[Bug middle-end/12081] New: Gcc can't be compiled with -mregparm=3

["mikulas at artax dot karlin dot mff dot cuni dot cz" <gcc-bugzilla at gcc dot gnu dot org>]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12081

           Summary: Gcc can't be compiled with -mregparm=3
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: mikulas at artax dot karlin dot mff dot cuni dot cz
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: i586-pc-linux-gnu
  GCC host triplet: i586-pc-linux-gnu
GCC target triplet: i586-pc-linux-gnu

When GCC is compiled with -mregparm=3 (system libraries are compiled with that flag too), it doesn't work. The problem is this line (maybe there are more buggy declarations, but this is the first one I hit):

typedef rtx (*insn_gen_fn) PARAMS ((rtx, ...));

Later, two-parameter functions are retyped to insn_gen_fn and called. The caller pushes arguments to stack, the calee expects them in registers.