From e331a65c794c93b7c7792b7ba08ab6069b9c086d Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Tue, 29 Apr 2008 04:58:38 +0000 Subject: [PATCH] don't delete the last store to an alloca if the store is volatile. llvm-svn: 50390 --- llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 2 +- .../Transforms/InstCombine/2008-04-28-VolatileStore.ll | 8 ++++++++ 2 files changed, 9 insertions(+), 1 deletion(-) create mode 100644 llvm/test/Transforms/InstCombine/2008-04-28-VolatileStore.ll diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index 655ab102599f..c707e6ee6705 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -10311,7 +10311,7 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) { // If the RHS is an alloca with a single use, zapify the store, making the // alloca dead. - if (Ptr->hasOneUse()) { + if (Ptr->hasOneUse() && !SI.isVolatile()) { if (isa(Ptr)) { EraseInstFromFunction(SI); ++NumCombined; diff --git a/llvm/test/Transforms/InstCombine/2008-04-28-VolatileStore.ll b/llvm/test/Transforms/InstCombine/2008-04-28-VolatileStore.ll new file mode 100644 index 000000000000..9bfe7aa14148 --- /dev/null +++ b/llvm/test/Transforms/InstCombine/2008-04-28-VolatileStore.ll @@ -0,0 +1,8 @@ +; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {volatile store} + +define void @test() { + %votf = alloca <4 x float> ; <<4 x float>*> [#uses=1] + volatile store <4 x float> zeroinitializer, <4 x float>* %votf, align 16 + ret void +} +