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Re: tree-ssa performance (was: treelang fix for rs6000 / treelang not proper front end)
- From: Theodore Papadopoulo <Theodore dot Papadopoulo at sophia dot inria dot fr>
- To: Gerald Pfeifer <pfeifer at dbai dot tuwien dot ac dot at>
- Cc: Steven Bosscher <s dot bosscher at student dot tudelft dot nl>, Diego Novillo <dnovillo at redhat dot com>, Andrew Haley <aph at redhat dot com>, Jeff Sturm <jsturm at one-point dot com>, Tim Josling <tej at melbpc dot org dot au>, Zack Weinberg <zack at codesourcery dot com>, doko at cs dot tu-berlin dot de, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>, Neil Booth <neil at daikokuya dot co dot uk>
- Date: Tue, 10 Jun 2003 18:38:51 +0200
- Subject: Re: tree-ssa performance (was: treelang fix for rs6000 / treelang not proper front end)
pfeifer@dbai.tuwien.ac.at said:
> This indicates that the SPEC tester is not sufficient wrt. to
> compile-time regressions.
Let me make a guess:
- Gerald, your test code is C++.
- SPEC is mostly (if not all) C ?
It has been said many times on this list that the compiler behaviour
is not the same for C and C++.
I bet that most of the slowdown reported is for C++, whereas most of
the new code introduced in the compiled is tested for not introducing
slowdowns against C code (ie SPEC+gcc itself).
Perhaps, (if the above guess is valid), it is the proper time to add
some specific C++ compile-time tests, and to start to measure the
slowdowns also for C++.
Indeed, it will not have the same value as SPEC (because it will be
unique to gcc), but in the meantime, it might help asserting the
impact of the changes for the different langages.
Theo.
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Theodore Papadopoulo
Email: Theodore.Papadopoulo@sophia.inria.fr Tel: (33) 04 92 38 76 01
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