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[Bug tree-optimization/28364] poor optimization choices when iterating over a std::string (probably not c++-specific)
- From: "zackw at panix dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 13 Jul 2006 08:28:13 -0000
- Subject: [Bug tree-optimization/28364] poor optimization choices when iterating over a std::string (probably not c++-specific)
- References: <bug-28364-37@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #21 from zackw at panix dot com 2006-07-13 08:28 -------
Subject: Re: poor optimization choices when iterating over a std::string
(probably not c++-specific)
> on your real program, how much performance do you gain by hand-rewriting
> the assembler to look the way you like? Just to make sure there really
> is a problem.
I'm a little annoyed by the suggestion that this wouldn't be a real
problem if I couldn't measure a performance difference.
Depending on workload, other activity on the same machine, and phase
of moon, this loop is between .1% and 1% of runtime, and my tweaks
make it go about a third faster.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=28364