1 //===- GuardWidening.cpp - ---- Guard widening ----------------------------===//
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 the guard widening pass. The semantics of the
11 // @llvm.experimental.guard intrinsic lets LLVM transform it so that it fails
12 // more often that it did before the transform. This optimization is called
13 // "widening" and can be used hoist and common runtime checks in situations like
16 // %cmp0 = 7 u< Length
17 // call @llvm.experimental.guard(i1 %cmp0) [ "deopt"(...) ]
18 // call @unknown_side_effects()
19 // %cmp1 = 9 u< Length
20 // call @llvm.experimental.guard(i1 %cmp1) [ "deopt"(...) ]
25 // %cmp0 = 9 u< Length
26 // call @llvm.experimental.guard(i1 %cmp0) [ "deopt"(...) ]
27 // call @unknown_side_effects()
30 // If %cmp0 is false, @llvm.experimental.guard will "deoptimize" back to a
31 // generic implementation of the same function, which will have the correct
32 // semantics from that point onward. It is always _legal_ to deoptimize (so
33 // replacing %cmp0 with false is "correct"), though it may not always be
34 // profitable to do so.
36 // NB! This pass is a work in progress. It hasn't been tuned to be "production
37 // ready" yet. It is known to have quadriatic running time and will not scale
38 // to large numbers of guards
40 //===----------------------------------------------------------------------===//
42 #include "llvm/Transforms/Scalar/GuardWidening.h"
43 #include "llvm/Pass.h"
44 #include "llvm/ADT/DenseMap.h"
45 #include "llvm/ADT/DepthFirstIterator.h"
46 #include "llvm/Analysis/LoopInfo.h"
47 #include "llvm/Analysis/PostDominators.h"
48 #include "llvm/Analysis/ValueTracking.h"
49 #include "llvm/IR/ConstantRange.h"
50 #include "llvm/IR/Dominators.h"
51 #include "llvm/IR/IntrinsicInst.h"
52 #include "llvm/IR/PatternMatch.h"
53 #include "llvm/Support/Debug.h"
54 #include "llvm/Support/KnownBits.h"
55 #include "llvm/Transforms/Scalar.h"
59 #define DEBUG_TYPE "guard-widening"
63 class GuardWideningImpl {
65 PostDominatorTree &PDT;
68 /// The set of guards whose conditions have been widened into dominating
70 SmallVector<IntrinsicInst *, 16> EliminatedGuards;
72 /// The set of guards which have been widened to include conditions to other
74 DenseSet<IntrinsicInst *> WidenedGuards;
76 /// Try to eliminate guard \p Guard by widening it into an earlier dominating
77 /// guard. \p DFSI is the DFS iterator on the dominator tree that is
78 /// currently visiting the block containing \p Guard, and \p GuardsPerBlock
79 /// maps BasicBlocks to the set of guards seen in that block.
80 bool eliminateGuardViaWidening(
81 IntrinsicInst *Guard, const df_iterator<DomTreeNode *> &DFSI,
82 const DenseMap<BasicBlock *, SmallVector<IntrinsicInst *, 8>> &
85 /// Used to keep track of which widening potential is more effective.
90 /// Widening is performance neutral as far as the cycles spent in check
91 /// conditions goes (but can still help, e.g., code layout, having less
95 /// Widening is profitable.
98 /// Widening is very profitable. Not significantly different from \c
99 /// WS_Positive, except by the order.
103 static StringRef scoreTypeToString(WideningScore WS);
105 /// Compute the score for widening the condition in \p DominatedGuard
106 /// (contained in \p DominatedGuardLoop) into \p DominatingGuard (contained in
107 /// \p DominatingGuardLoop).
108 WideningScore computeWideningScore(IntrinsicInst *DominatedGuard,
109 Loop *DominatedGuardLoop,
110 IntrinsicInst *DominatingGuard,
111 Loop *DominatingGuardLoop);
113 /// Helper to check if \p V can be hoisted to \p InsertPos.
114 bool isAvailableAt(Value *V, Instruction *InsertPos) {
115 SmallPtrSet<Instruction *, 8> Visited;
116 return isAvailableAt(V, InsertPos, Visited);
119 bool isAvailableAt(Value *V, Instruction *InsertPos,
120 SmallPtrSetImpl<Instruction *> &Visited);
122 /// Helper to hoist \p V to \p InsertPos. Guaranteed to succeed if \c
123 /// isAvailableAt returned true.
124 void makeAvailableAt(Value *V, Instruction *InsertPos);
126 /// Common helper used by \c widenGuard and \c isWideningCondProfitable. Try
127 /// to generate an expression computing the logical AND of \p Cond0 and \p
128 /// Cond1. Return true if the expression computing the AND is only as
129 /// expensive as computing one of the two. If \p InsertPt is true then
130 /// actually generate the resulting expression, make it available at \p
131 /// InsertPt and return it in \p Result (else no change to the IR is made).
132 bool widenCondCommon(Value *Cond0, Value *Cond1, Instruction *InsertPt,
135 /// Represents a range check of the form \c Base + \c Offset u< \c Length,
136 /// with the constraint that \c Length is not negative. \c CheckInst is the
137 /// pre-existing instruction in the IR that computes the result of this range
146 explicit RangeCheck(Value *Base, ConstantInt *Offset, Value *Length,
148 : Base(Base), Offset(Offset), Length(Length), CheckInst(CheckInst) {}
150 void setBase(Value *NewBase) { Base = NewBase; }
151 void setOffset(ConstantInt *NewOffset) { Offset = NewOffset; }
153 Value *getBase() const { return Base; }
154 ConstantInt *getOffset() const { return Offset; }
155 const APInt &getOffsetValue() const { return getOffset()->getValue(); }
156 Value *getLength() const { return Length; };
157 ICmpInst *getCheckInst() const { return CheckInst; }
159 void print(raw_ostream &OS, bool PrintTypes = false) {
161 Base->printAsOperand(OS, PrintTypes);
163 Offset->printAsOperand(OS, PrintTypes);
165 Length->printAsOperand(OS, PrintTypes);
168 LLVM_DUMP_METHOD void dump() {
174 /// Parse \p CheckCond into a conjunction (logical-and) of range checks; and
175 /// append them to \p Checks. Returns true on success, may clobber \c Checks
177 bool parseRangeChecks(Value *CheckCond, SmallVectorImpl<RangeCheck> &Checks) {
178 SmallPtrSet<Value *, 8> Visited;
179 return parseRangeChecks(CheckCond, Checks, Visited);
182 bool parseRangeChecks(Value *CheckCond, SmallVectorImpl<RangeCheck> &Checks,
183 SmallPtrSetImpl<Value *> &Visited);
185 /// Combine the checks in \p Checks into a smaller set of checks and append
186 /// them into \p CombinedChecks. Return true on success (i.e. all of checks
187 /// in \p Checks were combined into \p CombinedChecks). Clobbers \p Checks
188 /// and \p CombinedChecks on success and on failure.
189 bool combineRangeChecks(SmallVectorImpl<RangeCheck> &Checks,
190 SmallVectorImpl<RangeCheck> &CombinedChecks);
192 /// Can we compute the logical AND of \p Cond0 and \p Cond1 for the price of
193 /// computing only one of the two expressions?
194 bool isWideningCondProfitable(Value *Cond0, Value *Cond1) {
196 return widenCondCommon(Cond0, Cond1, /*InsertPt=*/nullptr, ResultUnused);
199 /// Widen \p ToWiden to fail if \p NewCondition is false (in addition to
200 /// whatever it is already checking).
201 void widenGuard(IntrinsicInst *ToWiden, Value *NewCondition) {
203 widenCondCommon(ToWiden->getArgOperand(0), NewCondition, ToWiden, Result);
204 ToWiden->setArgOperand(0, Result);
208 explicit GuardWideningImpl(DominatorTree &DT, PostDominatorTree &PDT,
210 : DT(DT), PDT(PDT), LI(LI) {}
212 /// The entry point for this pass.
216 struct GuardWideningLegacyPass : public FunctionPass {
218 GuardWideningPass Impl;
220 GuardWideningLegacyPass() : FunctionPass(ID) {
221 initializeGuardWideningLegacyPassPass(*PassRegistry::getPassRegistry());
224 bool runOnFunction(Function &F) override {
227 return GuardWideningImpl(
228 getAnalysis<DominatorTreeWrapperPass>().getDomTree(),
229 getAnalysis<PostDominatorTreeWrapperPass>().getPostDomTree(),
230 getAnalysis<LoopInfoWrapperPass>().getLoopInfo()).run();
233 void getAnalysisUsage(AnalysisUsage &AU) const override {
234 AU.setPreservesCFG();
235 AU.addRequired<DominatorTreeWrapperPass>();
236 AU.addRequired<PostDominatorTreeWrapperPass>();
237 AU.addRequired<LoopInfoWrapperPass>();
243 bool GuardWideningImpl::run() {
244 using namespace llvm::PatternMatch;
246 DenseMap<BasicBlock *, SmallVector<IntrinsicInst *, 8>> GuardsInBlock;
247 bool Changed = false;
249 for (auto DFI = df_begin(DT.getRootNode()), DFE = df_end(DT.getRootNode());
251 auto *BB = (*DFI)->getBlock();
252 auto &CurrentList = GuardsInBlock[BB];
255 if (match(&I, m_Intrinsic<Intrinsic::experimental_guard>()))
256 CurrentList.push_back(cast<IntrinsicInst>(&I));
258 for (auto *II : CurrentList)
259 Changed |= eliminateGuardViaWidening(II, DFI, GuardsInBlock);
262 for (auto *II : EliminatedGuards)
263 if (!WidenedGuards.count(II))
264 II->eraseFromParent();
269 bool GuardWideningImpl::eliminateGuardViaWidening(
270 IntrinsicInst *GuardInst, const df_iterator<DomTreeNode *> &DFSI,
271 const DenseMap<BasicBlock *, SmallVector<IntrinsicInst *, 8>> &
273 IntrinsicInst *BestSoFar = nullptr;
274 auto BestScoreSoFar = WS_IllegalOrNegative;
275 auto *GuardInstLoop = LI.getLoopFor(GuardInst->getParent());
277 // In the set of dominating guards, find the one we can merge GuardInst with
278 // for the most profit.
279 for (unsigned i = 0, e = DFSI.getPathLength(); i != e; ++i) {
280 auto *CurBB = DFSI.getPath(i)->getBlock();
281 auto *CurLoop = LI.getLoopFor(CurBB);
282 assert(GuardsInBlock.count(CurBB) && "Must have been populated by now!");
283 const auto &GuardsInCurBB = GuardsInBlock.find(CurBB)->second;
285 auto I = GuardsInCurBB.begin();
286 auto E = GuardsInCurBB.end();
291 for (auto &I : *CurBB) {
292 if (Index == GuardsInCurBB.size())
294 if (GuardsInCurBB[Index] == &I)
297 assert(Index == GuardsInCurBB.size() &&
298 "Guards expected to be in order!");
302 assert((i == (e - 1)) == (GuardInst->getParent() == CurBB) && "Bad DFS?");
305 // Corner case: make sure we're only looking at guards strictly dominating
306 // GuardInst when visiting GuardInst->getParent().
307 auto NewEnd = std::find(I, E, GuardInst);
308 assert(NewEnd != E && "GuardInst not in its own block?");
312 for (auto *Candidate : make_range(I, E)) {
314 computeWideningScore(GuardInst, GuardInstLoop, Candidate, CurLoop);
315 DEBUG(dbgs() << "Score between " << *GuardInst->getArgOperand(0)
316 << " and " << *Candidate->getArgOperand(0) << " is "
317 << scoreTypeToString(Score) << "\n");
318 if (Score > BestScoreSoFar) {
319 BestScoreSoFar = Score;
320 BestSoFar = Candidate;
325 if (BestScoreSoFar == WS_IllegalOrNegative) {
326 DEBUG(dbgs() << "Did not eliminate guard " << *GuardInst << "\n");
330 assert(BestSoFar != GuardInst && "Should have never visited same guard!");
331 assert(DT.dominates(BestSoFar, GuardInst) && "Should be!");
333 DEBUG(dbgs() << "Widening " << *GuardInst << " into " << *BestSoFar
334 << " with score " << scoreTypeToString(BestScoreSoFar) << "\n");
335 widenGuard(BestSoFar, GuardInst->getArgOperand(0));
336 GuardInst->setArgOperand(0, ConstantInt::getTrue(GuardInst->getContext()));
337 EliminatedGuards.push_back(GuardInst);
338 WidenedGuards.insert(BestSoFar);
342 GuardWideningImpl::WideningScore GuardWideningImpl::computeWideningScore(
343 IntrinsicInst *DominatedGuard, Loop *DominatedGuardLoop,
344 IntrinsicInst *DominatingGuard, Loop *DominatingGuardLoop) {
345 bool HoistingOutOfLoop = false;
347 if (DominatingGuardLoop != DominatedGuardLoop) {
348 if (DominatingGuardLoop &&
349 !DominatingGuardLoop->contains(DominatedGuardLoop))
350 return WS_IllegalOrNegative;
352 HoistingOutOfLoop = true;
355 if (!isAvailableAt(DominatedGuard->getArgOperand(0), DominatingGuard))
356 return WS_IllegalOrNegative;
358 bool HoistingOutOfIf =
359 !PDT.dominates(DominatedGuard->getParent(), DominatingGuard->getParent());
361 if (isWideningCondProfitable(DominatedGuard->getArgOperand(0),
362 DominatingGuard->getArgOperand(0)))
363 return HoistingOutOfLoop ? WS_VeryPositive : WS_Positive;
365 if (HoistingOutOfLoop)
368 return HoistingOutOfIf ? WS_IllegalOrNegative : WS_Neutral;
371 bool GuardWideningImpl::isAvailableAt(Value *V, Instruction *Loc,
372 SmallPtrSetImpl<Instruction *> &Visited) {
373 auto *Inst = dyn_cast<Instruction>(V);
374 if (!Inst || DT.dominates(Inst, Loc) || Visited.count(Inst))
377 if (!isSafeToSpeculativelyExecute(Inst, Loc, &DT) ||
378 Inst->mayReadFromMemory())
381 Visited.insert(Inst);
383 // We only want to go _up_ the dominance chain when recursing.
384 assert(!isa<PHINode>(Loc) &&
385 "PHIs should return false for isSafeToSpeculativelyExecute");
386 assert(DT.isReachableFromEntry(Inst->getParent()) &&
387 "We did a DFS from the block entry!");
388 return all_of(Inst->operands(),
389 [&](Value *Op) { return isAvailableAt(Op, Loc, Visited); });
392 void GuardWideningImpl::makeAvailableAt(Value *V, Instruction *Loc) {
393 auto *Inst = dyn_cast<Instruction>(V);
394 if (!Inst || DT.dominates(Inst, Loc))
397 assert(isSafeToSpeculativelyExecute(Inst, Loc, &DT) &&
398 !Inst->mayReadFromMemory() && "Should've checked with isAvailableAt!");
400 for (Value *Op : Inst->operands())
401 makeAvailableAt(Op, Loc);
403 Inst->moveBefore(Loc);
406 bool GuardWideningImpl::widenCondCommon(Value *Cond0, Value *Cond1,
407 Instruction *InsertPt, Value *&Result) {
408 using namespace llvm::PatternMatch;
411 // L >u C0 && L >u C1 -> L >u max(C0, C1)
412 ConstantInt *RHS0, *RHS1;
414 ICmpInst::Predicate Pred0, Pred1;
415 if (match(Cond0, m_ICmp(Pred0, m_Value(LHS), m_ConstantInt(RHS0))) &&
416 match(Cond1, m_ICmp(Pred1, m_Specific(LHS), m_ConstantInt(RHS1)))) {
419 ConstantRange::makeExactICmpRegion(Pred0, RHS0->getValue());
421 ConstantRange::makeExactICmpRegion(Pred1, RHS1->getValue());
423 // SubsetIntersect is a subset of the actual mathematical intersection of
424 // CR0 and CR1, while SupersetIntersect is a superset of the actual
425 // mathematical intersection. If these two ConstantRanges are equal, then
426 // we know we were able to represent the actual mathematical intersection
427 // of CR0 and CR1, and can use the same to generate an icmp instruction.
429 // Given what we're doing here and the semantics of guards, it would
430 // actually be correct to just use SubsetIntersect, but that may be too
431 // aggressive in cases we care about.
432 auto SubsetIntersect = CR0.inverse().unionWith(CR1.inverse()).inverse();
433 auto SupersetIntersect = CR0.intersectWith(CR1);
436 CmpInst::Predicate Pred;
437 if (SubsetIntersect == SupersetIntersect &&
438 SubsetIntersect.getEquivalentICmp(Pred, NewRHSAP)) {
440 ConstantInt *NewRHS = ConstantInt::get(Cond0->getContext(), NewRHSAP);
441 Result = new ICmpInst(InsertPt, Pred, LHS, NewRHS, "wide.chk");
449 SmallVector<GuardWideningImpl::RangeCheck, 4> Checks, CombinedChecks;
450 if (parseRangeChecks(Cond0, Checks) && parseRangeChecks(Cond1, Checks) &&
451 combineRangeChecks(Checks, CombinedChecks)) {
454 for (auto &RC : CombinedChecks) {
455 makeAvailableAt(RC.getCheckInst(), InsertPt);
457 Result = BinaryOperator::CreateAnd(RC.getCheckInst(), Result, "",
460 Result = RC.getCheckInst();
463 Result->setName("wide.chk");
469 // Base case -- just logical-and the two conditions together.
472 makeAvailableAt(Cond0, InsertPt);
473 makeAvailableAt(Cond1, InsertPt);
475 Result = BinaryOperator::CreateAnd(Cond0, Cond1, "wide.chk", InsertPt);
478 // We were not able to compute Cond0 AND Cond1 for the price of one.
482 bool GuardWideningImpl::parseRangeChecks(
483 Value *CheckCond, SmallVectorImpl<GuardWideningImpl::RangeCheck> &Checks,
484 SmallPtrSetImpl<Value *> &Visited) {
485 if (!Visited.insert(CheckCond).second)
488 using namespace llvm::PatternMatch;
491 Value *AndLHS, *AndRHS;
492 if (match(CheckCond, m_And(m_Value(AndLHS), m_Value(AndRHS))))
493 return parseRangeChecks(AndLHS, Checks) &&
494 parseRangeChecks(AndRHS, Checks);
497 auto *IC = dyn_cast<ICmpInst>(CheckCond);
498 if (!IC || !IC->getOperand(0)->getType()->isIntegerTy() ||
499 (IC->getPredicate() != ICmpInst::ICMP_ULT &&
500 IC->getPredicate() != ICmpInst::ICMP_UGT))
503 Value *CmpLHS = IC->getOperand(0), *CmpRHS = IC->getOperand(1);
504 if (IC->getPredicate() == ICmpInst::ICMP_UGT)
505 std::swap(CmpLHS, CmpRHS);
507 auto &DL = IC->getModule()->getDataLayout();
509 GuardWideningImpl::RangeCheck Check(
510 CmpLHS, cast<ConstantInt>(ConstantInt::getNullValue(CmpRHS->getType())),
513 if (!isKnownNonNegative(Check.getLength(), DL))
516 // What we have in \c Check now is a correct interpretation of \p CheckCond.
517 // Try to see if we can move some constant offsets into the \c Offset field.
520 auto &Ctx = CheckCond->getContext();
528 auto *BaseInst = dyn_cast<Instruction>(Check.getBase());
529 assert((!BaseInst || DT.isReachableFromEntry(BaseInst->getParent())) &&
530 "Unreachable instruction?");
533 if (match(Check.getBase(), m_Add(m_Value(OpLHS), m_ConstantInt(OpRHS)))) {
534 Check.setBase(OpLHS);
535 APInt NewOffset = Check.getOffsetValue() + OpRHS->getValue();
536 Check.setOffset(ConstantInt::get(Ctx, NewOffset));
538 } else if (match(Check.getBase(),
539 m_Or(m_Value(OpLHS), m_ConstantInt(OpRHS)))) {
540 KnownBits Known = computeKnownBits(OpLHS, DL);
541 if ((OpRHS->getValue() & Known.Zero) == OpRHS->getValue()) {
542 Check.setBase(OpLHS);
543 APInt NewOffset = Check.getOffsetValue() + OpRHS->getValue();
544 Check.setOffset(ConstantInt::get(Ctx, NewOffset));
550 Checks.push_back(Check);
554 bool GuardWideningImpl::combineRangeChecks(
555 SmallVectorImpl<GuardWideningImpl::RangeCheck> &Checks,
556 SmallVectorImpl<GuardWideningImpl::RangeCheck> &RangeChecksOut) {
557 unsigned OldCount = Checks.size();
558 while (!Checks.empty()) {
559 // Pick all of the range checks with a specific base and length, and try to
561 Value *CurrentBase = Checks.front().getBase();
562 Value *CurrentLength = Checks.front().getLength();
564 SmallVector<GuardWideningImpl::RangeCheck, 3> CurrentChecks;
566 auto IsCurrentCheck = [&](GuardWideningImpl::RangeCheck &RC) {
567 return RC.getBase() == CurrentBase && RC.getLength() == CurrentLength;
570 copy_if(Checks, std::back_inserter(CurrentChecks), IsCurrentCheck);
571 Checks.erase(remove_if(Checks, IsCurrentCheck), Checks.end());
573 assert(CurrentChecks.size() != 0 && "We know we have at least one!");
575 if (CurrentChecks.size() < 3) {
576 RangeChecksOut.insert(RangeChecksOut.end(), CurrentChecks.begin(),
577 CurrentChecks.end());
581 // CurrentChecks.size() will typically be 3 here, but so far there has been
582 // no need to hard-code that fact.
584 std::sort(CurrentChecks.begin(), CurrentChecks.end(),
585 [&](const GuardWideningImpl::RangeCheck &LHS,
586 const GuardWideningImpl::RangeCheck &RHS) {
587 return LHS.getOffsetValue().slt(RHS.getOffsetValue());
590 // Note: std::sort should not invalidate the ChecksStart iterator.
592 ConstantInt *MinOffset = CurrentChecks.front().getOffset(),
593 *MaxOffset = CurrentChecks.back().getOffset();
595 unsigned BitWidth = MaxOffset->getValue().getBitWidth();
596 if ((MaxOffset->getValue() - MinOffset->getValue())
597 .ugt(APInt::getSignedMinValue(BitWidth)))
600 APInt MaxDiff = MaxOffset->getValue() - MinOffset->getValue();
601 const APInt &HighOffset = MaxOffset->getValue();
602 auto OffsetOK = [&](const GuardWideningImpl::RangeCheck &RC) {
603 return (HighOffset - RC.getOffsetValue()).ult(MaxDiff);
606 if (MaxDiff.isMinValue() ||
607 !std::all_of(std::next(CurrentChecks.begin()), CurrentChecks.end(),
611 // We have a series of f+1 checks as:
613 // I+k_0 u< L ... Chk_0
614 // I+k_1 u< L ... Chk_1
616 // I+k_f u< L ... Chk_f
618 // with forall i in [0,f]: k_f-k_i u< k_f-k_0 ... Precond_0
619 // k_f-k_0 u< INT_MIN+k_f ... Precond_1
620 // k_f != k_0 ... Precond_2
623 // Chk_0 AND Chk_f implies all the other checks
625 // Informal proof sketch:
627 // We will show that the integer range [I+k_0,I+k_f] does not unsigned-wrap
628 // (i.e. going from I+k_0 to I+k_f does not cross the -1,0 boundary) and
629 // thus I+k_f is the greatest unsigned value in that range.
631 // This combined with Ckh_(f+1) shows that everything in that range is u< L.
632 // Via Precond_0 we know that all of the indices in Chk_0 through Chk_(f+1)
633 // lie in [I+k_0,I+k_f], this proving our claim.
635 // To see that [I+k_0,I+k_f] is not a wrapping range, note that there are
636 // two possibilities: I+k_0 u< I+k_f or I+k_0 >u I+k_f (they can't be equal
637 // since k_0 != k_f). In the former case, [I+k_0,I+k_f] is not a wrapping
638 // range by definition, and the latter case is impossible:
640 // 0-----I+k_f---I+k_0----L---INT_MAX,INT_MIN------------------(-1)
641 // xxxxxx xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
643 // For Chk_0 to succeed, we'd have to have k_f-k_0 (the range highlighted
644 // with 'x' above) to be at least >u INT_MIN.
646 RangeChecksOut.emplace_back(CurrentChecks.front());
647 RangeChecksOut.emplace_back(CurrentChecks.back());
650 assert(RangeChecksOut.size() <= OldCount && "We pessimized!");
651 return RangeChecksOut.size() != OldCount;
654 PreservedAnalyses GuardWideningPass::run(Function &F,
655 FunctionAnalysisManager &AM) {
656 auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
657 auto &LI = AM.getResult<LoopAnalysis>(F);
658 auto &PDT = AM.getResult<PostDominatorTreeAnalysis>(F);
659 if (!GuardWideningImpl(DT, PDT, LI).run())
660 return PreservedAnalyses::all();
662 PreservedAnalyses PA;
663 PA.preserveSet<CFGAnalyses>();
667 StringRef GuardWideningImpl::scoreTypeToString(WideningScore WS) {
669 case WS_IllegalOrNegative:
670 return "IllegalOrNegative";
675 case WS_VeryPositive:
676 return "VeryPositive";
679 llvm_unreachable("Fully covered switch above!");
682 char GuardWideningLegacyPass::ID = 0;
684 INITIALIZE_PASS_BEGIN(GuardWideningLegacyPass, "guard-widening", "Widen guards",
686 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
687 INITIALIZE_PASS_DEPENDENCY(PostDominatorTreeWrapperPass)
688 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
689 INITIALIZE_PASS_END(GuardWideningLegacyPass, "guard-widening", "Widen guards",
692 FunctionPass *llvm::createGuardWideningPass() {
693 return new GuardWideningLegacyPass();