IC: (X & C1) | C2 --> (X | C2) & (C1|C2)

IC: (X ^ C1) | C2 --> (X | C2) ^ (C1&~C2)

We are now guaranteed that all 'or's will be inside of 'and's, and all 'and's
will be inside of 'xor's, if the second operands are constants.

llvm-svn: 7264