From ad6f541840015690ad1483821eb9d8e5f7e50442 Mon Sep 17 00:00:00 2001 From: Duncan Sands Date: Sat, 30 Oct 2010 12:59:44 +0000 Subject: [PATCH] If a function does a volatile load from a global constant, do not consider it to be readonly. In fact, don't even consider it to be readonly if it does a volatile load from an AllocaInst either (it is debatable as to whether readonly would be correct or not in this case; play safe for the moment). This fixes PR8279. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117783 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/IPO/FunctionAttrs.cpp | 8 ++++---- test/Transforms/FunctionAttrs/2010-10-30-volatile.ll | 10 ++++++++++ 2 files changed, 14 insertions(+), 4 deletions(-) create mode 100644 test/Transforms/FunctionAttrs/2010-10-30-volatile.ll diff --git a/lib/Transforms/IPO/FunctionAttrs.cpp b/lib/Transforms/IPO/FunctionAttrs.cpp index d4bce9e48db..39f48145af1 100644 --- a/lib/Transforms/IPO/FunctionAttrs.cpp +++ b/lib/Transforms/IPO/FunctionAttrs.cpp @@ -188,12 +188,12 @@ bool FunctionAttrs::AddReadAttrs(const CallGraphSCC &SCC) { continue; } } else if (LoadInst *LI = dyn_cast(I)) { - // Ignore loads from local memory. - if (PointsToLocalMemory(LI->getPointerOperand())) + // Ignore non-volatile loads from local memory. + if (!LI->isVolatile() && PointsToLocalMemory(LI->getPointerOperand())) continue; } else if (StoreInst *SI = dyn_cast(I)) { - // Ignore stores to local memory. - if (PointsToLocalMemory(SI->getPointerOperand())) + // Ignore non-volatile stores to local memory. + if (!SI->isVolatile() && PointsToLocalMemory(SI->getPointerOperand())) continue; } diff --git a/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll b/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll new file mode 100644 index 00000000000..f21fabc493c --- /dev/null +++ b/test/Transforms/FunctionAttrs/2010-10-30-volatile.ll @@ -0,0 +1,10 @@ +; RUN: opt < %s -functionattrs -S | FileCheck %s +; PR8279 + +@g = constant i32 1 + +define void @foo() { +; CHECK: void @foo() { + %tmp = volatile load i32* @g + ret void +}