Re: [avr-gcc-list] Optimization around mul and restoring r1

[Oleksandr Redchuk]

2013/10/2 Georg-Johann Lay <address@hidden>

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.

--
wbr,
ReAl