Fix a DAG combine bug visitBRCOND() is transforming br(xor(x, y)) to br(x != y).
It cahced XOR's operands before calling visitXOR() but failed to update the
operands when visitXOR changed the XOR node.
rdar://12968664
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171999 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index ff00d0d..359c4cf 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6735,18 +6735,24 @@
if (Op0.getOpcode() == Op1.getOpcode()) {
// Avoid missing important xor optimizations.
SDValue Tmp = visitXOR(TheXor);
- if (Tmp.getNode() && Tmp.getNode() != TheXor) {
- DEBUG(dbgs() << "\nReplacing.8 ";
- TheXor->dump(&DAG);
- dbgs() << "\nWith: ";
- Tmp.getNode()->dump(&DAG);
- dbgs() << '\n');
- WorkListRemover DeadNodes(*this);
- DAG.ReplaceAllUsesOfValueWith(N1, Tmp);
- removeFromWorkList(TheXor);
- DAG.DeleteNode(TheXor);
- return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
- MVT::Other, Chain, Tmp, N2);
+ if (Tmp.getNode()) {
+ if (Tmp.getNode() != TheXor) {
+ DEBUG(dbgs() << "\nReplacing.8 ";
+ TheXor->dump(&DAG);
+ dbgs() << "\nWith: ";
+ Tmp.getNode()->dump(&DAG);
+ dbgs() << '\n');
+ WorkListRemover DeadNodes(*this);
+ DAG.ReplaceAllUsesOfValueWith(N1, Tmp);
+ removeFromWorkList(TheXor);
+ DAG.DeleteNode(TheXor);
+ return DAG.getNode(ISD::BRCOND, N->getDebugLoc(),
+ MVT::Other, Chain, Tmp, N2);
+ }
+
+ // visitXOR has changed XOR's operands.
+ Op0 = TheXor->getOperand(0);
+ Op1 = TheXor->getOperand(1);
}
}