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Teach InstructionSimplify to fold (A & B) & A -> A & B and (A | B) | A -> A | B.

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Reassociate does this but it doesn't catch all cases (e.g. if the operands are i1).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113651 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Benjamin Kramer
2010-09-10 22:39:55 +00:00
parent e2d50046fd
commit 6844c8ea5a
3 changed files with 55 additions and 0 deletions
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20
lib/Analysis/InstructionSimplify.cpp
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@@ -106,6 +106,16 @@ Value *llvm::SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD) {
(A == Op0 || B == Op0))
return Op0;
// (A & B) & A -> A & B
if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return Op0;
// A & (A & B) -> A & B
if (match(Op1, m_And(m_Value(A), m_Value(B))) &&
(A == Op0 || B == Op0))
return Op1;
return 0;
}
@@ -165,6 +175,16 @@ Value *llvm::SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD) {
(A == Op0 || B == Op0))
return Op0;
// (A | B) | A -> A | B
if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
(A == Op1 || B == Op1))
return Op0;
// A | (A | B) -> A | B
if (match(Op1, m_Or(m_Value(A), m_Value(B))) &&
(A == Op0 || B == Op0))
return Op1;
return 0;
}