[Bug tree-optimization/78821] GCC7: Copying whole 32 bits structure field by field not optimised into copying whole 32 bits at once

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78821

--- Comment #25 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Jakub Jelinek from comment #23)
> I believe enabled attribute can't depend on 
> optimize_function_for_size_p (cfun).

Indeed. Maybe preferred_for_size can come handy here (and in bswaphi_lowpart
that obviously predates introduction of this tune flag).