This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Loop unrolling
- Subject: Re: Loop unrolling
- From: Scott A Crosby <crosby at qwes dot math dot cmu dot edu>
- Date: Wed, 16 Sep 1998 02:28:31 -0400 (EDT)
- cc: egcs at cygnus dot com
On Wed, 3 Jun 1998, Nathan Myers wrote:
> This is absolutely correct. The performance of programs that use STL
> facilities, and similar libraries like Blitz++, is utterly dependent on
> the compiler crushing out "abstraction overhead", which often means
> empty loops.
>
> It is impossible in general for the programmer to ensure that empty loops
> are not generated, because with templates there is no one place in the source
> where all such knowledge is available.
>
> Perhaps in C code such loops cannot be eliminated without some political
> wrangling, but there can be no such excuse for g++.
I hate to bring up a 3 month-old horse, but has anyone added in such
functionality to remove empty loops, unconditionally? (Or, could a
complete newbie GCC/EGCS hacker add it in himself and submit a patch?)
Scott
--
This message is copyright 1998 by Scott A Crosby. Unauthorized
reproduction or duplication if forbidden without the express permission of
the author.