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Re: slow V3 configures (was Re: ICE during bootstrap.)
Phil Edwards <firstname.lastname@example.org> writes:
> On Tue, Dec 05, 2000 at 11:53:57AM -0800, Benjamin Kosnik wrote:
> > Following phil's advice and changing to
> > test-for-cached-answer-oh-it's-there-never-mind
> > else
> > push-current-language-on-stack
> > set-current-language-to-C++
> > test and cache
> > pop-language-from-stack
> > end
> > seems like the best approach.
> The odd thing is... this is what should be happening now. All the
> push-set-test-cache-pop stuff is done inside the list of commands "to be
> run if the value isn't cached". We still get serious pauses.
Well, not exactly. What's happening is
if have cached_answer; then :;
execute test to check for declaration and update cached_answer
if test $cached_answer = yes; then
AC_CHECK_FUNCS uses a for loop, which executes even if the cached
answer is returned. That's probably where all that time is lost.
One option is to use AC_CHECK_FUNC, but you lose the automatic
definition of HAVE_FOO and corressponding updates of config.h.in.
Another is to have parallel tests.
# check these unconditionally
AC_CHECK_FUNCS(sinf isnanf hypotf ...)
This may increase the 'configure' time somewhat for the first time,
but is likely to zoom through on re-runs.
> Anyhow, I patched all the math tests to explictly do the same test that
> AC_CACHE_VAL does before calling AC_CACHE_VAL itself. The speedup is
> /considerable/. The config.cache and bits/c++config.h results are identical.
> One downside: it's AC_CACHE_VAL that does the printing of "(cached)".
> My change means that a cached value still shows on the screen as
> checking for _expf declaration... no
> checking for _fabsf declaration... no
> checking for _floorf declaration... no
> checking for _fmodf declaration... no
> checking for _frexpf declaration... no
> checking for _ldexpf declaration... no
Looks like you are skipping the
if test x$glibcpp_cv_func_$1_use = x"yes"; then
part, so it's probably not a valid comparison :-)
Raja R Harinath ------------------------------ email@example.com
"When all else fails, read the instructions." -- Cahn's Axiom
"Our policy is, when in doubt, do the right thing." -- Roy L Ash