The change for PR9190 wasn't quite right. We need to avoid making the
transformation if we can't legally create a build vector of the correct
type. Check that we can make the transformation first, and add a TODO to
refactor this code with similar cases.
Fixes: PR9223 and rdar://9000350
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125631 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index f452d6a..e213d72 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1532,8 +1532,18 @@
}
// fold (sub x, x) -> 0
- if (N0 == N1)
- return DAG.getConstant(0, N->getValueType(0), LegalTypes);
+ // FIXME: Refactor this and xor and other similar operations together.
+ if (N0 == N1) {
+ if (!VT.isVector()) {
+ return DAG.getConstant(0, VT);
+ } else if (!LegalOperations || TLI.isOperationLegal(ISD::BUILD_VECTOR, VT)){
+ // Produce a vector of zeros.
+ SDValue El = DAG.getConstant(0, VT.getVectorElementType());
+ std::vector<SDValue> Ops(VT.getVectorNumElements(), El);
+ return DAG.getNode(ISD::BUILD_VECTOR, N->getDebugLoc(), VT,
+ &Ops[0], Ops.size());
+ }
+ }
// fold (sub c1, c2) -> c1-c2
if (N0C && N1C)
return DAG.FoldConstantArithmetic(ISD::SUB, VT, N0C, N1C);