Re: [avr-gcc-list] Gcc branches small comparison.

[Bruce D. Lightner]

Dmitry K. wrote:

> Hi all.
>
> Functions are from avr-libc-1.2.0, without ones too small or asm.
> (`*-new' are from patches).
>
> Results are in form: prog_words + stack_bytes
>
> -mmcu=atmega8 -Os -frename-registers
>                 3.2.3   3.3.5   3.4.3   4.0     4.0-nrr
>
> bsearch          69+12   68+12   67+12   66+12   66+12
> bsearch-new      70+12   70+12   69+12   76+14   76+14
> malloc          164+2   152+0   156+2   158+2   158+2
> free             99+2    92+2    92+2    86+2    86+2
> qsort           464+22  450+22  450+22  412+22  412+22
> do_random       102+14   91+10   93+10  173+14  173+14
> realloc         240+12  230+12  228+12  233+14  234+14
> strtol          308+36  291+36  295+36  318+36  312+36
> strtol-new      286+16  276+16  281+16  297+17  297+17
> strtoul         277+29  260+29  261+29  278+27  278+27
> strtoul-new     278+16  265+16  264+16  317+21  317+21
> vfprintf        672+36  652+36  626+36  694+37  694+37
> vfscanf         655+24  637+24  601+24  725+39  726+39
>
> Notes:
>     * Stack usage -- without nested calls.
>     * 4.0 is 20050116
>     * `-frename-registers' is not recommended in 4.0, so `4.0-nrr' is
>     without this option.

Thank you for taking the time to run these benchmarks and share the 
results with us!

The results for 4.0 clearly suck!  These are big differences for 
microcontrollers with very limited memory space.  Can you explain what is 
going on?

Or, am I being stupid assuming that things will *always* get better as 
time goes on?

Maybe things like "Moore's Law" are setting unrealistic expectations for 
those of us in this business.  Is the Second Law of Thermodynamics 
affecting "gcc" development?  Is ever increasing entropy is somehow 
negatively affecting "gcc" source code tree! :-)

Best regards,

Bruce

--
 Bruce D. Lightner
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