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| author | David Bolvansky <david.bolvansky@gmail.com> | 2018-10-31 14:18:57 +0000 |
|---|---|---|
| committer | David Bolvansky <david.bolvansky@gmail.com> | 2018-10-31 14:18:57 +0000 |
| commit | d0080c3a5f9b9f2143505bf1aca4ce5a0303da25 (patch) | |
| tree | 06a778bdb04abb3f281338675b7c3d68bf4f5568 /llvm/lib/CodeGen | |
| parent | 103a0559b752440e62323edbec47a59ae2dd24ef (diff) | |
| download | bcm5719-llvm-d0080c3a5f9b9f2143505bf1aca4ce5a0303da25.tar.gz bcm5719-llvm-d0080c3a5f9b9f2143505bf1aca4ce5a0303da25.zip | |
[DAGCombiner] Fold 0 div/rem X to 0
Reviewers: RKSimon, spatel, javed.absar, craig.topper, t.p.northover
Reviewed By: RKSimon
Subscribers: craig.topper, llvm-commits
Differential Revision: https://reviews.llvm.org/D52504
llvm-svn: 345721
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index fba2aa9cb52..e6ea4898717 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3128,8 +3128,11 @@ static SDValue simplifyDivRem(SDNode *N, SelectionDAG &DAG) { if (N0.isUndef()) return DAG.getConstant(0, DL, VT); - // TODO: 0 / X -> 0 - // TODO: 0 % X -> 0 + // 0 / X -> 0 + // 0 % X -> 0 + ConstantSDNode *N0C = isConstOrConstSplat(N0); + if (N0C && N0C->isNullValue()) + return N0; // X / X -> 1 // X % X -> 0 |
