[Bug middle-end/63568] Missed optimization (a & ~mask) | (b & mask) = a ^ ((a ^ b) & mask)

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63568

--- Comment #7 from Oleg Endo <olegendo at gcc dot gnu.org> ---
If you decide not to do the transform at the tree level, please change this to
a target PR and assign it to me.