diff options
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/InstructionCombining.cpp | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp index e65cfac..727f7bd 100644 --- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp @@ -5480,6 +5480,45 @@ Instruction *InstCombiner::visitICmpInst(ICmpInst &I) { return R; } + // See if it's the same type of instruction on the left and right. + if (BinaryOperator *Op0I = dyn_cast<BinaryOperator>(Op0)) { + if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) { + if (Op0I->getOpcode() == Op1I->getOpcode() && Op0I->hasOneUse() && + Op1I->hasOneUse() && Op0I->getOperand(1) == Op1I->getOperand(1) && + I.isEquality()) { + switch (Op0I->getOpcode()) { + default: break; + case Instruction::Add: + case Instruction::Sub: + case Instruction::Xor: + // a+x icmp eq/ne b+x --> a icmp b + return new ICmpInst(I.getPredicate(), Op0I->getOperand(0), + Op1I->getOperand(0)); + break; + case Instruction::Mul: + if (ConstantInt *CI = dyn_cast<ConstantInt>(Op0I->getOperand(1))) { + // a * Cst icmp eq/ne b * Cst --> a & 0x7f icmp b & 0x7f + if (!CI->isZero() && !CI->isOne()) { + const APInt &AP = CI->getValue(); + ConstantInt *Mask = ConstantInt::get( + APInt::getLowBitsSet(AP.getBitWidth(), + AP.getBitWidth() - + AP.countTrailingZeros())); + Instruction *And1 = BinaryOperator::CreateAnd(Op0I->getOperand(0), + Mask); + Instruction *And2 = BinaryOperator::CreateAnd(Op1I->getOperand(0), + Mask); + InsertNewInstBefore(And1, I); + InsertNewInstBefore(And2, I); + return new ICmpInst(I.getPredicate(), And1, And2); + } + } + break; + } + } + } + } + // ~x < ~y --> y < x { Value *A, *B; if (match(Op0, m_Not(m_Value(A))) && |