[Bug bootstrap/30853] New: warnings about traditional.c during bootstrap with -O3, leading to internal error

[sdack at gmx dot de]

Through a change in gcc-4.1.2/config/mh-x86omitfp to replace "-O2
-fomit-framepointer" with "-O3" the bootstrap process will fail with the
following warnings:

../../gcc-4.1.2/libcpp/traditional.c: In function '_cpp_scan_out_logical_line':
../../gcc-4.1.2/libcpp/traditional.c:349: warning: 'fmacro.args' may be used
uninitialized in this function
../../gcc-4.1.2/libcpp/traditional.c:349: warning: 'fmacro.node' may be used
uninitialized in this function
../../gcc-4.1.2/libcpp/traditional.c:349: warning: 'fmacro.offset' may be used
uninitialized in this function
../../gcc-4.1.2/libcpp/traditional.c:349: warning: 'fmacro.argc' may be used
uninitialized in this function
../../gcc-4.1.2/libcpp/traditional.c:349: warning: 'fmacro.line' may be used
uninitialized in this function

When bootstrapping without Werror it will produce some more warnings and
eventually fails (during a profiledbootstrap) in an internal compiler error.
Can be reproduced with:

1) Edit config/mh-x86omitfp and set BOOT_CFLAGS to "-O3"
2) configure --prefix=/home/sven/gnu --enable-languages=c --enable-bootstrap
3) make bootstrap

The following warnings probably explain why there is an internal compiler
error:
gengtype-lex.c:3400: warning: no previous prototype for 'yyget_lineno'
gengtype-lex.c:3409: warning: no previous prototype for 'yyget_in'
gengtype-lex.c:3417: warning: no previous prototype for 'yyget_out'
gengtype-lex.c:3425: warning: no previous prototype for 'yyget_leng'
gengtype-lex.c:3434: warning: no previous prototype for 'yyget_text'
gengtype-lex.c:3443: warning: no previous prototype for 'yyset_lineno'
gengtype-lex.c:3455: warning: no previous prototype for 'yyset_in'
gengtype-lex.c:3460: warning: no previous prototype for 'yyset_out'
gengtype-lex.c:3465: warning: no previous prototype for 'yyget_debug'
gengtype-lex.c:3470: warning: no previous prototype for 'yyset_debug'
gengtype-lex.c:3476: warning: no previous prototype for 'yylex_destroy'

build/gengtype
warning: structure `c_arg_info' used but not defined
warning: structure `c_switch' used but not defined
warning: structure `et_node' used but not defined
warning: structure `loop' used but not defined
warning: structure `ipa_reference_vars_info_d' used but not defined
warning: structure `reg_info_def' used but not defined
warning: structure `value_set' used but not defined
warning: structure `c_arg_info' used but not defined
warning: structure `c_switch' used but not defined
warning: structure `et_node' used but not defined
warning: structure `loop' used but not defined
warning: structure `ipa_reference_vars_info_d' used but not defined
warning: structure `reg_info_def' used but not defined
warning: structure `value_set' used but not defined


-- 
           Summary: warnings about traditional.c during bootstrap with -O3,
                    leading to internal error
           Product: gcc
           Version: 4.1.2
            Status: UNCONFIRMED
          Severity: minor
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sdack at gmx dot de
 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=30853