Fix slightly too aggressive conact_vector optimization.
(Would sometimes optimize away conacts used to extend a vector with undef values)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@181186 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 85f5df9..2e09ec0 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -9145,6 +9145,12 @@
return SDValue();
} else {
SingleSource = Op.getOperand(0);
+
+ // Check the source type is the same as the type of the result.
+ // If not, this concat may extend the vector, so we can not
+ // optimize it away.
+ if (SingleSource.getValueType() != N->getValueType(0))
+ return SDValue();
}
unsigned IdentityIndex = i * PartNumElem;