[Bug tree-optimization/90271] [missed-optimization] failure to keep variables in registers during "faux" memcpy

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90271

--- Comment #9 from rguenther at suse dot de <rguenther at suse dot de> ---
On April 29, 2019 9:23:21 PM GMT+02:00, "eyalroz at technion dot ac.il"
<gcc-bugzilla@gcc.gnu.org> wrote:
>https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90271
>
>--- Comment #8 from Eyal Rozenberg <eyalroz at technion dot ac.il> ---
>(In reply to rguenther@suse.de from comment #5)
>> int foo3()
>> {
>>   struct { int x; int y; } s;
>>   s.x = 3;
>>   char c = 1;
>>   return replace_bytes_3(&s.x,c);
>> }
>> 
>> Coalescing successful!
>> Merged into 1 stores
>
>This is very interesting! Do you think I could somehow adapt this
>example into
>a workaround, for existing GCC versions, rather than wait for the bug
>fix?

You'd have to experiment with different GCC versions, but yes.