diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 6f940760e0..3cf7a2be6f 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3030,6 +3030,9 @@ SDValue DAGCombiner::visitSHL(SDNode *N) { // fold (shl x, 0) -> x if (N1C && N1C->isNullValue()) return N0; + // fold (shl undef, x) -> 0 + if (N0.getOpcode() == ISD::UNDEF) + return DAG.getConstant(0, VT); // if (shl x, c) is known to be zero, return 0 if (DAG.MaskedValueIsZero(SDValue(N, 0), APInt::getAllOnesValue(OpSizeInBits))) |