Treat lifetime begin/end markers as allocations/frees respectively for the
purposes for GVN/DSE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85383 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp
index be5f9c1..0ec0e74 100644
--- a/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -185,10 +185,9 @@
if (invariantTag == Inst) {
invariantTag = 0;
continue;
-
- // If we pass an invariant-end marker, then we've just entered an invariant
- // region and can start ignoring dependencies.
} else if (IntrinsicInst* II = dyn_cast<IntrinsicInst>(Inst)) {
+ // If we pass an invariant-end marker, then we've just entered an
+ // invariant region and can start ignoring dependencies.
if (II->getIntrinsicID() == Intrinsic::invariant_end) {
uint64_t invariantSize = ~0ULL;
if (ConstantInt* CI = dyn_cast<ConstantInt>(II->getOperand(2)))
@@ -200,6 +199,19 @@
invariantTag = II->getOperand(1);
continue;
}
+
+ // If we reach a lifetime begin or end marker, then the query ends here
+ // because the value is undefined.
+ } else if (II->getIntrinsicID() == Intrinsic::lifetime_start ||
+ II->getIntrinsicID() == Intrinsic::lifetime_end) {
+ uint64_t invariantSize = ~0ULL;
+ if (ConstantInt* CI = dyn_cast<ConstantInt>(II->getOperand(1)))
+ invariantSize = CI->getZExtValue();
+
+ AliasAnalysis::AliasResult R =
+ AA->alias(II->getOperand(2), invariantSize, MemPtr, MemSize);
+ if (R == AliasAnalysis::MustAlias)
+ return MemDepResult::getDef(II);
}
}