slow V3 configures (was Re: ICE during bootstrap.)

[Raja R Harinath]

Raja R Harinath <harinath@cs.umn.edu> writes:
> Phil Edwards <pedwards@disaster.jaj.com> writes:
> > Anyhow, I patched all the math tests to explictly do the same test that
> > AC_CACHE_VAL does before calling AC_CACHE_VAL itself.  The speedup is
> > /considerable/.  The config.cache and bits/c++config.h results are identical.
> > 
> > One downside:  it's AC_CACHE_VAL that does the printing of "(cached)".
> > My change means that a cached value still shows on the screen as
> > 
> >     checking for _expf declaration... no
> >     checking for _fabsf declaration... no
> >     checking for _floorf declaration... no
> >     checking for _fmodf declaration... no
> >     checking for _frexpf declaration... no
> >     checking for _ldexpf declaration... no
> 
> Looks like you are skipping the 
>              ^^^^^^^ 
>   if test x$glibcpp_cv_func_$1_use = x"yes"; then
>     AC_CHECK_FUNCS($1)    
>   fi
> 
> part, so it's probably not a valid comparison :-)

Actually, I couldn't have made that deduction with the fragment you
should above.

Anyway, I'm _guessing_ that the reason you see the speedup is because
you "may be" skipping over the AC_CHECK_FUNCS test the moment
$glibcpp_cv_func_$1_use has a cached answer.

- Hari
-- 
Raja R Harinath ------------------------------ harinath@cs.umn.edu
"When all else fails, read the instructions."      -- Cahn's Axiom
"Our policy is, when in doubt, do the right thing."   -- Roy L Ash