unsigned Depth) const {
APInt KnownZero, KnownOne;
computeKnownBits(Op, KnownZero, KnownOne, Depth);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
return (KnownZero & Mask) == Mask;
}
// We know all of the bits for a constant!
KnownOne = cast<ConstantSDNode>(Op)->getAPIntValue();
KnownZero = ~KnownOne;
- return;
+ break;
case ISD::AND:
// If either the LHS or the RHS are Zero, the result is zero.
computeKnownBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// Output known-1 bits are only known if set in both the LHS & RHS.
KnownOne &= KnownOne2;
// Output known-0 are known to be clear if zero in either the LHS | RHS.
KnownZero |= KnownZero2;
- return;
+ break;
case ISD::OR:
computeKnownBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// Output known-0 bits are only known if clear in both the LHS & RHS.
KnownZero &= KnownZero2;
// Output known-1 are known to be set if set in either the LHS | RHS.
KnownOne |= KnownOne2;
- return;
+ break;
case ISD::XOR: {
computeKnownBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// Output known-0 bits are known if clear or set in both the LHS & RHS.
APInt KnownZeroOut = (KnownZero & KnownZero2) | (KnownOne & KnownOne2);
// Output known-1 are known to be set if set in only one of the LHS, RHS.
KnownOne = (KnownZero & KnownOne2) | (KnownOne & KnownZero2);
KnownZero = KnownZeroOut;
- return;
+ break;
}
case ISD::MUL: {
computeKnownBits(Op.getOperand(1), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// If low bits are zero in either operand, output low known-0 bits.
// Also compute a conserative estimate for high known-0 bits.
LeadZ = std::min(LeadZ, BitWidth);
KnownZero = APInt::getLowBitsSet(BitWidth, TrailZ) |
APInt::getHighBitsSet(BitWidth, LeadZ);
- return;
+ break;
}
case ISD::UDIV: {
// For the purposes of computing leading zeros we can conservatively
LeadZ + BitWidth - RHSUnknownLeadingOnes - 1);
KnownZero = APInt::getHighBitsSet(BitWidth, LeadZ);
- return;
+ break;
}
case ISD::SELECT:
computeKnownBits(Op.getOperand(2), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(1), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// Only known if known in both the LHS and RHS.
KnownOne &= KnownOne2;
KnownZero &= KnownZero2;
- return;
+ break;
case ISD::SELECT_CC:
computeKnownBits(Op.getOperand(3), KnownZero, KnownOne, Depth+1);
computeKnownBits(Op.getOperand(2), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
// Only known if known in both the LHS and RHS.
KnownOne &= KnownOne2;
KnownZero &= KnownZero2;
- return;
+ break;
case ISD::SADDO:
case ISD::UADDO:
case ISD::SSUBO:
case ISD::SMULO:
case ISD::UMULO:
if (Op.getResNo() != 1)
- return;
+ break;
// The boolean result conforms to getBooleanContents. Fall through.
case ISD::SETCC:
// If we know the result of a setcc has the top bits zero, use this info.
if (TLI->getBooleanContents(Op.getValueType().isVector()) ==
TargetLowering::ZeroOrOneBooleanContent && BitWidth > 1)
KnownZero |= APInt::getHighBitsSet(BitWidth, BitWidth - 1);
- return;
+ break;
case ISD::SHL:
// (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
- return;
+ break;
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero <<= ShAmt;
KnownOne <<= ShAmt;
// low bits known zero.
KnownZero |= APInt::getLowBitsSet(BitWidth, ShAmt);
}
- return;
+ break;
case ISD::SRL:
// (ushr X, C1) & C2 == 0 iff (-1 >> C1) & C2 == 0
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
- return;
+ break;
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = KnownZero.lshr(ShAmt);
KnownOne = KnownOne.lshr(ShAmt);
APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
KnownZero |= HighBits; // High bits known zero.
}
- return;
+ break;
case ISD::SRA:
if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
unsigned ShAmt = SA->getZExtValue();
// If the shift count is an invalid immediate, don't do anything.
if (ShAmt >= BitWidth)
- return;
+ break;
// If any of the demanded bits are produced by the sign extension, we also
// demand the input sign bit.
APInt HighBits = APInt::getHighBitsSet(BitWidth, ShAmt);
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = KnownZero.lshr(ShAmt);
KnownOne = KnownOne.lshr(ShAmt);
KnownOne |= HighBits; // New bits are known one.
}
}
- return;
+ break;
case ISD::SIGN_EXTEND_INREG: {
EVT EVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
unsigned EBits = EVT.getScalarType().getSizeInBits();
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
KnownOne &= InputDemandedBits;
KnownZero &= InputDemandedBits;
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
// If the sign bit of the input is known set or clear, then we know the
// top bits of the result.
KnownZero &= ~NewBits;
KnownOne &= ~NewBits;
}
- return;
+ break;
}
case ISD::CTTZ:
case ISD::CTTZ_ZERO_UNDEF:
unsigned LowBits = Log2_32(BitWidth)+1;
KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - LowBits);
KnownOne.clearAllBits();
- return;
+ break;
}
case ISD::LOAD: {
LoadSDNode *LD = cast<LoadSDNode>(Op);
} else if (const MDNode *Ranges = LD->getRanges()) {
computeKnownBitsLoad(*Ranges, KnownZero);
}
- return;
+ break;
}
case ISD::ZERO_EXTEND: {
EVT InVT = Op.getOperand(0).getValueType();
KnownZero = KnownZero.zext(BitWidth);
KnownOne = KnownOne.zext(BitWidth);
KnownZero |= NewBits;
- return;
+ break;
}
case ISD::SIGN_EXTEND: {
EVT InVT = Op.getOperand(0).getValueType();
// Note if the sign bit is known to be zero or one.
bool SignBitKnownZero = KnownZero.isNegative();
bool SignBitKnownOne = KnownOne.isNegative();
- assert(!(SignBitKnownZero && SignBitKnownOne) &&
- "Sign bit can't be known to be both zero and one!");
KnownZero = KnownZero.zext(BitWidth);
KnownOne = KnownOne.zext(BitWidth);
KnownZero |= NewBits;
else if (SignBitKnownOne)
KnownOne |= NewBits;
- return;
+ break;
}
case ISD::ANY_EXTEND: {
EVT InVT = Op.getOperand(0).getValueType();
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
KnownZero = KnownZero.zext(BitWidth);
KnownOne = KnownOne.zext(BitWidth);
- return;
+ break;
}
case ISD::TRUNCATE: {
EVT InVT = Op.getOperand(0).getValueType();
KnownZero = KnownZero.zext(InBits);
KnownOne = KnownOne.zext(InBits);
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
KnownZero = KnownZero.trunc(BitWidth);
KnownOne = KnownOne.trunc(BitWidth);
break;
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne, Depth+1);
KnownZero |= (~InMask);
KnownOne &= (~KnownZero);
- return;
+ break;
}
case ISD::FGETSIGN:
// All bits are zero except the low bit.
KnownZero = APInt::getHighBitsSet(BitWidth, BitWidth - 1);
- return;
+ break;
case ISD::SUB: {
if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0))) {
// common to both LHS & RHS. For example, 8+(X<<3) is known to have the
// low 3 bits clear.
computeKnownBits(Op.getOperand(0), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
unsigned KnownZeroOut = KnownZero2.countTrailingOnes();
computeKnownBits(Op.getOperand(1), KnownZero2, KnownOne2, Depth+1);
- assert((KnownZero2 & KnownOne2) == 0 && "Bits known to be one AND zero?");
KnownZeroOut = std::min(KnownZeroOut,
KnownZero2.countTrailingOnes());
if (Op.getOpcode() == ISD::ADD) {
KnownZero |= APInt::getLowBitsSet(BitWidth, KnownZeroOut);
- return;
+ break;
}
// With ADDE, a carry bit may be added in, so we can only use this
// are known zero.
if (KnownZeroOut >= 2) // ADDE
KnownZero |= APInt::getBitsSet(BitWidth, 1, KnownZeroOut);
- return;
+ break;
}
case ISD::SREM:
if (ConstantSDNode *Rem = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
}
}
- return;
+ break;
case ISD::UREM: {
if (ConstantSDNode *Rem = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
const APInt &RA = Rem->getAPIntValue();
APInt LowBits = (RA - 1);
KnownZero |= ~LowBits;
computeKnownBits(Op.getOperand(0), KnownZero, KnownOne,Depth+1);
- assert((KnownZero & KnownOne) == 0&&"Bits known to be one AND zero?");
break;
}
}
KnownZero2.countLeadingOnes());
KnownOne.clearAllBits();
KnownZero = APInt::getHighBitsSet(BitWidth, Leaders);
- return;
+ break;
}
case ISD::FrameIndex:
case ISD::TargetFrameIndex:
if (unsigned Align = InferPtrAlignment(Op)) {
// The low bits are known zero if the pointer is aligned.
KnownZero = APInt::getLowBitsSet(BitWidth, Log2_32(Align));
- return;
+ break;
}
break;
case ISD::INTRINSIC_VOID:
// Allow the target to implement this method for its nodes.
TLI->computeKnownBitsForTargetNode(Op, KnownZero, KnownOne, *this, Depth);
- return;
+ break;
}
+
+ assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
}
/// ComputeNumSignBits - Return the number of times the sign bit of the
projects / oota-llvm.git / blobdiff