Fix DAG combine which creates illegal vector shuffles. Patch by Heikki Kultala.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153035 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 32b9fa4..1bd1b95 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -7473,6 +7473,12 @@
// Check to see if this is a BUILD_VECTOR of a bunch of EXTRACT_VECTOR_ELT
// operations. If so, and if the EXTRACT_VECTOR_ELT vector inputs come from
// at most two distinct vectors, turn this into a shuffle node.
+
+ // May only combine to shuffle after legalize if shuffle is legal.
+ if (LegalOperations &&
+ !TLI.isOperationLegalOrCustom(ISD::VECTOR_SHUFFLE, VT))
+ return SDValue();
+
SDValue VecIn1, VecIn2;
for (unsigned i = 0; i != NumInScalars; ++i) {
// Ignore undef inputs.