diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/GVN.cpp | 21 |
1 files changed, 19 insertions, 2 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp index bf46bd98c3d..f0e0f381425 100644 --- a/llvm/lib/Transforms/Scalar/GVN.cpp +++ b/llvm/lib/Transforms/Scalar/GVN.cpp @@ -1063,6 +1063,15 @@ static Value *ConstructSSAForLoadSet(LoadInst *LI, if (V->getType()->isPointerTy()) for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i) AA->copyValue(LI, NewPHIs[i]); + + // Now that we've copied information to the new PHIs, scan through + // them again and inform alias analysis that we've added potentially + // escaping uses to any values that are operands to these PHIs. + for (unsigned i = 0, e = NewPHIs.size(); i != e; ++i) { + PHINode *P = NewPHIs[i]; + for (unsigned ii = 0, ee = P->getNumIncomingValues(); ii != ee; ++ii) + AA->addEscapingUse(P->getOperandUse(2*ii)); + } return V; } @@ -1957,8 +1966,16 @@ bool GVN::performPRE(Function &F) { insert_table(ValNo, Phi, CurrentBlock); CurInst->replaceAllUsesWith(Phi); - if (MD && Phi->getType()->isPointerTy()) - MD->invalidateCachedPointerInfo(Phi); + if (Phi->getType()->isPointerTy()) { + // Because we have added a PHI-use of the pointer value, it has now + // "escaped" from alias analysis' perspective. We need to inform + // AA of this. + for (unsigned ii = 0, ee = Phi->getNumIncomingValues(); ii != ee; ++ii) + VN.getAliasAnalysis()->addEscapingUse(Phi->getOperandUse(2*ii)); + + if (MD) + MD->invalidateCachedPointerInfo(Phi); + } VN.erase(CurInst); erase_table(ValNo, CurInst, CurrentBlock); |
