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| author | Simon Pilgrim <llvm-dev@redking.me.uk> | 2019-01-14 15:43:34 +0000 |
|---|---|---|
| committer | Simon Pilgrim <llvm-dev@redking.me.uk> | 2019-01-14 15:43:34 +0000 |
| commit | a1bd4a6ba46672564261f40f4ab9a9b1d0ae35d0 (patch) | |
| tree | 2957ad75373512e19838ffb71deafc2a054af66e /llvm/lib/CodeGen | |
| parent | fa1f5187482c12e949953e0b65f652af022e9d43 (diff) | |
| download | bcm5719-llvm-a1bd4a6ba46672564261f40f4ab9a9b1d0ae35d0.tar.gz bcm5719-llvm-a1bd4a6ba46672564261f40f4ab9a9b1d0ae35d0.zip | |
[DAGCombiner] Add (sub_sat x, x) -> 0 combine
llvm-svn: 351073
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index d564bda7987..b1770920f06 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -2800,6 +2800,10 @@ SDValue DAGCombiner::visitSUBSAT(SDNode *N) { if (N0.isUndef() || N1.isUndef()) return DAG.getConstant(0, DL, VT); + // fold (sub_sat x, x) -> 0 + if (N0 == N1) + return DAG.getConstant(0, DL, VT); + if (DAG.isConstantIntBuildVectorOrConstantInt(N0) && DAG.isConstantIntBuildVectorOrConstantInt(N1)) { // fold (sub_sat c1, c2) -> c3 |
