Shuxin Yang
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2d10010649
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Implement XOR reassociation. It is based on following rules:
rule 1: (x | c1) ^ c2 => (x & ~c1) ^ (c1^c2),
only useful when c1=c2
rule 2: (x & c1) ^ (x & c2) = (x & (c1^c2))
rule 3: (x | c1) ^ (x | c2) = (x & c3) ^ c3 where c3 = c1 ^ c2
rule 4: (x | c1) ^ (x & c2) => (x & c3) ^ c1, where c3 = ~c1 ^ c2
It reduces an application's size (in terms of # of instructions) by 8.9%.
Reviwed by Pete Cooper. Thanks a lot!
rdar://13212115
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@178409 91177308-0d34-0410-b5e6-96231b3b80d8
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2013-03-30 02:15:01 +00:00 |
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