1 //===- llvm/Transforms/Utils/LoopUtils.h - Loop utilities -------*- C++ -*-===//
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 defines some loop transformation utilities.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_TRANSFORMS_UTILS_LOOPUTILS_H
15 #define LLVM_TRANSFORMS_UTILS_LOOPUTILS_H
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/Optional.h"
19 #include "llvm/ADT/SetVector.h"
20 #include "llvm/ADT/SmallPtrSet.h"
21 #include "llvm/ADT/SmallVector.h"
22 #include "llvm/ADT/StringRef.h"
23 #include "llvm/Analysis/AliasAnalysis.h"
24 #include "llvm/Analysis/DemandedBits.h"
25 #include "llvm/Analysis/EHPersonalities.h"
26 #include "llvm/Analysis/TargetTransformInfo.h"
27 #include "llvm/IR/Dominators.h"
28 #include "llvm/IR/IRBuilder.h"
29 #include "llvm/IR/InstrTypes.h"
30 #include "llvm/IR/Operator.h"
31 #include "llvm/IR/ValueHandle.h"
32 #include "llvm/Support/Casting.h"
37 class AliasSetTracker;
42 class OptimizationRemarkEmitter;
43 class PredicatedScalarEvolution;
44 class PredIteratorCache;
45 class ScalarEvolution;
47 class TargetLibraryInfo;
48 class TargetTransformInfo;
50 /// \brief Captures loop safety information.
51 /// It keep information for loop & its header may throw exception.
52 struct LoopSafetyInfo {
53 bool MayThrow = false; // The current loop contains an instruction which
55 bool HeaderMayThrow = false; // Same as previous, but specific to loop header
56 // Used to update funclet bundle operands.
57 DenseMap<BasicBlock *, ColorVector> BlockColors;
59 LoopSafetyInfo() = default;
62 /// The RecurrenceDescriptor is used to identify recurrences variables in a
63 /// loop. Reduction is a special case of recurrence that has uses of the
64 /// recurrence variable outside the loop. The method isReductionPHI identifies
65 /// reductions that are basic recurrences.
67 /// Basic recurrences are defined as the summation, product, OR, AND, XOR, min,
68 /// or max of a set of terms. For example: for(i=0; i<n; i++) { total +=
69 /// array[i]; } is a summation of array elements. Basic recurrences are a
70 /// special case of chains of recurrences (CR). See ScalarEvolution for CR
73 /// This struct holds information about recurrence variables.
74 class RecurrenceDescriptor {
76 /// This enum represents the kinds of recurrences that we support.
78 RK_NoRecurrence, ///< Not a recurrence.
79 RK_IntegerAdd, ///< Sum of integers.
80 RK_IntegerMult, ///< Product of integers.
81 RK_IntegerOr, ///< Bitwise or logical OR of numbers.
82 RK_IntegerAnd, ///< Bitwise or logical AND of numbers.
83 RK_IntegerXor, ///< Bitwise or logical XOR of numbers.
84 RK_IntegerMinMax, ///< Min/max implemented in terms of select(cmp()).
85 RK_FloatAdd, ///< Sum of floats.
86 RK_FloatMult, ///< Product of floats.
87 RK_FloatMinMax ///< Min/max implemented in terms of select(cmp()).
90 // This enum represents the kind of minmax recurrence.
91 enum MinMaxRecurrenceKind {
101 RecurrenceDescriptor() = default;
103 RecurrenceDescriptor(Value *Start, Instruction *Exit, RecurrenceKind K,
104 MinMaxRecurrenceKind MK, Instruction *UAI, Type *RT,
105 bool Signed, SmallPtrSetImpl<Instruction *> &CI)
106 : StartValue(Start), LoopExitInstr(Exit), Kind(K), MinMaxKind(MK),
107 UnsafeAlgebraInst(UAI), RecurrenceType(RT), IsSigned(Signed) {
108 CastInsts.insert(CI.begin(), CI.end());
111 /// This POD struct holds information about a potential recurrence operation.
114 InstDesc(bool IsRecur, Instruction *I, Instruction *UAI = nullptr)
115 : IsRecurrence(IsRecur), PatternLastInst(I), MinMaxKind(MRK_Invalid),
116 UnsafeAlgebraInst(UAI) {}
118 InstDesc(Instruction *I, MinMaxRecurrenceKind K, Instruction *UAI = nullptr)
119 : IsRecurrence(true), PatternLastInst(I), MinMaxKind(K),
120 UnsafeAlgebraInst(UAI) {}
122 bool isRecurrence() { return IsRecurrence; }
124 bool hasUnsafeAlgebra() { return UnsafeAlgebraInst != nullptr; }
126 Instruction *getUnsafeAlgebraInst() { return UnsafeAlgebraInst; }
128 MinMaxRecurrenceKind getMinMaxKind() { return MinMaxKind; }
130 Instruction *getPatternInst() { return PatternLastInst; }
133 // Is this instruction a recurrence candidate.
135 // The last instruction in a min/max pattern (select of the select(icmp())
136 // pattern), or the current recurrence instruction otherwise.
137 Instruction *PatternLastInst;
138 // If this is a min/max pattern the comparison predicate.
139 MinMaxRecurrenceKind MinMaxKind;
140 // Recurrence has unsafe algebra.
141 Instruction *UnsafeAlgebraInst;
144 /// Returns a struct describing if the instruction 'I' can be a recurrence
145 /// variable of type 'Kind'. If the recurrence is a min/max pattern of
146 /// select(icmp()) this function advances the instruction pointer 'I' from the
147 /// compare instruction to the select instruction and stores this pointer in
148 /// 'PatternLastInst' member of the returned struct.
149 static InstDesc isRecurrenceInstr(Instruction *I, RecurrenceKind Kind,
150 InstDesc &Prev, bool HasFunNoNaNAttr);
152 /// Returns true if instruction I has multiple uses in Insts
153 static bool hasMultipleUsesOf(Instruction *I,
154 SmallPtrSetImpl<Instruction *> &Insts);
156 /// Returns true if all uses of the instruction I is within the Set.
157 static bool areAllUsesIn(Instruction *I, SmallPtrSetImpl<Instruction *> &Set);
159 /// Returns a struct describing if the instruction if the instruction is a
160 /// Select(ICmp(X, Y), X, Y) instruction pattern corresponding to a min(X, Y)
162 static InstDesc isMinMaxSelectCmpPattern(Instruction *I, InstDesc &Prev);
164 /// Returns identity corresponding to the RecurrenceKind.
165 static Constant *getRecurrenceIdentity(RecurrenceKind K, Type *Tp);
167 /// Returns the opcode of binary operation corresponding to the
169 static unsigned getRecurrenceBinOp(RecurrenceKind Kind);
171 /// Returns a Min/Max operation corresponding to MinMaxRecurrenceKind.
172 static Value *createMinMaxOp(IRBuilder<> &Builder, MinMaxRecurrenceKind RK,
173 Value *Left, Value *Right);
175 /// Returns true if Phi is a reduction of type Kind and adds it to the
176 /// RecurrenceDescriptor. If either \p DB is non-null or \p AC and \p DT are
177 /// non-null, the minimal bit width needed to compute the reduction will be
179 static bool AddReductionVar(PHINode *Phi, RecurrenceKind Kind, Loop *TheLoop,
180 bool HasFunNoNaNAttr,
181 RecurrenceDescriptor &RedDes,
182 DemandedBits *DB = nullptr,
183 AssumptionCache *AC = nullptr,
184 DominatorTree *DT = nullptr);
186 /// Returns true if Phi is a reduction in TheLoop. The RecurrenceDescriptor
187 /// is returned in RedDes. If either \p DB is non-null or \p AC and \p DT are
188 /// non-null, the minimal bit width needed to compute the reduction will be
190 static bool isReductionPHI(PHINode *Phi, Loop *TheLoop,
191 RecurrenceDescriptor &RedDes,
192 DemandedBits *DB = nullptr,
193 AssumptionCache *AC = nullptr,
194 DominatorTree *DT = nullptr);
196 /// Returns true if Phi is a first-order recurrence. A first-order recurrence
197 /// is a non-reduction recurrence relation in which the value of the
198 /// recurrence in the current loop iteration equals a value defined in the
199 /// previous iteration. \p SinkAfter includes pairs of instructions where the
200 /// first will be rescheduled to appear after the second if/when the loop is
201 /// vectorized. It may be augmented with additional pairs if needed in order
202 /// to handle Phi as a first-order recurrence.
204 isFirstOrderRecurrence(PHINode *Phi, Loop *TheLoop,
205 DenseMap<Instruction *, Instruction *> &SinkAfter,
208 RecurrenceKind getRecurrenceKind() { return Kind; }
210 MinMaxRecurrenceKind getMinMaxRecurrenceKind() { return MinMaxKind; }
212 TrackingVH<Value> getRecurrenceStartValue() { return StartValue; }
214 Instruction *getLoopExitInstr() { return LoopExitInstr; }
216 /// Returns true if the recurrence has unsafe algebra which requires a relaxed
217 /// floating-point model.
218 bool hasUnsafeAlgebra() { return UnsafeAlgebraInst != nullptr; }
220 /// Returns first unsafe algebra instruction in the PHI node's use-chain.
221 Instruction *getUnsafeAlgebraInst() { return UnsafeAlgebraInst; }
223 /// Returns true if the recurrence kind is an integer kind.
224 static bool isIntegerRecurrenceKind(RecurrenceKind Kind);
226 /// Returns true if the recurrence kind is a floating point kind.
227 static bool isFloatingPointRecurrenceKind(RecurrenceKind Kind);
229 /// Returns true if the recurrence kind is an arithmetic kind.
230 static bool isArithmeticRecurrenceKind(RecurrenceKind Kind);
232 /// Returns the type of the recurrence. This type can be narrower than the
233 /// actual type of the Phi if the recurrence has been type-promoted.
234 Type *getRecurrenceType() { return RecurrenceType; }
236 /// Returns a reference to the instructions used for type-promoting the
238 SmallPtrSet<Instruction *, 8> &getCastInsts() { return CastInsts; }
240 /// Returns true if all source operands of the recurrence are SExtInsts.
241 bool isSigned() { return IsSigned; }
244 // The starting value of the recurrence.
245 // It does not have to be zero!
246 TrackingVH<Value> StartValue;
247 // The instruction who's value is used outside the loop.
248 Instruction *LoopExitInstr = nullptr;
249 // The kind of the recurrence.
250 RecurrenceKind Kind = RK_NoRecurrence;
251 // If this a min/max recurrence the kind of recurrence.
252 MinMaxRecurrenceKind MinMaxKind = MRK_Invalid;
253 // First occurrence of unasfe algebra in the PHI's use-chain.
254 Instruction *UnsafeAlgebraInst = nullptr;
255 // The type of the recurrence.
256 Type *RecurrenceType = nullptr;
257 // True if all source operands of the recurrence are SExtInsts.
258 bool IsSigned = false;
259 // Instructions used for type-promoting the recurrence.
260 SmallPtrSet<Instruction *, 8> CastInsts;
263 /// A struct for saving information about induction variables.
264 class InductionDescriptor {
266 /// This enum represents the kinds of inductions that we support.
268 IK_NoInduction, ///< Not an induction variable.
269 IK_IntInduction, ///< Integer induction variable. Step = C.
270 IK_PtrInduction, ///< Pointer induction var. Step = C / sizeof(elem).
271 IK_FpInduction ///< Floating point induction variable.
275 /// Default constructor - creates an invalid induction.
276 InductionDescriptor() = default;
278 /// Get the consecutive direction. Returns:
279 /// 0 - unknown or non-consecutive.
280 /// 1 - consecutive and increasing.
281 /// -1 - consecutive and decreasing.
282 int getConsecutiveDirection() const;
284 /// Compute the transformed value of Index at offset StartValue using step
286 /// For integer induction, returns StartValue + Index * StepValue.
287 /// For pointer induction, returns StartValue[Index * StepValue].
288 /// FIXME: The newly created binary instructions should contain nsw/nuw
289 /// flags, which can be found from the original scalar operations.
290 Value *transform(IRBuilder<> &B, Value *Index, ScalarEvolution *SE,
291 const DataLayout& DL) const;
293 Value *getStartValue() const { return StartValue; }
294 InductionKind getKind() const { return IK; }
295 const SCEV *getStep() const { return Step; }
296 ConstantInt *getConstIntStepValue() const;
298 /// Returns true if \p Phi is an induction in the loop \p L. If \p Phi is an
299 /// induction, the induction descriptor \p D will contain the data describing
300 /// this induction. If by some other means the caller has a better SCEV
301 /// expression for \p Phi than the one returned by the ScalarEvolution
302 /// analysis, it can be passed through \p Expr. If the def-use chain
303 /// associated with the phi includes casts (that we know we can ignore
304 /// under proper runtime checks), they are passed through \p CastsToIgnore.
306 isInductionPHI(PHINode *Phi, const Loop* L, ScalarEvolution *SE,
307 InductionDescriptor &D, const SCEV *Expr = nullptr,
308 SmallVectorImpl<Instruction *> *CastsToIgnore = nullptr);
310 /// Returns true if \p Phi is a floating point induction in the loop \p L.
311 /// If \p Phi is an induction, the induction descriptor \p D will contain
312 /// the data describing this induction.
313 static bool isFPInductionPHI(PHINode *Phi, const Loop* L,
314 ScalarEvolution *SE, InductionDescriptor &D);
316 /// Returns true if \p Phi is a loop \p L induction, in the context associated
317 /// with the run-time predicate of PSE. If \p Assume is true, this can add
318 /// further SCEV predicates to \p PSE in order to prove that \p Phi is an
320 /// If \p Phi is an induction, \p D will contain the data describing this
322 static bool isInductionPHI(PHINode *Phi, const Loop* L,
323 PredicatedScalarEvolution &PSE,
324 InductionDescriptor &D, bool Assume = false);
326 /// Returns true if the induction type is FP and the binary operator does
327 /// not have the "fast-math" property. Such operation requires a relaxed FP
329 bool hasUnsafeAlgebra() {
330 return InductionBinOp && !cast<FPMathOperator>(InductionBinOp)->isFast();
333 /// Returns induction operator that does not have "fast-math" property
334 /// and requires FP unsafe mode.
335 Instruction *getUnsafeAlgebraInst() {
336 if (!InductionBinOp || cast<FPMathOperator>(InductionBinOp)->isFast())
338 return InductionBinOp;
341 /// Returns binary opcode of the induction operator.
342 Instruction::BinaryOps getInductionOpcode() const {
343 return InductionBinOp ? InductionBinOp->getOpcode() :
344 Instruction::BinaryOpsEnd;
347 /// Returns a reference to the type cast instructions in the induction
348 /// update chain, that are redundant when guarded with a runtime
349 /// SCEV overflow check.
350 const SmallVectorImpl<Instruction *> &getCastInsts() const {
351 return RedundantCasts;
355 /// Private constructor - used by \c isInductionPHI.
356 InductionDescriptor(Value *Start, InductionKind K, const SCEV *Step,
357 BinaryOperator *InductionBinOp = nullptr,
358 SmallVectorImpl<Instruction *> *Casts = nullptr);
361 TrackingVH<Value> StartValue;
363 InductionKind IK = IK_NoInduction;
365 const SCEV *Step = nullptr;
366 // Instruction that advances induction variable.
367 BinaryOperator *InductionBinOp = nullptr;
368 // Instructions used for type-casts of the induction variable,
369 // that are redundant when guarded with a runtime SCEV overflow check.
370 SmallVector<Instruction *, 2> RedundantCasts;
373 BasicBlock *InsertPreheaderForLoop(Loop *L, DominatorTree *DT, LoopInfo *LI,
376 /// Ensure that all exit blocks of the loop are dedicated exits.
378 /// For any loop exit block with non-loop predecessors, we split the loop
379 /// predecessors to use a dedicated loop exit block. We update the dominator
380 /// tree and loop info if provided, and will preserve LCSSA if requested.
381 bool formDedicatedExitBlocks(Loop *L, DominatorTree *DT, LoopInfo *LI,
384 /// Ensures LCSSA form for every instruction from the Worklist in the scope of
385 /// innermost containing loop.
387 /// For the given instruction which have uses outside of the loop, an LCSSA PHI
388 /// node is inserted and the uses outside the loop are rewritten to use this
391 /// LoopInfo and DominatorTree are required and, since the routine makes no
392 /// changes to CFG, preserved.
394 /// Returns true if any modifications are made.
395 bool formLCSSAForInstructions(SmallVectorImpl<Instruction *> &Worklist,
396 DominatorTree &DT, LoopInfo &LI);
398 /// \brief Put loop into LCSSA form.
400 /// Looks at all instructions in the loop which have uses outside of the
401 /// current loop. For each, an LCSSA PHI node is inserted and the uses outside
402 /// the loop are rewritten to use this node.
404 /// LoopInfo and DominatorTree are required and preserved.
406 /// If ScalarEvolution is passed in, it will be preserved.
408 /// Returns true if any modifications are made to the loop.
409 bool formLCSSA(Loop &L, DominatorTree &DT, LoopInfo *LI, ScalarEvolution *SE);
411 /// \brief Put a loop nest into LCSSA form.
413 /// This recursively forms LCSSA for a loop nest.
415 /// LoopInfo and DominatorTree are required and preserved.
417 /// If ScalarEvolution is passed in, it will be preserved.
419 /// Returns true if any modifications are made to the loop.
420 bool formLCSSARecursively(Loop &L, DominatorTree &DT, LoopInfo *LI,
421 ScalarEvolution *SE);
423 /// \brief Walk the specified region of the CFG (defined by all blocks
424 /// dominated by the specified block, and that are in the current loop) in
425 /// reverse depth first order w.r.t the DominatorTree. This allows us to visit
426 /// uses before definitions, allowing us to sink a loop body in one pass without
427 /// iteration. Takes DomTreeNode, AliasAnalysis, LoopInfo, DominatorTree,
428 /// DataLayout, TargetLibraryInfo, Loop, AliasSet information for all
429 /// instructions of the loop and loop safety information as
430 /// arguments. Diagnostics is emitted via \p ORE. It returns changed status.
431 bool sinkRegion(DomTreeNode *, AliasAnalysis *, LoopInfo *, DominatorTree *,
432 TargetLibraryInfo *, TargetTransformInfo *, Loop *,
433 AliasSetTracker *, LoopSafetyInfo *,
434 OptimizationRemarkEmitter *ORE);
436 /// \brief Walk the specified region of the CFG (defined by all blocks
437 /// dominated by the specified block, and that are in the current loop) in depth
438 /// first order w.r.t the DominatorTree. This allows us to visit definitions
439 /// before uses, allowing us to hoist a loop body in one pass without iteration.
440 /// Takes DomTreeNode, AliasAnalysis, LoopInfo, DominatorTree, DataLayout,
441 /// TargetLibraryInfo, Loop, AliasSet information for all instructions of the
442 /// loop and loop safety information as arguments. Diagnostics is emitted via \p
443 /// ORE. It returns changed status.
444 bool hoistRegion(DomTreeNode *, AliasAnalysis *, LoopInfo *, DominatorTree *,
445 TargetLibraryInfo *, Loop *, AliasSetTracker *,
446 LoopSafetyInfo *, OptimizationRemarkEmitter *ORE);
448 /// This function deletes dead loops. The caller of this function needs to
449 /// guarantee that the loop is infact dead.
450 /// The function requires a bunch or prerequisites to be present:
451 /// - The loop needs to be in LCSSA form
452 /// - The loop needs to have a Preheader
453 /// - A unique dedicated exit block must exist
455 /// This also updates the relevant analysis information in \p DT, \p SE, and \p
456 /// LI if pointers to those are provided.
457 /// It also updates the loop PM if an updater struct is provided.
459 void deleteDeadLoop(Loop *L, DominatorTree *DT, ScalarEvolution *SE,
462 /// \brief Try to promote memory values to scalars by sinking stores out of
463 /// the loop and moving loads to before the loop. We do this by looping over
464 /// the stores in the loop, looking for stores to Must pointers which are
465 /// loop invariant. It takes a set of must-alias values, Loop exit blocks
466 /// vector, loop exit blocks insertion point vector, PredIteratorCache,
467 /// LoopInfo, DominatorTree, Loop, AliasSet information for all instructions
468 /// of the loop and loop safety information as arguments.
469 /// Diagnostics is emitted via \p ORE. It returns changed status.
470 bool promoteLoopAccessesToScalars(const SmallSetVector<Value *, 8> &,
471 SmallVectorImpl<BasicBlock *> &,
472 SmallVectorImpl<Instruction *> &,
473 PredIteratorCache &, LoopInfo *,
474 DominatorTree *, const TargetLibraryInfo *,
475 Loop *, AliasSetTracker *, LoopSafetyInfo *,
476 OptimizationRemarkEmitter *);
478 /// Does a BFS from a given node to all of its children inside a given loop.
479 /// The returned vector of nodes includes the starting point.
480 SmallVector<DomTreeNode *, 16> collectChildrenInLoop(DomTreeNode *N,
481 const Loop *CurLoop);
483 /// \brief Computes safety information for a loop
484 /// checks loop body & header for the possibility of may throw
485 /// exception, it takes LoopSafetyInfo and loop as argument.
486 /// Updates safety information in LoopSafetyInfo argument.
487 void computeLoopSafetyInfo(LoopSafetyInfo *, Loop *);
489 /// Returns true if the instruction in a loop is guaranteed to execute at least
491 bool isGuaranteedToExecute(const Instruction &Inst, const DominatorTree *DT,
493 const LoopSafetyInfo *SafetyInfo);
495 /// \brief Returns the instructions that use values defined in the loop.
496 SmallVector<Instruction *, 8> findDefsUsedOutsideOfLoop(Loop *L);
498 /// \brief Find string metadata for loop
500 /// If it has a value (e.g. {"llvm.distribute", 1} return the value as an
501 /// operand or null otherwise. If the string metadata is not found return
502 /// Optional's not-a-value.
503 Optional<const MDOperand *> findStringMetadataForLoop(Loop *TheLoop,
506 /// \brief Set input string into loop metadata by keeping other values intact.
507 void addStringMetadataToLoop(Loop *TheLoop, const char *MDString,
510 /// \brief Get a loop's estimated trip count based on branch weight metadata.
511 /// Returns 0 when the count is estimated to be 0, or None when a meaningful
512 /// estimate can not be made.
513 Optional<unsigned> getLoopEstimatedTripCount(Loop *L);
515 /// Helper to consistently add the set of standard passes to a loop pass's \c
518 /// All loop passes should call this as part of implementing their \c
519 /// getAnalysisUsage.
520 void getLoopAnalysisUsage(AnalysisUsage &AU);
522 /// Returns true if the hoister and sinker can handle this instruction.
523 /// If SafetyInfo is null, we are checking for sinking instructions from
524 /// preheader to loop body (no speculation).
525 /// If SafetyInfo is not null, we are checking for hoisting/sinking
526 /// instructions from loop body to preheader/exit. Check if the instruction
527 /// can execute speculatively.
528 /// If \p ORE is set use it to emit optimization remarks.
529 bool canSinkOrHoistInst(Instruction &I, AAResults *AA, DominatorTree *DT,
530 Loop *CurLoop, AliasSetTracker *CurAST,
531 LoopSafetyInfo *SafetyInfo,
532 OptimizationRemarkEmitter *ORE = nullptr);
534 /// Generates a vector reduction using shufflevectors to reduce the value.
535 Value *getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
536 RecurrenceDescriptor::MinMaxRecurrenceKind
537 MinMaxKind = RecurrenceDescriptor::MRK_Invalid,
538 ArrayRef<Value *> RedOps = ArrayRef<Value *>());
540 /// Create a target reduction of the given vector. The reduction operation
541 /// is described by the \p Opcode parameter. min/max reductions require
542 /// additional information supplied in \p Flags.
543 /// The target is queried to determine if intrinsics or shuffle sequences are
544 /// required to implement the reduction.
546 createSimpleTargetReduction(IRBuilder<> &B, const TargetTransformInfo *TTI,
547 unsigned Opcode, Value *Src,
548 TargetTransformInfo::ReductionFlags Flags =
549 TargetTransformInfo::ReductionFlags(),
550 ArrayRef<Value *> RedOps = ArrayRef<Value *>());
552 /// Create a generic target reduction using a recurrence descriptor \p Desc
553 /// The target is queried to determine if intrinsics or shuffle sequences are
554 /// required to implement the reduction.
555 Value *createTargetReduction(IRBuilder<> &B, const TargetTransformInfo *TTI,
556 RecurrenceDescriptor &Desc, Value *Src,
559 /// Get the intersection (logical and) of all of the potential IR flags
560 /// of each scalar operation (VL) that will be converted into a vector (I).
561 /// If OpValue is non-null, we only consider operations similar to OpValue
562 /// when intersecting.
563 /// Flag set: NSW, NUW, exact, and all of fast-math.
564 void propagateIRFlags(Value *I, ArrayRef<Value *> VL, Value *OpValue = nullptr);
566 } // end namespace llvm
568 #endif // LLVM_TRANSFORMS_UTILS_LOOPUTILS_H