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| author | Simon Pilgrim <llvm-dev@redking.me.uk> | 2018-08-13 13:12:25 +0000 |
|---|---|---|
| committer | Simon Pilgrim <llvm-dev@redking.me.uk> | 2018-08-13 13:12:25 +0000 |
| commit | 26e3d3f1c855bf56420916bbc7cec808eed5c6fe (patch) | |
| tree | 5d961e091c89baa5bdd1348e297c58e0a84f8519 /llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | 0c23dc59fcf55491063e94b2f474e55112876c8e (diff) | |
| download | bcm5719-llvm-26e3d3f1c855bf56420916bbc7cec808eed5c6fe.tar.gz bcm5719-llvm-26e3d3f1c855bf56420916bbc7cec808eed5c6fe.zip | |
[DAGCombiner] simplifyDivRem - add comment describing divide by undef/zero combine. NFC.
llvm-svn: 339561
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index de3aefadb2b..aaff88ab5ea 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3076,6 +3076,11 @@ static SDValue simplifyDivRem(SDNode *N, SelectionDAG &DAG) { EVT VT = N->getValueType(0); SDLoc DL(N); + // X / undef -> undef + // X % undef -> undef + // X / 0 -> undef + // X % 0 -> undef + // NOTE: This includes vectors where any divisor element is zero/undef. if (DAG.isUndef(N->getOpcode(), {N0, N1})) return DAG.getUNDEF(VT); |
