-bool NaryReassociate::isKnownNonNegative(Value *V, Instruction *Ctxt) {
- bool NonNegative, Negative;
- // TODO: ComputeSignBits is expensive. Consider caching the results.
- ComputeSignBit(V, NonNegative, Negative, *DL, 0, AC, Ctxt, DT);
- return NonNegative;
-}
-
-bool NaryReassociate::maySignOverflow(AddOperator *AO, Instruction *Ctxt) {
- if (AO->hasNoSignedWrap())
- return false;
-
- Value *LHS = AO->getOperand(0), *RHS = AO->getOperand(1);
- // If LHS or RHS has the same sign as the sum, AO doesn't sign overflow.
- // TODO: handle the negative case as well.
- if (isKnownNonNegative(AO, Ctxt) &&
- (isKnownNonNegative(LHS, Ctxt) || isKnownNonNegative(RHS, Ctxt)))
- return false;
-
- return true;
-}
-