https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96691
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(~x | 123) ^ 321 can't be replaced by (x | 123) ^ ~321, that is not equivalent.
I think the equivalencies this is based on are that for any X, C, D
((~X | C) ^ D) == ((X | C) ^ (~D ^ C))
and
((~X & C) ^ D) == ((X & C) ^ (D ^ C))
so if C and D are integral constants (scalar or vector), we should simplify it
that way, and furthermore I'd say we should simplify
(X | Y) ^ (~Z ^ Y)
into
(~X | Y) ^ Z
as the latter has fewer operations.
