From b253a8b382824586066a299e1279838f41117e3b Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 29 Dec 2007 07:15:45 +0000
Subject: [PATCH] make sure not to zap volatile stores, thanks a lot to Dale
 for noticing this!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45402 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0ee45575633..cfa46e6b591 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4252,7 +4252,8 @@ SDOperand DAGCombiner::visitSTORE(SDNode *N) {
   if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(Value)) {
     if (Chain.Val == Ld && Ld->getBasePtr() == Ptr &&
         ST->getAddressingMode() == ISD::UNINDEXED &&
-        ST->getStoredVT() == Ld->getLoadedVT()) {
+        ST->getStoredVT() == Ld->getLoadedVT() &&
+        !ST->isVolatile()) {
       // The store is dead, remove it.
       return Chain;
     }
-- 
2.34.1