Remove any of the options (or change -O3 to -O2) and this will pass. Found
while compiling Ghostscript.

gcc-trunk -c -O3 -march=pentium4 -flto ttinterp.i
In file included from ./base/ttobjs.h:42:0,
                 from ./base/ttinterp.h:53,
                 from ./base/ttinterp.c:68:
./base/setjmp_.h:30:5: warning: variably modified ‘stuff’ at file scope
[enabled by default]
./base/ttinterp.c: In function ‘Ins_ROUND’:
./base/ttinterp.c:2172:15: internal compiler error: in get_alias_set, at
alias.c:734
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.


-- 
           Summary: Compiling a single file with -O3 -march=pentium4 -flto
                    ICEs
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: lto
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: moonshine at kapsi dot fi
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44865