return NonNegative;
}
+static bool isKnownNonEqual(Value *V1, Value *V2, const DataLayout &DL,
+ const Query &Q);
+
+bool llvm::isKnownNonEqual(Value *V1, Value *V2, const DataLayout &DL,
+ AssumptionCache *AC, const Instruction *CxtI,
+ const DominatorTree *DT) {
+ return ::isKnownNonEqual(V1, V2, DL, Query(AC,
+ safeCxtI(V1, safeCxtI(V2, CxtI)),
+ DT));
+}
+
static bool MaskedValueIsZero(Value *V, const APInt &Mask, const DataLayout &DL,
unsigned Depth, const Query &Q);
return KnownOne != 0;
}
+/// Return true if V2 == V1 + X, where X is known non-zero.
+static bool isAddOfNonZero(Value *V1, Value *V2, const DataLayout &DL,
+ const Query &Q) {
+ BinaryOperator *BO = dyn_cast<BinaryOperator>(V1);
+ if (!BO || BO->getOpcode() != Instruction::Add)
+ return false;
+ Value *Op = nullptr;
+ if (V2 == BO->getOperand(0))
+ Op = BO->getOperand(1);
+ else if (V2 == BO->getOperand(1))
+ Op = BO->getOperand(0);
+ else
+ return false;
+ return isKnownNonZero(Op, DL, 0, Q);
+}
+
+/// Return true if it is known that V1 != V2.
+static bool isKnownNonEqual(Value *V1, Value *V2, const DataLayout &DL,
+ const Query &Q) {
+ if (V1->getType()->isVectorTy() || V1 == V2)
+ return false;
+ if (V1->getType() != V2->getType())
+ // We can't look through casts yet.
+ return false;
+ if (isAddOfNonZero(V1, V2, DL, Q) || isAddOfNonZero(V2, V1, DL, Q))
+ return true;
+
+ if (IntegerType *Ty = dyn_cast<IntegerType>(V1->getType())) {
+ // Are any known bits in V1 contradictory to known bits in V2? If V1
+ // has a known zero where V2 has a known one, they must not be equal.
+ auto BitWidth = Ty->getBitWidth();
+ APInt KnownZero1(BitWidth, 0);
+ APInt KnownOne1(BitWidth, 0);
+ computeKnownBits(V1, KnownZero1, KnownOne1, DL, 0, Q);
+ APInt KnownZero2(BitWidth, 0);
+ APInt KnownOne2(BitWidth, 0);
+ computeKnownBits(V2, KnownZero2, KnownOne2, DL, 0, Q);
+
+ auto OppositeBits = (KnownZero1 & KnownOne2) | (KnownZero2 & KnownOne1);
+ if (OppositeBits.getBoolValue())
+ return true;
+ }
+ return false;
+}
+
/// Return true if 'V & Mask' is known to be zero. We use this predicate to
/// simplify operations downstream. Mask is known to be zero for bits that V
/// cannot have.