diff options
Diffstat (limited to 'llvm/lib/Analysis/AliasAnalysis.cpp')
-rw-r--r-- | llvm/lib/Analysis/AliasAnalysis.cpp | 52 |
1 files changed, 2 insertions, 50 deletions
diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp index fa1484d57de..3f1cf6aa3f8 100644 --- a/llvm/lib/Analysis/AliasAnalysis.cpp +++ b/llvm/lib/Analysis/AliasAnalysis.cpp @@ -388,53 +388,6 @@ AliasAnalysis::getModRefInfo(const AtomicRMWInst *RMW, const Location &Loc) { return ModRef; } -namespace { - /// Only find pointer captures which happen before the given instruction. Uses - /// the dominator tree to determine whether one instruction is before another. - /// Only support the case where the Value is defined in the same basic block - /// as the given instruction and the use. - struct CapturesBefore : public CaptureTracker { - CapturesBefore(const Instruction *I, DominatorTree *DT) - : BeforeHere(I), DT(DT), Captured(false) {} - - void tooManyUses() override { Captured = true; } - - bool shouldExplore(const Use *U) override { - Instruction *I = cast<Instruction>(U->getUser()); - BasicBlock *BB = I->getParent(); - // We explore this usage only if the usage can reach "BeforeHere". - // If use is not reachable from entry, there is no need to explore. - if (BeforeHere != I && !DT->isReachableFromEntry(BB)) - return false; - // If the value is defined in the same basic block as use and BeforeHere, - // there is no need to explore the use if BeforeHere dominates use. - // Check whether there is a path from I to BeforeHere. - if (BeforeHere != I && DT->dominates(BeforeHere, I) && - !isPotentiallyReachable(I, BeforeHere, DT)) - return false; - return true; - } - - bool captured(const Use *U) override { - Instruction *I = cast<Instruction>(U->getUser()); - BasicBlock *BB = I->getParent(); - // Same logic as in shouldExplore. - if (BeforeHere != I && !DT->isReachableFromEntry(BB)) - return false; - if (BeforeHere != I && DT->dominates(BeforeHere, I) && - !isPotentiallyReachable(I, BeforeHere, DT)) - return false; - Captured = true; - return true; - } - - const Instruction *BeforeHere; - DominatorTree *DT; - - bool Captured; - }; -} - // FIXME: this is really just shoring-up a deficiency in alias analysis. // BasicAA isn't willing to spend linear time determining whether an alloca // was captured before or after this particular call, while we are. However, @@ -454,9 +407,8 @@ AliasAnalysis::callCapturesBefore(const Instruction *I, if (!CS.getInstruction() || CS.getInstruction() == Object) return AliasAnalysis::ModRef; - CapturesBefore CB(I, DT); - llvm::PointerMayBeCaptured(Object, &CB); - if (CB.Captured) + if (llvm::PointerMayBeCapturedBefore(Object, /* ReturnCaptures */ true, + /* StoreCaptures */ true, I, DT)) return AliasAnalysis::ModRef; unsigned ArgNo = 0; |