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| author | Duncan Sands <baldrick@free.fr> | 2011-10-28 18:17:44 +0000 |
|---|---|---|
| committer | Duncan Sands <baldrick@free.fr> | 2011-10-28 18:17:44 +0000 |
| commit | 92af0a8a7fcf1dd426f11afd54796abe241827c2 (patch) | |
| tree | 28ebbeb7915d5be7c62df0cc963d31f477a595cf /llvm/lib/Analysis/InstructionSimplify.cpp | |
| parent | dde461c8b10b2d49921e3b17dfce4d5284331d88 (diff) | |
| download | bcm5719-llvm-92af0a8a7fcf1dd426f11afd54796abe241827c2.tar.gz bcm5719-llvm-92af0a8a7fcf1dd426f11afd54796abe241827c2.zip | |
Fold icmp ugt (udiv X, Y), X to false. Spotted by my super-optimizer
in 186.crafty.
llvm-svn: 143209
Diffstat (limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | llvm/lib/Analysis/InstructionSimplify.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp index 31cbbba5962..6bef0aedeec 100644 --- a/llvm/lib/Analysis/InstructionSimplify.cpp +++ b/llvm/lib/Analysis/InstructionSimplify.cpp @@ -1574,6 +1574,9 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, // 'srem x, CI2' produces (-|CI2|, |CI2|). Upper = CI2->getValue().abs(); Lower = (-Upper) + 1; + } else if (match(LHS, m_UDiv(m_ConstantInt(CI2), m_Value()))) { + // 'udiv CI2, x' produces [0, CI2]. + Upper = CI2->getValue(); } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) { // 'udiv x, CI2' produces [0, UINT_MAX / CI2]. APInt NegOne = APInt::getAllOnesValue(Width); @@ -1880,6 +1883,15 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS, } } + // x udiv y <=u x. + if (LBO && match(LBO, m_UDiv(m_Specific(RHS), m_Value()))) { + // icmp pred (X /u Y), X + if (Pred == ICmpInst::ICMP_UGT) + return getFalse(ITy); + if (Pred == ICmpInst::ICMP_ULE) + return getTrue(ITy); + } + if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() && LBO->getOperand(1) == RBO->getOperand(1)) { switch (LBO->getOpcode()) { |
