Fix an issue with the IR sink pass found by inspection. (I'm not sure anyone is actually using this, but might as well fix it since I found the issue.)

llvm-svn: 138965

1 files changed, 6 insertions, 7 deletions

diff --git a/llvm/lib/Transforms/Scalar/Sink.cpp b/llvm/lib/Transforms/Scalar/Sink.cpp
index 705f4420490..c83f56c4d2d 100644
--- a/llvm/lib/Transforms/Scalar/Sink.cpp
+++ b/llvm/lib/Transforms/Scalar/Sink.cpp
@@ -153,9 +153,13 @@ bool Sinking::ProcessBlock(BasicBlock &BB) {
 
 static bool isSafeToMove(Instruction *Inst, AliasAnalysis *AA,
                          SmallPtrSet<Instruction *, 8> &Stores) {
-  if (LoadInst *L = dyn_cast<LoadInst>(Inst)) {
-    if (L->isVolatile()) return false;
 
+  if (Inst->mayWriteToMemory()) {
+    Stores.insert(Inst);
+    return false;
+  }
+
+  if (LoadInst *L = dyn_cast<LoadInst>(Inst)) {
     AliasAnalysis::Location Loc = AA->getLocation(L);
     for (SmallPtrSet<Instruction *, 8>::iterator I = Stores.begin(),
          E = Stores.end(); I != E; ++I)
@@ -163,11 +167,6 @@ static bool isSafeToMove(Instruction *Inst, AliasAnalysis *AA,
         return false;
   }
 
-  if (Inst->mayWriteToMemory()) {
-    Stores.insert(Inst);
-    return false;
-  }
-
   if (isa<TerminatorInst>(Inst) || isa<PHINode>(Inst))
     return false;