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Reapply r153423; the original commit was fine. The failing test, distray, had

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undefined behavior, which Rafael was kind enough to fix.

Original commit message for r153423:
Use the new range metadata in computeMaskedBits and add a new optimization to
instruction simplify that lets us remove an and when loding a boolean value.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153521 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chad Rosier
2012-03-27 17:44:52 +00:00
parent 805543068e
commit d23a64cc16
3 changed files with 56 additions and 0 deletions
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15
lib/Analysis/InstructionSimplify.cpp
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@ -1370,6 +1370,21 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const Query &Q,
return Op1;
}
unsigned Bitwidth = Op1->getType()->getScalarSizeInBits();
APInt DemandedMask = APInt::getAllOnesValue(Bitwidth);
APInt KnownZero0 = APInt::getNullValue(Bitwidth);
APInt KnownOne0 = APInt::getNullValue(Bitwidth);
ComputeMaskedBits(Op0, DemandedMask, KnownZero0, KnownOne0);
APInt KnownZero1 = APInt::getNullValue(Bitwidth);
APInt KnownOne1 = APInt::getNullValue(Bitwidth);
ComputeMaskedBits(Op1, DemandedMask, KnownZero1, KnownOne1);
if ((KnownZero0 | KnownOne1).isAllOnesValue())
return Op0;
if ((KnownZero1 | KnownOne0).isAllOnesValue())
return Op1;
// Try some generic simplifications for associative operations.
if (Value *V = SimplifyAssociativeBinOp(Instruction::And, Op0, Op1, Q,
MaxRecurse))