Re: [gentoo-user] revdep-rebuild (gawk) issues

[Alan McKinnon <alan.mckinnon@gmail.com>]

On Tue, 29 May 2012 22:56:07 +0200
Rafa Griman <rafagriman@gmail.com> wrote:

> Hi Vaeth :)
> 
> On Tue, May 29, 2012 at 7:02 PM, Vaeth
> <vaeth@mathematik.uni-wuerzburg.de> wrote:
> > On Tue, 29 May 2012, Rafa Griman wrote:
> >>
> >> gawk: cmd. line:3: error: Unmatched [ or [^: /[^[:space:]]/
> >
> >
> > Your gawk is broken. This happens if you emerged gawk with
> > current gcc and aggressive FLAGS like -DNDEBUG or -flto.
> > Not sure whether it is a bug of gawk or gcc.
> 
> 
> So it seems to be the CFLAGS :( As I said in my previous e-mail, I was
> "experimenting" a bit with them ... I'll be more conservative ;)

Well, on the one hand the flags don;t seem to be too bad overall, but
on the other hand there's the golden rule of Gentoo:

Don't stuff around with CFLAGS

Why not? Well, there's the ricer phenomenon where changed CFLAGS
worsen performance and stability but the user's own bias convinces
him/her that it's actually vastly improved.

Some tweaks are perfectly OK, like the multimedia and cpu-specific
stuff (sse, mmx and all their related cousins). These are normally safe
and can give huge gains with video playback. Likewise for the GPU tweaks
once those hit mainline usage.

One last tweak, if the code is built on the machine that will run it
(the usual case, replace -march and -mtune with just "-march=native".
It has exactly the same effect but is easier to read, is
self-documenting and allows the compiler to attempt it's best (the
compiler usually does know much better what to do than you do)

-- 
Alan McKinnnon
alan.mckinnon@gmail.com