diff options
| author | Craig Topper <craig.topper@gmail.com> | 2012-12-10 08:12:29 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@gmail.com> | 2012-12-10 08:12:29 +0000 |
| commit | d8005db486025146ce451c795d838258264f28b4 (patch) | |
| tree | fef5a4b463560d7f79b658bf05b95e4dd57e6c49 /llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | f9573f1174ddc104386eaa908c0495a74beffdb1 (diff) | |
| download | bcm5719-llvm-d8005db486025146ce451c795d838258264f28b4.tar.gz bcm5719-llvm-d8005db486025146ce451c795d838258264f28b4.zip | |
Teach DAG combine to handle vector add/sub with vectors of all 0s.
llvm-svn: 169727
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 6a433370412..e774c138d28 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1381,6 +1381,12 @@ SDValue DAGCombiner::visitADD(SDNode *N) { if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; + + // fold (add x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N1; } // fold (add x, undef) -> undef @@ -1624,6 +1630,10 @@ SDValue DAGCombiner::visitSUB(SDNode *N) { if (VT.isVector()) { SDValue FoldedVOp = SimplifyVBinOp(N); if (FoldedVOp.getNode()) return FoldedVOp; + + // fold (sub x, 0) -> x, vector edition + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N0; } // fold (sub x, x) -> 0 |
