diff options
Diffstat (limited to 'lib/Transforms/Scalar/DeadStoreElimination.cpp')
| -rw-r--r-- | lib/Transforms/Scalar/DeadStoreElimination.cpp | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp index dd66416e7f..d9f5bc51cb 100644 --- a/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -191,6 +191,7 @@ static bool isStoreAtLeastAsWideAs(Instruction *I1, Instruction *I2, I1Size >= I2Size; } + bool DSE::runOnBasicBlock(BasicBlock &BB) { MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>(); TD = getAnalysisIfAvailable<TargetData>(); @@ -239,7 +240,7 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) { } } } - + if (!InstDep.isDef()) { // If this is a may-aliased store that is clobbering the store value, we // can keep searching past it for another must-aliased pointer that stores @@ -250,12 +251,16 @@ bool DSE::runOnBasicBlock(BasicBlock &BB) { // we can remove the first store to P even though we don't know if P and Q // alias. if (StoreInst *SI = dyn_cast<StoreInst>(Inst)) { - AliasAnalysis::Location Loc = - getAnalysis<AliasAnalysis>().getLocation(SI); - while (InstDep.isClobber() && isa<StoreInst>(InstDep.getInst()) && - InstDep.getInst() != &BB.front()) - InstDep = MD.getPointerDependencyFrom(Loc, false, InstDep.getInst(), - &BB); + AliasAnalysis &AA = getAnalysis<AliasAnalysis>(); + AliasAnalysis::Location Loc = AA.getLocation(SI); + while (InstDep.isClobber() && InstDep.getInst() != &BB.front()) { + // Can't look past this instruction if it might read 'Loc'. + if (AA.getModRefInfo(InstDep.getInst(), Loc) & AliasAnalysis::Ref) + break; + + InstDep = MD.getPointerDependencyFrom(Loc, false, + InstDep.getInst(), &BB); + } } } |