[Bug tree-optimization/17863] New: threefold performance loss

[kunert at physik dot tu-dresden dot de]

I see a threefold performance loss. This is a rather big chunk of code and it is
probably difficult to extract a small testcase, because there is no pronounced
hot spot. To reproduce just compile and run the code.

commandline: g++ -O3 -march=pentium4 ttest.cc -o t34a -static

Execution time of the compiled code:

with GCC 3.4.1: 6.6s
with todays GCC 4.0.0: 18.9s

machine is a 2.4 GHz P4.

-- 
           Summary: threefold performance loss
           Product: gcc
           Version: 4.0.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kunert at physik dot tu-dresden dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17863