I can't convince myself that this is safe, remove the recursive call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26725 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-03-13 06:42:16 +00:00
parent 79dbea5ab4
commit b6b17ffbc6

View File

@ -565,23 +565,6 @@ bool TargetLowering::SimplifyDemandedBits(SDOperand Op, uint64_t DemandedMask,
break;
}
case ISD::ADD:
if (ConstantSDNode *AA = dyn_cast<ConstantSDNode>(Op.getOperand(1))) {
if (SimplifyDemandedBits(Op.getOperand(0), DemandedMask, KnownZero,
KnownOne, TLO, Depth+1))
return true;
// Compute the KnownOne/KnownZero masks for the constant, so we can set
// KnownZero appropriately if we're adding a constant that has all low
// bits cleared.
ComputeMaskedBits(Op.getOperand(1),
MVT::getIntVTBitMask(Op.getValueType()),
KnownZero2, KnownOne2, Depth+1);
uint64_t KnownZeroOut = std::min(CountTrailingZeros_64(~KnownZero),
CountTrailingZeros_64(~KnownZero2));
KnownZero = (1ULL << KnownZeroOut) - 1;
KnownOne = 0;
}
break;
case ISD::SUB:
// Just use ComputeMaskedBits to compute output bits, there are no
// simplifications that can be done here, and sub always demands all input
@ -843,7 +826,8 @@ void TargetLowering::ComputeMaskedBits(SDOperand Op, uint64_t Mask,
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;
// 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));