diff options
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 963a1feba8..1b00855a67 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1103,6 +1103,10 @@ SDOperand DAGCombiner::visitSUB(SDNode *N) { // fold (sub x, x) -> 0 if (N0 == N1) + if (ISD::isBuildVectorAllZeros(N0.Val)) + // Zero vectors might be normalized to a particular vector type to ensure + // they are CSE'd. Return it as it is. + return N0; return DAG.getConstant(0, N->getValueType(0)); // fold (sub c1, c2) -> c1-c2 if (N0C && N1C) |