ConstantRange ConstantRange::makeICmpRegion(unsigned Pred, const ConstantRange &CR) { uint32_t W = CR.getBitWidth(); switch (Pred) { default: assert(!"Invalid ICmp predicate to makeICmpRegion()"); case ICmpInst::ICMP_EQ: return CR; case ICmpInst::ICMP_NE: if (CR.isSingleElement()) return ConstantRange(CR.getUpper(), CR.getLower()); return ConstantRange(W); case ICmpInst::ICMP_ULT: return ConstantRange(APInt::getMinValue(W), CR.getUnsignedMax()); case ICmpInst::ICMP_SLT: return ConstantRange(APInt::getSignedMinValue(W), CR.getSignedMax()); case ICmpInst::ICMP_ULE: { APInt UMax(CR.getUnsignedMax()); if (UMax.isMaxValue()) return ConstantRange(W); return ConstantRange(APInt::getMinValue(W), UMax + 1); } case ICmpInst::ICMP_SLE: { APInt SMax(CR.getSignedMax()); if (SMax.isMaxSignedValue() || (SMax+1).isMaxSignedValue()) return ConstantRange(W); return ConstantRange(APInt::getSignedMinValue(W), SMax + 1); } case ICmpInst::ICMP_UGT: return ConstantRange(CR.getUnsignedMin() + 1, APInt::getNullValue(W)); case ICmpInst::ICMP_SGT: return ConstantRange(CR.getSignedMin() + 1, APInt::getSignedMinValue(W)); case ICmpInst::ICMP_UGE: { APInt UMin(CR.getUnsignedMin()); if (UMin.isMinValue()) return ConstantRange(W); return ConstantRange(UMin, APInt::getNullValue(W)); } case ICmpInst::ICMP_SGE: { APInt SMin(CR.getSignedMin()); if (SMin.isMinSignedValue()) return ConstantRange(W); return ConstantRange(SMin, APInt::getSignedMinValue(W)); } } }
ConstantRange ConstantRange::makeGuaranteedNoWrapRegion(Instruction::BinaryOps BinOp, const ConstantRange &Other, unsigned NoWrapKind) { typedef OverflowingBinaryOperator OBO; // Computes the intersection of CR0 and CR1. It is different from // intersectWith in that the ConstantRange returned will only contain elements // in both CR0 and CR1 (i.e. SubsetIntersect(X, Y) is a *subset*, proper or // not, of both X and Y). auto SubsetIntersect = [](const ConstantRange &CR0, const ConstantRange &CR1) { return CR0.inverse().unionWith(CR1.inverse()).inverse(); }; assert(BinOp >= Instruction::BinaryOpsBegin && BinOp < Instruction::BinaryOpsEnd && "Binary operators only!"); assert((NoWrapKind == OBO::NoSignedWrap || NoWrapKind == OBO::NoUnsignedWrap || NoWrapKind == (OBO::NoUnsignedWrap | OBO::NoSignedWrap)) && "NoWrapKind invalid!"); unsigned BitWidth = Other.getBitWidth(); if (BinOp != Instruction::Add) // Conservative answer: empty set return ConstantRange(BitWidth, false); if (auto *C = Other.getSingleElement()) if (C->isMinValue()) // Full set: nothing signed / unsigned wraps when added to 0. return ConstantRange(BitWidth); ConstantRange Result(BitWidth); if (NoWrapKind & OBO::NoUnsignedWrap) Result = SubsetIntersect(Result, ConstantRange(APInt::getNullValue(BitWidth), -Other.getUnsignedMax())); if (NoWrapKind & OBO::NoSignedWrap) { APInt SignedMin = Other.getSignedMin(); APInt SignedMax = Other.getSignedMax(); if (SignedMax.isStrictlyPositive()) Result = SubsetIntersect( Result, ConstantRange(APInt::getSignedMinValue(BitWidth), APInt::getSignedMinValue(BitWidth) - SignedMax)); if (SignedMin.isNegative()) Result = SubsetIntersect( Result, ConstantRange(APInt::getSignedMinValue(BitWidth) - SignedMin, APInt::getSignedMinValue(BitWidth))); } return Result; }
ConstantRange ConstantRange::smin(const ConstantRange &Other) const { // X smin Y is: range(smin(X_smin, Y_smin), // smin(X_smax, Y_smax)) if (isEmptySet() || Other.isEmptySet()) return ConstantRange(getBitWidth(), /*isFullSet=*/false); APInt NewL = APIntOps::smin(getSignedMin(), Other.getSignedMin()); APInt NewU = APIntOps::smin(getSignedMax(), Other.getSignedMax()) + 1; if (NewU == NewL) return ConstantRange(getBitWidth(), /*isFullSet=*/true); return ConstantRange(NewL, NewU); }
ConstantRange ConstantRange::multiply(const ConstantRange &Other) const { // TODO: If either operand is a single element and the multiply is known to // be non-wrapping, round the result min and max value to the appropriate // multiple of that element. If wrapping is possible, at least adjust the // range according to the greatest power-of-two factor of the single element. if (isEmptySet() || Other.isEmptySet()) return ConstantRange(getBitWidth(), /*isFullSet=*/false); // Multiplication is signedness-independent. However different ranges can be // obtained depending on how the input ranges are treated. These different // ranges are all conservatively correct, but one might be better than the // other. We calculate two ranges; one treating the inputs as unsigned // and the other signed, then return the smallest of these ranges. // Unsigned range first. APInt this_min = getUnsignedMin().zext(getBitWidth() * 2); APInt this_max = getUnsignedMax().zext(getBitWidth() * 2); APInt Other_min = Other.getUnsignedMin().zext(getBitWidth() * 2); APInt Other_max = Other.getUnsignedMax().zext(getBitWidth() * 2); ConstantRange Result_zext = ConstantRange(this_min * Other_min, this_max * Other_max + 1); ConstantRange UR = Result_zext.truncate(getBitWidth()); // If the unsigned range doesn't wrap, and isn't negative then it's a range // from one positive number to another which is as good as we can generate. // In this case, skip the extra work of generating signed ranges which aren't // going to be better than this range. if (!UR.isWrappedSet() && (UR.getUpper().isNonNegative() || UR.getUpper().isMinSignedValue())) return UR; // Now the signed range. Because we could be dealing with negative numbers // here, the lower bound is the smallest of the cartesian product of the // lower and upper ranges; for example: // [-1,4) * [-2,3) = min(-1*-2, -1*2, 3*-2, 3*2) = -6. // Similarly for the upper bound, swapping min for max. this_min = getSignedMin().sext(getBitWidth() * 2); this_max = getSignedMax().sext(getBitWidth() * 2); Other_min = Other.getSignedMin().sext(getBitWidth() * 2); Other_max = Other.getSignedMax().sext(getBitWidth() * 2); auto L = {this_min * Other_min, this_min * Other_max, this_max * Other_min, this_max * Other_max}; auto Compare = [](const APInt &A, const APInt &B) { return A.slt(B); }; ConstantRange Result_sext(std::min(L, Compare), std::max(L, Compare) + 1); ConstantRange SR = Result_sext.truncate(getBitWidth()); return UR.isSizeStrictlySmallerThan(SR) ? UR : SR; }
ConstantRange ConstantRange::makeAllowedICmpRegion(CmpInst::Predicate Pred, const ConstantRange &CR) { if (CR.isEmptySet()) return CR; uint32_t W = CR.getBitWidth(); switch (Pred) { default: llvm_unreachable("Invalid ICmp predicate to makeAllowedICmpRegion()"); case CmpInst::ICMP_EQ: return CR; case CmpInst::ICMP_NE: if (CR.isSingleElement()) return ConstantRange(CR.getUpper(), CR.getLower()); return ConstantRange(W); case CmpInst::ICMP_ULT: { APInt UMax(CR.getUnsignedMax()); if (UMax.isMinValue()) return ConstantRange(W, /* empty */ false); return ConstantRange(APInt::getMinValue(W), UMax); } case CmpInst::ICMP_SLT: { APInt SMax(CR.getSignedMax()); if (SMax.isMinSignedValue()) return ConstantRange(W, /* empty */ false); return ConstantRange(APInt::getSignedMinValue(W), SMax); } case CmpInst::ICMP_ULE: { APInt UMax(CR.getUnsignedMax()); if (UMax.isMaxValue()) return ConstantRange(W); return ConstantRange(APInt::getMinValue(W), UMax + 1); } case CmpInst::ICMP_SLE: { APInt SMax(CR.getSignedMax()); if (SMax.isMaxSignedValue()) return ConstantRange(W); return ConstantRange(APInt::getSignedMinValue(W), SMax + 1); } case CmpInst::ICMP_UGT: { APInt UMin(CR.getUnsignedMin()); if (UMin.isMaxValue()) return ConstantRange(W, /* empty */ false); return ConstantRange(UMin + 1, APInt::getNullValue(W)); } case CmpInst::ICMP_SGT: { APInt SMin(CR.getSignedMin()); if (SMin.isMaxSignedValue()) return ConstantRange(W, /* empty */ false); return ConstantRange(SMin + 1, APInt::getSignedMinValue(W)); } case CmpInst::ICMP_UGE: { APInt UMin(CR.getUnsignedMin()); if (UMin.isMinValue()) return ConstantRange(W); return ConstantRange(UMin, APInt::getNullValue(W)); } case CmpInst::ICMP_SGE: { APInt SMin(CR.getSignedMin()); if (SMin.isMinSignedValue()) return ConstantRange(W); return ConstantRange(SMin, APInt::getSignedMinValue(W)); } } }