From 02bf06e293b1f6eebc23c3b8fcb75ebd85c92e11 Mon Sep 17 00:00:00 2001
From: Peizhao Ou <peizhaoo@uci.edu>
Date: Tue, 17 Jul 2018 12:07:00 -0700
Subject: [PATCH] Ensures non-acquire RMWs are transformed to acquire RMWs

---
 lib/CodeGen/AtomicExpandPass.cpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/lib/CodeGen/AtomicExpandPass.cpp b/lib/CodeGen/AtomicExpandPass.cpp
index 6152055a5bc..8665551bb75 100644
--- a/lib/CodeGen/AtomicExpandPass.cpp
+++ b/lib/CodeGen/AtomicExpandPass.cpp
@@ -131,6 +131,15 @@ bool AtomicExpand::runOnFunction(Function &F) {
           }
           break;
         }
+        case Instruction::AtomicRMW: {
+          auto* RMW = dyn_cast<AtomicRMWInst>(&*I);
+          if (RMW->getOrdering() == Monotonic) {
+            RMW->setOrdering(Acquire);
+          } else if (RMW->getOrdering() == Release) {
+            RMW->setOrdering(AcquireRelease);
+          }
+          break;
+        }
         default: {
           break;
         }
-- 
2.34.1