> Am 10.12.2022 um 13:15 schrieb Georg-Johann Lay <a...@gjlay.de>:
>
>
>
>> Am 09.12.22 um 22:14 schrieb Vladimir Makarov:
>>> On 2022-12-09 14:23, Georg-Johann Lay wrote:
>>> There is the following code size regression, filed as
>>>
>>> https://gcc.gnu.org/PR90706
>>>
>> I am sorry, I feel your frustration. I was not aware of this PR.
>> Unfortunately, the PR was marked as P4 and I have too many open PRs and
>> should prioritize them.
>> I've just started to work on this issue. It is hard for me to say when it
>> will be fixed. I'll give an update on the next week.
>
> Hi Vladimir,
>
> Thank you so much.
>
> As far as I understand, avr is a ternary target and hence PRs for avr will
> have priority P4 or P5?
Yes, since AVR is not primary or secondary regressions specific to AVR are P4
or lower.
If the same issue can be observed on a target that is secondary or primary that
would change this aspect.
Richard
> Johann
>
>
>>> Simple test cases are, for example
>>>
>>> #define PORT (*((unsigned char volatile*) 0x24))
>>>
>>> unsigned short var16;
>>>
>>> void func (void)
>>> {
>>> if (2048000ul * var16 > 1200000ul)
>>> PORT |= 1;
>>> }
>>>
>>> When I compile it with
>>>
>>> $ avr-gcc -Os bloat1.c -c && avr-size bloat1.o
>>>
>>> the code size increases from 36 bytes (v8) to 88 bytes (v13).
>>>
>>> Apart from that, register pressure is much higher because a frame pointer
>>> is set up for no reason, and the values go through stack slots for no
>>> reason.
>>>
>>> Even test cases which don't require any code like
>>>
>>> long func2 (void)
>>> {
>>> long var32;
>>> __asm ("; some code %0" : "=r" (var32));
>>> return var32;
>>> }
>>>
>>> increase in register pressure (x2), stack usage (from 0 to 6 bytes) and
>>> code size from 2 bytes (v8) to 34 bytes (v13).
>>>
>>> Some projects like QMK "solved" the problem by declaring GCC > v8 to be
>>> "incompatible" with their project, see
>>> https://github.com/qmk/qmk_firmware/issues/6719
>>>
>>> In own projects I observed the problem, too, and the only solution is to
>>> use v8 or older. Options like -fcaller-saves or -fira-algorithm= have no
>>> effect.
>>>
>>> To configure, I used --target=avr --disable-nls --with-dwarf2
>>> --enable-languages=c,c++ --with-gnu-as --with-gnu-ld --disable-shared, so
>>> nothing special.
>>>
>>> The problem is present in v9, v10, v11, v12 and master (future v13), so
>>> sitting around for quite a while, so maybe it's not fixed because RA
>>> maintainers are not aware of the problem.
