[avr-gcc-list] Re: -O vs. -O2

[Nathan Cooprider]

Nuts. I hope my original posting of this bounces off the server and did 
not spam all your boxes. I didn't realize how big the source file was.

If the file was blocked (as I hope it was) then you can find a tarred up 
version of it on my web page instead:

http://www.cs.utah.edu/~coop/file.tgz

I apologize again for my stupidity.

Nathan

Nathan Cooprider wrote:
> Some level of -O2 is breaking my application. I think this is a known 
> bug, but I am trying to find which specific option is breaking things so 
> I can still optimize as much as possible. I am attaching the file I want 
> to compile.
>
> avr-gcc -mmcu=atmega128 -O -fdollars-in-identifiers file.c
>
> Compiles just fine, but
>
> avr-gcc -mmcu=atmega128 -O2 -fdollars-in-identifiers file.c
>
> does not. Also
>
> avr-gcc -mmcu=atmega128 -O -fdollars-in-identifiers -fthread-jumps 
> -fcrossjumping -foptimize-sibling-calls -fcse-follow-jumps 
> -fcse-skip-blocks -fgcse -fgcse-lm -fexpensive-optimizations 
> -frerun-cse-after-loop -fcaller-saves -fpeephole2 -fschedule-insns 
> -fschedule-insns2 -fsched-interblock -fsched-spec -fregmove 
> -fstrict-aliasing -fdelete-null-pointer-checks -freorder-blocks 
> -freorder-functions -falign-functions -falign-jumps -falign-loops 
> -falign-labels file.c
>
> compiles fine as well, which is strange because I manually add to -O all 
> the options to make it -O2.
>
> The error I get (for the -O2 compilation) is:
>
> file.c: In function `TrickleTimerImplP$0$adjustTimer':
> file.c:32409: error: unable to find a register to spill in class 
> `BASE_POINTER_REGS'
>
> I would just like to isolate the optimization option that is triggering 
> the bug, but apparently I am missing something. I got my optimization 
> list from http://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
>
> Any thoughts/comments would be appreciated. Thanks.
>
> Nathan