From 729b5ff1c51532b0301074a9fe3b80304c114b01 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Mon, 31 Mar 2008 20:32:52 +0000
Subject: Fix a DAGCombiner optimization to respect volatile qualification.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48994 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

(limited to 'lib/CodeGen')

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9f44c6a..4eccb81 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4387,7 +4387,8 @@ SDOperand DAGCombiner::visitLOAD(SDNode *N) {
   // value.
   // TODO: Handle store large -> read small portion.
   // TODO: Handle TRUNCSTORE/LOADEXT
-  if (LD->getExtensionType() == ISD::NON_EXTLOAD) {
+  if (LD->getExtensionType() == ISD::NON_EXTLOAD &&
+      !LD->isVolatile()) {
     if (ISD::isNON_TRUNCStore(Chain.Val)) {
       StoreSDNode *PrevST = cast<StoreSDNode>(Chain);
       if (PrevST->getBasePtr() == Ptr &&
-- 
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