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| author | Craig Topper <craig.topper@intel.com> | 2017-12-11 08:33:20 +0000 |
|---|---|---|
| committer | Craig Topper <craig.topper@intel.com> | 2017-12-11 08:33:20 +0000 |
| commit | ad45bf5895182563b2d107e4ecb76d0e340ebd17 (patch) | |
| tree | 72a939dc51278ff2055ab7cff68a9eeaf66240c6 /llvm/lib/CodeGen | |
| parent | 65ed4d4492321f3f6f0417dc9be4c5e5cc910b1e (diff) | |
| download | bcm5719-llvm-ad45bf5895182563b2d107e4ecb76d0e340ebd17.tar.gz bcm5719-llvm-ad45bf5895182563b2d107e4ecb76d0e340ebd17.zip | |
[DAGCombiner] Support folding (mulhs/u X, 0)->0 for vectors.
We should probably also fold (mulhs/u X, 1) for vectors, but that's harder.
llvm-svn: 320344
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 2170670a0b6..4cc86ed2d36 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3099,6 +3099,14 @@ SDValue DAGCombiner::visitMULHS(SDNode *N) { EVT VT = N->getValueType(0); SDLoc DL(N); + if (VT.isVector()) { + // fold (mulhs x, 0) -> 0 + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N1; + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N0; + } + // fold (mulhs x, 0) -> 0 if (isNullConstant(N1)) return N1; @@ -3138,6 +3146,14 @@ SDValue DAGCombiner::visitMULHU(SDNode *N) { EVT VT = N->getValueType(0); SDLoc DL(N); + if (VT.isVector()) { + // fold (mulhu x, 0) -> 0 + if (ISD::isBuildVectorAllZeros(N1.getNode())) + return N1; + if (ISD::isBuildVectorAllZeros(N0.getNode())) + return N0; + } + // fold (mulhu x, 0) -> 0 if (isNullConstant(N1)) return N1; |
