return BinaryOperator::CreateSDiv(Op1I->getOperand(0),
ConstantExpr::getNeg(DivRHS));
+ // 0 - (C << X) -> (-C << X)
+ if (Op1I->getOpcode() == Instruction::Shl)
+ if (ConstantInt *CSI = dyn_cast<ConstantInt>(Op0))
+ if (CSI->isZero())
+ if (Value *ShlLHSNeg = dyn_castNegVal(Op1I->getOperand(0)))
+ return BinaryOperator::CreateShl(ShlLHSNeg, Op1I->getOperand(1));
+
// X - X*C --> X * (1-C)
ConstantInt *C2 = 0;
if (dyn_castFoldableMul(Op1I, C2) == Op0) {