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Re: c++ speed 3.3/4.0/4.1
- From: Joe Buck <Joe dot Buck at synopsys dot COM>
- To: Jack Howarth <howarth at bromo dot msbb dot uc dot edu>
- Cc: gcc at gcc dot gnu dot org
- Date: Sun, 4 Dec 2005 21:23:00 -0800
- Subject: Re: c++ speed 3.3/4.0/4.1
- References: <20051204230954.8A7EB1DC0EB@bromo.msbb.uc.edu>
On Sun, Dec 04, 2005 at 06:09:54PM -0500, Jack Howarth wrote:
> I was happy to see some recovery in the c++ code generation with
> gcc 4.1. Now xplor-nih only exhibits a 7% speed loss using g++-4.1
> compared to g++-3.3. I assume this is due to the total rewrite of
> the optimizers in gcc > 4.0. Is there any tricks on can use to coax
> the c++ performance from the g++ 4.1 to be equivalent to that seen in
> g++-3.3 or will we have to wait for later versions of gcc for that?
You could try to isolate some inner loops that are slower for 4.1 than
3.3, and submit them as bug reports.