[Bug middle-end/32913] New: -fprofile-generate/use: Program 24% slower than without

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

This is with the polyhedron test "fatigue" on AMD Athlon64 X2 4800+ with
openSUSE 10.3b6 x86-64 and today's GCC 4.3.0 20070727.

Test case available from:
http://www.polyhedron.co.uk/MFL6VW74649

Using on one hand
gfortran -march=opteron -ffast-math -funroll-loops -ftree-loop-linear
-ftree-vectorize -msse3 -O3 fatigue.f90

and on the other hand the same with once -fprofile-generate and then, after one
./a.out run, -fprofile-use.

http://physik.fu-berlin.de/~tburnus/gcc-trunk/benchmark/#rt

Result: 12.32s [100]  15.30s [124]
thus the profile-use case is 24% slower.

This seems to be no regression as the non-profile version became faster around
2007-03-20 whereas the profile-use version stayed at the old execution time.


-- 
           Summary: -fprofile-generate/use: Program 24% slower than without
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32913