Re: optimization/7713: Performance regression from gcc 2.95.3

Re: optimization/7713: Performance regression from gcc 2.95.3

[bangerth]

Synopsis: Performance regression from gcc 2.95.3

State-Changed-From-To: open->feedback
State-Changed-By: bangerth
State-Changed-When: Sat Mar 22 18:00:59 2003
State-Changed-Why:
    Jerry, nobody seems to have ever looked at this report --
    since otherwise they would have noticed that there's no
    testcase. Do you still have it so that we can attach it
    to the PR?
    
    Thanks
      Wolfgang

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7713

Re: optimization/7713: Performance regression from gcc 2.95.3

[bangerth]

Synopsis: Performance regression from gcc 2.95.3

State-Changed-From-To: feedback->open
State-Changed-By: bangerth
State-Changed-When: Mon Mar 24 15:42:26 2003
State-Changed-Why:
    Feedback reveived

http://gcc.gnu.org/cgi-bin/gnatsweb.pl?cmd=view%20audit-trail&database=gcc&pr=7713

optimization/7713: Performance regression from gcc 2.95.3

[jlquinn]

>Number:         7713
>Category:       optimization
>Synopsis:       Performance regression from gcc 2.95.3
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          pessimizes-code
>Submitter-Id:   net
>Arrival-Date:   Sat Aug 24 13:56:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     jlquinn@optonline.net
>Release:        gcc-3.2
>Organization:
>Environment:
powerpc-unknown-linux-gnu
glibc 2.2.5
binutils 2.12.90.0.9
Debian Woody
240MHz 604e
1MB cache
>Description:
Running C benchmark found here:
http://www.cwi.nl/~tromp/c4/fhour.html

I was looking at runtimes from different compilers, gcc 2.95.4 (.3 plus Debian patches) and released gcc 3.2 included.

If I compile with gcc 2.95 -O2, I get the following performance numbers from the program:

207.2 Kpos/sec, 208.7 Kpos/sec

gcc 2.95 -O2 -mcpu=604e
214.5 Kpos/sec, 215.2 Kpos/sec

gcc 3.2 -O2
197.9 201.2

gcc 3.2 -O2 -mcpu=604e
199.4 201.1 198.7

I've played with some other settings and have been unable to  get 3.2 to match or beat 2.95's performance here.

Note, using the 3.3 mainline of about July 23, I got about equivalent runtime performance on the same benchmark.

>How-To-Repeat:
Build with the same compile-time flags.

Run as:

c4 < input

>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: