[LegalizeDAG] Fix ATOMIC_CMP_SWAP_WITH_SUCCESS legalization.

The code wasn't zero-extending correctly, so the comparison could
spuriously fail.

Adds some AArch64 tests to cover this case.

Inspired by D41791.

Differential Revision: https://reviews.llvm.org/D41798

llvm-svn: 322767

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index c7f31828e21..b69c362db67 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -2965,12 +2965,12 @@ bool SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     case ISD::ZERO_EXTEND:
       LHS = DAG.getNode(ISD::AssertZext, dl, OuterType, Res,
                         DAG.getValueType(AtomicType));
-      RHS = DAG.getNode(ISD::ZERO_EXTEND, dl, OuterType, Node->getOperand(2));
+      RHS = DAG.getZeroExtendInReg(Node->getOperand(2), dl, AtomicType);
       ExtRes = LHS;
       break;
     case ISD::ANY_EXTEND:
       LHS = DAG.getZeroExtendInReg(Res, dl, AtomicType);
-      RHS = DAG.getNode(ISD::ZERO_EXTEND, dl, OuterType, Node->getOperand(2));
+      RHS = DAG.getZeroExtendInReg(Node->getOperand(2), dl, AtomicType);
       break;
     default:
       llvm_unreachable("Invalid atomic op extension");