// Is the set of underlying objects all noalias calls?
auto IsNAC = [](SmallVectorImpl<Value *> &Objects) {
- return std::all_of(Objects.begin(), Objects.end(),
- [](Value *V){ return isNoAliasCall(V); });
+ return std::all_of(Objects.begin(), Objects.end(), isNoAliasCall);
};
// Is the set of underlying objects all things which must be disjoint from
return nullptr;
}
-static ConstantRange GetConstantRangeFromMetadata(MDNode *Ranges, uint32_t BitWidth) {
- const unsigned NumRanges = Ranges->getNumOperands() / 2;
- assert(NumRanges >= 1);
-
- ConstantRange CR(BitWidth, false);
- for (unsigned i = 0; i < NumRanges; ++i) {
- auto *Low =
- mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 0));
- auto *High =
- mdconst::extract<ConstantInt>(Ranges->getOperand(2 * i + 1));
-
- // Union will merge two ranges to one and potentially introduce a range
- // not covered by the original two ranges. For example, [1, 5) and [8, 10)
- // will become [1, 10). In this case, we can not fold comparison between
- // constant 6 and a value of the above ranges. In practice, most values
- // have only one range, so it might not be worth handling this by
- // introducing additional complexity.
- CR = CR.unionWith(ConstantRange(Low->getValue(), High->getValue()));
- }
-
- return CR;
-}
-
/// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
/// fold the result. If not, this returns null.
static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
// X >=u 1 -> X
if (match(RHS, m_One()))
return LHS;
+ if (isImpliedCondition(RHS, LHS, Q.DL))
+ return getTrue(ITy);
+ break;
+ case ICmpInst::ICMP_SGE:
+ /// For signed comparison, the values for an i1 are 0 and -1
+ /// respectively. This maps into a truth table of:
+ /// LHS | RHS | LHS >=s RHS | LHS implies RHS
+ /// 0 | 0 | 1 (0 >= 0) | 1
+ /// 0 | 1 | 1 (0 >= -1) | 1
+ /// 1 | 0 | 0 (-1 >= 0) | 0
+ /// 1 | 1 | 1 (-1 >= -1) | 1
+ if (isImpliedCondition(LHS, RHS, Q.DL))
+ return getTrue(ITy);
break;
case ICmpInst::ICMP_SLT:
// X <s 0 -> X
if (match(RHS, m_One()))
return LHS;
break;
+ case ICmpInst::ICMP_ULE:
+ if (isImpliedCondition(LHS, RHS, Q.DL))
+ return getTrue(ITy);
+ break;
}
}
if (auto *I = dyn_cast<Instruction>(LHS))
if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
- LHS_CR = LHS_CR.intersectWith(GetConstantRangeFromMetadata(Ranges, Width));
+ LHS_CR = LHS_CR.intersectWith(getConstantRangeFromMetadata(*Ranges));
if (!LHS_CR.isFullSet()) {
if (RHS_CR.contains(LHS_CR))
if (RHS_Instr->getMetadata(LLVMContext::MD_range) &&
LHS_Instr->getMetadata(LLVMContext::MD_range)) {
- uint32_t BitWidth = Q.DL.getTypeSizeInBits(RHS->getType());
-
- auto RHS_CR = GetConstantRangeFromMetadata(
- RHS_Instr->getMetadata(LLVMContext::MD_range), BitWidth);
- auto LHS_CR = GetConstantRangeFromMetadata(
- LHS_Instr->getMetadata(LLVMContext::MD_range), BitWidth);
+ auto RHS_CR = getConstantRangeFromMetadata(
+ *RHS_Instr->getMetadata(LLVMContext::MD_range));
+ auto LHS_CR = getConstantRangeFromMetadata(
+ *LHS_Instr->getMetadata(LLVMContext::MD_range));
auto Satisfied_CR = ConstantRange::makeSatisfyingICmpRegion(Pred, RHS_CR);
if (Satisfied_CR.contains(LHS_CR))
}
}
+ // icmp eq|ne X, Y -> false|true if X != Y
+ if ((Pred == ICmpInst::ICMP_EQ || Pred == ICmpInst::ICMP_NE) &&
+ isKnownNonEqual(LHS, RHS, Q.DL, Q.AC, Q.CxtI, Q.DT)) {
+ LLVMContext &Ctx = LHS->getType()->getContext();
+ return Pred == ICmpInst::ICMP_NE ?
+ ConstantInt::getTrue(Ctx) : ConstantInt::getFalse(Ctx);
+ }
+
// Special logic for binary operators.
BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
break;
}
+ // In general, it is possible for computeKnownBits to determine all bits in a
+ // value even when the operands are not all constants.
+ if (!Result && I->getType()->isIntegerTy()) {
+ unsigned BitWidth = I->getType()->getScalarSizeInBits();
+ APInt KnownZero(BitWidth, 0);
+ APInt KnownOne(BitWidth, 0);
+ computeKnownBits(I, KnownZero, KnownOne, DL, /*Depth*/0, AC, I, DT);
+ if ((KnownZero | KnownOne).isAllOnesValue())
+ Result = ConstantInt::get(I->getContext(), KnownOne);
+ }
+
/// If called on unreachable code, the above logic may report that the
/// instruction simplified to itself. Make life easier for users by
/// detecting that case here, returning a safe value instead.