diff options
author | Nick Lewycky <nicholas@mxc.ca> | 2011-03-05 04:28:48 +0000 |
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committer | Nick Lewycky <nicholas@mxc.ca> | 2011-03-05 04:28:48 +0000 |
commit | 9feda1730c225589e144fb1f86a86a8cf3f39c9e (patch) | |
tree | e024f109b317ad7d10ff2c005376054d3cfa50e7 /lib/Transforms | |
parent | 874be74179b087be36a6e7869f3aa8b70732aca1 (diff) |
Try once again to optimize "icmp (srem X, Y), Y" by turning the comparison into
true/false or "icmp slt/sge Y, 0".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127063 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Transforms')
-rw-r--r-- | lib/Transforms/InstCombine/InstCombineCompares.cpp | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp index fe117c9814..239cd23a2c 100644 --- a/lib/Transforms/InstCombine/InstCombineCompares.cpp +++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp @@ -2314,6 +2314,35 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { BO0->hasOneUse() && BO1->hasOneUse()) return new ICmpInst(Pred, D, B); + BinaryOperator *SRem = NULL; + // icmp Y, (srem X, Y) + if (BO0 && BO0->getOpcode() == Instruction::SRem && + Op1 == BO0->getOperand(1)) + SRem = BO0; + // icmp (srem X, Y), Y + else if (BO1 && BO1->getOpcode() == Instruction::SRem && + Op0 == BO1->getOperand(1)) + SRem = BO1; + if (SRem) { + // We don't check hasOneUse to avoid increasing register pressure because + // the value we use is the same value this instruction was already using. + switch (SRem == BO0 ? ICmpInst::getSwappedPredicate(Pred) : Pred) { + default: break; + case ICmpInst::ICMP_EQ: + return ReplaceInstUsesWith(I, ConstantInt::getFalse(I.getContext())); + case ICmpInst::ICMP_NE: + return ReplaceInstUsesWith(I, ConstantInt::getTrue(I.getContext())); + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + return new ICmpInst(ICmpInst::ICMP_SGT, SRem->getOperand(1), + Constant::getAllOnesValue(SRem->getType())); + case ICmpInst::ICMP_SLT: + case ICmpInst::ICMP_SLE: + return new ICmpInst(ICmpInst::ICMP_SLT, SRem->getOperand(1), + Constant::getNullValue(SRem->getType())); + } + } + if (BO0 && BO1 && BO0->getOpcode() == BO1->getOpcode() && BO0->hasOneUse() && BO1->hasOneUse() && BO0->getOperand(1) == BO1->getOperand(1)) { |