 if (Q
.IIQ
.hasNoSignedWrap(B
) || Q
.IIQ
.hasNoUnsignedWrap(B
))
3657 if (isa
<PossiblyExactOperator
>(B
) && Q
.IIQ
.isExact(B
))
3661 if (B
->getOperand(0) == Op
)
3662 return SimplifyBinOp(B
->getOpcode(), RepOp
, B
->getOperand(1), Q
,
3664 if (B
->getOperand(1) == Op
)
3665 return SimplifyBinOp(B
->getOpcode(), B
->getOperand(0), RepOp
, Q
,
3670 // Same for CmpInsts.
3671 if (CmpInst
*C
= dyn_cast
<CmpInst
>(I
)) {
3673 if (C
->getOperand(0) == Op
)
3674 return SimplifyCmpInst(C
->getPredicate(), RepOp
, C
->getOperand(1), Q
,
3676 if (C
->getOperand(1) == Op
)
3677 return SimplifyCmpInst(C
->getPredicate(), C
->getOperand(0), RepOp
, Q
,
3683 if (auto *GEP
= dyn_cast
<GetElementPtrInst
>(I
)) {
3685 SmallVector
<Value
*, 8> NewOps(GEP
->getNumOperands());
3686 transform(GEP
->operands(), NewOps
.begin(),
3687 [&](Value
*V
) { return V
== Op
? RepOp
: V
; });
3688 return SimplifyGEPInst(GEP
->getSourceElementType(), NewOps
, Q
,
3693 // TODO: We could hand off more cases to instsimplify here.
3695 // If all operands are constant after substituting Op for RepOp then we can
3696 // constant fold the instruction.
3697 if (Constant
*CRepOp
= dyn_cast
<Constant
>(RepOp
)) {
3698 // Build a list of all constant operands.
3699 SmallVector
<Constant
*, 8> ConstOps
;
3700 for (unsigned i
= 0, e
= I
->getNumOperands(); i
!= e
; ++i
) {
3701 if (I
->getOperand(i
) == Op
)
3702 ConstOps
.push_back(CRepOp
);
3703 else if (Constant
*COp
= dyn_cast
<Constant
>(I
->getOperand(i
)))
3704 ConstOps
.push_back(COp
);
3709 // All operands were constants, fold it.
3710 if (ConstOps
.size() == I
->getNumOperands()) {
3711 if (CmpInst
*C
= dyn_cast
<CmpInst
>(I
))
3712 return ConstantFoldCompareInstOperands(C
->getPredicate(), ConstOps
[0],
3713 ConstOps
[1], Q
.DL
, Q
.TLI
);
3715 if (LoadInst
*LI
= dyn_cast
<LoadInst
>(I
))
3716 if (!LI
->isVolatile())
3717 return ConstantFoldLoadFromConstPtr(ConstOps
[0], LI
->getType(), Q
.DL
);
3719 return ConstantFoldInstOperands(I
, ConstOps
, Q
.DL
, Q
.TLI
);
3726 /// Try to simplify a select instruction when its condition operand is an
3727 /// integer comparison where one operand of the compare is a constant.
3728 static Value
*simplifySelectBitTest(Value
*TrueVal
, Value
*FalseVal
, Value
*X
,
3729 const APInt
*Y
, bool TrueWhenUnset
) {
3732 // (X & Y) == 0 ? X & ~Y : X --> X
3733 // (X & Y) != 0 ? X & ~Y : X --> X & ~Y
3734 if (FalseVal
== X
&& match(TrueVal
, m_And(m_Specific(X
), m_APInt(C
))) &&
3736 return TrueWhenUnset
? FalseVal
: TrueVal
;
3738 // (X & Y) == 0 ? X : X & ~Y --> X & ~Y
3739 // (X & Y) != 0 ? X : X & ~Y --> X
3740 if (TrueVal
== X
&& match(FalseVal
, m_And(m_Specific(X
), m_APInt(C
))) &&
3742 return TrueWhenUnset
? FalseVal
: TrueVal
;
3744 if (Y
->isPowerOf2()) {
3745 // (X & Y) == 0 ? X | Y : X --> X | Y
3746 // (X & Y) != 0 ? X | Y : X --> X
3747 if (FalseVal
== X
&& match(TrueVal
, m_Or(m_Specific(X
), m_APInt(C
))) &&
3749 return TrueWhenUnset
? TrueVal
: FalseVal
;
3751 // (X & Y) == 0 ? X : X | Y --> X
3752 // (X & Y) != 0 ? X : X | Y --> X | Y
3753 if (TrueVal
== X
&& match(FalseVal
, m_Or(m_Specific(X
), m_APInt(C
))) &&
3755 return TrueWhenUnset
? TrueVal
: FalseVal
;
3761 /// An alternative way to test if a bit is set or not uses sgt/slt instead of
3763 static Value
*simplifySelectWithFakeICmpEq(Value
*CmpLHS
, Value
*CmpRHS
,
3764 ICmpInst::Predicate Pred
,
3765 Value
*TrueVal
, Value
*FalseVal
) {
3768 if (!decomposeBitTestICmp(CmpLHS
, CmpRHS
, Pred
, X
, Mask
))
3771 return simplifySelectBitTest(TrueVal
, FalseVal
, X
, &Mask
,
3772 Pred
== ICmpInst::ICMP_EQ
);
3775 /// Try to simplify a select instruction when its condition operand is an
3776 /// integer comparison.
3777 static Value
*simplifySelectWithICmpCond(Value
*CondVal
, Value
*TrueVal
,
3778 Value
*FalseVal
, const SimplifyQuery
&Q
,
3779 unsigned MaxRecurse
) {
3780 ICmpInst::Predicate Pred
;
3781 Value
*CmpLHS
, *CmpRHS
;
3782 if (!match(CondVal
, m_ICmp(Pred
, m_Value(CmpLHS
), m_Value(CmpRHS
))))
3785 if (ICmpInst::isEquality(Pred
) && match(CmpRHS
, m_Zero())) {
3788 if (match(CmpLHS
, m_And(m_Value(X
), m_APInt(Y
))))
3789 if (Value
*V
= simplifySelectBitTest(TrueVal
, FalseVal
, X
, Y
,
3790 Pred
== ICmpInst::ICMP_EQ
))
3794 // Check for other compares that behave like bit test.
3795 if (Value
*V
= simplifySelectWithFakeICmpEq(CmpLHS
, CmpRHS
, Pred
,
3799 // If we have an equality comparison, then we know the value in one of the
3800 // arms of the select. See if substituting this value into the arm and
3801 // simplifying the result yields the same value as the other arm.
3802 if (Pred
== ICmpInst::ICMP_EQ
) {
3803 if (SimplifyWithOpReplaced(FalseVal
, CmpLHS
, CmpRHS
, Q
, MaxRecurse
) ==
3805 SimplifyWithOpReplaced(FalseVal
, CmpRHS
, CmpLHS
, Q
, MaxRecurse
) ==
3808 if (SimplifyWithOpReplaced(TrueVal
, CmpLHS
, CmpRHS
, Q
, MaxRecurse
) ==
3810 SimplifyWithOpReplaced(TrueVal
, CmpRHS
, CmpLHS
, Q
, MaxRecurse
) ==
3813 } else if (Pred
== ICmpInst::ICMP_NE
) {
3814 if (SimplifyWithOpReplaced(TrueVal
, CmpLHS
, CmpRHS
, Q
, MaxRecurse
) ==
3816 SimplifyWithOpReplaced(TrueVal
, CmpRHS
, CmpLHS
, Q
, MaxRecurse
) ==
3819 if (SimplifyWithOpReplaced(FalseVal
, CmpLHS
, CmpRHS
, Q
, MaxRecurse
) ==
3821 SimplifyWithOpReplaced(FalseVal
, CmpRHS
, CmpLHS
, Q
, MaxRecurse
) ==
3829 /// Given operands for a SelectInst, see if we can fold the result.
3830 /// If not, this returns null.
3831 static Value
*SimplifySelectInst(Value
*Cond
, Value
*TrueVal
, Value
*FalseVal
,
3832 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
3833 if (auto *CondC
= dyn_cast
<Constant
>(Cond
)) {
3834 if (auto *TrueC
= dyn_cast
<Constant
>(TrueVal
))
3835 if (auto *FalseC
= dyn_cast
<Constant
>(FalseVal
))
3836 return ConstantFoldSelectInstruction(CondC
, TrueC
, FalseC
);
3838 // select undef, X, Y -> X or Y
3839 if (isa
<UndefValue
>(CondC
))
3840 return isa
<Constant
>(FalseVal
) ? FalseVal
: TrueVal
;
3842 // TODO: Vector constants with undef elements don't simplify.
3844 // select true, X, Y -> X
3845 if (CondC
->isAllOnesValue())
3847 // select false, X, Y -> Y
3848 if (CondC
->isNullValue())
3852 // select ?, X, X -> X
3853 if (TrueVal
== FalseVal
)
3856 if (isa
<UndefValue
>(TrueVal
)) // select ?, undef, X -> X
3858 if (isa
<UndefValue
>(FalseVal
)) // select ?, X, undef -> X
3862 simplifySelectWithICmpCond(Cond
, TrueVal
, FalseVal
, Q
, MaxRecurse
))
3865 if (Value
*V
= foldSelectWithBinaryOp(Cond
, TrueVal
, FalseVal
))
3871 Value
*llvm::SimplifySelectInst(Value
*Cond
, Value
*TrueVal
, Value
*FalseVal
,
3872 const SimplifyQuery
&Q
) {
3873 return ::SimplifySelectInst(Cond
, TrueVal
, FalseVal
, Q
, RecursionLimit
);
3876 /// Given operands for an GetElementPtrInst, see if we can fold the result.
3877 /// If not, this returns null.
3878 static Value
*SimplifyGEPInst(Type
*SrcTy
, ArrayRef
<Value
*> Ops
,
3879 const SimplifyQuery
&Q
, unsigned) {
3880 // The type of the GEP pointer operand.
3882 cast
<PointerType
>(Ops
[0]->getType()->getScalarType())->getAddressSpace();
3884 // getelementptr P -> P.
3885 if (Ops
.size() == 1)
3888 // Compute the (pointer) type returned by the GEP instruction.
3889 Type
*LastType
= GetElementPtrInst::getIndexedType(SrcTy
, Ops
.slice(1));
3890 Type
*GEPTy
= PointerType::get(LastType
, AS
);
3891 if (VectorType
*VT
= dyn_cast
<VectorType
>(Ops
[0]->getType()))
3892 GEPTy
= VectorType::get(GEPTy
, VT
->getNumElements());
3893 else if (VectorType
*VT
= dyn_cast
<VectorType
>(Ops
[1]->getType()))
3894 GEPTy
= VectorType::get(GEPTy
, VT
->getNumElements());
3896 if (isa
<UndefValue
>(Ops
[0]))
3897 return UndefValue::get(GEPTy
);
3899 if (Ops
.size() == 2) {
3900 // getelementptr P, 0 -> P.
3901 if (match(Ops
[1], m_Zero()) && Ops
[0]->getType() == GEPTy
)
3905 if (Ty
->isSized()) {
3908 uint64_t TyAllocSize
= Q
.DL
.getTypeAllocSize(Ty
);
3909 // getelementptr P, N -> P if P points to a type of zero size.
3910 if (TyAllocSize
== 0 && Ops
[0]->getType() == GEPTy
)
3913 // The following transforms are only safe if the ptrtoint cast
3914 // doesn't truncate the pointers.
3915 if (Ops
[1]->getType()->getScalarSizeInBits() ==
3916 Q
.DL
.getIndexSizeInBits(AS
)) {
3917 auto PtrToIntOrZero
= [GEPTy
](Value
*P
) -> Value
* {
3918 if (match(P
, m_Zero()))
3919 return Constant::getNullValue(GEPTy
);
3921 if (match(P
, m_PtrToInt(m_Value(Temp
))))
3922 if (Temp
->getType() == GEPTy
)
3927 // getelementptr V, (sub P, V) -> P if P points to a type of size 1.
3928 if (TyAllocSize
== 1 &&
3929 match(Ops
[1], m_Sub(m_Value(P
), m_PtrToInt(m_Specific(Ops
[0])))))
3930 if (Value
*R
= PtrToIntOrZero(P
))
3933 // getelementptr V, (ashr (sub P, V), C) -> Q
3934 // if P points to a type of size 1 << C.
3936 m_AShr(m_Sub(m_Value(P
), m_PtrToInt(m_Specific(Ops
[0]))),
3937 m_ConstantInt(C
))) &&
3938 TyAllocSize
== 1ULL << C
)
3939 if (Value
*R
= PtrToIntOrZero(P
))
3942 // getelementptr V, (sdiv (sub P, V), C) -> Q
3943 // if P points to a type of size C.
3945 m_SDiv(m_Sub(m_Value(P
), m_PtrToInt(m_Specific(Ops
[0]))),
3946 m_SpecificInt(TyAllocSize
))))
3947 if (Value
*R
= PtrToIntOrZero(P
))
3953 if (Q
.DL
.getTypeAllocSize(LastType
) == 1 &&
3954 all_of(Ops
.slice(1).drop_back(1),
3955 [](Value
*Idx
) { return match(Idx
, m_Zero()); })) {
3957 Q
.DL
.getIndexSizeInBits(Ops
[0]->getType()->getPointerAddressSpace());
3958 if (Q
.DL
.getTypeSizeInBits(Ops
.back()->getType()) == IdxWidth
) {
3959 APInt
BasePtrOffset(IdxWidth
, 0);
3960 Value
*StrippedBasePtr
=
3961 Ops
[0]->stripAndAccumulateInBoundsConstantOffsets(Q
.DL
,
3964 // gep (gep V, C), (sub 0, V) -> C
3965 if (match(Ops
.back(),
3966 m_Sub(m_Zero(), m_PtrToInt(m_Specific(StrippedBasePtr
))))) {
3967 auto *CI
= ConstantInt::get(GEPTy
->getContext(), BasePtrOffset
);
3968 return ConstantExpr::getIntToPtr(CI
, GEPTy
);
3970 // gep (gep V, C), (xor V, -1) -> C-1
3971 if (match(Ops
.back(),
3972 m_Xor(m_PtrToInt(m_Specific(StrippedBasePtr
)), m_AllOnes()))) {
3973 auto *CI
= ConstantInt::get(GEPTy
->getContext(), BasePtrOffset
- 1);
3974 return ConstantExpr::getIntToPtr(CI
, GEPTy
);
3979 // Check to see if this is constant foldable.
3980 if (!all_of(Ops
, [](Value
*V
) { return isa
<Constant
>(V
); }))
3983 auto *CE
= ConstantExpr::getGetElementPtr(SrcTy
, cast
<Constant
>(Ops
[0]),
3985 if (auto *CEFolded
= ConstantFoldConstant(CE
, Q
.DL
))
3990 Value
*llvm::SimplifyGEPInst(Type
*SrcTy
, ArrayRef
<Value
*> Ops
,
3991 const SimplifyQuery
&Q
) {
3992 return ::SimplifyGEPInst(SrcTy
, Ops
, Q
, RecursionLimit
);
3995 /// Given operands for an InsertValueInst, see if we can fold the result.
3996 /// If not, this returns null.
3997 static Value
*SimplifyInsertValueInst(Value
*Agg
, Value
*Val
,
3998 ArrayRef
<unsigned> Idxs
, const SimplifyQuery
&Q
,
4000 if (Constant
*CAgg
= dyn_cast
<Constant
>(Agg
))
4001 if (Constant
*CVal
= dyn_cast
<Constant
>(Val
))
4002 return ConstantFoldInsertValueInstruction(CAgg
, CVal
, Idxs
);
4004 // insertvalue x, undef, n -> x
4005 if (match(Val
, m_Undef()))
4008 // insertvalue x, (extractvalue y, n), n
4009 if (ExtractValueInst
*EV
= dyn_cast
<ExtractValueInst
>(Val
))
4010 if (EV
->getAggregateOperand()->getType() == Agg
->getType() &&
4011 EV
->getIndices() == Idxs
) {
4012 // insertvalue undef, (extractvalue y, n), n -> y
4013 if (match(Agg
, m_Undef()))
4014 return EV
->getAggregateOperand();
4016 // insertvalue y, (extractvalue y, n), n -> y
4017 if (Agg
== EV
->getAggregateOperand())
4024 Value
*llvm::SimplifyInsertValueInst(Value
*Agg
, Value
*Val
,
4025 ArrayRef
<unsigned> Idxs
,
4026 const SimplifyQuery
&Q
) {
4027 return ::SimplifyInsertValueInst(Agg
, Val
, Idxs
, Q
, RecursionLimit
);
4030 Value
*llvm::SimplifyInsertElementInst(Value
*Vec
, Value
*Val
, Value
*Idx
,
4031 const SimplifyQuery
&Q
) {
4032 // Try to constant fold.
4033 auto *VecC
= dyn_cast
<Constant
>(Vec
);
4034 auto *ValC
= dyn_cast
<Constant
>(Val
);
4035 auto *IdxC
= dyn_cast
<Constant
>(Idx
);
4036 if (VecC
&& ValC
&& IdxC
)
4037 return ConstantFoldInsertElementInstruction(VecC
, ValC
, IdxC
);
4039 // Fold into undef if index is out of bounds.
4040 if (auto *CI
= dyn_cast
<ConstantInt
>(Idx
)) {
4041 uint64_t NumElements
= cast
<VectorType
>(Vec
->getType())->getNumElements();
4042 if (CI
->uge(NumElements
))
4043 return UndefValue::get(Vec
->getType());
4046 // If index is undef, it might be out of bounds (see above case)
4047 if (isa
<UndefValue
>(Idx
))
4048 return UndefValue::get(Vec
->getType());
4053 /// Given operands for an ExtractValueInst, see if we can fold the result.
4054 /// If not, this returns null.
4055 static Value
*SimplifyExtractValueInst(Value
*Agg
, ArrayRef
<unsigned> Idxs
,
4056 const SimplifyQuery
&, unsigned) {
4057 if (auto *CAgg
= dyn_cast
<Constant
>(Agg
))
4058 return ConstantFoldExtractValueInstruction(CAgg
, Idxs
);
4060 // extractvalue x, (insertvalue y, elt, n), n -> elt
4061 unsigned NumIdxs
= Idxs
.size();
4062 for (auto *IVI
= dyn_cast
<InsertValueInst
>(Agg
); IVI
!= nullptr;
4063 IVI
= dyn_cast
<InsertValueInst
>(IVI
->getAggregateOperand())) {
4064 ArrayRef
<unsigned> InsertValueIdxs
= IVI
->getIndices();
4065 unsigned NumInsertValueIdxs
= InsertValueIdxs
.size();
4066 unsigned NumCommonIdxs
= std::min(NumInsertValueIdxs
, NumIdxs
);
4067 if (InsertValueIdxs
.slice(0, NumCommonIdxs
) ==
4068 Idxs
.slice(0, NumCommonIdxs
)) {
4069 if (NumIdxs
== NumInsertValueIdxs
)
4070 return IVI
->getInsertedValueOperand();
4078 Value
*llvm::SimplifyExtractValueInst(Value
*Agg
, ArrayRef
<unsigned> Idxs
,
4079 const SimplifyQuery
&Q
) {
4080 return ::SimplifyExtractValueInst(Agg
, Idxs
, Q
, RecursionLimit
);
4083 /// Given operands for an ExtractElementInst, see if we can fold the result.
4084 /// If not, this returns null.
4085 static Value
*SimplifyExtractElementInst(Value
*Vec
, Value
*Idx
, const SimplifyQuery
&,
4087 if (auto *CVec
= dyn_cast
<Constant
>(Vec
)) {
4088 if (auto *CIdx
= dyn_cast
<Constant
>(Idx
))
4089 return ConstantFoldExtractElementInstruction(CVec
, CIdx
);
4091 // The index is not relevant if our vector is a splat.
4092 if (auto *Splat
= CVec
->getSplatValue())
4095 if (isa
<UndefValue
>(Vec
))
4096 return UndefValue::get(Vec
->getType()->getVectorElementType());
4099 // If extracting a specified index from the vector, see if we can recursively
4100 // find a previously computed scalar that was inserted into the vector.
4101 if (auto *IdxC
= dyn_cast
<ConstantInt
>(Idx
)) {
4102 if (IdxC
->getValue().uge(Vec
->getType()->getVectorNumElements()))
4103 // definitely out of bounds, thus undefined result
4104 return UndefValue::get(Vec
->getType()->getVectorElementType());
4105 if (Value
*Elt
= findScalarElement(Vec
, IdxC
->getZExtValue()))
4109 // An undef extract index can be arbitrarily chosen to be an out-of-range
4110 // index value, which would result in the instruction being undef.
4111 if (isa
<UndefValue
>(Idx
))
4112 return UndefValue::get(Vec
->getType()->getVectorElementType());
4117 Value
*llvm::SimplifyExtractElementInst(Value
*Vec
, Value
*Idx
,
4118 const SimplifyQuery
&Q
) {
4119 return ::SimplifyExtractElementInst(Vec
, Idx
, Q
, RecursionLimit
);
4122 /// See if we can fold the given phi. If not, returns null.
4123 static Value
*SimplifyPHINode(PHINode
*PN
, const SimplifyQuery
&Q
) {
4124 // If all of the PHI's incoming values are the same then replace the PHI node
4125 // with the common value.
4126 Value
*CommonValue
= nullptr;
4127 bool HasUndefInput
= false;
4128 for (Value
*Incoming
: PN
->incoming_values()) {
4129 // If the incoming value is the phi node itself, it can safely be skipped.
4130 if (Incoming
== PN
) continue;
4131 if (isa
<UndefValue
>(Incoming
)) {
4132 // Remember that we saw an undef value, but otherwise ignore them.
4133 HasUndefInput
= true;
4136 if (CommonValue
&& Incoming
!= CommonValue
)
4137 return nullptr; // Not the same, bail out.
4138 CommonValue
= Incoming
;
4141 // If CommonValue is null then all of the incoming values were either undef or
4142 // equal to the phi node itself.
4144 return UndefValue::get(PN
->getType());
4146 // If we have a PHI node like phi(X, undef, X), where X is defined by some
4147 // instruction, we cannot return X as the result of the PHI node unless it
4148 // dominates the PHI block.
4150 return valueDominatesPHI(CommonValue
, PN
, Q
.DT
) ? CommonValue
: nullptr;
4155 static Value
*SimplifyCastInst(unsigned CastOpc
, Value
*Op
,
4156 Type
*Ty
, const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4157 if (auto *C
= dyn_cast
<Constant
>(Op
))
4158 return ConstantFoldCastOperand(CastOpc
, C
, Ty
, Q
.DL
);
4160 if (auto *CI
= dyn_cast
<CastInst
>(Op
)) {
4161 auto *Src
= CI
->getOperand(0);
4162 Type
*SrcTy
= Src
->getType();
4163 Type
*MidTy
= CI
->getType();
4165 if (Src
->getType() == Ty
) {
4166 auto FirstOp
= static_cast<Instruction::CastOps
>(CI
->getOpcode());
4167 auto SecondOp
= static_cast<Instruction::CastOps
>(CastOpc
);
4169 SrcTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(SrcTy
) : nullptr;
4171 MidTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(MidTy
) : nullptr;
4173 DstTy
->isPtrOrPtrVectorTy() ? Q
.DL
.getIntPtrType(DstTy
) : nullptr;
4174 if (CastInst::isEliminableCastPair(FirstOp
, SecondOp
, SrcTy
, MidTy
, DstTy
,
4175 SrcIntPtrTy
, MidIntPtrTy
,
4176 DstIntPtrTy
) == Instruction::BitCast
)
4182 if (CastOpc
== Instruction::BitCast
)
4183 if (Op
->getType() == Ty
)
4189 Value
*llvm::SimplifyCastInst(unsigned CastOpc
, Value
*Op
, Type
*Ty
,
4190 const SimplifyQuery
&Q
) {
4191 return ::SimplifyCastInst(CastOpc
, Op
, Ty
, Q
, RecursionLimit
);
4194 /// For the given destination element of a shuffle, peek through shuffles to
4195 /// match a root vector source operand that contains that element in the same
4196 /// vector lane (ie, the same mask index), so we can eliminate the shuffle(s).
4197 static Value
*foldIdentityShuffles(int DestElt
, Value
*Op0
, Value
*Op1
,
4198 int MaskVal
, Value
*RootVec
,
4199 unsigned MaxRecurse
) {
4203 // Bail out if any mask value is undefined. That kind of shuffle may be
4204 // simplified further based on demanded bits or other folds.
4208 // The mask value chooses which source operand we need to look at next.
4209 int InVecNumElts
= Op0
->getType()->getVectorNumElements();
4210 int RootElt
= MaskVal
;
4211 Value
*SourceOp
= Op0
;
4212 if (MaskVal
>= InVecNumElts
) {
4213 RootElt
= MaskVal
- InVecNumElts
;
4217 // If the source operand is a shuffle itself, look through it to find the
4218 // matching root vector.
4219 if (auto *SourceShuf
= dyn_cast
<ShuffleVectorInst
>(SourceOp
)) {
4220 return foldIdentityShuffles(
4221 DestElt
, SourceShuf
->getOperand(0), SourceShuf
->getOperand(1),
4222 SourceShuf
->getMaskValue(RootElt
), RootVec
, MaxRecurse
);
4225 // TODO: Look through bitcasts? What if the bitcast changes the vector element
4228 // The source operand is not a shuffle. Initialize the root vector value for
4229 // this shuffle if that has not been done yet.
4233 // Give up as soon as a source operand does not match the existing root value.
4234 if (RootVec
!= SourceOp
)
4237 // The element must be coming from the same lane in the source vector
4238 // (although it may have crossed lanes in intermediate shuffles).
4239 if (RootElt
!= DestElt
)
4245 static Value
*SimplifyShuffleVectorInst(Value
*Op0
, Value
*Op1
, Constant
*Mask
,
4246 Type
*RetTy
, const SimplifyQuery
&Q
,
4247 unsigned MaxRecurse
) {
4248 if (isa
<UndefValue
>(Mask
))
4249 return UndefValue::get(RetTy
);
4251 Type
*InVecTy
= Op0
->getType();
4252 unsigned MaskNumElts
= Mask
->getType()->getVectorNumElements();
4253 unsigned InVecNumElts
= InVecTy
->getVectorNumElements();
4255 SmallVector
<int, 32> Indices
;
4256 ShuffleVectorInst::getShuffleMask(Mask
, Indices
);
4257 assert(MaskNumElts
== Indices
.size() &&
4258 "Size of Indices not same as number of mask elements?");
4260 // Canonicalization: If mask does not select elements from an input vector,
4261 // replace that input vector with undef.
4262 bool MaskSelects0
= false, MaskSelects1
= false;
4263 for (unsigned i
= 0; i
!= MaskNumElts
; ++i
) {
4264 if (Indices
[i
] == -1)
4266 if ((unsigned)Indices
[i
] < InVecNumElts
)
4267 MaskSelects0
= true;
4269 MaskSelects1
= true;
4272 Op0
= UndefValue::get(InVecTy
);
4274 Op1
= UndefValue::get(InVecTy
);
4276 auto *Op0Const
= dyn_cast
<Constant
>(Op0
);
4277 auto *Op1Const
= dyn_cast
<Constant
>(Op1
);
4279 // If all operands are constant, constant fold the shuffle.
4280 if (Op0Const
&& Op1Const
)
4281 return ConstantFoldShuffleVectorInstruction(Op0Const
, Op1Const
, Mask
);
4283 // Canonicalization: if only one input vector is constant, it shall be the
4285 if (Op0Const
&& !Op1Const
) {
4286 std::swap(Op0
, Op1
);
4287 ShuffleVectorInst::commuteShuffleMask(Indices
, InVecNumElts
);
4290 // A shuffle of a splat is always the splat itself. Legal if the shuffle's
4291 // value type is same as the input vectors' type.
4292 if (auto *OpShuf
= dyn_cast
<ShuffleVectorInst
>(Op0
))
4293 if (isa
<UndefValue
>(Op1
) && RetTy
== InVecTy
&&
4294 OpShuf
->getMask()->getSplatValue())
4297 // Don't fold a shuffle with undef mask elements. This may get folded in a
4298 // better way using demanded bits or other analysis.
4299 // TODO: Should we allow this?
4300 if (find(Indices
, -1) != Indices
.end())
4303 // Check if every element of this shuffle can be mapped back to the
4304 // corresponding element of a single root vector. If so, we don't need this
4305 // shuffle. This handles simple identity shuffles as well as chains of
4306 // shuffles that may widen/narrow and/or move elements across lanes and back.
4307 Value
*RootVec
= nullptr;
4308 for (unsigned i
= 0; i
!= MaskNumElts
; ++i
) {
4309 // Note that recursion is limited for each vector element, so if any element
4310 // exceeds the limit, this will fail to simplify.
4312 foldIdentityShuffles(i
, Op0
, Op1
, Indices
[i
], RootVec
, MaxRecurse
);
4314 // We can't replace a widening/narrowing shuffle with one of its operands.
4315 if (!RootVec
|| RootVec
->getType() != RetTy
)
4321 /// Given operands for a ShuffleVectorInst, fold the result or return null.
4322 Value
*llvm::SimplifyShuffleVectorInst(Value
*Op0
, Value
*Op1
, Constant
*Mask
,
4323 Type
*RetTy
, const SimplifyQuery
&Q
) {
4324 return ::SimplifyShuffleVectorInst(Op0
, Op1
, Mask
, RetTy
, Q
, RecursionLimit
);
4327 static Constant
*propagateNaN(Constant
*In
) {
4328 // If the input is a vector with undef elements, just return a default NaN.
4330 return ConstantFP::getNaN(In
->getType());
4332 // Propagate the existing NaN constant when possible.
4333 // TODO: Should we quiet a signaling NaN?
4337 static Constant
*simplifyFPBinop(Value
*Op0
, Value
*Op1
) {
4338 if (isa
<UndefValue
>(Op0
) || isa
<UndefValue
>(Op1
))
4339 return ConstantFP::getNaN(Op0
->getType());
4341 if (match(Op0
, m_NaN()))
4342 return propagateNaN(cast
<Constant
>(Op0
));
4343 if (match(Op1
, m_NaN()))
4344 return propagateNaN(cast
<Constant
>(Op1
));
4349 /// Given operands for an FAdd, see if we can fold the result. If not, this
4351 static Value
*SimplifyFAddInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4352 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4353 if (Constant
*C
= foldOrCommuteConstant(Instruction::FAdd
, Op0
, Op1
, Q
))
4356 if (Constant
*C
= simplifyFPBinop(Op0
, Op1
))
4360 if (match(Op1
, m_NegZeroFP()))
4363 // fadd X, 0 ==> X, when we know X is not -0
4364 if (match(Op1
, m_PosZeroFP()) &&
4365 (FMF
.noSignedZeros() || CannotBeNegativeZero(Op0
, Q
.TLI
)))
4368 // With nnan: (+/-0.0 - X) + X --> 0.0 (and commuted variant)
4369 // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
4370 // Negative zeros are allowed because we always end up with positive zero:
4371 // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4372 // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
4373 // X = 0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
4374 // X = 0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
4375 if (FMF
.noNaNs() && (match(Op0
, m_FSub(m_AnyZeroFP(), m_Specific(Op1
))) ||
4376 match(Op1
, m_FSub(m_AnyZeroFP(), m_Specific(Op0
)))))
4377 return ConstantFP::getNullValue(Op0
->getType());
4379 // (X - Y) + Y --> X
4380 // Y + (X - Y) --> X
4382 if (FMF
.noSignedZeros() && FMF
.allowReassoc() &&
4383 (match(Op0
, m_FSub(m_Value(X
), m_Specific(Op1
))) ||
4384 match(Op1
, m_FSub(m_Value(X
), m_Specific(Op0
)))))
4390 /// Given operands for an FSub, see if we can fold the result. If not, this
4392 static Value
*SimplifyFSubInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4393 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4394 if (Constant
*C
= foldOrCommuteConstant(Instruction::FSub
, Op0
, Op1
, Q
))
4397 if (Constant
*C
= simplifyFPBinop(Op0
, Op1
))
4401 if (match(Op1
, m_PosZeroFP()))
4404 // fsub X, -0 ==> X, when we know X is not -0
4405 if (match(Op1
, m_NegZeroFP()) &&
4406 (FMF
.noSignedZeros() || CannotBeNegativeZero(Op0
, Q
.TLI
)))
4409 // fsub -0.0, (fsub -0.0, X) ==> X
4411 if (match(Op0
, m_NegZeroFP()) &&
4412 match(Op1
, m_FSub(m_NegZeroFP(), m_Value(X
))))
4415 // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
4416 if (FMF
.noSignedZeros() && match(Op0
, m_AnyZeroFP()) &&
4417 match(Op1
, m_FSub(m_AnyZeroFP(), m_Value(X
))))
4420 // fsub nnan x, x ==> 0.0
4421 if (FMF
.noNaNs() && Op0
== Op1
)
4422 return Constant::getNullValue(Op0
->getType());
4424 // Y - (Y - X) --> X
4425 // (X + Y) - Y --> X
4426 if (FMF
.noSignedZeros() && FMF
.allowReassoc() &&
4427 (match(Op1
, m_FSub(m_Specific(Op0
), m_Value(X
))) ||
4428 match(Op0
, m_c_FAdd(m_Specific(Op1
), m_Value(X
)))))
4434 /// Given the operands for an FMul, see if we can fold the result
4435 static Value
*SimplifyFMulInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4436 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4437 if (Constant
*C
= foldOrCommuteConstant(Instruction::FMul
, Op0
, Op1
, Q
))
4440 if (Constant
*C
= simplifyFPBinop(Op0
, Op1
))
4443 // fmul X, 1.0 ==> X
4444 if (match(Op1
, m_FPOne()))
4447 // fmul nnan nsz X, 0 ==> 0
4448 if (FMF
.noNaNs() && FMF
.noSignedZeros() && match(Op1
, m_AnyZeroFP()))
4449 return ConstantFP::getNullValue(Op0
->getType());
4451 // sqrt(X) * sqrt(X) --> X, if we can:
4452 // 1. Remove the intermediate rounding (reassociate).
4453 // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
4454 // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
4456 if (Op0
== Op1
&& match(Op0
, m_Intrinsic
<Intrinsic::sqrt
>(m_Value(X
))) &&
4457 FMF
.allowReassoc() && FMF
.noNaNs() && FMF
.noSignedZeros())
4463 Value
*llvm::SimplifyFAddInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4464 const SimplifyQuery
&Q
) {
4465 return ::SimplifyFAddInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
);
4469 Value
*llvm::SimplifyFSubInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4470 const SimplifyQuery
&Q
) {
4471 return ::SimplifyFSubInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
);
4474 Value
*llvm::SimplifyFMulInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4475 const SimplifyQuery
&Q
) {
4476 return ::SimplifyFMulInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
);
4479 static Value
*SimplifyFDivInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4480 const SimplifyQuery
&Q
, unsigned) {
4481 if (Constant
*C
= foldOrCommuteConstant(Instruction::FDiv
, Op0
, Op1
, Q
))
4484 if (Constant
*C
= simplifyFPBinop(Op0
, Op1
))
4488 if (match(Op1
, m_FPOne()))
4492 // Requires that NaNs are off (X could be zero) and signed zeroes are
4493 // ignored (X could be positive or negative, so the output sign is unknown).
4494 if (FMF
.noNaNs() && FMF
.noSignedZeros() && match(Op0
, m_AnyZeroFP()))
4495 return ConstantFP::getNullValue(Op0
->getType());
4498 // X / X -> 1.0 is legal when NaNs are ignored.
4499 // We can ignore infinities because INF/INF is NaN.
4501 return ConstantFP::get(Op0
->getType(), 1.0);
4503 // (X * Y) / Y --> X if we can reassociate to the above form.
4505 if (FMF
.allowReassoc() && match(Op0
, m_c_FMul(m_Value(X
), m_Specific(Op1
))))
4508 // -X / X -> -1.0 and
4509 // X / -X -> -1.0 are legal when NaNs are ignored.
4510 // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
4511 if (match(Op0
, m_FNegNSZ(m_Specific(Op1
))) ||
4512 match(Op1
, m_FNegNSZ(m_Specific(Op0
))))
4513 return ConstantFP::get(Op0
->getType(), -1.0);
4519 Value
*llvm::SimplifyFDivInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4520 const SimplifyQuery
&Q
) {
4521 return ::SimplifyFDivInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
);
4524 static Value
*SimplifyFRemInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4525 const SimplifyQuery
&Q
, unsigned) {
4526 if (Constant
*C
= foldOrCommuteConstant(Instruction::FRem
, Op0
, Op1
, Q
))
4529 if (Constant
*C
= simplifyFPBinop(Op0
, Op1
))
4532 // Unlike fdiv, the result of frem always matches the sign of the dividend.
4533 // The constant match may include undef elements in a vector, so return a full
4534 // zero constant as the result.
4537 if (match(Op0
, m_PosZeroFP()))
4538 return ConstantFP::getNullValue(Op0
->getType());
4540 if (match(Op0
, m_NegZeroFP()))
4541 return ConstantFP::getNegativeZero(Op0
->getType());
4547 Value
*llvm::SimplifyFRemInst(Value
*Op0
, Value
*Op1
, FastMathFlags FMF
,
4548 const SimplifyQuery
&Q
) {
4549 return ::SimplifyFRemInst(Op0
, Op1
, FMF
, Q
, RecursionLimit
);
4552 //=== Helper functions for higher up the class hierarchy.
4554 /// Given operands for a BinaryOperator, see if we can fold the result.
4555 /// If not, this returns null.
4556 static Value
*SimplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
4557 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4559 case Instruction::Add
:
4560 return SimplifyAddInst(LHS
, RHS
, false, false, Q
, MaxRecurse
);
4561 case Instruction::Sub
:
4562 return SimplifySubInst(LHS
, RHS
, false, false, Q
, MaxRecurse
);
4563 case Instruction::Mul
:
4564 return SimplifyMulInst(LHS
, RHS
, Q
, MaxRecurse
);
4565 case Instruction::SDiv
:
4566 return SimplifySDivInst(LHS
, RHS
, Q
, MaxRecurse
);
4567 case Instruction::UDiv
:
4568 return SimplifyUDivInst(LHS
, RHS
, Q
, MaxRecurse
);
4569 case Instruction::SRem
:
4570 return SimplifySRemInst(LHS
, RHS
, Q
, MaxRecurse
);
4571 case Instruction::URem
:
4572 return SimplifyURemInst(LHS
, RHS
, Q
, MaxRecurse
);
4573 case Instruction::Shl
:
4574 return SimplifyShlInst(LHS
, RHS
, false, false, Q
, MaxRecurse
);
4575 case Instruction::LShr
:
4576 return SimplifyLShrInst(LHS
, RHS
, false, Q
, MaxRecurse
);
4577 case Instruction::AShr
:
4578 return SimplifyAShrInst(LHS
, RHS
, false, Q
, MaxRecurse
);
4579 case Instruction::And
:
4580 return SimplifyAndInst(LHS
, RHS
, Q
, MaxRecurse
);
4581 case Instruction::Or
:
4582 return SimplifyOrInst(LHS
, RHS
, Q
, MaxRecurse
);
4583 case Instruction::Xor
:
4584 return SimplifyXorInst(LHS
, RHS
, Q
, MaxRecurse
);
4585 case Instruction::FAdd
:
4586 return SimplifyFAddInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4587 case Instruction::FSub
:
4588 return SimplifyFSubInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4589 case Instruction::FMul
:
4590 return SimplifyFMulInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4591 case Instruction::FDiv
:
4592 return SimplifyFDivInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4593 case Instruction::FRem
:
4594 return SimplifyFRemInst(LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4596 llvm_unreachable("Unexpected opcode");
4600 /// Given operands for a BinaryOperator, see if we can fold the result.
4601 /// If not, this returns null.
4602 /// In contrast to SimplifyBinOp, try to use FastMathFlag when folding the
4603 /// result. In case we don't need FastMathFlags, simply fall to SimplifyBinOp.
4604 static Value
*SimplifyFPBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
4605 const FastMathFlags
&FMF
, const SimplifyQuery
&Q
,
4606 unsigned MaxRecurse
) {
4608 case Instruction::FAdd
:
4609 return SimplifyFAddInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
4610 case Instruction::FSub
:
4611 return SimplifyFSubInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
4612 case Instruction::FMul
:
4613 return SimplifyFMulInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
4614 case Instruction::FDiv
:
4615 return SimplifyFDivInst(LHS
, RHS
, FMF
, Q
, MaxRecurse
);
4617 return SimplifyBinOp(Opcode
, LHS
, RHS
, Q
, MaxRecurse
);
4621 Value
*llvm::SimplifyBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
4622 const SimplifyQuery
&Q
) {
4623 return ::SimplifyBinOp(Opcode
, LHS
, RHS
, Q
, RecursionLimit
);
4626 Value
*llvm::SimplifyFPBinOp(unsigned Opcode
, Value
*LHS
, Value
*RHS
,
4627 FastMathFlags FMF
, const SimplifyQuery
&Q
) {
4628 return ::SimplifyFPBinOp(Opcode
, LHS
, RHS
, FMF
, Q
, RecursionLimit
);
4631 /// Given operands for a CmpInst, see if we can fold the result.
4632 static Value
*SimplifyCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
4633 const SimplifyQuery
&Q
, unsigned MaxRecurse
) {
4634 if (CmpInst::isIntPredicate((CmpInst::Predicate
)Predicate
))
4635 return SimplifyICmpInst(Predicate
, LHS
, RHS
, Q
, MaxRecurse
);
4636 return SimplifyFCmpInst(Predicate
, LHS
, RHS
, FastMathFlags(), Q
, MaxRecurse
);
4639 Value
*llvm::SimplifyCmpInst(unsigned Predicate
, Value
*LHS
, Value
*RHS
,
4640 const SimplifyQuery
&Q
) {
4641 return ::SimplifyCmpInst(Predicate
, LHS
, RHS
, Q
, RecursionLimit
);
4644 static bool IsIdempotent(Intrinsic::ID ID
) {
4646 default: return false;
4648 // Unary idempotent: f(f(x)) = f(x)
4649 case Intrinsic::fabs
:
4650 case Intrinsic::floor
:
4651 case Intrinsic::ceil
:
4652 case Intrinsic::trunc
:
4653 case Intrinsic::rint
:
4654 case Intrinsic::nearbyint
:
4655 case Intrinsic::round
:
4656 case Intrinsic::canonicalize
:
4661 static Value
*SimplifyRelativeLoad(Constant
*Ptr
, Constant
*Offset
,
4662 const DataLayout
&DL
) {
4663 GlobalValue
*PtrSym
;
4665 if (!IsConstantOffsetFromGlobal(Ptr
, PtrSym
, PtrOffset
, DL
))
4668 Type
*Int8PtrTy
= Type::getInt8PtrTy(Ptr
->getContext());
4669 Type
*Int32Ty
= Type::getInt32Ty(Ptr
->getContext());
4670 Type
*Int32PtrTy
= Int32Ty
->getPointerTo();
4671 Type
*Int64Ty
= Type::getInt64Ty(Ptr
->getContext());
4673 auto *OffsetConstInt
= dyn_cast
<ConstantInt
>(Offset
);
4674 if (!OffsetConstInt
|| OffsetConstInt
->getType()->getBitWidth() > 64)
4677 uint64_t OffsetInt
= OffsetConstInt
->getSExtValue();
4678 if (OffsetInt
% 4 != 0)
4681 Constant
*C
= ConstantExpr::getGetElementPtr(
4682 Int32Ty
, ConstantExpr::getBitCast(Ptr
, Int32PtrTy
),
4683 ConstantInt::get(Int64Ty
, OffsetInt
/ 4));
4684 Constant
*Loaded
= ConstantFoldLoadFromConstPtr(C
, Int32Ty
, DL
);
4688 auto *LoadedCE
= dyn_cast
<ConstantExpr
>(Loaded
);
4692 if (LoadedCE
->getOpcode() == Instruction::Trunc
) {
4693 LoadedCE
= dyn_cast
<ConstantExpr
>(LoadedCE
->getOperand(0));
4698 if (LoadedCE
->getOpcode() != Instruction::Sub
)
4701 auto *LoadedLHS
= dyn_cast
<ConstantExpr
>(LoadedCE
->getOperand(0));
4702 if (!LoadedLHS
|| LoadedLHS
->getOpcode() != Instruction::PtrToInt
)
4704 auto *LoadedLHSPtr
= LoadedLHS
->getOperand(0);
4706 Constant
*LoadedRHS
= LoadedCE
->getOperand(1);
4707 GlobalValue
*LoadedRHSSym
;
4708 APInt LoadedRHSOffset
;
4709 if (!IsConstantOffsetFromGlobal(LoadedRHS
, LoadedRHSSym
, LoadedRHSOffset
,
4711 PtrSym
!= LoadedRHSSym
|| PtrOffset
!= LoadedRHSOffset
)
4714 return ConstantExpr::getBitCast(LoadedLHSPtr
, Int8PtrTy
);
4717 static bool maskIsAllZeroOrUndef(Value
*Mask
) {
4718 auto *ConstMask
= dyn_cast
<Constant
>(Mask
);
4721 if (ConstMask
->isNullValue() || isa
<UndefValue
>(ConstMask
))
4723 for (unsigned I
= 0, E
= ConstMask
->getType()->getVectorNumElements(); I
!= E
;
4725 if (auto *MaskElt
= ConstMask
->getAggregateElement(I
))
4726 if (MaskElt
->isNullValue() || isa
<UndefValue
>(MaskElt
))
4733 static Value
*simplifyUnaryIntrinsic(Function
*F
, Value
*Op0
,
4734 const SimplifyQuery
&Q
) {
4735 // Idempotent functions return the same result when called repeatedly.
4736 Intrinsic::ID IID
= F
->getIntrinsicID();
4737 if (IsIdempotent(IID
))
4738 if (auto *II
= dyn_cast
<IntrinsicInst
>(Op0
))
4739 if (II
->getIntrinsicID() == IID
)
4744 case Intrinsic::fabs
:
4745 if (SignBitMustBeZero(Op0
, Q
.TLI
)) return Op0
;
4747 case Intrinsic::bswap
:
4748 // bswap(bswap(x)) -> x
4749 if (match(Op0
, m_BSwap(m_Value(X
)))) return X
;
4751 case Intrinsic::bitreverse
:
4752 // bitreverse(bitreverse(x)) -> x
4753 if (match(Op0
, m_BitReverse(m_Value(X
)))) return X
;
4755 case Intrinsic::exp
:
4757 if (Q
.CxtI
->hasAllowReassoc() &&
4758 match(Op0
, m_Intrinsic
<Intrinsic::log
>(m_Value(X
)))) return X
;
4760 case Intrinsic::exp2
:
4761 // exp2(log2(x)) -> x
4762 if (Q
.CxtI
->hasAllowReassoc() &&
4763 match(Op0
, m_Intrinsic
<Intrinsic::log2
>(m_Value(X
)))) return X
;
4765 case Intrinsic::log
:
4767 if (Q
.CxtI
->hasAllowReassoc() &&
4768 match(Op0
, m_Intrinsic
<Intrinsic::exp
>(m_Value(X
)))) return X
;
4770 case Intrinsic::log2
:
4771 // log2(exp2(x)) -> x
4772 if (Q
.CxtI
->hasAllowReassoc() &&
4773 match(Op0
, m_Intrinsic
<Intrinsic::exp2
>(m_Value(X
)))) return X
;
4782 static Value
*simplifyBinaryIntrinsic(Function
*F
, Value
*Op0
, Value
*Op1
,
4783 const SimplifyQuery
&Q
) {
4784 Intrinsic::ID IID
= F
->getIntrinsicID();
4785 Type
*ReturnType
= F
->getReturnType();
4787 case Intrinsic::usub_with_overflow
:
4788 case Intrinsic::ssub_with_overflow
:
4789 // X - X -> { 0, false }
4791 return Constant::getNullValue(ReturnType
);
4792 // X - undef -> undef
4793 // undef - X -> undef
4794 if (isa
<UndefValue
>(Op0
) || isa
<UndefValue
>(Op1
))
4795 return UndefValue::get(ReturnType
);
4797 case Intrinsic::uadd_with_overflow
:
4798 case Intrinsic::sadd_with_overflow
:
4799 // X + undef -> undef
4800 if (isa
<UndefValue
>(Op0
) || isa
<UndefValue
>(Op1
))
4801 return UndefValue::get(ReturnType
);
4803 case Intrinsic::umul_with_overflow
:
4804 case Intrinsic::smul_with_overflow
:
4805 // 0 * X -> { 0, false }
4806 // X * 0 -> { 0, false }
4807 if (match(Op0
, m_Zero()) || match(Op1
, m_Zero()))
4808 return Constant::getNullValue(ReturnType
);
4809 // undef * X -> { 0, false }
4810 // X * undef -> { 0, false }
4811 if (match(Op0
, m_Undef()) || match(Op1
, m_Undef()))
4812 return Constant::getNullValue(ReturnType
);
4814 case Intrinsic::load_relative
:
4815 if (auto *C0
= dyn_cast
<Constant
>(Op0
))
4816 if (auto *C1
= dyn_cast
<Constant
>(Op1
))
4817 return SimplifyRelativeLoad(C0
, C1
, Q
.DL
);
4819 case Intrinsic::powi
:
4820 if (auto *Power
= dyn_cast
<ConstantInt
>(Op1
)) {
4821 // powi(x, 0) -> 1.0
4822 if (Power
->isZero())
4823 return ConstantFP::get(Op0
->getType(), 1.0);
4829 case Intrinsic::maxnum
:
4830 case Intrinsic::minnum
: {
4831 // If the arguments are the same, this is a no-op.
4832 if (Op0
== Op1
) return Op0
;
4834 // If one argument is NaN or undef, return the other argument.
4835 if (match(Op0
, m_CombineOr(m_NaN(), m_Undef()))) return Op1
;
4836 if (match(Op1
, m_CombineOr(m_NaN(), m_Undef()))) return Op0
;
4838 // Min/max of the same operation with common operand:
4839 // m(m(X, Y)), X --> m(X, Y) (4 commuted variants)
4840 if (auto *M0
= dyn_cast
<IntrinsicInst
>(Op0
))
4841 if (M0
->getIntrinsicID() == IID
&&
4842 (M0
->getOperand(0) == Op1
|| M0
->getOperand(1) == Op1
))
4844 if (auto *M1
= dyn_cast
<IntrinsicInst
>(Op1
))
4845 if (M1
->getIntrinsicID() == IID
&&
4846 (M1
->getOperand(0) == Op0
|| M1
->getOperand(1) == Op0
))
4849 // minnum(X, -Inf) --> -Inf (and commuted variant)
4850 // maxnum(X, +Inf) --> +Inf (and commuted variant)
4851 bool UseNegInf
= IID
== Intrinsic::minnum
;
4853 if ((match(Op0
, m_APFloat(C
)) && C
->isInfinity() &&
4854 C
->isNegative() == UseNegInf
) ||
4855 (match(Op1
, m_APFloat(C
)) && C
->isInfinity() &&
4856 C
->isNegative() == UseNegInf
))
4857 return ConstantFP::getInfinity(ReturnType
, UseNegInf
);
4859 // TODO: minnum(nnan x, inf) -> x
4860 // TODO: minnum(nnan ninf x, flt_max) -> x
4861 // TODO: maxnum(nnan x, -inf) -> x
4862 // TODO: maxnum(nnan ninf x, -flt_max) -> x
4872 template <typename IterTy
>
4873 static Value
*simplifyIntrinsic(Function
*F
, IterTy ArgBegin
, IterTy ArgEnd
,
4874 const SimplifyQuery
&Q
) {
4875 // Intrinsics with no operands have some kind of side effect. Don't simplify.
4876 unsigned NumOperands
= std::distance(ArgBegin
, ArgEnd
);
4877 if (NumOperands
== 0)
4880 Intrinsic::ID IID
= F
->getIntrinsicID();
4881 if (NumOperands
== 1)
4882 return simplifyUnaryIntrinsic(F
, ArgBegin
[0], Q
);
4884 if (NumOperands
== 2)
4885 return simplifyBinaryIntrinsic(F
, ArgBegin
[0], ArgBegin
[1], Q
);
4887 // Handle intrinsics with 3 or more arguments.
4889 case Intrinsic::masked_load
: {
4890 Value
*MaskArg
= ArgBegin
[2];
4891 Value
*PassthruArg
= ArgBegin
[3];
4892 // If the mask is all zeros or undef, the "passthru" argument is the result.
4893 if (maskIsAllZeroOrUndef(MaskArg
))
4897 case Intrinsic::fshl
:
4898 case Intrinsic::fshr
: {
4899 Value
*ShAmtArg
= ArgBegin
[2];
4900 const APInt
*ShAmtC
;
4901 if (match(ShAmtArg
, m_APInt(ShAmtC
))) {
4902 // If there's effectively no shift, return the 1st arg or 2nd arg.
4903 // TODO: For vectors, we could check each element of a non-splat constant.
4904 APInt BitWidth
= APInt(ShAmtC
->getBitWidth(), ShAmtC
->getBitWidth());
4905 if (ShAmtC
->urem(BitWidth
).isNullValue())
4906 return ArgBegin
[IID
== Intrinsic::fshl
? 0 : 1];
4915 template <typename IterTy
>
4916 static Value
*SimplifyCall(ImmutableCallSite CS
, Value
*V
, IterTy ArgBegin
,
4917 IterTy ArgEnd
, const SimplifyQuery
&Q
,
4918 unsigned MaxRecurse
) {
4919 Type
*Ty
= V
->getType();
4920 if (PointerType
*PTy
= dyn_cast
<PointerType
>(Ty
))
4921 Ty
= PTy
->getElementType();
4922 FunctionType
*FTy
= cast
<FunctionType
>(Ty
);
4924 // call undef -> undef
4925 // call null -> undef
4926 if (isa
<UndefValue
>(V
) || isa
<ConstantPointerNull
>(V
))
4927 return UndefValue::get(FTy
->getReturnType());
4929 Function
*F
= dyn_cast
<Function
>(V
);
4933 if (F
->isIntrinsic())
4934 if (Value
*Ret
= simplifyIntrinsic(F
, ArgBegin
, ArgEnd
, Q
))
4937 if (!canConstantFoldCallTo(CS
, F
))
4940 SmallVector
<Constant
*, 4> ConstantArgs
;
4941 ConstantArgs
.reserve(ArgEnd
- ArgBegin
);
4942 for (IterTy I
= ArgBegin
, E
= ArgEnd
; I
!= E
; ++I
) {
4943 Constant
*C
= dyn_cast
<Constant
>(*I
);
4946 ConstantArgs
.push_back(C
);
4949 return ConstantFoldCall(CS
, F
, ConstantArgs
, Q
.TLI
);
4952 Value
*llvm::SimplifyCall(ImmutableCallSite CS
, Value
*V
,
4953 User::op_iterator ArgBegin
, User::op_iterator ArgEnd
,
4954 const SimplifyQuery
&Q
) {
4955 return ::SimplifyCall(CS
, V
, ArgBegin
, ArgEnd
, Q
, RecursionLimit
);
4958 Value
*llvm::SimplifyCall(ImmutableCallSite CS
, Value
*V
,
4959 ArrayRef
<Value
*> Args
, const SimplifyQuery
&Q
) {
4960 return ::SimplifyCall(CS
, V
, Args
.begin(), Args
.end(), Q
, RecursionLimit
);
4963 Value
*llvm::SimplifyCall(ImmutableCallSite ICS
, const SimplifyQuery
&Q
) {
4964 CallSite
CS(const_cast<Instruction
*>(ICS
.getInstruction()));
4965 return ::SimplifyCall(CS
, CS
.getCalledValue(), CS
.arg_begin(), CS
.arg_end(),
4969 /// See if we can compute a simplified version of this instruction.
4970 /// If not, this returns null.
4972 Value
*llvm::SimplifyInstruction(Instruction
*I
, const SimplifyQuery
&SQ
,
4973 OptimizationRemarkEmitter
*ORE
) {
4974 const SimplifyQuery Q
= SQ
.CxtI
? SQ
: SQ
.getWithInstruction(I
);
4977 switch (I
->getOpcode()) {
4979 Result
= ConstantFoldInstruction(I
, Q
.DL
, Q
.TLI
);
4981 case Instruction::FAdd
:
4982 Result
= SimplifyFAddInst(I
->getOperand(0), I
->getOperand(1),
4983 I
->getFastMathFlags(), Q
);
4985 case Instruction::Add
:
4987 SimplifyAddInst(I
->getOperand(0), I
->getOperand(1),
4988 Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
4989 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
);
4991 case Instruction::FSub
:
4992 Result
= SimplifyFSubInst(I
->getOperand(0), I
->getOperand(1),
4993 I
->getFastMathFlags(), Q
);
4995 case Instruction::Sub
:
4997 SimplifySubInst(I
->getOperand(0), I
->getOperand(1),
4998 Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
4999 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
);
5001 case Instruction::FMul
:
5002 Result
= SimplifyFMulInst(I
->getOperand(0), I
->getOperand(1),
5003 I
->getFastMathFlags(), Q
);
5005 case Instruction::Mul
:
5006 Result
= SimplifyMulInst(I
->getOperand(0), I
->getOperand(1), Q
);
5008 case Instruction::SDiv
:
5009 Result
= SimplifySDivInst(I
->getOperand(0), I
->getOperand(1), Q
);
5011 case Instruction::UDiv
:
5012 Result
= SimplifyUDivInst(I
->getOperand(0), I
->getOperand(1), Q
);
5014 case Instruction::FDiv
:
5015 Result
= SimplifyFDivInst(I
->getOperand(0), I
->getOperand(1),
5016 I
->getFastMathFlags(), Q
);
5018 case Instruction::SRem
:
5019 Result
= SimplifySRemInst(I
->getOperand(0), I
->getOperand(1), Q
);
5021 case Instruction::URem
:
5022 Result
= SimplifyURemInst(I
->getOperand(0), I
->getOperand(1), Q
);
5024 case Instruction::FRem
:
5025 Result
= SimplifyFRemInst(I
->getOperand(0), I
->getOperand(1),
5026 I
->getFastMathFlags(), Q
);
5028 case Instruction::Shl
:
5030 SimplifyShlInst(I
->getOperand(0), I
->getOperand(1),
5031 Q
.IIQ
.hasNoSignedWrap(cast
<BinaryOperator
>(I
)),
5032 Q
.IIQ
.hasNoUnsignedWrap(cast
<BinaryOperator
>(I
)), Q
);
5034 case Instruction::LShr
:
5035 Result
= SimplifyLShrInst(I
->getOperand(0), I
->getOperand(1),
5036 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
);
5038 case Instruction::AShr
:
5039 Result
= SimplifyAShrInst(I
->getOperand(0), I
->getOperand(1),
5040 Q
.IIQ
.isExact(cast
<BinaryOperator
>(I
)), Q
);
5042 case Instruction::And
:
5043 Result
= SimplifyAndInst(I
->getOperand(0), I
->getOperand(1), Q
);
5045 case Instruction::Or
:
5046 Result
= SimplifyOrInst(I
->getOperand(0), I
->getOperand(1), Q
);
5048 case Instruction::Xor
:
5049 Result
= SimplifyXorInst(I
->getOperand(0), I
->getOperand(1), Q
);
5051 case Instruction::ICmp
:
5052 Result
= SimplifyICmpInst(cast
<ICmpInst
>(I
)->getPredicate(),
5053 I
->getOperand(0), I
->getOperand(1), Q
);
5055 case Instruction::FCmp
:
5057 SimplifyFCmpInst(cast
<FCmpInst
>(I
)->getPredicate(), I
->getOperand(0),
5058 I
->getOperand(1), I
->getFastMathFlags(), Q
);
5060 case Instruction::Select
:
5061 Result
= SimplifySelectInst(I
->getOperand(0), I
->getOperand(1),
5062 I
->getOperand(2), Q
);
5064 case Instruction::GetElementPtr
: {
5065 SmallVector
<Value
*, 8> Ops(I
->op_begin(), I
->op_end());
5066 Result
= SimplifyGEPInst(cast
<GetElementPtrInst
>(I
)->getSourceElementType(),
5070 case Instruction::InsertValue
: {
5071 InsertValueInst
*IV
= cast
<InsertValueInst
>(I
);
5072 Result
= SimplifyInsertValueInst(IV
->getAggregateOperand(),
5073 IV
->getInsertedValueOperand(),
5074 IV
->getIndices(), Q
);
5077 case Instruction::InsertElement
: {
5078 auto *IE
= cast
<InsertElementInst
>(I
);
5079 Result
= SimplifyInsertElementInst(IE
->getOperand(0), IE
->getOperand(1),
5080 IE
->getOperand(2), Q
);
5083 case Instruction::ExtractValue
: {
5084 auto *EVI
= cast
<ExtractValueInst
>(I
);
5085 Result
= SimplifyExtractValueInst(EVI
->getAggregateOperand(),
5086 EVI
->getIndices(), Q
);
5089 case Instruction::ExtractElement
: {
5090 auto *EEI
= cast
<ExtractElementInst
>(I
);
5091 Result
= SimplifyExtractElementInst(EEI
->getVectorOperand(),
5092 EEI
->getIndexOperand(), Q
);
5095 case Instruction::ShuffleVector
: {
5096 auto *SVI
= cast
<ShuffleVectorInst
>(I
);
5097 Result
= SimplifyShuffleVectorInst(SVI
->getOperand(0), SVI
->getOperand(1),
5098 SVI
->getMask(), SVI
->getType(), Q
);
5101 case Instruction::PHI
:
5102 Result
= SimplifyPHINode(cast
<PHINode
>(I
), Q
);
5104 case Instruction::Call
: {
5105 CallSite
CS(cast
<CallInst
>(I
));
5106 Result
= SimplifyCall(CS
, Q
);
5109 #define HANDLE_CAST_INST(num, opc, clas) case Instruction::opc:
5110 #include "llvm/IR/Instruction.def"
5111 #undef HANDLE_CAST_INST
5113 SimplifyCastInst(I
->getOpcode(), I
->getOperand(0), I
->getType(), Q
);
5115 case Instruction::Alloca
:
5116 // No simplifications for Alloca and it can't be constant folded.
5121 // In general, it is possible for computeKnownBits to determine all bits in a
5122 // value even when the operands are not all constants.
5123 if (!Result
&& I
->getType()->isIntOrIntVectorTy()) {
5124 KnownBits Known
= computeKnownBits(I
, Q
.DL
, /*Depth*/ 0, Q
.AC
, I
, Q
.DT
, ORE
);
5125 if (Known
.isConstant())
5126 Result
= ConstantInt::get(I
->getType(), Known
.getConstant());
5129 /// If called on unreachable code, the above logic may report that the
5130 /// instruction simplified to itself. Make life easier for users by
5131 /// detecting that case here, returning a safe value instead.
5132 return Result
== I
? UndefValue::get(I
->getType()) : Result
;
5135 /// Implementation of recursive simplification through an instruction's
5138 /// This is the common implementation of the recursive simplification routines.
5139 /// If we have a pre-simplified value in 'SimpleV', that is forcibly used to
5140 /// replace the instruction 'I'. Otherwise, we simply add 'I' to the list of
5141 /// instructions to process and attempt to simplify it using
5142 /// InstructionSimplify.
5144 /// This routine returns 'true' only when *it* simplifies something. The passed
5145 /// in simplified value does not count toward this.
5146 static bool replaceAndRecursivelySimplifyImpl(Instruction
*I
, Value
*SimpleV
,
5147 const TargetLibraryInfo
*TLI
,
5148 const DominatorTree
*DT
,
5149 AssumptionCache
*AC
) {
5150 bool Simplified
= false;
5151 SmallSetVector
<Instruction
*, 8> Worklist
;
5152 const DataLayout
&DL
= I
->getModule()->getDataLayout();
5154 // If we have an explicit value to collapse to, do that round of the
5155 // simplification loop by hand initially.
5157 for (User
*U
: I
->users())
5159 Worklist
.insert(cast
<Instruction
>(U
));
5161 // Replace the instruction with its simplified value.
5162 I
->replaceAllUsesWith(SimpleV
);
5164 // Gracefully handle edge cases where the instruction is not wired into any
5166 if (I
->getParent() && !I
->isEHPad() && !I
->isTerminator() &&
5167 !I
->mayHaveSideEffects())
5168 I
->eraseFromParent();
5173 // Note that we must test the size on each iteration, the worklist can grow.
5174 for (unsigned Idx
= 0; Idx
!= Worklist
.size(); ++Idx
) {
5177 // See if this instruction simplifies.
5178 SimpleV
= SimplifyInstruction(I
, {DL
, TLI
, DT
, AC
});
5184 // Stash away all the uses of the old instruction so we can check them for
5185 // recursive simplifications after a RAUW. This is cheaper than checking all
5186 // uses of To on the recursive step in most cases.
5187 for (User
*U
: I
->users())
5188 Worklist
.insert(cast
<Instruction
>(U
));
5190 // Replace the instruction with its simplified value.
5191 I
->replaceAllUsesWith(SimpleV
);
5193 // Gracefully handle edge cases where the instruction is not wired into any
5195 if (I
->getParent() && !I
->isEHPad() && !I
->isTerminator() &&
5196 !I
->mayHaveSideEffects())
5197 I
->eraseFromParent();
5202 bool llvm::recursivelySimplifyInstruction(Instruction
*I
,
5203 const TargetLibraryInfo
*TLI
,
5204 const DominatorTree
*DT
,
5205 AssumptionCache
*AC
) {
5206 return replaceAndRecursivelySimplifyImpl(I
, nullptr, TLI
, DT
, AC
);
5209 bool llvm::replaceAndRecursivelySimplify(Instruction
*I
, Value
*SimpleV
,
5210 const TargetLibraryInfo
*TLI
,
5211 const DominatorTree
*DT
,
5212 AssumptionCache
*AC
) {
5213 assert(I
!= SimpleV
&& "replaceAndRecursivelySimplify(X,X) is not valid!");
5214 assert(SimpleV
&& "Must provide a simplified value.");
5215 return replaceAndRecursivelySimplifyImpl(I
, SimpleV
, TLI
, DT
, AC
);
5219 const SimplifyQuery
getBestSimplifyQuery(Pass
&P
, Function
&F
) {
5220 auto *DTWP
= P
.getAnalysisIfAvailable
<DominatorTreeWrapperPass
>();
5221 auto *DT
= DTWP
? &DTWP
->getDomTree() : nullptr;
5222 auto *TLIWP
= P
.getAnalysisIfAvailable
<TargetLibraryInfoWrapperPass
>();
5223 auto *TLI
= TLIWP
? &TLIWP
->getTLI() : nullptr;
5224 auto *ACWP
= P
.getAnalysisIfAvailable
<AssumptionCacheTracker
>();
5225 auto *AC
= ACWP
? &ACWP
->getAssumptionCache(F
) : nullptr;
5226 return {F
.getParent()->getDataLayout(), TLI
, DT
, AC
};
5229 const SimplifyQuery
getBestSimplifyQuery(LoopStandardAnalysisResults
&AR
,
5230 const DataLayout
&DL
) {
5231 return {DL
, &AR
.TLI
, &AR
.DT
, &AR
.AC
};
5234 template <class T
, class... TArgs
>
5235 const SimplifyQuery
getBestSimplifyQuery(AnalysisManager
<T
, TArgs
...> &AM
,
5237 auto *DT
= AM
.template getCachedResult
<DominatorTreeAnalysis
>(F
);
5238 auto *TLI
= AM
.template getCachedResult
<TargetLibraryAnalysis
>(F
);
5239 auto *AC
= AM
.template getCachedResult
<AssumptionAnalysis
>(F
);
5240 return {F
.getParent()->getDataLayout(), TLI
, DT
, AC
};
5242 template const SimplifyQuery
getBestSimplifyQuery(AnalysisManager
<Function
> &,