[gentoo-dev] Re: GCC3.1 bootstrap fails

[Prashanth Aditya Susarla <aditya@iitk.ac.in>]

>do -not- use  -fomit-frame-pointer during bootstrap! (can anyone who
>actually got this to -work- using omit-frame-pointer speak up??) 
>
>This causes breakage in glibc.

That's interesting. When I used default-1.0, I used all the flags which
one particular FAQ on gentoo.org mentioned (-fforce-addr
-fomit-frame-pointer -funroll-loops blah blah blah along with -march=i686
-O3 of course) and everything worked fine (atleast compiled fine though I
was not truly happy with the performance (lots of memory leaks and
subsequent crashes of kswapd primarily). So maybe this is an issue only
with gcc-3.x and/or binutils-2.12.x. But I toned down the optimizations
and the bootstrap worked fine.

>this is due to a broken glibc (omit frame pointer and -O3. I think glibc
>strips out -O3 but  not the -f flags. )

gcc does this. glibc retains whatever you specify. Anyway, that's beside
the point - only for the sake of information ;-).

>> problem is that most binaries segfault soon after glibc is built.
>Try again with -O2 -pipe  and you will get a working system :)

Infact, I finally used the default options for Athlon systems (-march=i686
-pipe -O3.... not -O2 but -O3) and glibc didn't break. As I said earlier,
this is strange because all those crazy optimizations worked in the case
of the default-1.0 profile. 

>emerge system
>/(watch it break down and cry in xfree because you overoptimized)

So you're saying that if I use -march=athlon-tbird -fomit-frame-pointer
-O3 [-pipe] -mmmx -m3dnow (the latter only for the sake of multimedia apps
like xmms, mplayer etc.) the xfree ebuild b0rks out? That's too bad,
really. And the thing with xfree is that experimenting stops being an
option if the very first emerge itself doesn't work :-(. Not all of us
have all the time in the world...

Regards,
Prashanth Aditya Susarla