optimization/8361: [3.3/3.4 regression] C++ compile-time performance regression

Gerald Pfeifer pfeifer@dbai.tuwien.ac.at
Mon Mar 24 15:14:00 GMT 2003


The following reply was made to PR optimization/8361; it has been noted by GNATS.

From: Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>
To: gcc-gnats@gcc.gnu.org, gcc-prs@gcc.gnu.org, gcc-bugs@gcc.gnu.org
Cc: Steven Bosscher <s.bosscher@student.tudelft.nl>
Subject: Re: optimization/8361: [3.3/3.4 regression] C++ compile-time
 performance regression
Date: Mon, 24 Mar 2003 15:18:53 +0100 (CET)

 I have now tested Mark's fix for PR 8361 and while that does not affect
 non-optimizing performance, the difference for -O3 is noticable.
 
 Below are the results of the 3.3-branch from 03/15 versus 03/24 (without
 explicit --disable-checking):
 
   % \time /files/pfeifer/gcc-3.3-0315/bin/g++ -c generate.ii
        28.50 real        27.57 user         0.75 sys
   % \time /files/pfeifer/gcc-3.3-0324/bin/g++ -c generate.ii
        28.70 real        27.42 user         0.69 sys
 
 No difference for non-optimizing compilation...
 
   % \time /files/pfeifer/gcc-3.3-0315/bin/g++ -O3 -c generate.ii
       109.55 real       105.85 user         3.06 sys
   % \time /files/pfeifer/gcc-3.3-0324/bin/g++ -O3 -c generate.ii
        81.28 real        77.41 user         3.55 sys
 
 ...but a nice speedup for -O3!
 
 Gerald



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