diff options
Diffstat (limited to 'lib/Transforms')
| -rw-r--r-- | lib/Transforms/Scalar/InstructionCombining.cpp | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp index 9e40dc3239..c1eb3ebe45 100644 --- a/lib/Transforms/Scalar/InstructionCombining.cpp +++ b/lib/Transforms/Scalar/InstructionCombining.cpp @@ -795,10 +795,16 @@ Instruction *InstCombiner::visitSub(BinaryOperator &I) { if (BinaryOperator *Op1I = dyn_cast<BinaryOperator>(Op1)) { if (Op1I->getOpcode() == Instruction::Add && !Op0->getType()->isFloatingPoint()) { - if (Op1I->getOperand(0) == Op0) // X-(X+Y) == -Y + if (Op1I->getOperand(0) == Op0) // X-(X+Y) == -Y return BinaryOperator::createNeg(Op1I->getOperand(1), I.getName()); - else if (Op1I->getOperand(1) == Op0) // X-(Y+X) == -Y + else if (Op1I->getOperand(1) == Op0) // X-(Y+X) == -Y return BinaryOperator::createNeg(Op1I->getOperand(0), I.getName()); + else if (ConstantInt *CI1 = dyn_cast<ConstantInt>(I.getOperand(0))) { + if (ConstantInt *CI2 = dyn_cast<ConstantInt>(Op1I->getOperand(1))) + // C1-(X+C2) --> (C1-C2)-X + return BinaryOperator::createSub(ConstantExpr::getSub(CI1, CI2), + Op1I->getOperand(0)); + } } if (Op1I->hasOneUse()) { |