1 files changed, 29 insertions, 4 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 077339a346c..dc1e8d3d241 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4658,9 +4658,26 @@ void SelectionDAGBuilder::visitAtomicLoad(const LoadInst &I) {
                            AAMDNodes(), nullptr, SSID, Order);
 
   InChain = TLI.prepareVolatileOrAtomicLoad(InChain, dl, DAG);
-  SDValue L =
-      DAG.getAtomic(ISD::ATOMIC_LOAD, dl, MemVT, MemVT, InChain,
-                    getValue(I.getPointerOperand()), MMO);
+
+  SDValue Ptr = getValue(I.getPointerOperand());
+
+  if (TLI.lowerAtomicLoadAsLoadSDNode(I)) {
+    // TODO: Once this is better exercised by tests, it should be merged with
+    // the normal path for loads to prevent future divergence.
+    SDValue L = DAG.getLoad(MemVT, dl, InChain, Ptr, MMO);
+    if (MemVT != VT)
+      L = DAG.getPtrExtOrTrunc(L, dl, VT);
+
+    setValue(&I, L);
+    if (!I.isUnordered()) {
+      SDValue OutChain = L.getValue(1);
+      DAG.setRoot(OutChain);
+    }
+    return;
+  }
+  
+  SDValue L = DAG.getAtomic(ISD::ATOMIC_LOAD, dl, MemVT, MemVT, InChain,
+                            Ptr, MMO);
 
   SDValue OutChain = L.getValue(1);
   if (MemVT != VT)
@@ -4699,9 +4716,17 @@ void SelectionDAGBuilder::visitAtomicStore(const StoreInst &I) {
   SDValue Val = getValue(I.getValueOperand());
   if (Val.getValueType() != MemVT)
     Val = DAG.getPtrExtOrTrunc(Val, dl, MemVT);
+  SDValue Ptr = getValue(I.getPointerOperand());
 
+  if (TLI.lowerAtomicStoreAsStoreSDNode(I)) {
+    // TODO: Once this is better exercised by tests, it should be merged with
+    // the normal path for stores to prevent future divergence.
+    SDValue S = DAG.getStore(InChain, dl, Val, Ptr, MMO);
+    DAG.setRoot(S);
+    return;
+  }
   SDValue OutChain = DAG.getAtomic(ISD::ATOMIC_STORE, dl, MemVT, InChain,
-                                   getValue(I.getPointerOperand()), Val, MMO);
+                                   Ptr, Val, MMO);
 
 
   DAG.setRoot(OutChain);