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| author | Simon Pilgrim <llvm-dev@redking.me.uk> | 2019-08-30 10:42:14 +0000 |
|---|---|---|
| committer | Simon Pilgrim <llvm-dev@redking.me.uk> | 2019-08-30 10:42:14 +0000 |
| commit | 7cbf823f9357cdefe30fba8981ce776dafb21958 (patch) | |
| tree | 31b2c51906ec5933404e55fd3fced3dd0cbaf317 | |
| parent | 01a3c25c27b0769f9014c07f8fd3fcc17eac6c6b (diff) | |
| download | bcm5719-llvm-7cbf823f9357cdefe30fba8981ce776dafb21958.tar.gz bcm5719-llvm-7cbf823f9357cdefe30fba8981ce776dafb21958.zip | |
[DAGCombine] visitMULHS/visitMULHU - isBuildVectorAllZeros doesn't mean node is all zeros
Return a proper zero vector, just in case some elements are undef.
Noticed by inspection after dealing with a similar issue in PR43159.
llvm-svn: 370460
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 16089999485..1b98b937ca4 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -4183,10 +4183,10 @@ SDValue DAGCombiner::visitMULHS(SDNode *N) { if (VT.isVector()) { // fold (mulhs x, 0) -> 0 - if (ISD::isBuildVectorAllZeros(N1.getNode())) - return N1; - if (ISD::isBuildVectorAllZeros(N0.getNode())) - return N0; + // do not return N0/N1, because undef node may exist. + if (ISD::isBuildVectorAllZeros(N0.getNode()) || + ISD::isBuildVectorAllZeros(N1.getNode())) + return DAG.getConstant(0, DL, VT); } // fold (mulhs x, 0) -> 0 @@ -4230,10 +4230,10 @@ SDValue DAGCombiner::visitMULHU(SDNode *N) { if (VT.isVector()) { // fold (mulhu x, 0) -> 0 - if (ISD::isBuildVectorAllZeros(N1.getNode())) - return N1; - if (ISD::isBuildVectorAllZeros(N0.getNode())) - return N0; + // do not return N0/N1, because undef node may exist. + if (ISD::isBuildVectorAllZeros(N0.getNode()) || + ISD::isBuildVectorAllZeros(N1.getNode())) + return DAG.getConstant(0, DL, VT); } // fold (mulhu x, 0) -> 0 |
