1 files changed, 18 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index d3aea37f944..24ddfb9585c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -4532,6 +4532,24 @@ void SelectionDAGLegalize::PromoteNode(SDNode *Node) {
     Results.push_back(CvtVec);
     break;
   }
+  case ISD::ATOMIC_SWAP: {
+    AtomicSDNode *AM = cast<AtomicSDNode>(Node);
+    SDLoc SL(Node);
+    SDValue CastVal = DAG.getNode(ISD::BITCAST, SL, NVT, AM->getVal());
+    assert(NVT.getSizeInBits() == OVT.getSizeInBits() &&
+           "unexpected promotion type");
+    assert(AM->getMemoryVT().getSizeInBits() == NVT.getSizeInBits() &&
+           "unexpected atomic_swap with illegal type");
+
+    SDValue NewAtomic
+      = DAG.getAtomic(ISD::ATOMIC_SWAP, SL, NVT,
+                      DAG.getVTList(NVT, MVT::Other),
+                      { AM->getChain(), AM->getBasePtr(), CastVal },
+                      AM->getMemOperand());
+    Results.push_back(DAG.getNode(ISD::BITCAST, SL, OVT, NewAtomic));
+    Results.push_back(NewAtomic.getValue(1));
+    break;
+  }
   }
 
   // Replace the original node with the legalized result.