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For PR1205:

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Provide an APIntified version of MaskedValueIsZero. This will (temporarily)
cause a "defined but not used" message from the compiler. It will be used
in the next patch in this series.

Patch by Sheng Zhou.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35019 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Reid Spencer 2007-03-08 01:52:58 +00:00
parent 3e7594f187
commit e7816b5c9e
1 changed files with 10 additions and 0 deletions
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10
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -979,6 +979,16 @@ static bool MaskedValueIsZero(Value *V, uint64_t Mask, unsigned Depth = 0) {
return (KnownZero & Mask) == Mask;
}
/// 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.
static bool MaskedValueIsZero(Value *V, const APInt& Mask, unsigned Depth = 0) {
APInt KnownZero(Mask), KnownOne(Mask);
ComputeMaskedBits(V, Mask, KnownZero, KnownOne, Depth);
assert((KnownZero & KnownOne) == 0 && "Bits known to be one AND zero?");
return (KnownZero & Mask) == Mask;
}
/// ShrinkDemandedConstant - Check to see if the specified operand of the
/// specified instruction is a constant integer. If so, check to see if there
/// are any bits set in the constant that are not demanded. If so, shrink the