diff options
| author | David Majnemer <david.majnemer@gmail.com> | 2014-07-02 06:42:13 +0000 |
|---|---|---|
| committer | David Majnemer <david.majnemer@gmail.com> | 2014-07-02 06:42:13 +0000 |
| commit | f28e2a4282c586ab41f39c177ca9bebc9244c53f (patch) | |
| tree | 1a69867fb73c64ada122852a375d355c7705e60d /llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | |
| parent | c1bedac3bdeadec448266cf372c2437e8e3692b8 (diff) | |
| download | bcm5719-llvm-f28e2a4282c586ab41f39c177ca9bebc9244c53f.tar.gz bcm5719-llvm-f28e2a4282c586ab41f39c177ca9bebc9244c53f.zip | |
InstCombine: Optimize x/INT_MIN to x==INT_MIN
The result of x/INT_MIN is either 0 or 1, we can just use an icmp
instead.
llvm-svn: 212167
Diffstat (limited to 'llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp')
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp index 497c0b49ab3..6c6e7d81516 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp @@ -993,6 +993,10 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) { } if (Constant *RHS = dyn_cast<Constant>(Op1)) { + // X/INT_MIN -> X == INT_MIN + if (RHS->isMinSignedValue()) + return new ZExtInst(Builder->CreateICmpEQ(Op0, Op1), I.getType()); + // -X/C --> X/-C provided the negation doesn't overflow. if (SubOperator *Sub = dyn_cast<SubOperator>(Op0)) if (match(Sub->getOperand(0), m_Zero()) && Sub->hasNoSignedWrap()) |
