Add comments and test for atomic load/store and mem2reg.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137690 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eli Friedman
2011-08-15 23:55:52 +00:00
parent 02e603f87a
commit fd06b3cfa1
2 changed files with 16 additions and 0 deletions

View File

@@ -86,11 +86,15 @@ bool llvm::isAllocaPromotable(const AllocaInst *AI) {
UI != UE; ++UI) { // Loop over all of the uses of the alloca
const User *U = *UI;
if (const LoadInst *LI = dyn_cast<LoadInst>(U)) {
// Note that atomic loads can be transformed; atomic semantics do
// not have any meaning for a local alloca.
if (LI->isVolatile())
return false;
} else if (const StoreInst *SI = dyn_cast<StoreInst>(U)) {
if (SI->getOperand(0) == AI)
return false; // Don't allow a store OF the AI, only INTO the AI.
// Note that atomic stores can be transformed; atomic semantics do
// not have any meaning for a local alloca.
if (SI->isVolatile())
return false;
} else if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(U)) {