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| author | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-04-30 04:56:00 +0000 |
|---|---|---|
| committer | Sanjoy Das <sanjoy@playingwithpointers.com> | 2015-04-30 04:56:00 +0000 |
| commit | a8c178f280806d6a0fadb8067e9e433a61e3296b (patch) | |
| tree | ba0515ac8dfa5407f574d7b4cccee7632c455d25 /llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | |
| parent | 9c821037434dc106543d6905f5519b1129eb904f (diff) | |
| download | llvm-a8c178f280806d6a0fadb8067e9e433a61e3296b.zip llvm-a8c178f280806d6a0fadb8067e9e433a61e3296b.tar.gz llvm-a8c178f280806d6a0fadb8067e9e433a61e3296b.tar.bz2 | |
[InstCombine] Add a new formula for SMIN.
Summary:
After this change `MatchSelectPattern` recognizes the following form
of SMIN:
Y >s C ? ~Y : ~C == ~Y <s ~C ? ~Y : ~C = SMIN(~Y, ~C)
Reviewers: majnemer
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9352
llvm-svn: 236202
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp index b28611f..6739314 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp @@ -86,6 +86,17 @@ MatchSelectPattern(Value *V, Value *&LHS, Value *&RHS) { return (CmpLHS == FalseVal) ? SPF_ABS : SPF_NABS; } } + + // Y >s C ? ~Y : ~C == ~Y <s ~C ? ~Y : ~C = SMIN(~Y, ~C) + if (const auto *C2 = dyn_cast<ConstantInt>(FalseVal)) { + if (C1->getType() == C2->getType() && ~C1->getValue() == C2->getValue() && + (match(TrueVal, m_Not(m_Specific(CmpLHS))) || + match(CmpLHS, m_Not(m_Specific(TrueVal))))) { + LHS = TrueVal; + RHS = FalseVal; + return SPF_SMIN; + } + } } // TODO: (X > 4) ? X : 5 --> (X >= 5) ? X : 5 --> MAX(X, 5) |