1 //===- SplitKit.h - Toolkit for splitting live ranges -----------*- C++ -*-===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
7 //===----------------------------------------------------------------------===//
9 // This file contains the SplitAnalysis class as well as mutator functions for
10 // live range splitting.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_LIB_CODEGEN_SPLITKIT_H
15 #define LLVM_LIB_CODEGEN_SPLITKIT_H
17 #include "llvm/ADT/ArrayRef.h"
18 #include "llvm/ADT/BitVector.h"
19 #include "llvm/ADT/DenseMap.h"
20 #include "llvm/ADT/DenseSet.h"
21 #include "llvm/ADT/IntervalMap.h"
22 #include "llvm/ADT/PointerIntPair.h"
23 #include "llvm/ADT/SmallPtrSet.h"
24 #include "llvm/ADT/SmallVector.h"
25 #include "llvm/CodeGen/LiveInterval.h"
26 #include "llvm/CodeGen/LiveIntervalCalc.h"
27 #include "llvm/CodeGen/LiveIntervals.h"
28 #include "llvm/CodeGen/MachineBasicBlock.h"
29 #include "llvm/CodeGen/MachineFunction.h"
30 #include "llvm/CodeGen/SlotIndexes.h"
31 #include "llvm/MC/LaneBitmask.h"
32 #include "llvm/Support/Compiler.h"
40 class MachineBlockFrequencyInfo
;
41 class MachineDominatorTree
;
42 class MachineLoopInfo
;
43 class MachineRegisterInfo
;
44 class TargetInstrInfo
;
45 class TargetRegisterInfo
;
49 /// Determines the latest safe point in a block in which we can insert a split,
50 /// spill or other instruction related with CurLI.
51 class LLVM_LIBRARY_VISIBILITY InsertPointAnalysis
{
53 const LiveIntervals
&LIS
;
55 /// Last legal insert point in each basic block in the current function.
56 /// The first entry is the first terminator, the second entry is the
57 /// last valid point to insert a split or spill for a variable that is
58 /// live into a landing pad or inlineasm_br successor.
59 SmallVector
<std::pair
<SlotIndex
, SlotIndex
>, 8> LastInsertPoint
;
61 SlotIndex
computeLastInsertPoint(const LiveInterval
&CurLI
,
62 const MachineBasicBlock
&MBB
);
65 InsertPointAnalysis(const LiveIntervals
&lis
, unsigned BBNum
);
67 /// Return the base index of the last valid insert point for \pCurLI in \pMBB.
68 SlotIndex
getLastInsertPoint(const LiveInterval
&CurLI
,
69 const MachineBasicBlock
&MBB
) {
70 unsigned Num
= MBB
.getNumber();
71 // Inline the common simple case.
72 if (LastInsertPoint
[Num
].first
.isValid() &&
73 !LastInsertPoint
[Num
].second
.isValid())
74 return LastInsertPoint
[Num
].first
;
75 return computeLastInsertPoint(CurLI
, MBB
);
78 /// Returns the last insert point as an iterator for \pCurLI in \pMBB.
79 MachineBasicBlock::iterator
getLastInsertPointIter(const LiveInterval
&CurLI
,
80 MachineBasicBlock
&MBB
);
82 /// Return the base index of the first insert point in \pMBB.
83 SlotIndex
getFirstInsertPoint(MachineBasicBlock
&MBB
) {
84 SlotIndex Res
= LIS
.getMBBStartIdx(&MBB
);
86 MachineBasicBlock::iterator MII
= MBB
.SkipPHIsLabelsAndDebug(MBB
.begin());
88 Res
= LIS
.getInstructionIndex(*MII
);
95 /// SplitAnalysis - Analyze a LiveInterval, looking for live range splitting
97 class LLVM_LIBRARY_VISIBILITY SplitAnalysis
{
99 const MachineFunction
&MF
;
100 const VirtRegMap
&VRM
;
101 const LiveIntervals
&LIS
;
102 const MachineLoopInfo
&Loops
;
103 const TargetInstrInfo
&TII
;
105 /// Additional information about basic blocks where the current variable is
106 /// live. Such a block will look like one of these templates:
108 /// 1. | o---x | Internal to block. Variable is only live in this block.
109 /// 2. |---x | Live-in, kill.
110 /// 3. | o---| Def, live-out.
111 /// 4. |---x o---| Live-in, kill, def, live-out. Counted by NumGapBlocks.
112 /// 5. |---o---o---| Live-through with uses or defs.
113 /// 6. |-----------| Live-through without uses. Counted by NumThroughBlocks.
115 /// Two BlockInfo entries are created for template 4. One for the live-in
116 /// segment, and one for the live-out segment. These entries look as if the
117 /// block were split in the middle where the live range isn't live.
119 /// Live-through blocks without any uses don't get BlockInfo entries. They
120 /// are simply listed in ThroughBlocks instead.
123 MachineBasicBlock
*MBB
;
124 SlotIndex FirstInstr
; ///< First instr accessing current reg.
125 SlotIndex LastInstr
; ///< Last instr accessing current reg.
126 SlotIndex FirstDef
; ///< First non-phi valno->def, or SlotIndex().
127 bool LiveIn
; ///< Current reg is live in.
128 bool LiveOut
; ///< Current reg is live out.
130 /// isOneInstr - Returns true when this BlockInfo describes a single
132 bool isOneInstr() const {
133 return SlotIndex::isSameInstr(FirstInstr
, LastInstr
);
136 void print(raw_ostream
&OS
) const;
141 // Current live interval.
142 const LiveInterval
*CurLI
= nullptr;
144 /// Insert Point Analysis.
145 InsertPointAnalysis IPA
;
147 // Sorted slot indexes of using instructions.
148 SmallVector
<SlotIndex
, 8> UseSlots
;
150 /// UseBlocks - Blocks where CurLI has uses.
151 SmallVector
<BlockInfo
, 8> UseBlocks
;
153 /// NumGapBlocks - Number of duplicate entries in UseBlocks for blocks where
154 /// the live range has a gap.
155 unsigned NumGapBlocks
;
157 /// ThroughBlocks - Block numbers where CurLI is live through without uses.
158 BitVector ThroughBlocks
;
160 /// NumThroughBlocks - Number of live-through blocks.
161 unsigned NumThroughBlocks
;
163 // Sumarize statistics by counting instructions using CurLI.
166 /// calcLiveBlockInfo - Compute per-block information about CurLI.
167 void calcLiveBlockInfo();
170 SplitAnalysis(const VirtRegMap
&vrm
, const LiveIntervals
&lis
,
171 const MachineLoopInfo
&mli
);
173 /// analyze - set CurLI to the specified interval, and analyze how it may be
175 void analyze(const LiveInterval
*li
);
177 /// clear - clear all data structures so SplitAnalysis is ready to analyze a
181 /// getParent - Return the last analyzed interval.
182 const LiveInterval
&getParent() const { return *CurLI
; }
184 /// isOriginalEndpoint - Return true if the original live range was killed or
185 /// (re-)defined at Idx. Idx should be the 'def' slot for a normal kill/def,
186 /// and 'use' for an early-clobber def.
187 /// This can be used to recognize code inserted by earlier live range
189 bool isOriginalEndpoint(SlotIndex Idx
) const;
191 /// getUseSlots - Return an array of SlotIndexes of instructions using CurLI.
192 /// This include both use and def operands, at most one entry per instruction.
193 ArrayRef
<SlotIndex
> getUseSlots() const { return UseSlots
; }
195 /// getUseBlocks - Return an array of BlockInfo objects for the basic blocks
196 /// where CurLI has uses.
197 ArrayRef
<BlockInfo
> getUseBlocks() const { return UseBlocks
; }
199 /// getNumThroughBlocks - Return the number of through blocks.
200 unsigned getNumThroughBlocks() const { return NumThroughBlocks
; }
202 /// isThroughBlock - Return true if CurLI is live through MBB without uses.
203 bool isThroughBlock(unsigned MBB
) const { return ThroughBlocks
.test(MBB
); }
205 /// getThroughBlocks - Return the set of through blocks.
206 const BitVector
&getThroughBlocks() const { return ThroughBlocks
; }
208 /// getNumLiveBlocks - Return the number of blocks where CurLI is live.
209 unsigned getNumLiveBlocks() const {
210 return getUseBlocks().size() - NumGapBlocks
+ getNumThroughBlocks();
213 /// countLiveBlocks - Return the number of blocks where li is live. This is
214 /// guaranteed to return the same number as getNumLiveBlocks() after calling
216 unsigned countLiveBlocks(const LiveInterval
*li
) const;
218 using BlockPtrSet
= SmallPtrSet
<const MachineBasicBlock
*, 16>;
220 /// shouldSplitSingleBlock - Returns true if it would help to create a local
221 /// live range for the instructions in BI. There is normally no benefit to
222 /// creating a live range for a single instruction, but it does enable
223 /// register class inflation if the instruction has a restricted register
226 /// @param BI The block to be isolated.
227 /// @param SingleInstrs True when single instructions should be isolated.
228 bool shouldSplitSingleBlock(const BlockInfo
&BI
, bool SingleInstrs
) const;
230 SlotIndex
getLastSplitPoint(unsigned Num
) {
231 return IPA
.getLastInsertPoint(*CurLI
, *MF
.getBlockNumbered(Num
));
234 SlotIndex
getLastSplitPoint(MachineBasicBlock
*BB
) {
235 return IPA
.getLastInsertPoint(*CurLI
, *BB
);
238 MachineBasicBlock::iterator
getLastSplitPointIter(MachineBasicBlock
*BB
) {
239 return IPA
.getLastInsertPointIter(*CurLI
, *BB
);
242 SlotIndex
getFirstSplitPoint(unsigned Num
) {
243 return IPA
.getFirstInsertPoint(*MF
.getBlockNumbered(Num
));
247 /// SplitEditor - Edit machine code and LiveIntervals for live range
250 /// - Create a SplitEditor from a SplitAnalysis.
251 /// - Start a new live interval with openIntv.
252 /// - Mark the places where the new interval is entered using enterIntv*
253 /// - Mark the ranges where the new interval is used with useIntv*
254 /// - Mark the places where the interval is exited with exitIntv*.
255 /// - Finish the current interval with closeIntv and repeat from 2.
256 /// - Rewrite instructions with finish().
258 class LLVM_LIBRARY_VISIBILITY SplitEditor
{
263 MachineRegisterInfo
&MRI
;
264 MachineDominatorTree
&MDT
;
265 const TargetInstrInfo
&TII
;
266 const TargetRegisterInfo
&TRI
;
267 const MachineBlockFrequencyInfo
&MBFI
;
268 VirtRegAuxInfo
&VRAI
;
271 /// ComplementSpillMode - Select how the complement live range should be
272 /// created. SplitEditor automatically creates interval 0 to contain
273 /// anything that isn't added to another interval. This complement interval
274 /// can get quite complicated, and it can sometimes be an advantage to allow
275 /// it to overlap the other intervals. If it is going to spill anyway, no
276 /// registers are wasted by keeping a value in two places at the same time.
277 enum ComplementSpillMode
{
278 /// SM_Partition(Default) - Try to create the complement interval so it
279 /// doesn't overlap any other intervals, and the original interval is
280 /// partitioned. This may require a large number of back copies and extra
281 /// PHI-defs. Only segments marked with overlapIntv will be overlapping.
284 /// SM_Size - Overlap intervals to minimize the number of inserted COPY
285 /// instructions. Copies to the complement interval are hoisted to their
286 /// common dominator, so only one COPY is required per value in the
287 /// complement interval. This also means that no extra PHI-defs need to be
288 /// inserted in the complement interval.
291 /// SM_Speed - Overlap intervals to minimize the expected execution
292 /// frequency of the inserted copies. This is very similar to SM_Size, but
293 /// the complement interval may get some extra PHI-defs.
298 /// Edit - The current parent register and new intervals created.
299 LiveRangeEdit
*Edit
= nullptr;
301 /// Index into Edit of the currently open interval.
302 /// The index 0 is used for the complement, so the first interval started by
303 /// openIntv will be 1.
304 unsigned OpenIdx
= 0;
306 /// The current spill mode, selected by reset().
307 ComplementSpillMode SpillMode
= SM_Partition
;
309 using RegAssignMap
= IntervalMap
<SlotIndex
, unsigned>;
311 /// Allocator for the interval map. This will eventually be shared with
312 /// SlotIndexes and LiveIntervals.
313 RegAssignMap::Allocator Allocator
;
315 /// RegAssign - Map of the assigned register indexes.
316 /// Edit.get(RegAssign.lookup(Idx)) is the register that should be live at
318 RegAssignMap RegAssign
;
320 using ValueForcePair
= PointerIntPair
<VNInfo
*, 1>;
321 using ValueMap
= DenseMap
<std::pair
<unsigned, unsigned>, ValueForcePair
>;
323 /// Values - keep track of the mapping from parent values to values in the new
324 /// intervals. Given a pair (RegIdx, ParentVNI->id), Values contains:
326 /// 1. No entry - the value is not mapped to Edit.get(RegIdx).
327 /// 2. (Null, false) - the value is mapped to multiple values in
328 /// Edit.get(RegIdx). Each value is represented by a minimal live range at
329 /// its def. The full live range can be inferred exactly from the range
330 /// of RegIdx in RegAssign.
331 /// 3. (Null, true). As above, but the ranges in RegAssign are too large, and
332 /// the live range must be recomputed using ::extend().
333 /// 4. (VNI, false) The value is mapped to a single new value.
334 /// The new value has no live ranges anywhere.
337 /// LICalc - Cache for computing live ranges and SSA update. Each instance
338 /// can only handle non-overlapping live ranges, so use a separate
339 /// LiveIntervalCalc instance for the complement interval when in spill mode.
340 LiveIntervalCalc LICalc
[2];
342 /// getLICalc - Return the LICalc to use for RegIdx. In spill mode, the
343 /// complement interval can overlap the other intervals, so it gets its own
344 /// LICalc instance. When not in spill mode, all intervals can share one.
345 LiveIntervalCalc
&getLICalc(unsigned RegIdx
) {
346 return LICalc
[SpillMode
!= SM_Partition
&& RegIdx
!= 0];
349 /// Find a subrange corresponding to the exact lane mask @p LM in the live
350 /// interval @p LI. The interval @p LI is assumed to contain such a subrange.
351 /// This function is used to find corresponding subranges between the
352 /// original interval and the new intervals.
353 LiveInterval::SubRange
&getSubRangeForMaskExact(LaneBitmask LM
,
356 /// Find a subrange corresponding to the lane mask @p LM, or a superset of it,
357 /// in the live interval @p LI. The interval @p LI is assumed to contain such
358 /// a subrange. This function is used to find corresponding subranges between
359 /// the original interval and the new intervals.
360 LiveInterval::SubRange
&getSubRangeForMask(LaneBitmask LM
, LiveInterval
&LI
);
362 /// Add a segment to the interval LI for the value number VNI. If LI has
363 /// subranges, corresponding segments will be added to them as well, but
364 /// with newly created value numbers. If Original is true, dead def will
365 /// only be added a subrange of LI if the corresponding subrange of the
366 /// original interval has a def at this index. Otherwise, all subranges
367 /// of LI will be updated.
368 void addDeadDef(LiveInterval
&LI
, VNInfo
*VNI
, bool Original
);
370 /// defValue - define a value in RegIdx from ParentVNI at Idx.
371 /// Idx does not have to be ParentVNI->def, but it must be contained within
372 /// ParentVNI's live range in ParentLI. The new value is added to the value
373 /// map. The value being defined may either come from rematerialization
374 /// (or an inserted copy), or it may be coming from the original interval.
375 /// The parameter Original should be true in the latter case, otherwise
376 /// it should be false.
377 /// Return the new LI value.
378 VNInfo
*defValue(unsigned RegIdx
, const VNInfo
*ParentVNI
, SlotIndex Idx
,
381 /// forceRecompute - Force the live range of ParentVNI in RegIdx to be
382 /// recomputed by LiveRangeCalc::extend regardless of the number of defs.
383 /// This is used for values whose live range doesn't match RegAssign exactly.
384 /// They could have rematerialized, or back-copies may have been moved.
385 void forceRecompute(unsigned RegIdx
, const VNInfo
&ParentVNI
);
387 /// Calls forceRecompute() on any affected regidx and on ParentVNI
388 /// predecessors in case of a phi definition.
389 void forceRecomputeVNI(const VNInfo
&ParentVNI
);
391 /// defFromParent - Define Reg from ParentVNI at UseIdx using either
392 /// rematerialization or a COPY from parent. Return the new value.
393 VNInfo
*defFromParent(unsigned RegIdx
,
396 MachineBasicBlock
&MBB
,
397 MachineBasicBlock::iterator I
);
399 /// removeBackCopies - Remove the copy instructions that defines the values
400 /// in the vector in the complement interval.
401 void removeBackCopies(SmallVectorImpl
<VNInfo
*> &Copies
);
403 /// getShallowDominator - Returns the least busy dominator of MBB that is
404 /// also dominated by DefMBB. Busy is measured by loop depth.
405 MachineBasicBlock
*findShallowDominator(MachineBasicBlock
*MBB
,
406 MachineBasicBlock
*DefMBB
);
408 /// Find out all the backCopies dominated by others.
409 void computeRedundantBackCopies(DenseSet
<unsigned> &NotToHoistSet
,
410 SmallVectorImpl
<VNInfo
*> &BackCopies
);
412 /// Hoist back-copies to the complement interval. It tries to hoist all
413 /// the back-copies to one BB if it is beneficial, or else simply remove
414 /// redundant backcopies dominated by others.
417 /// transferValues - Transfer values to the new ranges.
418 /// Return true if any ranges were skipped.
419 bool transferValues();
421 /// Live range @p LR corresponding to the lane Mask @p LM has a live
422 /// PHI def at the beginning of block @p B. Extend the range @p LR of
423 /// all predecessor values that reach this def. If @p LR is a subrange,
424 /// the array @p Undefs is the set of all locations where it is undefined
425 /// via <def,read-undef> in other subranges for the same register.
426 void extendPHIRange(MachineBasicBlock
&B
, LiveIntervalCalc
&LIC
,
427 LiveRange
&LR
, LaneBitmask LM
,
428 ArrayRef
<SlotIndex
> Undefs
);
430 /// extendPHIKillRanges - Extend the ranges of all values killed by original
432 void extendPHIKillRanges();
434 /// rewriteAssigned - Rewrite all uses of Edit.getReg() to assigned registers.
435 void rewriteAssigned(bool ExtendRanges
);
437 /// deleteRematVictims - Delete defs that are dead after rematerializing.
438 void deleteRematVictims();
440 /// Add a copy instruction copying \p FromReg to \p ToReg before
441 /// \p InsertBefore. This can be invoked with a \p LaneMask which may make it
442 /// necessary to construct a sequence of copies to cover it exactly.
443 SlotIndex
buildCopy(Register FromReg
, Register ToReg
, LaneBitmask LaneMask
,
444 MachineBasicBlock
&MBB
, MachineBasicBlock::iterator InsertBefore
,
445 bool Late
, unsigned RegIdx
);
447 SlotIndex
buildSingleSubRegCopy(Register FromReg
, Register ToReg
,
448 MachineBasicBlock
&MB
, MachineBasicBlock::iterator InsertBefore
,
449 unsigned SubIdx
, LiveInterval
&DestLI
, bool Late
, SlotIndex Def
);
452 /// Create a new SplitEditor for editing the LiveInterval analyzed by SA.
453 /// Newly created intervals will be appended to newIntervals.
454 SplitEditor(SplitAnalysis
&SA
, AAResults
&AA
, LiveIntervals
&LIS
,
455 VirtRegMap
&VRM
, MachineDominatorTree
&MDT
,
456 MachineBlockFrequencyInfo
&MBFI
, VirtRegAuxInfo
&VRAI
);
458 /// reset - Prepare for a new split.
459 void reset(LiveRangeEdit
&, ComplementSpillMode
= SM_Partition
);
461 /// Create a new virtual register and live interval.
462 /// Return the interval index, starting from 1. Interval index 0 is the
463 /// implicit complement interval.
466 /// currentIntv - Return the current interval index.
467 unsigned currentIntv() const { return OpenIdx
; }
469 /// selectIntv - Select a previously opened interval index.
470 void selectIntv(unsigned Idx
);
472 /// enterIntvBefore - Enter the open interval before the instruction at Idx.
473 /// If the parent interval is not live before Idx, a COPY is not inserted.
474 /// Return the beginning of the new live range.
475 SlotIndex
enterIntvBefore(SlotIndex Idx
);
477 /// enterIntvAfter - Enter the open interval after the instruction at Idx.
478 /// Return the beginning of the new live range.
479 SlotIndex
enterIntvAfter(SlotIndex Idx
);
481 /// enterIntvAtEnd - Enter the open interval at the end of MBB.
482 /// Use the open interval from the inserted copy to the MBB end.
483 /// Return the beginning of the new live range.
484 SlotIndex
enterIntvAtEnd(MachineBasicBlock
&MBB
);
486 /// useIntv - indicate that all instructions in MBB should use OpenLI.
487 void useIntv(const MachineBasicBlock
&MBB
);
489 /// useIntv - indicate that all instructions in range should use OpenLI.
490 void useIntv(SlotIndex Start
, SlotIndex End
);
492 /// leaveIntvAfter - Leave the open interval after the instruction at Idx.
493 /// Return the end of the live range.
494 SlotIndex
leaveIntvAfter(SlotIndex Idx
);
496 /// leaveIntvBefore - Leave the open interval before the instruction at Idx.
497 /// Return the end of the live range.
498 SlotIndex
leaveIntvBefore(SlotIndex Idx
);
500 /// leaveIntvAtTop - Leave the interval at the top of MBB.
501 /// Add liveness from the MBB top to the copy.
502 /// Return the end of the live range.
503 SlotIndex
leaveIntvAtTop(MachineBasicBlock
&MBB
);
505 /// overlapIntv - Indicate that all instructions in range should use the open
506 /// interval if End does not have tied-def usage of the register and in this
507 /// case compliment interval is used. Let the complement interval be live.
509 /// This doubles the register pressure, but is sometimes required to deal with
510 /// register uses after the last valid split point.
512 /// The Start index should be a return value from a leaveIntv* call, and End
513 /// should be in the same basic block. The parent interval must have the same
514 /// value across the range.
516 void overlapIntv(SlotIndex Start
, SlotIndex End
);
518 /// finish - after all the new live ranges have been created, compute the
519 /// remaining live range, and rewrite instructions to use the new registers.
520 /// @param LRMap When not null, this vector will map each live range in Edit
521 /// back to the indices returned by openIntv.
522 /// There may be extra indices created by dead code elimination.
523 void finish(SmallVectorImpl
<unsigned> *LRMap
= nullptr);
525 /// dump - print the current interval mapping to dbgs().
528 // ===--- High level methods ---===
530 /// splitSingleBlock - Split CurLI into a separate live interval around the
531 /// uses in a single block. This is intended to be used as part of a larger
532 /// split, and doesn't call finish().
533 void splitSingleBlock(const SplitAnalysis::BlockInfo
&BI
);
535 /// splitLiveThroughBlock - Split CurLI in the given block such that it
536 /// enters the block in IntvIn and leaves it in IntvOut. There may be uses in
537 /// the block, but they will be ignored when placing split points.
539 /// @param MBBNum Block number.
540 /// @param IntvIn Interval index entering the block.
541 /// @param LeaveBefore When set, leave IntvIn before this point.
542 /// @param IntvOut Interval index leaving the block.
543 /// @param EnterAfter When set, enter IntvOut after this point.
544 void splitLiveThroughBlock(unsigned MBBNum
,
545 unsigned IntvIn
, SlotIndex LeaveBefore
,
546 unsigned IntvOut
, SlotIndex EnterAfter
);
548 /// splitRegInBlock - Split CurLI in the given block such that it enters the
549 /// block in IntvIn and leaves it on the stack (or not at all). Split points
550 /// are placed in a way that avoids putting uses in the stack interval. This
551 /// may require creating a local interval when there is interference.
553 /// @param BI Block descriptor.
554 /// @param IntvIn Interval index entering the block. Not 0.
555 /// @param LeaveBefore When set, leave IntvIn before this point.
556 void splitRegInBlock(const SplitAnalysis::BlockInfo
&BI
,
557 unsigned IntvIn
, SlotIndex LeaveBefore
);
559 /// splitRegOutBlock - Split CurLI in the given block such that it enters the
560 /// block on the stack (or isn't live-in at all) and leaves it in IntvOut.
561 /// Split points are placed to avoid interference and such that the uses are
562 /// not in the stack interval. This may require creating a local interval
563 /// when there is interference.
565 /// @param BI Block descriptor.
566 /// @param IntvOut Interval index leaving the block.
567 /// @param EnterAfter When set, enter IntvOut after this point.
568 void splitRegOutBlock(const SplitAnalysis::BlockInfo
&BI
,
569 unsigned IntvOut
, SlotIndex EnterAfter
);
572 } // end namespace llvm
574 #endif // LLVM_LIB_CODEGEN_SPLITKIT_H