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Diffstat (limited to 'lib/CodeGen/SelectionDAG/TargetLowering.cpp')
-rw-r--r--lib/CodeGen/SelectionDAG/TargetLowering.cpp561
1 files changed, 8 insertions, 553 deletions
diff --git a/lib/CodeGen/SelectionDAG/TargetLowering.cpp b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
index caedf5745d..b2c9016639 100644
--- a/lib/CodeGen/SelectionDAG/TargetLowering.cpp
+++ b/lib/CodeGen/SelectionDAG/TargetLowering.cpp
@@ -375,7 +375,7 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
if (Depth != 0) {
// If not at the root, Just compute the KnownZero/KnownOne bits to
// simplify things downstream.
- ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
+ TLO.DAG.ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
return false;
}
// If this is the root being simplified, allow it to have multiple uses,
@@ -404,8 +404,8 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
// the RHS.
if (ConstantSDNode *RHSC = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
uint64_t LHSZero, LHSOne;
- ComputeMaskedBits(Op.getOperand(0), DemandedMask,
- LHSZero, LHSOne, Depth+1);
+ TLO.DAG.ComputeMaskedBits(Op.getOperand(0), DemandedMask,
+ LHSZero, LHSOne, Depth+1);
// If the LHS already has zeros where RHSC does, this and is dead.
if ((LHSZero & DemandedMask) == (~RHSC->getValue() & DemandedMask))
return TLO.CombineTo(Op, Op.getOperand(0));
@@ -862,7 +862,7 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
case ISD::INTRINSIC_W_CHAIN:
case ISD::INTRINSIC_VOID:
// Just use ComputeMaskedBits to compute output bits.
- ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
+ TLO.DAG.ComputeMaskedBits(Op, DemandedMask, KnownZero, KnownOne, Depth);
break;
}
@@ -874,337 +874,6 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
return false;
}
-/// MaskedValueIsZero - 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.
-bool TargetLowering::MaskedValueIsZero(SDOperand Op, uint64_t Mask,
- unsigned Depth) const {
- // The masks are not wide enough to represent this type! Should use APInt.
- if (Op.getValueType() == MVT::i128)
- return false;
-
- uint64_t KnownZero, KnownOne;
- ComputeMaskedBits(Op, Mask, KnownZero, KnownOne, Depth);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- return (KnownZero & Mask) == Mask;
-}
-
-/// ComputeMaskedBits - Determine which of the bits specified in Mask are
-/// known to be either zero or one and return them in the KnownZero/KnownOne
-/// bitsets. This code only analyzes bits in Mask, in order to short-circuit
-/// processing.
-void TargetLowering::ComputeMaskedBits(SDOperand Op, uint64_t Mask,
- uint64_t &KnownZero, uint64_t &KnownOne,
- unsigned Depth) const {
- KnownZero = KnownOne = 0; // Don't know anything.
- if (Depth == 6 || Mask == 0)
- return; // Limit search depth.
-
- // The masks are not wide enough to represent this type! Should use APInt.
- if (Op.getValueType() == MVT::i128)
- return;
-
- uint64_t KnownZero2, KnownOne2;
-
- switch (Op.getOpcode()) {
- case ISD::Constant:
- // We know all of the bits for a constant!
- KnownOne = cast<ConstantSDNode>(Op)->getValue() & Mask;
- KnownZero = ~KnownOne & Mask;
- return;
- case ISD::AND:
- // If either the LHS or the RHS are Zero, the result is zero.
- ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1);
- Mask &= ~KnownZero;
- ComputeMaskedBits(Op.getOperand(0), Mask, 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;
- case ISD::OR:
- ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1);
- Mask &= ~KnownOne;
- ComputeMaskedBits(Op.getOperand(0), Mask, 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;
- case ISD::XOR: {
- ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1);
- ComputeMaskedBits(Op.getOperand(0), Mask, 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.
- uint64_t 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;
- }
- case ISD::SELECT:
- ComputeMaskedBits(Op.getOperand(2), Mask, KnownZero, KnownOne, Depth+1);
- ComputeMaskedBits(Op.getOperand(1), Mask, 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;
- case ISD::SELECT_CC:
- ComputeMaskedBits(Op.getOperand(3), Mask, KnownZero, KnownOne, Depth+1);
- ComputeMaskedBits(Op.getOperand(2), Mask, 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;
- case ISD::SETCC:
- // If we know the result of a setcc has the top bits zero, use this info.
- if (getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult)
- KnownZero |= (MVT::getIntVTBitMask(Op.getValueType()) ^ 1ULL);
- return;
- case ISD::SHL:
- // (shl X, C1) & C2 == 0 iff (X & C2 >>u C1) == 0
- if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- ComputeMaskedBits(Op.getOperand(0), Mask >> SA->getValue(),
- KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- KnownZero <<= SA->getValue();
- KnownOne <<= SA->getValue();
- KnownZero |= (1ULL << SA->getValue())-1; // low bits known zero.
- }
- return;
- case ISD::SRL:
- // (ushr X, C1) & C2 == 0 iff (-1 >> C1) & C2 == 0
- if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- MVT::ValueType VT = Op.getValueType();
- unsigned ShAmt = SA->getValue();
-
- uint64_t TypeMask = MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op.getOperand(0), (Mask << ShAmt) & TypeMask,
- KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- KnownZero &= TypeMask;
- KnownOne &= TypeMask;
- KnownZero >>= ShAmt;
- KnownOne >>= ShAmt;
-
- uint64_t HighBits = (1ULL << ShAmt)-1;
- HighBits <<= MVT::getSizeInBits(VT)-ShAmt;
- KnownZero |= HighBits; // High bits known zero.
- }
- return;
- case ISD::SRA:
- if (ConstantSDNode *SA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- MVT::ValueType VT = Op.getValueType();
- unsigned ShAmt = SA->getValue();
-
- // Compute the new bits that are at the top now.
- uint64_t TypeMask = MVT::getIntVTBitMask(VT);
-
- uint64_t InDemandedMask = (Mask << ShAmt) & TypeMask;
- // If any of the demanded bits are produced by the sign extension, we also
- // demand the input sign bit.
- uint64_t HighBits = (1ULL << ShAmt)-1;
- HighBits <<= MVT::getSizeInBits(VT) - ShAmt;
- if (HighBits & Mask)
- InDemandedMask |= MVT::getIntVTSignBit(VT);
-
- ComputeMaskedBits(Op.getOperand(0), InDemandedMask, KnownZero, KnownOne,
- Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- KnownZero &= TypeMask;
- KnownOne &= TypeMask;
- KnownZero >>= ShAmt;
- KnownOne >>= ShAmt;
-
- // Handle the sign bits.
- uint64_t SignBit = MVT::getIntVTSignBit(VT);
- SignBit >>= ShAmt; // Adjust to where it is now in the mask.
-
- if (KnownZero & SignBit) {
- KnownZero |= HighBits; // New bits are known zero.
- } else if (KnownOne & SignBit) {
- KnownOne |= HighBits; // New bits are known one.
- }
- }
- return;
- case ISD::SIGN_EXTEND_INREG: {
- MVT::ValueType EVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
-
- // Sign extension. Compute the demanded bits in the result that are not
- // present in the input.
- uint64_t NewBits = ~MVT::getIntVTBitMask(EVT) & Mask;
-
- uint64_t InSignBit = MVT::getIntVTSignBit(EVT);
- int64_t InputDemandedBits = Mask & MVT::getIntVTBitMask(EVT);
-
- // If the sign extended bits are demanded, we know that the sign
- // bit is demanded.
- if (NewBits)
- InputDemandedBits |= InSignBit;
-
- ComputeMaskedBits(Op.getOperand(0), InputDemandedBits,
- KnownZero, KnownOne, Depth+1);
- 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.
- if (KnownZero & InSignBit) { // Input sign bit known clear
- KnownZero |= NewBits;
- KnownOne &= ~NewBits;
- } else if (KnownOne & InSignBit) { // Input sign bit known set
- KnownOne |= NewBits;
- KnownZero &= ~NewBits;
- } else { // Input sign bit unknown
- KnownZero &= ~NewBits;
- KnownOne &= ~NewBits;
- }
- return;
- }
- case ISD::CTTZ:
- case ISD::CTLZ:
- case ISD::CTPOP: {
- MVT::ValueType VT = Op.getValueType();
- unsigned LowBits = Log2_32(MVT::getSizeInBits(VT))+1;
- KnownZero = ~((1ULL << LowBits)-1) & MVT::getIntVTBitMask(VT);
- KnownOne = 0;
- return;
- }
- case ISD::LOAD: {
- if (ISD::isZEXTLoad(Op.Val)) {
- LoadSDNode *LD = cast<LoadSDNode>(Op);
- MVT::ValueType VT = LD->getLoadedVT();
- KnownZero |= ~MVT::getIntVTBitMask(VT) & Mask;
- }
- return;
- }
- case ISD::ZERO_EXTEND: {
- uint64_t InMask = MVT::getIntVTBitMask(Op.getOperand(0).getValueType());
- uint64_t NewBits = (~InMask) & Mask;
- ComputeMaskedBits(Op.getOperand(0), Mask & InMask, KnownZero,
- KnownOne, Depth+1);
- KnownZero |= NewBits & Mask;
- KnownOne &= ~NewBits;
- return;
- }
- case ISD::SIGN_EXTEND: {
- MVT::ValueType InVT = Op.getOperand(0).getValueType();
- unsigned InBits = MVT::getSizeInBits(InVT);
- uint64_t InMask = MVT::getIntVTBitMask(InVT);
- uint64_t InSignBit = 1ULL << (InBits-1);
- uint64_t NewBits = (~InMask) & Mask;
- uint64_t InDemandedBits = Mask & InMask;
-
- // If any of the sign extended bits are demanded, we know that the sign
- // bit is demanded.
- if (NewBits & Mask)
- InDemandedBits |= InSignBit;
-
- ComputeMaskedBits(Op.getOperand(0), InDemandedBits, KnownZero,
- KnownOne, Depth+1);
- // If the sign bit is known zero or one, the top bits match.
- if (KnownZero & InSignBit) {
- KnownZero |= NewBits;
- KnownOne &= ~NewBits;
- } else if (KnownOne & InSignBit) {
- KnownOne |= NewBits;
- KnownZero &= ~NewBits;
- } else { // Otherwise, top bits aren't known.
- KnownOne &= ~NewBits;
- KnownZero &= ~NewBits;
- }
- return;
- }
- case ISD::ANY_EXTEND: {
- MVT::ValueType VT = Op.getOperand(0).getValueType();
- ComputeMaskedBits(Op.getOperand(0), Mask & MVT::getIntVTBitMask(VT),
- KnownZero, KnownOne, Depth+1);
- return;
- }
- case ISD::TRUNCATE: {
- ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero, KnownOne, Depth+1);
- assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
- uint64_t OutMask = MVT::getIntVTBitMask(Op.getValueType());
- KnownZero &= OutMask;
- KnownOne &= OutMask;
- break;
- }
- case ISD::AssertZext: {
- MVT::ValueType VT = cast<VTSDNode>(Op.getOperand(1))->getVT();
- uint64_t InMask = MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op.getOperand(0), Mask & InMask, KnownZero,
- KnownOne, Depth+1);
- KnownZero |= (~InMask) & Mask;
- return;
- }
- case ISD::ADD: {
- // If either the LHS or the RHS are Zero, the result is zero.
- ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1);
- ComputeMaskedBits(Op.getOperand(0), Mask, 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 low clear bits
- // common to both LHS & RHS. For example, 8+(X<<3) is known to have the
- // low 3 bits clear.
- uint64_t KnownZeroOut = std::min(CountTrailingZeros_64(~KnownZero),
- CountTrailingZeros_64(~KnownZero2));
-
- KnownZero = (1ULL << KnownZeroOut) - 1;
- KnownOne = 0;
- return;
- }
- case ISD::SUB: {
- ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0));
- if (!CLHS) return;
-
- // We know that the top bits of C-X are clear if X contains less bits
- // than C (i.e. no wrap-around can happen). For example, 20-X is
- // positive if we can prove that X is >= 0 and < 16.
- MVT::ValueType VT = CLHS->getValueType(0);
- if ((CLHS->getValue() & MVT::getIntVTSignBit(VT)) == 0) { // sign bit clear
- unsigned NLZ = CountLeadingZeros_64(CLHS->getValue()+1);
- uint64_t MaskV = (1ULL << (63-NLZ))-1; // NLZ can't be 64 with no sign bit
- MaskV = ~MaskV & MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op.getOperand(1), MaskV, KnownZero, KnownOne, Depth+1);
-
- // If all of the MaskV bits are known to be zero, then we know the output
- // top bits are zero, because we now know that the output is from [0-C].
- if ((KnownZero & MaskV) == MaskV) {
- unsigned NLZ2 = CountLeadingZeros_64(CLHS->getValue());
- KnownZero = ~((1ULL << (64-NLZ2))-1) & Mask; // Top bits known zero.
- KnownOne = 0; // No one bits known.
- } else {
- KnownZero = KnownOne = 0; // Otherwise, nothing known.
- }
- }
- return;
- }
- default:
- // Allow the target to implement this method for its nodes.
- if (Op.getOpcode() >= ISD::BUILTIN_OP_END) {
- case ISD::INTRINSIC_WO_CHAIN:
- case ISD::INTRINSIC_W_CHAIN:
- case ISD::INTRINSIC_VOID:
- computeMaskedBitsForTargetNode(Op, Mask, KnownZero, KnownOne);
- }
- return;
- }
-}
-
/// computeMaskedBitsForTargetNode - Determine which of the bits specified
/// in Mask are known to be either zero or one and return them in the
/// KnownZero/KnownOne bitsets.
@@ -1212,6 +881,7 @@ void TargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
uint64_t Mask,
uint64_t &KnownZero,
uint64_t &KnownOne,
+ const SelectionDAG &DAG,
unsigned Depth) const {
assert((Op.getOpcode() >= ISD::BUILTIN_OP_END ||
Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
@@ -1223,222 +893,6 @@ void TargetLowering::computeMaskedBitsForTargetNode(const SDOperand Op,
KnownOne = 0;
}
-/// ComputeNumSignBits - Return the number of times the sign bit of the
-/// register is replicated into the other bits. We know that at least 1 bit
-/// is always equal to the sign bit (itself), but other cases can give us
-/// information. For example, immediately after an "SRA X, 2", we know that
-/// the top 3 bits are all equal to each other, so we return 3.
-unsigned TargetLowering::ComputeNumSignBits(SDOperand Op, unsigned Depth) const{
- MVT::ValueType VT = Op.getValueType();
- assert(MVT::isInteger(VT) && "Invalid VT!");
- unsigned VTBits = MVT::getSizeInBits(VT);
- unsigned Tmp, Tmp2;
-
- if (Depth == 6)
- return 1; // Limit search depth.
-
- switch (Op.getOpcode()) {
- default: break;
- case ISD::AssertSext:
- Tmp = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
- return VTBits-Tmp+1;
- case ISD::AssertZext:
- Tmp = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
- return VTBits-Tmp;
-
- case ISD::Constant: {
- uint64_t Val = cast<ConstantSDNode>(Op)->getValue();
- // If negative, invert the bits, then look at it.
- if (Val & MVT::getIntVTSignBit(VT))
- Val = ~Val;
-
- // Shift the bits so they are the leading bits in the int64_t.
- Val <<= 64-VTBits;
-
- // Return # leading zeros. We use 'min' here in case Val was zero before
- // shifting. We don't want to return '64' as for an i32 "0".
- return std::min(VTBits, CountLeadingZeros_64(Val));
- }
-
- case ISD::SIGN_EXTEND:
- Tmp = VTBits-MVT::getSizeInBits(Op.getOperand(0).getValueType());
- return ComputeNumSignBits(Op.getOperand(0), Depth+1) + Tmp;
-
- case ISD::SIGN_EXTEND_INREG:
- // Max of the input and what this extends.
- Tmp = MVT::getSizeInBits(cast<VTSDNode>(Op.getOperand(1))->getVT());
- Tmp = VTBits-Tmp+1;
-
- Tmp2 = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- return std::max(Tmp, Tmp2);
-
- case ISD::SRA:
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- // SRA X, C -> adds C sign bits.
- if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- Tmp += C->getValue();
- if (Tmp > VTBits) Tmp = VTBits;
- }
- return Tmp;
- case ISD::SHL:
- if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- // shl destroys sign bits.
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (C->getValue() >= VTBits || // Bad shift.
- C->getValue() >= Tmp) break; // Shifted all sign bits out.
- return Tmp - C->getValue();
- }
- break;
- case ISD::AND:
- case ISD::OR:
- case ISD::XOR: // NOT is handled here.
- // Logical binary ops preserve the number of sign bits.
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (Tmp == 1) return 1; // Early out.
- Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1);
- return std::min(Tmp, Tmp2);
-
- case ISD::SELECT:
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (Tmp == 1) return 1; // Early out.
- Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1);
- return std::min(Tmp, Tmp2);
-
- case ISD::SETCC:
- // If setcc returns 0/-1, all bits are sign bits.
- if (getSetCCResultContents() == ZeroOrNegativeOneSetCCResult)
- return VTBits;
- break;
- case ISD::ROTL:
- case ISD::ROTR:
- if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
- unsigned RotAmt = C->getValue() & (VTBits-1);
-
- // Handle rotate right by N like a rotate left by 32-N.
- if (Op.getOpcode() == ISD::ROTR)
- RotAmt = (VTBits-RotAmt) & (VTBits-1);
-
- // If we aren't rotating out all of the known-in sign bits, return the
- // number that are left. This handles rotl(sext(x), 1) for example.
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (Tmp > RotAmt+1) return Tmp-RotAmt;
- }
- break;
- case ISD::ADD:
- // Add can have at most one carry bit. Thus we know that the output
- // is, at worst, one more bit than the inputs.
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (Tmp == 1) return 1; // Early out.
-
- // Special case decrementing a value (ADD X, -1):
- if (ConstantSDNode *CRHS = dyn_cast<ConstantSDNode>(Op.getOperand(0)))
- if (CRHS->isAllOnesValue()) {
- uint64_t KnownZero, KnownOne;
- uint64_t Mask = MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op.getOperand(0), Mask, KnownZero, KnownOne, Depth+1);
-
- // If the input is known to be 0 or 1, the output is 0/-1, which is all
- // sign bits set.
- if ((KnownZero|1) == Mask)
- return VTBits;
-
- // If we are subtracting one from a positive number, there is no carry
- // out of the result.
- if (KnownZero & MVT::getIntVTSignBit(VT))
- return Tmp;
- }
-
- Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1);
- if (Tmp2 == 1) return 1;
- return std::min(Tmp, Tmp2)-1;
- break;
-
- case ISD::SUB:
- Tmp2 = ComputeNumSignBits(Op.getOperand(1), Depth+1);
- if (Tmp2 == 1) return 1;
-
- // Handle NEG.
- if (ConstantSDNode *CLHS = dyn_cast<ConstantSDNode>(Op.getOperand(0)))
- if (CLHS->getValue() == 0) {
- uint64_t KnownZero, KnownOne;
- uint64_t Mask = MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op.getOperand(1), Mask, KnownZero, KnownOne, Depth+1);
- // If the input is known to be 0 or 1, the output is 0/-1, which is all
- // sign bits set.
- if ((KnownZero|1) == Mask)
- return VTBits;
-
- // If the input is known to be positive (the sign bit is known clear),
- // the output of the NEG has the same number of sign bits as the input.
- if (KnownZero & MVT::getIntVTSignBit(VT))
- return Tmp2;
-
- // Otherwise, we treat this like a SUB.
- }
-
- // Sub can have at most one carry bit. Thus we know that the output
- // is, at worst, one more bit than the inputs.
- Tmp = ComputeNumSignBits(Op.getOperand(0), Depth+1);
- if (Tmp == 1) return 1; // Early out.
- return std::min(Tmp, Tmp2)-1;
- break;
- case ISD::TRUNCATE:
- // FIXME: it's tricky to do anything useful for this, but it is an important
- // case for targets like X86.
- break;
- }
-
- // Handle LOADX separately here. EXTLOAD case will fallthrough.
- if (Op.getOpcode() == ISD::LOAD) {
- LoadSDNode *LD = cast<LoadSDNode>(Op);
- unsigned ExtType = LD->getExtensionType();
- switch (ExtType) {
- default: break;
- case ISD::SEXTLOAD: // '17' bits known
- Tmp = MVT::getSizeInBits(LD->getLoadedVT());
- return VTBits-Tmp+1;
- case ISD::ZEXTLOAD: // '16' bits known
- Tmp = MVT::getSizeInBits(LD->getLoadedVT());
- return VTBits-Tmp;
- }
- }
-
- // Allow the target to implement this method for its nodes.
- if (Op.getOpcode() >= ISD::BUILTIN_OP_END ||
- Op.getOpcode() == ISD::INTRINSIC_WO_CHAIN ||
- Op.getOpcode() == ISD::INTRINSIC_W_CHAIN ||
- Op.getOpcode() == ISD::INTRINSIC_VOID) {
- unsigned NumBits = ComputeNumSignBitsForTargetNode(Op, Depth);
- if (NumBits > 1) return NumBits;
- }
-
- // Finally, if we can prove that the top bits of the result are 0's or 1's,
- // use this information.
- uint64_t KnownZero, KnownOne;
- uint64_t Mask = MVT::getIntVTBitMask(VT);
- ComputeMaskedBits(Op, Mask, KnownZero, KnownOne, Depth);
-
- uint64_t SignBit = MVT::getIntVTSignBit(VT);
- if (KnownZero & SignBit) { // SignBit is 0
- Mask = KnownZero;
- } else if (KnownOne & SignBit) { // SignBit is 1;
- Mask = KnownOne;
- } else {
- // Nothing known.
- return 1;
- }
-
- // Okay, we know that the sign bit in Mask is set. Use CLZ to determine
- // the number of identical bits in the top of the input value.
- Mask ^= ~0ULL;
- Mask <<= 64-VTBits;
- // Return # leading zeros. We use 'min' here in case Val was zero before
- // shifting. We don't want to return '64' as for an i32 "0".
- return std::min(VTBits, CountLeadingZeros_64(Mask));
-}
-
-
-
/// ComputeNumSignBitsForTargetNode - This method can be implemented by
/// targets that want to expose additional information about sign bits to the
/// DAG Combiner.
@@ -1597,7 +1051,8 @@ TargetLowering::SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
cast<ConstantSDNode>(N0.getOperand(1))->getValue() == 1) {
// If this is (X^1) == 0/1, swap the RHS and eliminate the xor. We
// can only do this if the top bits are known zero.
- if (MaskedValueIsZero(N0, MVT::getIntVTBitMask(N0.getValueType())-1)){
+ if (DAG.MaskedValueIsZero(N0,
+ MVT::getIntVTBitMask(N0.getValueType())-1)){
// Okay, get the un-inverted input value.
SDOperand Val;
if (N0.getOpcode() == ISD::XOR)
@@ -1761,7 +1216,7 @@ TargetLowering::SimplifySetCC(MVT::ValueType VT, SDOperand N0, SDOperand N1,
if (N0.getOpcode() == ISD::XOR)
// If we know that all of the inverted bits are zero, don't bother
// performing the inversion.
- if (MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue()))
+ if (DAG.MaskedValueIsZero(N0.getOperand(0), ~LHSR->getValue()))
return DAG.getSetCC(VT, N0.getOperand(0),
DAG.getConstant(LHSR->getValue()^RHSC->getValue(),
N0.getValueType()), Cond);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2025-05-04 08:55:46 +0000