In Praise of GCC 3.4.3.20050110

Bob P · Posted: Sat Jan 22, 2005 4:48 pm Post subject: In Praise of GCC 3.4.3.20050110

My luck being what it is, I caught the upgrade from GCC 3.4.3-r1 to GCC 3.4.3.20050110 about a week ago when I was updating my main Gentoo box, and committed to a full system rebuild before it was hard masked out of the portage tree.

I already had a fully functional GCC 3.4.3-r1 system that was built using the "proper" but painfully detailed method of rebuilding the toolkit components redundantly (so that the entire toolkit was built with a 3.4.3-r1 compiler that was compiled on a 3.4.3-r1 compiler that was built with a 3.4.3-r1 compiler). after rebuliding the toolkit, I did the complete emerge -e system (twice) and a complete emerge -e world (twice). the result was a very stable GCC 3.4.3-r1 system. of course, why would any basement-dwelling linux geek be satisfied with that? i just had to upgrade to GCC 3.4.3.20050110.

So I downloaded 20050110. then i rebuilt the entire toolkit three times, so that i would have a toolkit built on a compiler that was compiled with a compiler that was built on itself. then i changed some USE flags to get rid of a host of unwanted gnome dependencies. that bottom line was that i needed to rebuild the system again. so i did an emerge -e system, and then did the "emerge -uDv --newuse world", depclean, and revdep-rebuild. i was amazed by the results:

much to my amazement, i was able to complete the entire system rebuild using GCC 3.4.3.20050110 using the following set of flags, which many experienced gentoo users would consider "insane":

Deranger · Veteran Joined: 26 Aug 2004 Posts: 1215 Location: Finland

I'm still using 3.4.3-r1, but that sounds really great. However, I suggest removing -funroll-loops (bloats binaries, totally useless) and moving from -O3 to -O2 (-O2 is faster in many cases, and produces not-so-bloated binaries) when you are rebuilding your toolchain next time

It might sound useless to build a proper toolchain, but it really isn't!
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piwacet · Guru Joined: 29 Dec 2004 Posts: 376

Yeah - I actually caught this compiler also during it's brief life.... while I was doing Bob P's Stage 1 install on Stage 3 tarball with gcc-3.4.3.... So my system, also, had it's entire toolchain compiled 3 times with this now masked version of gcc 3.4.3, and I have subsequently emerged my entire world using this toolchain.

My system is rock-solid. Maybe because Bob P and I both have pentium 3's? Perhaps we're avoiding architecture-specific bugs in the compiler.

Although I used much more conservative C-flags the whole way through:

Torangan · Tux's lil' helper Joined: 21 Mar 2003 Posts: 128

Just out of curiosity - does neither of you use LDFLAGS="-Wl,-O1"? I found that it really does improve the startup times of some applications without harm.
BTW I also had the mentioned version of GCC on my system for some time and could go back to former one without problems. In fact, I had no problems with it at all (I didn't do an emerge -e world, takes too much time).

Deranger · Veteran Joined: 26 Aug 2004 Posts: 1215 Location: Finland

Bob P · Posted: Sun Jan 23, 2005 3:59 pm Post subject:

nope, no LDFLAGS for me. there's a limit to how far i want to push the insane flag settings while still expecting things to work. but then perhaps my success is only an artifact of aggressive flag filtration on the part of the developers anyway. :roll:

about the LDFLAGS: i may put them on my list of things to try next time, provided my next system build comes along before 2005.0, where LDFLAGS will probably be set invisibly by the developers.
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Duncan Mac Leod · Posted: Mon Jan 24, 2005 9:19 pm Post subject:

sigSEGV2003 · Posted: Mon Jan 24, 2005 9:24 pm Post subject:

GCC 3.4.3.20050110 on athlon-tbird with -O3 and no problems at all here.

Gnufsh · Guru Joined: 28 Dec 2002 Posts: 400 Location: Portland, OR

It seems to be back in ~x86 now, I'm compiling it now.

brullonulla · Posted: Tue Jan 25, 2005 6:14 pm Post subject:

I came on this thread by chance and I'm scared!

Do I need to re-emerge my whole system at every GCC upgrade or do you do it just because it's fancy?

I'm a young (2 months) gentoo user, and I never read about it in the docs, so please let me know...
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firephoto · Posted: Tue Jan 25, 2005 8:11 pm Post subject:

I noticed it's back too but haven't updated again since there's no mention of it getting unmasked in the changlog just a reference to something else. I noticed that it's properly not slotted too.

Bob P · Posted: Wed Jan 26, 2005 11:37 am Post subject:

Bob P · Posted: Wed Jan 26, 2005 11:40 am Post subject:

Devport · Guru Joined: 14 Dec 2004 Posts: 331

Bob P · Posted: Wed Jan 26, 2005 7:10 pm Post subject:

hiroki · Posted: Wed Jan 26, 2005 7:19 pm Post subject:

hi!

anyone using gcc-3.4.3-20050110 forbuilding the kernel?
today i tried to build gentoo-dev-sources-2.6.10-r6 with it. it worked, compiled without errors, but when i boot ... it's booting veeeeery slow. like slow motion >< every line that appears on the console needs several seconds, some even take a minute... how can this happen?
the X server also took years (!) to start. after loggin in (via GDM) X had average speed (as usual). so just the console seems sooooo slow. how come? any ideas?

grtz.

MrApples · Guru Joined: 13 Dec 2002 Posts: 511

try building whatever kernel you were using before with it, and see if there is a difference
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TwoMinds · Posted: Thu Jan 27, 2005 3:05 am Post subject:

...I had a problem building the same kernel I had... everything goes fine: kernel + qc-usb + 3dfx.ko + svgalib but subfs now doesn't work... it's built and loaded but can't access any mount giving no medium found...
quickpgk gcc-3.4.3-20050110 && emerge =gcc-3.4.3-r1 and rebuilding everything works...

hiroki · Posted: Thu Jan 27, 2005 4:10 am Post subject:

Hauser · Posted: Fri Jan 28, 2005 1:37 pm Post subject:

MrApples · Guru Joined: 13 Dec 2002 Posts: 511

Stormblazer · Posted: Fri Jan 28, 2005 4:09 pm Post subject:

Is there a script I can use to rebuild the toolchain (redundant fashion), because I don't want to do it by hand, and I also don't think I should use the bootstrap script.
Or do I just emerge the toolchain 3 times?
I'm planning on remerging the whole thing too

finally, what do these flags do? I haven't seen them before (I also like using insane flag settings

)
fmerge-all-constants
fvisibility=hidden
fvisibility-inlines=hidden

Roguelazer · Posted: Fri Jan 28, 2005 4:15 pm Post subject:

Stormblazer:

Deranger · Veteran Joined: 26 Aug 2004 Posts: 1215 Location: Finland

A complete toolchain rebuild is basically the following:

MrApples · Guru Joined: 13 Dec 2002 Posts: 511

while rebuilding the toolchain 2 or 3 times is fine, i would also really recommend the wrapper script from hielvc
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