On 02/10/13 09:34, Oleksandr Redchuk wrote: > 2013/10/2 Georg-Johann Lay <a...@gjlay.de <mailto:a...@gjlay.de>> > > David Brown schrieb: > > In general, it would be a good thing to delay the zeroing of r1, > and it > is worth searching the issue database for previous issues and > filing a > new "missed optimisation" issue if it is not there already: > > > IMHO everyone working on the avr back-end is aware of this problem. > > > May be, reassigning __zero_reg__ to R2 and using R1:R0 as > __temp_reg_hi__:__temp_reg__ will be better but I can't estimate both > complexity of changes and code size/perfomance gain effect. >
I believe this has been discussed before, and the conclusion was that this would have been a good idea if it had come in the early days of avr-gcc, but it is not worth breaking the established ABI. I think the changes in gcc would be relatively simple - but the changes in the support libraries in gcc and avr-libc would be much greater. And of course anyone with assembly code that works along with avr-gcc will be in trouble too. mvh., David _______________________________________________ AVR-GCC-list mailing list AVR-GCC-list@nongnu.org https://lists.nongnu.org/mailman/listinfo/avr-gcc-list
