comparison of 2.95.2 and 3.2 optimizers on SPARC

[Brad Spencer]

On Thu, Jan 02, 2003 at 01:38:52PM -0600, Loren James Rittle wrote:
> Martin,
> 
> Oops and, likewise, sorry I didn't see that issue.  I can now confirm
> your report.  Thank you (again) for taking the time to report it and
> the follow up.
> 
> On FreeBSD/i386 with 2.95.X:
> 
> S rittle@latour; time a.out 1000000 stdio >/dev/null
>      2r     1.6u     0.0s       a.out 1000000 stdio
> S rittle@latour; time a.out 1000000 iostream >/dev/null
>      1r     0.9u     0.0s       a.out 1000000 iostream
> 
> On FreeBSD/i386 with mainline:
> 
> S rittle@latour; time a.out 1000000 stdio >/dev/null
>      1r     1.6u     0.0s       a.out 1000000 stdio
> S rittle@latour; time a.out 1000000 iostream >/dev/null
>     14r    14.4u     0.0s       a.out 1000000 iostream
> 

I posted a patch in October[1] that tried to avoid some unnecessary
work that is done every time a numeric is converted to a string.  It
was against the 3.2 release, so it's a bit out of date now, but the
idea is still valid.   I've attached a somewhat more modern version
for the gcc-3.3 series.  Perhaps this addresses part of the slowdown?

References:

[1] http://gcc.gnu.org/ml/libstdc++/2002-10/msg00056.html 

-- 
------------------------------------------------------------------
Brad Spencer - spencer@infointeractive.com - "It's quite nice..."
Systems Architect | InfoInterActive Corp. | A Canadian AOL Company
-------------- next part --------------
ChangeLog
        
2002-10-08    <spencer@infointeractive.com>

	* include/bits/locale_facets.tcc (__convert_from_v): Avoid
	expensive operations when C locale is already set.
        
*** ../../../../reference_gcc/gcc-3.2/libstdc++-v3/include/bits/locale_facets.tcc	Tue Oct  8 17:48:11 2002
--- locale_facets.tcc	Tue Oct  8 17:53:41 2002
*************** namespace std
*** 1977,1992 ****
      {
        int __ret;
        char* __old = setlocale(LC_ALL, NULL);
!       char* __sav = static_cast<char*>(malloc(strlen(__old) + 1));
!       if (__sav)
!         strcpy(__sav, __old);
!       setlocale(LC_ALL, "C");
        if (__prec >= 0)
          __ret = snprintf(__out, __size, __fmt, __prec, __v);
        else
          __ret = snprintf(__out, __size, __fmt, __v);
!       setlocale(LC_ALL, __sav);
!       free(__sav);
        return __ret;
      }
  #else
--- 1977,2007 ----
      {
        int __ret;
        char* __old = setlocale(LC_ALL, NULL);
! 
!       // Only do all this expensive malloc/free, string copy and locale
!       // setting if the locale is not already what we want.
!       char* __sav;
!       if (!(__old[0] == 'C' && __old[1] == '\0'))
!         {
!           __sav = static_cast<char*>(malloc(strlen(__old) + 1));
!           if (__sav)
!             strcpy(__sav, __old);
!           setlocale(LC_ALL, "C");
!         }
!       else
!         __sav = 0;
! 
        if (__prec >= 0)
          __ret = snprintf(__out, __size, __fmt, __prec, __v);
        else
          __ret = snprintf(__out, __size, __fmt, __v);
! 
!       // Do we need to clean up?
!       if(__sav)
!         {        
!           setlocale(LC_ALL, __sav);
!           free(__sav);
!         }
        return __ret;
      }
  #else
*************** namespace std
*** 1997,2012 ****
      {
        int __ret;
        char* __old = setlocale(LC_ALL, NULL);
!       char* __sav = static_cast<char*>(malloc(strlen(__old) + 1));
!       if (__sav)
!         strcpy(__sav, __old);
!       setlocale(LC_ALL, "C");
        if (__prec >= 0)
          __ret = sprintf(__out, __fmt, __prec, __v);
        else
          __ret = sprintf(__out, __fmt, __v);
!       setlocale(LC_ALL, __sav);
!       free(__sav);
        return __ret;
      }
  #endif
--- 2012,2042 ----
      {
        int __ret;
        char* __old = setlocale(LC_ALL, NULL);
! 
!       // Only do all this expensive malloc/free, string copy and locale
!       // setting if the locale is not already what we want.
!       char* __sav;
!       if (!(__old[0] == 'C' && __old[1] == '\0'))
!         {
!           __sav = static_cast<char*>(malloc(strlen(__old) + 1));
!           if (__sav)
!             strcpy(__sav, __old);
!           setlocale(LC_ALL, "C");
!         }
!       else
!         __sav = 0;
! 
        if (__prec >= 0)
          __ret = sprintf(__out, __fmt, __prec, __v);
        else
          __ret = sprintf(__out, __fmt, __v);
! 
!       // Do we need to clean up?
!       if(__sav)
!         {        
!           setlocale(LC_ALL, __sav);
!           free(__sav);
!         }
        return __ret;
      }
  #endif