[Bug target/34163] New: 10% performance regression since Nov 1 on Polyhedron's "NF" on AMD64

["burnus at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

According to http://www.suse.de/~gcctest/c++bench/polyhedron/, the run time of
"NF" increased from 37.70s to 41.57s (+10%) between 071031 and 071101. This is
an AMD Opteron system.

The same result I obtained at
http://physik.fu-berlin.de/~tburnus/gcc-trunk/benchmark/
also on an AMD64. Interestingly, while x86-64 (-m64) gets slower, using -m32 I
don't see any change (apart of noise) - neither for x87 nor for SSE(3).

To boil it down to version numbers, I believe the change must have happened
between the following versions:
Fast:
  4.3.0 20071031 (experimental) [trunk revision 129791]
Slow:
  4.3.0 20071031 (experimental) [trunk revision 129797]

As culpits there are essentially only the following checkins possible:

- PR tree-optimization/32377 (compute_overlap_steps_for_affine_univar)
  Make it work also for unknown number of iterations.  [Sebastian Pop]

- PR middle-end/33779 fold-const.c (extract_muldiv_1): Make sure to not
  introduce new undefined integer overflow.  [Richard Guenther]

- PR fortran/33897 decl.c (gfc_match_entry): Do not make ENTRY name
  global for contained procedures.
  parse.c (gfc_fixup_sibling_symbols): Fix code for determining whether
  a procedure is external.     [Paul Thomas]

The Polyhedron test case is available from:
http://www.polyhedron.co.uk/MFL6VW74649


-- 
           Summary: 10% performance regression since Nov 1 on Polyhedron's
                    "NF" on AMD64
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=34163