I tried compiling my open source application with GCC. My application uses
OpenMP to make use of available CPU cores and run faster. I got an internal
compiler error from GCC, even though the same code compiles and runs fine
(using both cores) under Intel's ICC. It also compiles and runs fine with GCC
when I don't use the -fopenmp option (but then it only uses one core).

My GCC -v output: 

Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ./configure --enable-languages=c,c++ --prefix=/opt/gcc-4.2.3
--exec_prefix=/opt/gcc-4.2.3
Thread model: posix
Version gcc 4.2.3

My system: (uname -a)
Linux home 2.6.23 #2 SMP PREEMPT Sun Nov 11 11:44:34 EET 2007 i686 Intel(R)
Core(TM)2 Duo CPU     E4500  @ 2.20GHz GenuineIntel GNU/Linux

The command line that triggers the bug is simple:

g++ -c -fopenmp Scene.ii

It reports:
src/Scene.cc: In member function 'void Scene::renderPhong(const Camera&,
Screen&)':
src/Scene.cc:165: åóùôåñéêü óöÜëìá ìåôáãëùôôéóôÞ: in create_tmp_var, at
gimplify.c:487
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.

Scene.ii (the preprocessed output), is available here:
http://users.softlab.ntua.gr/~ttsiod/Scene.ii.bz2

If you remove the -fopenmp, the code compiles fine.

In case you want to see what the code is used for, the open source project and
its full code is available here:

http://users.softlab.ntua.gr/~ttsiod/renderer.html


-- 
           Summary: Usage of openmp pragmas causes internal compiler error
           Product: gcc
           Version: 4.2.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ttsiod at softlab dot ntua dot gr
 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=35247