diff options
| 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 | c65c747bc4ee7d3ca8463d33708bbb2aed38a809 (patch) | |
| tree | b4fe02a85576afb4210e7f0a704a7c7a46cf4804 /lib/Analysis/InstructionSimplify.cpp | |
| parent | cb9fed665550376b7c65c7e1157a58911193e2e2 (diff) | |
Fold icmp ugt (udiv X, Y), X to false. Spotted by my super-optimizer
in 186.crafty.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143209 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/Analysis/InstructionSimplify.cpp')
| -rw-r--r-- | lib/Analysis/InstructionSimplify.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp index 31cbbba596..6bef0aedee 100644 --- a/lib/Analysis/InstructionSimplify.cpp +++ b/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()) { |