Re: EGCS vs GCC performance

[jbuck at synopsys dot com]

>    If anybody's interested, I just did a (very) informal performance
>    test between EGCS 1.0.1 and GCC 2.7.2. The test involved compiling
>    and executing some heavily-templated numerical code on a HP 715
>    running HP-UX 9.05.
...
>    The result, in a nutshell, is that EGCS outperforms GCC
>    significantly in both compile-time and run-time.

HP, if I understand correctly, is the platform that has benefited the
most from the Haifa scheduler.  The story isn't as great on some other
platforms; ix86/Pentium performance seems to have actually gotten worse
in some cases according to several reports.  But I'm sure this will be
addressed soon.

> I executed "time make" using GCC: 
> 
> g++ -ansi -frepo -O3 -I/usr/local/lib/TNT -I/usr/local/lib/C++  -c kubo.C
> 
>     (... etc etc)
> 
> real    5m40.990s
> user    4m54.180s
> sys     0m30.970s
> 
> 	A lot of time was used recompiling the source to get the
> 	templates right; this took seven iterations. (The -frepo flag
> 	is convenient, but it does take a while the first time.

This is why I dislike -frepo.  If you're willing to trade larger
object files (and possibly a larger executable if on your platform
the linker cannot eliminate duplicate functions) in exchange for
much faster compile/link time, just don't use -frepo.