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[GlobalISel] GISelKnownBits::computeKnownBitsImpl - Replace TargetOpcode::G_MUL handling with the common KnownBits::computeForMul implementation 

Avoid code duplication
This commit is contained in:
Simon Pilgrim 2020-11-04 17:06:19 +00:00
parent 3ebcef4b73
commit 0b8711e1af
1 changed files with 1 additions and 14 deletions
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15
llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
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@ -287,20 +287,7 @@ void GISelKnownBits::computeKnownBitsImpl(Register R, KnownBits &Known,
Depth + 1); Depth + 1);
computeKnownBitsImpl(MI.getOperand(1).getReg(), Known2, DemandedElts, computeKnownBitsImpl(MI.getOperand(1).getReg(), Known2, DemandedElts,
Depth + 1); Depth + 1);
// If low bits are zero in either operand, output low known-0 bits. Known = KnownBits::computeForMul(Known, Known2);
// Also compute a conservative estimate for high known-0 bits.
// More trickiness is possible, but this is sufficient for the
// interesting case of alignment computation.
unsigned TrailZ =
Known.countMinTrailingZeros() + Known2.countMinTrailingZeros();
unsigned LeadZ =
std::max(Known.countMinLeadingZeros() + Known2.countMinLeadingZeros(),
BitWidth) -
BitWidth;
Known.resetAll();
Known.Zero.setLowBits(std::min(TrailZ, BitWidth));
Known.Zero.setHighBits(std::min(LeadZ, BitWidth));
break; break;
} }
case TargetOpcode::G_SELECT: { case TargetOpcode::G_SELECT: {