Re: Compilation performance comparison of gcc3.4.1 and gcc3.5.0 2004-08-30 on MICO sources

["Giovanni Bajo" <giovannibajo@libero.it>]

Karel Gardas wrote:

> 1) typecode.cc: 40% regression on O1 while 7% speedup on O2

Can you please file a new bugreport with this -O1 regression, attacching this
preprocessed testcase and the time reports to it? Also link Steven's message in
it: http://gcc.gnu.org/ml/gcc/2004-08/msg01602.html, which contains the
analysys of this.
Then we can set that the new bug blocks PR 13776.

I think it is better to track these issues with different PRs, and just
connects them to PR 13776 (which is quite confusing at this point) just with
the Bugzilla relationships.

> -O2: 33% basic_seq.cc and following with 27% static.cc

Can you open also a new bugreport about the regression of basic_seq.cc, which
regresses at all optimization levels? Again, attacch preprocessed testcases, a
comparison with 3.4 for all optimization levels, and the relative time reports.

Actually, I should also note that at this point we cannot probably do much
about compile time regressions at -O1/2/3. GCC 3.5 features more than 60 new
optimization passes, so it is already a half miracle we don't regress
everywhere. Code generation is also improved of course, so we have to lose a
little somwhere. Of course, big regressions (>20% on files of non-trivial size)
could probably still analyzed a little to see if we find obvious offenders.

Thank you for doing this, it is of great help!

Giovanni Bajo