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| author | Simon Pilgrim <llvm-dev@redking.me.uk> | 2018-07-11 09:22:42 +0000 |
|---|---|---|
| committer | Simon Pilgrim <llvm-dev@redking.me.uk> | 2018-07-11 09:22:42 +0000 |
| commit | df9d59771be1fac62718023528c678bcaf7c28b4 (patch) | |
| tree | ce5a9a78277e4ceb694d7de8179350f1de2a0f2c /llvm/lib/CodeGen | |
| parent | 97cf111689572b6c14c04554e1194406e758ca96 (diff) | |
| download | bcm5719-llvm-df9d59771be1fac62718023528c678bcaf7c28b4.tar.gz bcm5719-llvm-df9d59771be1fac62718023528c678bcaf7c28b4.zip | |
[DAGCombiner] Support non-uniform X%C -> X-(X/C)*C folds
First stage in PR38057 - support non-uniform constant vectors in the combine to reuse the division-by-constant logic.
We can definitely do better for srem pow2 remainders (and avoid that extra multiply....) but this at least helps keep everything on the vector unit.
Differential Revision: https://reviews.llvm.org/D48975
llvm-svn: 336774
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index fa0c4661e14..b2525b79807 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3297,7 +3297,10 @@ SDValue DAGCombiner::visitREM(SDNode *N) { // by skipping the simplification if isIntDivCheap(). When div is not cheap, // combine will not return a DIVREM. Regardless, checking cheapness here // makes sense since the simplification results in fatter code. - if (N1C && !N1C->isNullValue() && !TLI.isIntDivCheap(VT, Attr)) { + // TODO: replace matchUnaryPredicate with SelectionDAG::isKnownNeverZero(N1). + if (ISD::matchUnaryPredicate( + N1, [](ConstantSDNode *C) { return !C->isNullValue(); }) && + !TLI.isIntDivCheap(VT, Attr)) { SDValue OptimizedDiv = isSigned ? visitSDIVLike(N0, N1, N) : visitUDIVLike(N0, N1, N); if (OptimizedDiv.getNode() && OptimizedDiv.getOpcode() != ISD::UDIVREM && |
