SimplifyCFG: don't turn volatile stores to null/undef into unreachable. Fixes PR7369.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105914 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/SimplifyCFGPass.cpp b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
index 97441008c46c74c408a1ec4d43311f0435f99d41..49d93a2fcc271a6ad12ca5036ccf437a67e46469 100644 (file)
--- a/lib/Transforms/Scalar/SimplifyCFGPass.cpp
+++ b/lib/Transforms/Scalar/SimplifyCFGPass.cpp
@@ -137,6 +137,9 @@ static bool MarkAliveBlocks(BasicBlock *BB,
       // they should be changed to unreachable by passes that can't modify the
       // CFG.
       if (StoreInst *SI = dyn_cast<StoreInst>(BBI)) {
+        // Don't touch volatile stores.
+        if (SI->isVolatile()) continue;
+
         Value *Ptr = SI->getOperand(1);
         
         if (isa<UndefValue>(Ptr) ||