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path: root/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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-rw-r--r--lib/CodeGen/SelectionDAG/DAGCombiner.cpp10
1 files changed, 10 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6a43337041..e774c138d2 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/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