diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 9e06f0fd6f9..ef191580568 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -14554,6 +14554,12 @@ SDValue DAGCombiner::visitINSERT_SUBVECTOR(SDNode *N) { if (N1.isUndef()) return N0; + // If this is an insert of an extracted vector into an undef vector, we can + // just use the input to the extract. + if (N0.isUndef() && N1.getOpcode() == ISD::EXTRACT_SUBVECTOR && + N1.getOperand(1) == N2 && N1.getOperand(0).getValueType() == VT) + return N1.getOperand(0); + // Combine INSERT_SUBVECTORs where we are inserting to the same index. // INSERT_SUBVECTOR( INSERT_SUBVECTOR( Vec, SubOld, Idx ), SubNew, Idx ) // --> INSERT_SUBVECTOR( Vec, SubNew, Idx ) |
