[PR27599] [SystemZ] [SelectionDAG] Fix extension of atomic cmpxchg result.
Currently, SelectionDAG assumes 8/16-bit cmpxchg returns either a sign
extended result, or a zero extended result. SystemZ takes a third
option by returning junk in the high bits (rotated contents of the other
bytes in the memory word). In that case, don't use Assert*ext, and
zero-extend the result ourselves if a comparison is needed.
Differential Revision: http://reviews.llvm.org/D19800
llvm-svn: 269075
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index a06932b..b8918d2 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -2837,25 +2837,38 @@
cast<AtomicSDNode>(Node)->getFailureOrdering(),
cast<AtomicSDNode>(Node)->getSynchScope());
+ SDValue ExtRes = Res;
SDValue LHS = Res;
SDValue RHS = Node->getOperand(1);
EVT AtomicType = cast<AtomicSDNode>(Node)->getMemoryVT();
EVT OuterType = Node->getValueType(0);
- if (TLI.hasSignExtendedAtomicOps()) {
+ switch (TLI.getExtendForAtomicOps()) {
+ case ISD::SIGN_EXTEND:
LHS = DAG.getNode(ISD::AssertSext, dl, OuterType, Res,
DAG.getValueType(AtomicType));
RHS = DAG.getNode(ISD::SIGN_EXTEND_INREG, dl, OuterType,
Node->getOperand(2), DAG.getValueType(AtomicType));
- } else {
- LHS = DAG.getNode(ISD::AssertZext, dl, OuterType, Res, DAG.getValueType(AtomicType));
+ ExtRes = LHS;
+ break;
+ 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));
+ ExtRes = LHS;
+ break;
+ case ISD::ANY_EXTEND:
+ LHS = DAG.getZeroExtendInReg(Res, dl, AtomicType);
+ RHS = DAG.getNode(ISD::ZERO_EXTEND, dl, OuterType, Node->getOperand(2));
+ break;
+ default:
+ llvm_unreachable("Invalid atomic op extension");
}
SDValue Success =
DAG.getSetCC(dl, Node->getValueType(1), LHS, RHS, ISD::SETEQ);
- Results.push_back(LHS.getValue(0));
+ Results.push_back(ExtRes.getValue(0));
Results.push_back(Success);
Results.push_back(Res.getValue(1));
break;