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[ValueTracking] Use setAllBits/setSignBit/setLowBits/setHighBits. NFCI 

llvm-svn: 298583
This commit is contained in:
Craig Topper 2017-03-23 07:06:39 +00:00
parent 28f105d7a6
commit d73c6b4ef8
1 changed files with 22 additions and 20 deletions
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42
llvm/lib/Analysis/ValueTracking.cpp
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@ -352,8 +352,9 @@ static void computeKnownBitsMul(const Value *Op0, const Value *Op1, bool NSW,
TrailZ = std::min(TrailZ, BitWidth);
LeadZ = std::min(LeadZ, BitWidth);
KnownZero = APInt::getLowBitsSet(BitWidth, TrailZ) |
APInt::getHighBitsSet(BitWidth, LeadZ);
KnownZero.clearAllBits();
KnownZero.setLowBits(TrailZ);
KnownZero.setHighBits(LeadZ);
// Only make use of no-wrap flags if we failed to compute the sign bit
// directly. This matters if the multiplication always overflows, in
@ -361,9 +362,9 @@ static void computeKnownBitsMul(const Value *Op0, const Value *Op1, bool NSW,
// though as the program is invoking undefined behaviour we can choose
// whatever we like here.
if (isKnownNonNegative && !KnownOne.isNegative())
KnownZero.setBit(BitWidth - 1);
KnownZero.setSignBit();
else if (isKnownNegative && !KnownZero.isNegative())
KnownOne.setBit(BitWidth - 1);
KnownOne.setSignBit();
}
void llvm::computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
@ -1094,21 +1095,20 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
case Instruction::Shl: {
// (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0
bool NSW = cast<OverflowingBinaryOperator>(I)->hasNoSignedWrap();
auto KZF = [BitWidth, NSW](const APInt &KnownZero, unsigned ShiftAmt) {
APInt KZResult =
(KnownZero << ShiftAmt) |
APInt::getLowBitsSet(BitWidth, ShiftAmt); // Low bits known 0.
auto KZF = [NSW](const APInt &KnownZero, unsigned ShiftAmt) {
APInt KZResult = KnownZero << ShiftAmt;
KZResult.setLowBits(ShiftAmt); // Low bits known 0.
// If this shift has "nsw" keyword, then the result is either a poison
// value or has the same sign bit as the first operand.
if (NSW && KnownZero.isNegative())
KZResult.setBit(BitWidth - 1);
KZResult.setSignBit();
return KZResult;
};
auto KOF = [BitWidth, NSW](const APInt &KnownOne, unsigned ShiftAmt) {
auto KOF = [NSW](const APInt &KnownOne, unsigned ShiftAmt) {
APInt KOResult = KnownOne << ShiftAmt;
if (NSW && KnownOne.isNegative())
KOResult.setBit(BitWidth - 1);
KOResult.setSignBit();
return KOResult;
};
@ -1197,7 +1197,7 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
Q);
// If it's known zero, our sign bit is also zero.
if (LHSKnownZero.isNegative())
KnownZero.setBit(BitWidth - 1);
KnownZero.setSignBit();
}
break;
@ -1221,7 +1221,8 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
unsigned Leaders = std::max(KnownZero.countLeadingOnes(),
KnownZero2.countLeadingOnes());
KnownOne.clearAllBits();
KnownZero = APInt::getHighBitsSet(BitWidth, Leaders);
KnownZero.clearAllBits();
KnownZero.setHighBits(Leaders);
break;
}
@ -1340,7 +1341,7 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
// (add negative, negative) --> negative
if (Opcode == Instruction::Add) {
if (KnownZero2.isNegative() && KnownZero3.isNegative())
KnownZero.setBit(BitWidth - 1);
KnownZero.setSignBit();
else if (KnownOne2.isNegative() && KnownOne3.isNegative())
KnownOne.setBit(BitWidth - 1);
}
@ -1349,15 +1350,15 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
// (sub nsw negative, non-negative) --> negative
else if (Opcode == Instruction::Sub && LL == I) {
if (KnownZero2.isNegative() && KnownOne3.isNegative())
KnownZero.setBit(BitWidth - 1);
KnownZero.setSignBit();
else if (KnownOne2.isNegative() && KnownZero3.isNegative())
KnownOne.setBit(BitWidth - 1);
KnownOne.setSignBit();
}
// (mul nsw non-negative, non-negative) --> non-negative
else if (Opcode == Instruction::Mul && KnownZero2.isNegative() &&
KnownZero3.isNegative())
KnownZero.setBit(BitWidth - 1);
KnownZero.setSignBit();
}
break;
@ -1376,8 +1377,8 @@ static void computeKnownBitsFromOperator(const Operator *I, APInt &KnownZero,
if (dyn_cast_or_null<UndefValue>(P->hasConstantValue()))
break;
KnownZero = APInt::getAllOnesValue(BitWidth);
KnownOne = APInt::getAllOnesValue(BitWidth);
KnownZero.setAllBits();
KnownOne.setAllBits();
for (Value *IncValue : P->incoming_values()) {
// Skip direct self references.
if (IncValue == P) continue;
@ -1519,6 +1520,7 @@ void computeKnownBits(const Value *V, APInt &KnownZero, APInt &KnownOne,
KnownZero.getBitWidth() == BitWidth &&
KnownOne.getBitWidth() == BitWidth &&
"V, KnownOne and KnownZero should have same BitWidth");
(void)BitWidth;
const APInt *C;
if (match(V, m_APInt(C))) {
@ -1530,7 +1532,7 @@ void computeKnownBits(const Value *V, APInt &KnownZero, APInt &KnownOne,
// Null and aggregate-zero are all-zeros.
if (isa<ConstantPointerNull>(V) || isa<ConstantAggregateZero>(V)) {
KnownOne.clearAllBits();
KnownZero = APInt::getAllOnesValue(BitWidth);
KnownZero.setAllBits();
return;
}
// Handle a constant vector by taking the intersection of the known bits of