1 //===-- LoopUtils.cpp - Loop Utility functions -------------------------===//
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 common loop utility functions.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Transforms/Utils/LoopUtils.h"
15 #include "llvm/Analysis/AliasAnalysis.h"
16 #include "llvm/Analysis/BasicAliasAnalysis.h"
17 #include "llvm/Analysis/GlobalsModRef.h"
18 #include "llvm/Analysis/LoopInfo.h"
19 #include "llvm/Analysis/LoopPass.h"
20 #include "llvm/Analysis/ScalarEvolution.h"
21 #include "llvm/Analysis/ScalarEvolutionAliasAnalysis.h"
22 #include "llvm/Analysis/ScalarEvolutionExpander.h"
23 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
24 #include "llvm/Analysis/TargetTransformInfo.h"
25 #include "llvm/IR/Dominators.h"
26 #include "llvm/IR/Instructions.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/IR/PatternMatch.h"
29 #include "llvm/IR/ValueHandle.h"
30 #include "llvm/Pass.h"
31 #include "llvm/Support/Debug.h"
34 using namespace llvm::PatternMatch;
36 #define DEBUG_TYPE "loop-utils"
38 bool RecurrenceDescriptor::areAllUsesIn(Instruction *I,
39 SmallPtrSetImpl<Instruction *> &Set) {
40 for (User::op_iterator Use = I->op_begin(), E = I->op_end(); Use != E; ++Use)
41 if (!Set.count(dyn_cast<Instruction>(*Use)))
46 bool RecurrenceDescriptor::isIntegerRecurrenceKind(RecurrenceKind Kind) {
55 case RK_IntegerMinMax:
61 bool RecurrenceDescriptor::isFloatingPointRecurrenceKind(RecurrenceKind Kind) {
62 return (Kind != RK_NoRecurrence) && !isIntegerRecurrenceKind(Kind);
65 bool RecurrenceDescriptor::isArithmeticRecurrenceKind(RecurrenceKind Kind) {
79 RecurrenceDescriptor::lookThroughAnd(PHINode *Phi, Type *&RT,
80 SmallPtrSetImpl<Instruction *> &Visited,
81 SmallPtrSetImpl<Instruction *> &CI) {
82 if (!Phi->hasOneUse())
85 const APInt *M = nullptr;
86 Instruction *I, *J = cast<Instruction>(Phi->use_begin()->getUser());
88 // Matches either I & 2^x-1 or 2^x-1 & I. If we find a match, we update RT
89 // with a new integer type of the corresponding bit width.
90 if (match(J, m_CombineOr(m_And(m_Instruction(I), m_APInt(M)),
91 m_And(m_APInt(M), m_Instruction(I))))) {
92 int32_t Bits = (*M + 1).exactLogBase2();
94 RT = IntegerType::get(Phi->getContext(), Bits);
103 bool RecurrenceDescriptor::getSourceExtensionKind(
104 Instruction *Start, Instruction *Exit, Type *RT, bool &IsSigned,
105 SmallPtrSetImpl<Instruction *> &Visited,
106 SmallPtrSetImpl<Instruction *> &CI) {
108 SmallVector<Instruction *, 8> Worklist;
109 bool FoundOneOperand = false;
110 unsigned DstSize = RT->getPrimitiveSizeInBits();
111 Worklist.push_back(Exit);
113 // Traverse the instructions in the reduction expression, beginning with the
115 while (!Worklist.empty()) {
116 Instruction *I = Worklist.pop_back_val();
117 for (Use &U : I->operands()) {
119 // Terminate the traversal if the operand is not an instruction, or we
120 // reach the starting value.
121 Instruction *J = dyn_cast<Instruction>(U.get());
122 if (!J || J == Start)
125 // Otherwise, investigate the operation if it is also in the expression.
126 if (Visited.count(J)) {
127 Worklist.push_back(J);
131 // If the operand is not in Visited, it is not a reduction operation, but
132 // it does feed into one. Make sure it is either a single-use sign- or
133 // zero-extend instruction.
134 CastInst *Cast = dyn_cast<CastInst>(J);
135 bool IsSExtInst = isa<SExtInst>(J);
136 if (!Cast || !Cast->hasOneUse() || !(isa<ZExtInst>(J) || IsSExtInst))
139 // Ensure the source type of the extend is no larger than the reduction
140 // type. It is not necessary for the types to be identical.
141 unsigned SrcSize = Cast->getSrcTy()->getPrimitiveSizeInBits();
142 if (SrcSize > DstSize)
145 // Furthermore, ensure that all such extends are of the same kind.
146 if (FoundOneOperand) {
147 if (IsSigned != IsSExtInst)
150 FoundOneOperand = true;
151 IsSigned = IsSExtInst;
154 // Lastly, if the source type of the extend matches the reduction type,
155 // add the extend to CI so that we can avoid accounting for it in the
157 if (SrcSize == DstSize)
164 bool RecurrenceDescriptor::AddReductionVar(PHINode *Phi, RecurrenceKind Kind,
165 Loop *TheLoop, bool HasFunNoNaNAttr,
166 RecurrenceDescriptor &RedDes) {
167 if (Phi->getNumIncomingValues() != 2)
170 // Reduction variables are only found in the loop header block.
171 if (Phi->getParent() != TheLoop->getHeader())
174 // Obtain the reduction start value from the value that comes from the loop
176 Value *RdxStart = Phi->getIncomingValueForBlock(TheLoop->getLoopPreheader());
178 // ExitInstruction is the single value which is used outside the loop.
179 // We only allow for a single reduction value to be used outside the loop.
180 // This includes users of the reduction, variables (which form a cycle
181 // which ends in the phi node).
182 Instruction *ExitInstruction = nullptr;
183 // Indicates that we found a reduction operation in our scan.
184 bool FoundReduxOp = false;
186 // We start with the PHI node and scan for all of the users of this
187 // instruction. All users must be instructions that can be used as reduction
188 // variables (such as ADD). We must have a single out-of-block user. The cycle
189 // must include the original PHI.
190 bool FoundStartPHI = false;
192 // To recognize min/max patterns formed by a icmp select sequence, we store
193 // the number of instruction we saw from the recognized min/max pattern,
194 // to make sure we only see exactly the two instructions.
195 unsigned NumCmpSelectPatternInst = 0;
196 InstDesc ReduxDesc(false, nullptr);
198 // Data used for determining if the recurrence has been type-promoted.
199 Type *RecurrenceType = Phi->getType();
200 SmallPtrSet<Instruction *, 4> CastInsts;
201 Instruction *Start = Phi;
202 bool IsSigned = false;
204 SmallPtrSet<Instruction *, 8> VisitedInsts;
205 SmallVector<Instruction *, 8> Worklist;
207 // Return early if the recurrence kind does not match the type of Phi. If the
208 // recurrence kind is arithmetic, we attempt to look through AND operations
209 // resulting from the type promotion performed by InstCombine. Vector
210 // operations are not limited to the legal integer widths, so we may be able
211 // to evaluate the reduction in the narrower width.
212 if (RecurrenceType->isFloatingPointTy()) {
213 if (!isFloatingPointRecurrenceKind(Kind))
216 if (!isIntegerRecurrenceKind(Kind))
218 if (isArithmeticRecurrenceKind(Kind))
219 Start = lookThroughAnd(Phi, RecurrenceType, VisitedInsts, CastInsts);
222 Worklist.push_back(Start);
223 VisitedInsts.insert(Start);
225 // A value in the reduction can be used:
226 // - By the reduction:
227 // - Reduction operation:
228 // - One use of reduction value (safe).
229 // - Multiple use of reduction value (not safe).
231 // - All uses of the PHI must be the reduction (safe).
232 // - Otherwise, not safe.
233 // - By instructions outside of the loop (safe).
234 // * One value may have several outside users, but all outside
235 // uses must be of the same value.
236 // - By an instruction that is not part of the reduction (not safe).
238 // * An instruction type other than PHI or the reduction operation.
239 // * A PHI in the header other than the initial PHI.
240 while (!Worklist.empty()) {
241 Instruction *Cur = Worklist.back();
245 // If the instruction has no users then this is a broken chain and can't be
246 // a reduction variable.
247 if (Cur->use_empty())
250 bool IsAPhi = isa<PHINode>(Cur);
252 // A header PHI use other than the original PHI.
253 if (Cur != Phi && IsAPhi && Cur->getParent() == Phi->getParent())
256 // Reductions of instructions such as Div, and Sub is only possible if the
257 // LHS is the reduction variable.
258 if (!Cur->isCommutative() && !IsAPhi && !isa<SelectInst>(Cur) &&
259 !isa<ICmpInst>(Cur) && !isa<FCmpInst>(Cur) &&
260 !VisitedInsts.count(dyn_cast<Instruction>(Cur->getOperand(0))))
263 // Any reduction instruction must be of one of the allowed kinds. We ignore
264 // the starting value (the Phi or an AND instruction if the Phi has been
267 ReduxDesc = isRecurrenceInstr(Cur, Kind, ReduxDesc, HasFunNoNaNAttr);
268 if (!ReduxDesc.isRecurrence())
272 // A reduction operation must only have one use of the reduction value.
273 if (!IsAPhi && Kind != RK_IntegerMinMax && Kind != RK_FloatMinMax &&
274 hasMultipleUsesOf(Cur, VisitedInsts))
277 // All inputs to a PHI node must be a reduction value.
278 if (IsAPhi && Cur != Phi && !areAllUsesIn(Cur, VisitedInsts))
281 if (Kind == RK_IntegerMinMax &&
282 (isa<ICmpInst>(Cur) || isa<SelectInst>(Cur)))
283 ++NumCmpSelectPatternInst;
284 if (Kind == RK_FloatMinMax && (isa<FCmpInst>(Cur) || isa<SelectInst>(Cur)))
285 ++NumCmpSelectPatternInst;
287 // Check whether we found a reduction operator.
288 FoundReduxOp |= !IsAPhi && Cur != Start;
290 // Process users of current instruction. Push non-PHI nodes after PHI nodes
291 // onto the stack. This way we are going to have seen all inputs to PHI
292 // nodes once we get to them.
293 SmallVector<Instruction *, 8> NonPHIs;
294 SmallVector<Instruction *, 8> PHIs;
295 for (User *U : Cur->users()) {
296 Instruction *UI = cast<Instruction>(U);
298 // Check if we found the exit user.
299 BasicBlock *Parent = UI->getParent();
300 if (!TheLoop->contains(Parent)) {
301 // If we already know this instruction is used externally, move on to
303 if (ExitInstruction == Cur)
306 // Exit if you find multiple values used outside or if the header phi
307 // node is being used. In this case the user uses the value of the
308 // previous iteration, in which case we would loose "VF-1" iterations of
309 // the reduction operation if we vectorize.
310 if (ExitInstruction != nullptr || Cur == Phi)
313 // The instruction used by an outside user must be the last instruction
314 // before we feed back to the reduction phi. Otherwise, we loose VF-1
315 // operations on the value.
316 if (!is_contained(Phi->operands(), Cur))
319 ExitInstruction = Cur;
323 // Process instructions only once (termination). Each reduction cycle
324 // value must only be used once, except by phi nodes and min/max
325 // reductions which are represented as a cmp followed by a select.
326 InstDesc IgnoredVal(false, nullptr);
327 if (VisitedInsts.insert(UI).second) {
328 if (isa<PHINode>(UI))
331 NonPHIs.push_back(UI);
332 } else if (!isa<PHINode>(UI) &&
333 ((!isa<FCmpInst>(UI) && !isa<ICmpInst>(UI) &&
334 !isa<SelectInst>(UI)) ||
335 !isMinMaxSelectCmpPattern(UI, IgnoredVal).isRecurrence()))
338 // Remember that we completed the cycle.
340 FoundStartPHI = true;
342 Worklist.append(PHIs.begin(), PHIs.end());
343 Worklist.append(NonPHIs.begin(), NonPHIs.end());
346 // This means we have seen one but not the other instruction of the
347 // pattern or more than just a select and cmp.
348 if ((Kind == RK_IntegerMinMax || Kind == RK_FloatMinMax) &&
349 NumCmpSelectPatternInst != 2)
352 if (!FoundStartPHI || !FoundReduxOp || !ExitInstruction)
355 // If we think Phi may have been type-promoted, we also need to ensure that
356 // all source operands of the reduction are either SExtInsts or ZEstInsts. If
357 // so, we will be able to evaluate the reduction in the narrower bit width.
359 if (!getSourceExtensionKind(Start, ExitInstruction, RecurrenceType,
360 IsSigned, VisitedInsts, CastInsts))
363 // We found a reduction var if we have reached the original phi node and we
364 // only have a single instruction with out-of-loop users.
366 // The ExitInstruction(Instruction which is allowed to have out-of-loop users)
367 // is saved as part of the RecurrenceDescriptor.
369 // Save the description of this reduction variable.
370 RecurrenceDescriptor RD(
371 RdxStart, ExitInstruction, Kind, ReduxDesc.getMinMaxKind(),
372 ReduxDesc.getUnsafeAlgebraInst(), RecurrenceType, IsSigned, CastInsts);
378 /// Returns true if the instruction is a Select(ICmp(X, Y), X, Y) instruction
379 /// pattern corresponding to a min(X, Y) or max(X, Y).
380 RecurrenceDescriptor::InstDesc
381 RecurrenceDescriptor::isMinMaxSelectCmpPattern(Instruction *I, InstDesc &Prev) {
383 assert((isa<ICmpInst>(I) || isa<FCmpInst>(I) || isa<SelectInst>(I)) &&
384 "Expect a select instruction");
385 Instruction *Cmp = nullptr;
386 SelectInst *Select = nullptr;
388 // We must handle the select(cmp()) as a single instruction. Advance to the
390 if ((Cmp = dyn_cast<ICmpInst>(I)) || (Cmp = dyn_cast<FCmpInst>(I))) {
391 if (!Cmp->hasOneUse() || !(Select = dyn_cast<SelectInst>(*I->user_begin())))
392 return InstDesc(false, I);
393 return InstDesc(Select, Prev.getMinMaxKind());
396 // Only handle single use cases for now.
397 if (!(Select = dyn_cast<SelectInst>(I)))
398 return InstDesc(false, I);
399 if (!(Cmp = dyn_cast<ICmpInst>(I->getOperand(0))) &&
400 !(Cmp = dyn_cast<FCmpInst>(I->getOperand(0))))
401 return InstDesc(false, I);
402 if (!Cmp->hasOneUse())
403 return InstDesc(false, I);
408 // Look for a min/max pattern.
409 if (m_UMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
410 return InstDesc(Select, MRK_UIntMin);
411 else if (m_UMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
412 return InstDesc(Select, MRK_UIntMax);
413 else if (m_SMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
414 return InstDesc(Select, MRK_SIntMax);
415 else if (m_SMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
416 return InstDesc(Select, MRK_SIntMin);
417 else if (m_OrdFMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
418 return InstDesc(Select, MRK_FloatMin);
419 else if (m_OrdFMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
420 return InstDesc(Select, MRK_FloatMax);
421 else if (m_UnordFMin(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
422 return InstDesc(Select, MRK_FloatMin);
423 else if (m_UnordFMax(m_Value(CmpLeft), m_Value(CmpRight)).match(Select))
424 return InstDesc(Select, MRK_FloatMax);
426 return InstDesc(false, I);
429 RecurrenceDescriptor::InstDesc
430 RecurrenceDescriptor::isRecurrenceInstr(Instruction *I, RecurrenceKind Kind,
431 InstDesc &Prev, bool HasFunNoNaNAttr) {
432 bool FP = I->getType()->isFloatingPointTy();
433 Instruction *UAI = Prev.getUnsafeAlgebraInst();
434 if (!UAI && FP && !I->hasUnsafeAlgebra())
435 UAI = I; // Found an unsafe (unvectorizable) algebra instruction.
437 switch (I->getOpcode()) {
439 return InstDesc(false, I);
440 case Instruction::PHI:
441 return InstDesc(I, Prev.getMinMaxKind(), Prev.getUnsafeAlgebraInst());
442 case Instruction::Sub:
443 case Instruction::Add:
444 return InstDesc(Kind == RK_IntegerAdd, I);
445 case Instruction::Mul:
446 return InstDesc(Kind == RK_IntegerMult, I);
447 case Instruction::And:
448 return InstDesc(Kind == RK_IntegerAnd, I);
449 case Instruction::Or:
450 return InstDesc(Kind == RK_IntegerOr, I);
451 case Instruction::Xor:
452 return InstDesc(Kind == RK_IntegerXor, I);
453 case Instruction::FMul:
454 return InstDesc(Kind == RK_FloatMult, I, UAI);
455 case Instruction::FSub:
456 case Instruction::FAdd:
457 return InstDesc(Kind == RK_FloatAdd, I, UAI);
458 case Instruction::FCmp:
459 case Instruction::ICmp:
460 case Instruction::Select:
461 if (Kind != RK_IntegerMinMax &&
462 (!HasFunNoNaNAttr || Kind != RK_FloatMinMax))
463 return InstDesc(false, I);
464 return isMinMaxSelectCmpPattern(I, Prev);
468 bool RecurrenceDescriptor::hasMultipleUsesOf(
469 Instruction *I, SmallPtrSetImpl<Instruction *> &Insts) {
470 unsigned NumUses = 0;
471 for (User::op_iterator Use = I->op_begin(), E = I->op_end(); Use != E;
473 if (Insts.count(dyn_cast<Instruction>(*Use)))
481 bool RecurrenceDescriptor::isReductionPHI(PHINode *Phi, Loop *TheLoop,
482 RecurrenceDescriptor &RedDes) {
484 BasicBlock *Header = TheLoop->getHeader();
485 Function &F = *Header->getParent();
486 bool HasFunNoNaNAttr =
487 F.getFnAttribute("no-nans-fp-math").getValueAsString() == "true";
489 if (AddReductionVar(Phi, RK_IntegerAdd, TheLoop, HasFunNoNaNAttr, RedDes)) {
490 DEBUG(dbgs() << "Found an ADD reduction PHI." << *Phi << "\n");
493 if (AddReductionVar(Phi, RK_IntegerMult, TheLoop, HasFunNoNaNAttr, RedDes)) {
494 DEBUG(dbgs() << "Found a MUL reduction PHI." << *Phi << "\n");
497 if (AddReductionVar(Phi, RK_IntegerOr, TheLoop, HasFunNoNaNAttr, RedDes)) {
498 DEBUG(dbgs() << "Found an OR reduction PHI." << *Phi << "\n");
501 if (AddReductionVar(Phi, RK_IntegerAnd, TheLoop, HasFunNoNaNAttr, RedDes)) {
502 DEBUG(dbgs() << "Found an AND reduction PHI." << *Phi << "\n");
505 if (AddReductionVar(Phi, RK_IntegerXor, TheLoop, HasFunNoNaNAttr, RedDes)) {
506 DEBUG(dbgs() << "Found a XOR reduction PHI." << *Phi << "\n");
509 if (AddReductionVar(Phi, RK_IntegerMinMax, TheLoop, HasFunNoNaNAttr,
511 DEBUG(dbgs() << "Found a MINMAX reduction PHI." << *Phi << "\n");
514 if (AddReductionVar(Phi, RK_FloatMult, TheLoop, HasFunNoNaNAttr, RedDes)) {
515 DEBUG(dbgs() << "Found an FMult reduction PHI." << *Phi << "\n");
518 if (AddReductionVar(Phi, RK_FloatAdd, TheLoop, HasFunNoNaNAttr, RedDes)) {
519 DEBUG(dbgs() << "Found an FAdd reduction PHI." << *Phi << "\n");
522 if (AddReductionVar(Phi, RK_FloatMinMax, TheLoop, HasFunNoNaNAttr, RedDes)) {
523 DEBUG(dbgs() << "Found an float MINMAX reduction PHI." << *Phi << "\n");
526 // Not a reduction of known type.
530 bool RecurrenceDescriptor::isFirstOrderRecurrence(PHINode *Phi, Loop *TheLoop,
533 // Ensure the phi node is in the loop header and has two incoming values.
534 if (Phi->getParent() != TheLoop->getHeader() ||
535 Phi->getNumIncomingValues() != 2)
538 // Ensure the loop has a preheader and a single latch block. The loop
539 // vectorizer will need the latch to set up the next iteration of the loop.
540 auto *Preheader = TheLoop->getLoopPreheader();
541 auto *Latch = TheLoop->getLoopLatch();
542 if (!Preheader || !Latch)
545 // Ensure the phi node's incoming blocks are the loop preheader and latch.
546 if (Phi->getBasicBlockIndex(Preheader) < 0 ||
547 Phi->getBasicBlockIndex(Latch) < 0)
550 // Get the previous value. The previous value comes from the latch edge while
551 // the initial value comes form the preheader edge.
552 auto *Previous = dyn_cast<Instruction>(Phi->getIncomingValueForBlock(Latch));
553 if (!Previous || !TheLoop->contains(Previous) || isa<PHINode>(Previous))
556 // Ensure every user of the phi node is dominated by the previous value.
557 // The dominance requirement ensures the loop vectorizer will not need to
558 // vectorize the initial value prior to the first iteration of the loop.
559 for (User *U : Phi->users())
560 if (auto *I = dyn_cast<Instruction>(U)) {
561 if (!DT->dominates(Previous, I))
568 /// This function returns the identity element (or neutral element) for
570 Constant *RecurrenceDescriptor::getRecurrenceIdentity(RecurrenceKind K,
576 // Adding, Xoring, Oring zero to a number does not change it.
577 return ConstantInt::get(Tp, 0);
579 // Multiplying a number by 1 does not change it.
580 return ConstantInt::get(Tp, 1);
582 // AND-ing a number with an all-1 value does not change it.
583 return ConstantInt::get(Tp, -1, true);
585 // Multiplying a number by 1 does not change it.
586 return ConstantFP::get(Tp, 1.0L);
588 // Adding zero to a number does not change it.
589 return ConstantFP::get(Tp, 0.0L);
591 llvm_unreachable("Unknown recurrence kind");
595 /// This function translates the recurrence kind to an LLVM binary operator.
596 unsigned RecurrenceDescriptor::getRecurrenceBinOp(RecurrenceKind Kind) {
599 return Instruction::Add;
601 return Instruction::Mul;
603 return Instruction::Or;
605 return Instruction::And;
607 return Instruction::Xor;
609 return Instruction::FMul;
611 return Instruction::FAdd;
612 case RK_IntegerMinMax:
613 return Instruction::ICmp;
615 return Instruction::FCmp;
617 llvm_unreachable("Unknown recurrence operation");
621 Value *RecurrenceDescriptor::createMinMaxOp(IRBuilder<> &Builder,
622 MinMaxRecurrenceKind RK,
623 Value *Left, Value *Right) {
624 CmpInst::Predicate P = CmpInst::ICMP_NE;
627 llvm_unreachable("Unknown min/max recurrence kind");
629 P = CmpInst::ICMP_ULT;
632 P = CmpInst::ICMP_UGT;
635 P = CmpInst::ICMP_SLT;
638 P = CmpInst::ICMP_SGT;
641 P = CmpInst::FCMP_OLT;
644 P = CmpInst::FCMP_OGT;
648 // We only match FP sequences with unsafe algebra, so we can unconditionally
649 // set it on any generated instructions.
650 IRBuilder<>::FastMathFlagGuard FMFG(Builder);
652 FMF.setUnsafeAlgebra();
653 Builder.setFastMathFlags(FMF);
656 if (RK == MRK_FloatMin || RK == MRK_FloatMax)
657 Cmp = Builder.CreateFCmp(P, Left, Right, "rdx.minmax.cmp");
659 Cmp = Builder.CreateICmp(P, Left, Right, "rdx.minmax.cmp");
661 Value *Select = Builder.CreateSelect(Cmp, Left, Right, "rdx.minmax.select");
665 InductionDescriptor::InductionDescriptor(Value *Start, InductionKind K,
666 const SCEV *Step, BinaryOperator *BOp)
667 : StartValue(Start), IK(K), Step(Step), InductionBinOp(BOp) {
668 assert(IK != IK_NoInduction && "Not an induction");
670 // Start value type should match the induction kind and the value
671 // itself should not be null.
672 assert(StartValue && "StartValue is null");
673 assert((IK != IK_PtrInduction || StartValue->getType()->isPointerTy()) &&
674 "StartValue is not a pointer for pointer induction");
675 assert((IK != IK_IntInduction || StartValue->getType()->isIntegerTy()) &&
676 "StartValue is not an integer for integer induction");
678 // Check the Step Value. It should be non-zero integer value.
679 assert((!getConstIntStepValue() || !getConstIntStepValue()->isZero()) &&
680 "Step value is zero");
682 assert((IK != IK_PtrInduction || getConstIntStepValue()) &&
683 "Step value should be constant for pointer induction");
684 assert((IK == IK_FpInduction || Step->getType()->isIntegerTy()) &&
685 "StepValue is not an integer");
687 assert((IK != IK_FpInduction || Step->getType()->isFloatingPointTy()) &&
688 "StepValue is not FP for FpInduction");
689 assert((IK != IK_FpInduction || (InductionBinOp &&
690 (InductionBinOp->getOpcode() == Instruction::FAdd ||
691 InductionBinOp->getOpcode() == Instruction::FSub))) &&
692 "Binary opcode should be specified for FP induction");
695 int InductionDescriptor::getConsecutiveDirection() const {
696 ConstantInt *ConstStep = getConstIntStepValue();
697 if (ConstStep && (ConstStep->isOne() || ConstStep->isMinusOne()))
698 return ConstStep->getSExtValue();
702 ConstantInt *InductionDescriptor::getConstIntStepValue() const {
703 if (isa<SCEVConstant>(Step))
704 return dyn_cast<ConstantInt>(cast<SCEVConstant>(Step)->getValue());
708 Value *InductionDescriptor::transform(IRBuilder<> &B, Value *Index,
710 const DataLayout& DL) const {
712 SCEVExpander Exp(*SE, DL, "induction");
713 assert(Index->getType() == Step->getType() &&
714 "Index type does not match StepValue type");
716 case IK_IntInduction: {
717 assert(Index->getType() == StartValue->getType() &&
718 "Index type does not match StartValue type");
720 // FIXME: Theoretically, we can call getAddExpr() of ScalarEvolution
721 // and calculate (Start + Index * Step) for all cases, without
722 // special handling for "isOne" and "isMinusOne".
723 // But in the real life the result code getting worse. We mix SCEV
724 // expressions and ADD/SUB operations and receive redundant
725 // intermediate values being calculated in different ways and
726 // Instcombine is unable to reduce them all.
728 if (getConstIntStepValue() &&
729 getConstIntStepValue()->isMinusOne())
730 return B.CreateSub(StartValue, Index);
731 if (getConstIntStepValue() &&
732 getConstIntStepValue()->isOne())
733 return B.CreateAdd(StartValue, Index);
734 const SCEV *S = SE->getAddExpr(SE->getSCEV(StartValue),
735 SE->getMulExpr(Step, SE->getSCEV(Index)));
736 return Exp.expandCodeFor(S, StartValue->getType(), &*B.GetInsertPoint());
738 case IK_PtrInduction: {
739 assert(isa<SCEVConstant>(Step) &&
740 "Expected constant step for pointer induction");
741 const SCEV *S = SE->getMulExpr(SE->getSCEV(Index), Step);
742 Index = Exp.expandCodeFor(S, Index->getType(), &*B.GetInsertPoint());
743 return B.CreateGEP(nullptr, StartValue, Index);
745 case IK_FpInduction: {
746 assert(Step->getType()->isFloatingPointTy() && "Expected FP Step value");
747 assert(InductionBinOp &&
748 (InductionBinOp->getOpcode() == Instruction::FAdd ||
749 InductionBinOp->getOpcode() == Instruction::FSub) &&
750 "Original bin op should be defined for FP induction");
752 Value *StepValue = cast<SCEVUnknown>(Step)->getValue();
754 // Floating point operations had to be 'fast' to enable the induction.
756 Flags.setUnsafeAlgebra();
758 Value *MulExp = B.CreateFMul(StepValue, Index);
759 if (isa<Instruction>(MulExp))
760 // We have to check, the MulExp may be a constant.
761 cast<Instruction>(MulExp)->setFastMathFlags(Flags);
763 Value *BOp = B.CreateBinOp(InductionBinOp->getOpcode() , StartValue,
764 MulExp, "induction");
765 if (isa<Instruction>(BOp))
766 cast<Instruction>(BOp)->setFastMathFlags(Flags);
773 llvm_unreachable("invalid enum");
776 bool InductionDescriptor::isFPInductionPHI(PHINode *Phi, const Loop *TheLoop,
778 InductionDescriptor &D) {
780 // Here we only handle FP induction variables.
781 assert(Phi->getType()->isFloatingPointTy() && "Unexpected Phi type");
783 if (TheLoop->getHeader() != Phi->getParent())
786 // The loop may have multiple entrances or multiple exits; we can analyze
787 // this phi if it has a unique entry value and a unique backedge value.
788 if (Phi->getNumIncomingValues() != 2)
790 Value *BEValue = nullptr, *StartValue = nullptr;
791 if (TheLoop->contains(Phi->getIncomingBlock(0))) {
792 BEValue = Phi->getIncomingValue(0);
793 StartValue = Phi->getIncomingValue(1);
795 assert(TheLoop->contains(Phi->getIncomingBlock(1)) &&
796 "Unexpected Phi node in the loop");
797 BEValue = Phi->getIncomingValue(1);
798 StartValue = Phi->getIncomingValue(0);
801 BinaryOperator *BOp = dyn_cast<BinaryOperator>(BEValue);
805 Value *Addend = nullptr;
806 if (BOp->getOpcode() == Instruction::FAdd) {
807 if (BOp->getOperand(0) == Phi)
808 Addend = BOp->getOperand(1);
809 else if (BOp->getOperand(1) == Phi)
810 Addend = BOp->getOperand(0);
811 } else if (BOp->getOpcode() == Instruction::FSub)
812 if (BOp->getOperand(0) == Phi)
813 Addend = BOp->getOperand(1);
818 // The addend should be loop invariant
819 if (auto *I = dyn_cast<Instruction>(Addend))
820 if (TheLoop->contains(I))
823 // FP Step has unknown SCEV
824 const SCEV *Step = SE->getUnknown(Addend);
825 D = InductionDescriptor(StartValue, IK_FpInduction, Step, BOp);
829 bool InductionDescriptor::isInductionPHI(PHINode *Phi, const Loop *TheLoop,
830 PredicatedScalarEvolution &PSE,
831 InductionDescriptor &D,
833 Type *PhiTy = Phi->getType();
835 // Handle integer and pointer inductions variables.
836 // Now we handle also FP induction but not trying to make a
837 // recurrent expression from the PHI node in-place.
839 if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy() &&
840 !PhiTy->isFloatTy() && !PhiTy->isDoubleTy() && !PhiTy->isHalfTy())
843 if (PhiTy->isFloatingPointTy())
844 return isFPInductionPHI(Phi, TheLoop, PSE.getSE(), D);
846 const SCEV *PhiScev = PSE.getSCEV(Phi);
847 const auto *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);
849 // We need this expression to be an AddRecExpr.
851 AR = PSE.getAsAddRec(Phi);
854 DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n");
858 return isInductionPHI(Phi, TheLoop, PSE.getSE(), D, AR);
861 bool InductionDescriptor::isInductionPHI(PHINode *Phi, const Loop *TheLoop,
863 InductionDescriptor &D,
865 Type *PhiTy = Phi->getType();
866 // We only handle integer and pointer inductions variables.
867 if (!PhiTy->isIntegerTy() && !PhiTy->isPointerTy())
870 // Check that the PHI is consecutive.
871 const SCEV *PhiScev = Expr ? Expr : SE->getSCEV(Phi);
872 const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(PhiScev);
875 DEBUG(dbgs() << "LV: PHI is not a poly recurrence.\n");
879 if (AR->getLoop() != TheLoop) {
880 // FIXME: We should treat this as a uniform. Unfortunately, we
881 // don't currently know how to handled uniform PHIs.
882 DEBUG(dbgs() << "LV: PHI is a recurrence with respect to an outer loop.\n");
887 Phi->getIncomingValueForBlock(AR->getLoop()->getLoopPreheader());
888 const SCEV *Step = AR->getStepRecurrence(*SE);
889 // Calculate the pointer stride and check if it is consecutive.
890 // The stride may be a constant or a loop invariant integer value.
891 const SCEVConstant *ConstStep = dyn_cast<SCEVConstant>(Step);
892 if (!ConstStep && !SE->isLoopInvariant(Step, TheLoop))
895 if (PhiTy->isIntegerTy()) {
896 D = InductionDescriptor(StartValue, IK_IntInduction, Step);
900 assert(PhiTy->isPointerTy() && "The PHI must be a pointer");
901 // Pointer induction should be a constant.
905 ConstantInt *CV = ConstStep->getValue();
906 Type *PointerElementType = PhiTy->getPointerElementType();
907 // The pointer stride cannot be determined if the pointer element type is not
909 if (!PointerElementType->isSized())
912 const DataLayout &DL = Phi->getModule()->getDataLayout();
913 int64_t Size = static_cast<int64_t>(DL.getTypeAllocSize(PointerElementType));
917 int64_t CVSize = CV->getSExtValue();
920 auto *StepValue = SE->getConstant(CV->getType(), CVSize / Size,
922 D = InductionDescriptor(StartValue, IK_PtrInduction, StepValue);
926 /// \brief Returns the instructions that use values defined in the loop.
927 SmallVector<Instruction *, 8> llvm::findDefsUsedOutsideOfLoop(Loop *L) {
928 SmallVector<Instruction *, 8> UsedOutside;
930 for (auto *Block : L->getBlocks())
931 // FIXME: I believe that this could use copy_if if the Inst reference could
932 // be adapted into a pointer.
933 for (auto &Inst : *Block) {
934 auto Users = Inst.users();
935 if (any_of(Users, [&](User *U) {
936 auto *Use = cast<Instruction>(U);
937 return !L->contains(Use->getParent());
939 UsedOutside.push_back(&Inst);
945 void llvm::getLoopAnalysisUsage(AnalysisUsage &AU) {
946 // By definition, all loop passes need the LoopInfo analysis and the
947 // Dominator tree it depends on. Because they all participate in the loop
948 // pass manager, they must also preserve these.
949 AU.addRequired<DominatorTreeWrapperPass>();
950 AU.addPreserved<DominatorTreeWrapperPass>();
951 AU.addRequired<LoopInfoWrapperPass>();
952 AU.addPreserved<LoopInfoWrapperPass>();
954 // We must also preserve LoopSimplify and LCSSA. We locally access their IDs
955 // here because users shouldn't directly get them from this header.
956 extern char &LoopSimplifyID;
957 extern char &LCSSAID;
958 AU.addRequiredID(LoopSimplifyID);
959 AU.addPreservedID(LoopSimplifyID);
960 AU.addRequiredID(LCSSAID);
961 AU.addPreservedID(LCSSAID);
962 // This is used in the LPPassManager to perform LCSSA verification on passes
963 // which preserve lcssa form
964 AU.addRequired<LCSSAVerificationPass>();
965 AU.addPreserved<LCSSAVerificationPass>();
967 // Loop passes are designed to run inside of a loop pass manager which means
968 // that any function analyses they require must be required by the first loop
969 // pass in the manager (so that it is computed before the loop pass manager
970 // runs) and preserved by all loop pasess in the manager. To make this
971 // reasonably robust, the set needed for most loop passes is maintained here.
972 // If your loop pass requires an analysis not listed here, you will need to
973 // carefully audit the loop pass manager nesting structure that results.
974 AU.addRequired<AAResultsWrapperPass>();
975 AU.addPreserved<AAResultsWrapperPass>();
976 AU.addPreserved<BasicAAWrapperPass>();
977 AU.addPreserved<GlobalsAAWrapperPass>();
978 AU.addPreserved<SCEVAAWrapperPass>();
979 AU.addRequired<ScalarEvolutionWrapperPass>();
980 AU.addPreserved<ScalarEvolutionWrapperPass>();
983 /// Manually defined generic "LoopPass" dependency initialization. This is used
984 /// to initialize the exact set of passes from above in \c
985 /// getLoopAnalysisUsage. It can be used within a loop pass's initialization
988 /// INITIALIZE_PASS_DEPENDENCY(LoopPass)
990 /// As-if "LoopPass" were a pass.
991 void llvm::initializeLoopPassPass(PassRegistry &Registry) {
992 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
993 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
994 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
995 INITIALIZE_PASS_DEPENDENCY(LCSSAWrapperPass)
996 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
997 INITIALIZE_PASS_DEPENDENCY(BasicAAWrapperPass)
998 INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
999 INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
1000 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
1003 /// \brief Find string metadata for loop
1005 /// If it has a value (e.g. {"llvm.distribute", 1} return the value as an
1006 /// operand or null otherwise. If the string metadata is not found return
1007 /// Optional's not-a-value.
1008 Optional<const MDOperand *> llvm::findStringMetadataForLoop(Loop *TheLoop,
1010 MDNode *LoopID = TheLoop->getLoopID();
1011 // Return none if LoopID is false.
1015 // First operand should refer to the loop id itself.
1016 assert(LoopID->getNumOperands() > 0 && "requires at least one operand");
1017 assert(LoopID->getOperand(0) == LoopID && "invalid loop id");
1019 // Iterate over LoopID operands and look for MDString Metadata
1020 for (unsigned i = 1, e = LoopID->getNumOperands(); i < e; ++i) {
1021 MDNode *MD = dyn_cast<MDNode>(LoopID->getOperand(i));
1024 MDString *S = dyn_cast<MDString>(MD->getOperand(0));
1027 // Return true if MDString holds expected MetaData.
1028 if (Name.equals(S->getString()))
1029 switch (MD->getNumOperands()) {
1033 return &MD->getOperand(1);
1035 llvm_unreachable("loop metadata has 0 or 1 operand");
1041 /// Returns true if the instruction in a loop is guaranteed to execute at least
1043 bool llvm::isGuaranteedToExecute(const Instruction &Inst,
1044 const DominatorTree *DT, const Loop *CurLoop,
1045 const LoopSafetyInfo *SafetyInfo) {
1046 // We have to check to make sure that the instruction dominates all
1047 // of the exit blocks. If it doesn't, then there is a path out of the loop
1048 // which does not execute this instruction, so we can't hoist it.
1050 // If the instruction is in the header block for the loop (which is very
1051 // common), it is always guaranteed to dominate the exit blocks. Since this
1052 // is a common case, and can save some work, check it now.
1053 if (Inst.getParent() == CurLoop->getHeader())
1054 // If there's a throw in the header block, we can't guarantee we'll reach
1056 return !SafetyInfo->HeaderMayThrow;
1058 // Somewhere in this loop there is an instruction which may throw and make us
1060 if (SafetyInfo->MayThrow)
1063 // Get the exit blocks for the current loop.
1064 SmallVector<BasicBlock *, 8> ExitBlocks;
1065 CurLoop->getExitBlocks(ExitBlocks);
1067 // Verify that the block dominates each of the exit blocks of the loop.
1068 for (BasicBlock *ExitBlock : ExitBlocks)
1069 if (!DT->dominates(Inst.getParent(), ExitBlock))
1072 // As a degenerate case, if the loop is statically infinite then we haven't
1073 // proven anything since there are no exit blocks.
1074 if (ExitBlocks.empty())
1077 // FIXME: In general, we have to prove that the loop isn't an infinite loop.
1078 // See http::llvm.org/PR24078 . (The "ExitBlocks.empty()" check above is
1079 // just a special case of this.)
1083 Optional<unsigned> llvm::getLoopEstimatedTripCount(Loop *L) {
1084 // Only support loops with a unique exiting block, and a latch.
1085 if (!L->getExitingBlock())
1088 // Get the branch weights for the the loop's backedge.
1089 BranchInst *LatchBR =
1090 dyn_cast<BranchInst>(L->getLoopLatch()->getTerminator());
1091 if (!LatchBR || LatchBR->getNumSuccessors() != 2)
1094 assert((LatchBR->getSuccessor(0) == L->getHeader() ||
1095 LatchBR->getSuccessor(1) == L->getHeader()) &&
1096 "At least one edge out of the latch must go to the header");
1098 // To estimate the number of times the loop body was executed, we want to
1099 // know the number of times the backedge was taken, vs. the number of times
1100 // we exited the loop.
1101 uint64_t TrueVal, FalseVal;
1102 if (!LatchBR->extractProfMetadata(TrueVal, FalseVal))
1105 if (!TrueVal || !FalseVal)
1108 // Divide the count of the backedge by the count of the edge exiting the loop,
1109 // rounding to nearest.
1110 if (LatchBR->getSuccessor(0) == L->getHeader())
1111 return (TrueVal + (FalseVal / 2)) / FalseVal;
1113 return (FalseVal + (TrueVal / 2)) / TrueVal;
1116 /// \brief Adds a 'fast' flag to floating point operations.
1117 static Value *addFastMathFlag(Value *V) {
1118 if (isa<FPMathOperator>(V)) {
1119 FastMathFlags Flags;
1120 Flags.setUnsafeAlgebra();
1121 cast<Instruction>(V)->setFastMathFlags(Flags);
1126 // Helper to generate a log2 shuffle reduction.
1128 llvm::getShuffleReduction(IRBuilder<> &Builder, Value *Src, unsigned Op,
1129 RecurrenceDescriptor::MinMaxRecurrenceKind MinMaxKind,
1130 ArrayRef<Value *> RedOps) {
1131 unsigned VF = Src->getType()->getVectorNumElements();
1132 // VF is a power of 2 so we can emit the reduction using log2(VF) shuffles
1133 // and vector ops, reducing the set of values being computed by half each
1135 assert(isPowerOf2_32(VF) &&
1136 "Reduction emission only supported for pow2 vectors!");
1137 Value *TmpVec = Src;
1138 SmallVector<Constant *, 32> ShuffleMask(VF, nullptr);
1139 for (unsigned i = VF; i != 1; i >>= 1) {
1140 // Move the upper half of the vector to the lower half.
1141 for (unsigned j = 0; j != i / 2; ++j)
1142 ShuffleMask[j] = Builder.getInt32(i / 2 + j);
1144 // Fill the rest of the mask with undef.
1145 std::fill(&ShuffleMask[i / 2], ShuffleMask.end(),
1146 UndefValue::get(Builder.getInt32Ty()));
1148 Value *Shuf = Builder.CreateShuffleVector(
1149 TmpVec, UndefValue::get(TmpVec->getType()),
1150 ConstantVector::get(ShuffleMask), "rdx.shuf");
1152 if (Op != Instruction::ICmp && Op != Instruction::FCmp) {
1153 // Floating point operations had to be 'fast' to enable the reduction.
1154 TmpVec = addFastMathFlag(Builder.CreateBinOp((Instruction::BinaryOps)Op,
1155 TmpVec, Shuf, "bin.rdx"));
1157 assert(MinMaxKind != RecurrenceDescriptor::MRK_Invalid &&
1159 TmpVec = RecurrenceDescriptor::createMinMaxOp(Builder, MinMaxKind, TmpVec,
1162 if (!RedOps.empty())
1163 propagateIRFlags(TmpVec, RedOps);
1165 // The result is in the first element of the vector.
1166 return Builder.CreateExtractElement(TmpVec, Builder.getInt32(0));
1169 /// Create a simple vector reduction specified by an opcode and some
1170 /// flags (if generating min/max reductions).
1171 Value *llvm::createSimpleTargetReduction(
1172 IRBuilder<> &Builder, const TargetTransformInfo *TTI, unsigned Opcode,
1173 Value *Src, TargetTransformInfo::ReductionFlags Flags,
1174 ArrayRef<Value *> RedOps) {
1175 assert(isa<VectorType>(Src->getType()) && "Type must be a vector");
1177 Value *ScalarUdf = UndefValue::get(Src->getType()->getVectorElementType());
1178 std::function<Value*()> BuildFunc;
1179 using RD = RecurrenceDescriptor;
1180 RD::MinMaxRecurrenceKind MinMaxKind = RD::MRK_Invalid;
1181 // TODO: Support creating ordered reductions.
1182 FastMathFlags FMFUnsafe;
1183 FMFUnsafe.setUnsafeAlgebra();
1186 case Instruction::Add:
1187 BuildFunc = [&]() { return Builder.CreateAddReduce(Src); };
1189 case Instruction::Mul:
1190 BuildFunc = [&]() { return Builder.CreateMulReduce(Src); };
1192 case Instruction::And:
1193 BuildFunc = [&]() { return Builder.CreateAndReduce(Src); };
1195 case Instruction::Or:
1196 BuildFunc = [&]() { return Builder.CreateOrReduce(Src); };
1198 case Instruction::Xor:
1199 BuildFunc = [&]() { return Builder.CreateXorReduce(Src); };
1201 case Instruction::FAdd:
1203 auto Rdx = Builder.CreateFAddReduce(ScalarUdf, Src);
1204 cast<CallInst>(Rdx)->setFastMathFlags(FMFUnsafe);
1208 case Instruction::FMul:
1210 auto Rdx = Builder.CreateFMulReduce(ScalarUdf, Src);
1211 cast<CallInst>(Rdx)->setFastMathFlags(FMFUnsafe);
1215 case Instruction::ICmp:
1216 if (Flags.IsMaxOp) {
1217 MinMaxKind = Flags.IsSigned ? RD::MRK_SIntMax : RD::MRK_UIntMax;
1219 return Builder.CreateIntMaxReduce(Src, Flags.IsSigned);
1222 MinMaxKind = Flags.IsSigned ? RD::MRK_SIntMin : RD::MRK_UIntMin;
1224 return Builder.CreateIntMinReduce(Src, Flags.IsSigned);
1228 case Instruction::FCmp:
1229 if (Flags.IsMaxOp) {
1230 MinMaxKind = RD::MRK_FloatMax;
1231 BuildFunc = [&]() { return Builder.CreateFPMaxReduce(Src, Flags.NoNaN); };
1233 MinMaxKind = RD::MRK_FloatMin;
1234 BuildFunc = [&]() { return Builder.CreateFPMinReduce(Src, Flags.NoNaN); };
1238 llvm_unreachable("Unhandled opcode");
1241 if (TTI->useReductionIntrinsic(Opcode, Src->getType(), Flags))
1243 return getShuffleReduction(Builder, Src, Opcode, MinMaxKind, RedOps);
1246 /// Create a vector reduction using a given recurrence descriptor.
1247 Value *llvm::createTargetReduction(IRBuilder<> &Builder,
1248 const TargetTransformInfo *TTI,
1249 RecurrenceDescriptor &Desc, Value *Src,
1251 // TODO: Support in-order reductions based on the recurrence descriptor.
1252 RecurrenceDescriptor::RecurrenceKind RecKind = Desc.getRecurrenceKind();
1253 TargetTransformInfo::ReductionFlags Flags;
1254 Flags.NoNaN = NoNaN;
1255 auto getSimpleRdx = [&](unsigned Opc) {
1256 return createSimpleTargetReduction(Builder, TTI, Opc, Src, Flags);
1259 case RecurrenceDescriptor::RK_FloatAdd:
1260 return getSimpleRdx(Instruction::FAdd);
1261 case RecurrenceDescriptor::RK_FloatMult:
1262 return getSimpleRdx(Instruction::FMul);
1263 case RecurrenceDescriptor::RK_IntegerAdd:
1264 return getSimpleRdx(Instruction::Add);
1265 case RecurrenceDescriptor::RK_IntegerMult:
1266 return getSimpleRdx(Instruction::Mul);
1267 case RecurrenceDescriptor::RK_IntegerAnd:
1268 return getSimpleRdx(Instruction::And);
1269 case RecurrenceDescriptor::RK_IntegerOr:
1270 return getSimpleRdx(Instruction::Or);
1271 case RecurrenceDescriptor::RK_IntegerXor:
1272 return getSimpleRdx(Instruction::Xor);
1273 case RecurrenceDescriptor::RK_IntegerMinMax: {
1274 switch (Desc.getMinMaxRecurrenceKind()) {
1275 case RecurrenceDescriptor::MRK_SIntMax:
1276 Flags.IsSigned = true;
1277 Flags.IsMaxOp = true;
1279 case RecurrenceDescriptor::MRK_UIntMax:
1280 Flags.IsMaxOp = true;
1282 case RecurrenceDescriptor::MRK_SIntMin:
1283 Flags.IsSigned = true;
1285 case RecurrenceDescriptor::MRK_UIntMin:
1288 llvm_unreachable("Unhandled MRK");
1290 return getSimpleRdx(Instruction::ICmp);
1292 case RecurrenceDescriptor::RK_FloatMinMax: {
1294 Desc.getMinMaxRecurrenceKind() == RecurrenceDescriptor::MRK_FloatMax;
1295 return getSimpleRdx(Instruction::FCmp);
1298 llvm_unreachable("Unhandled RecKind");
1302 void llvm::propagateIRFlags(Value *I, ArrayRef<Value *> VL) {
1303 if (auto *VecOp = dyn_cast<Instruction>(I)) {
1304 if (auto *I0 = dyn_cast<Instruction>(VL[0])) {
1305 // VecOVp is initialized to the 0th scalar, so start counting from index
1307 VecOp->copyIRFlags(I0);
1308 for (int i = 1, e = VL.size(); i < e; ++i) {
1309 if (auto *Scalar = dyn_cast<Instruction>(VL[i]))
1310 VecOp->andIRFlags(Scalar);