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InstCombine: ((A & ~B) ^ (~A & B)) to A ^ B

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Proof using CVC3 follows:
$ cat t.cvc
A, B : BITVECTOR(32);
QUERY BVXOR((A & ~B),(~A & B)) = BVXOR(A,B);
$ cvc3 t.cvc
Valid.

Differential Revision: http://reviews.llvm.org/D4898


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@215974 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Mayur Pandey
2014-08-19 08:19:19 +00:00
parent 7ce4ac12fc
commit ecdb0ab90f
2 changed files with 23 additions and 0 deletions
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lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+10
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@@ -2522,6 +2522,16 @@ Instruction *InstCombiner::visitXor(BinaryOperator &I) {
match(Op1I, m_Or(m_Specific(A), m_Not(m_Specific(B))))) {
return BinaryOperator::CreateXor(A, B);
}
// (A & ~B) ^ (~A & B) -> A ^ B
if (match(Op0I, m_And(m_Value(A), m_Not(m_Value(B)))) &&
match(Op1I, m_And(m_Not(m_Specific(A)), m_Specific(B)))) {
return BinaryOperator::CreateXor(A, B);
}
// (~A & B) ^ (A & ~B) -> A ^ B
if (match(Op0I, m_And(m_Not(m_Value(A)), m_Value(B))) &&
match(Op1I, m_And(m_Specific(A), m_Not(m_Specific(B))))) {
return BinaryOperator::CreateXor(A, B);
}
// (A ^ B)^(A | B) -> A & B
if (match(Op0I, m_Xor(m_Value(A), m_Value(B))) &&
match(Op1I, m_Or(m_Value(C), m_Value(D)))) {