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| author | Eli Friedman <efriedma@codeaurora.org> | 2016-12-15 22:41:40 +0000 |
|---|---|---|
| committer | Eli Friedman <efriedma@codeaurora.org> | 2016-12-15 22:41:40 +0000 |
| commit | 379294676dff67faf8f8e2b14b976ff44e62b7df (patch) | |
| tree | 258b73e2a9800a187f48fc90520ee5d9b8eac45f /llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | 0bd0fe4e7d3fc3d4c66dc32362c0cde892939600 (diff) | |
| download | bcm5719-llvm-379294676dff67faf8f8e2b14b976ff44e62b7df.tar.gz bcm5719-llvm-379294676dff67faf8f8e2b14b976ff44e62b7df.zip | |
Don't combine splats with other shuffles.
We sometimes end up creating shuffles which are worse than the obvious
translation of the IR.
Fixes https://llvm.org/bugs/show_bug.cgi?id=31301 .
Differential Revision: https://reviews.llvm.org/D27793
llvm-svn: 289882
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 2e9b1e88586..a0f2b63424a 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -14377,6 +14377,11 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { Level < AfterLegalizeDAG && TLI.isTypeLegal(VT)) { ShuffleVectorSDNode *OtherSV = cast<ShuffleVectorSDNode>(N0); + // Don't try to fold splats; they're likely to simplify somehow, or they + // might be free. + if (OtherSV->isSplat()) + return SDValue(); + // The incoming shuffle must be of the same type as the result of the // current shuffle. assert(OtherSV->getOperand(0).getValueType() == VT && |
