diff options
| -rw-r--r-- | lib/Transforms/Scalar/DeadStoreElimination.cpp | 6 | ||||
| -rw-r--r-- | test/Transforms/DeadStoreElimination/volatile-load.ll | 8 |
2 files changed, 11 insertions, 3 deletions
diff --git a/lib/Transforms/Scalar/DeadStoreElimination.cpp b/lib/Transforms/Scalar/DeadStoreElimination.cpp index f9d1205ada..89afa911e7 100644 --- a/lib/Transforms/Scalar/DeadStoreElimination.cpp +++ b/lib/Transforms/Scalar/DeadStoreElimination.cpp @@ -326,9 +326,9 @@ bool DSE::handleEndBlock(BasicBlock& BB, // If we encounter a use of the pointer, it is no longer considered dead if (LoadInst* L = dyn_cast<LoadInst>(BBI)) { - // However, if this load is unused, we can go ahead and remove it, and - // not have to worry about it making our pointer undead! - if (L->use_empty()) { + // However, if this load is unused and not volatile, we can go ahead and remove it, + // and not have to worry about it making our pointer undead! + if (L->use_empty() && !L->isVolatile()) { MD.removeInstruction(L); // DCE instructions only used to calculate that load diff --git a/test/Transforms/DeadStoreElimination/volatile-load.ll b/test/Transforms/DeadStoreElimination/volatile-load.ll new file mode 100644 index 0000000000..c458284dca --- /dev/null +++ b/test/Transforms/DeadStoreElimination/volatile-load.ll @@ -0,0 +1,8 @@ +; RUN: llvm-as < %s | opt -dse | llvm-dis | grep {volatile load} + +@g_1 = global i32 0 + +define void @foo() nounwind { + %t = volatile load i32* @g_1 + ret void +} |