[Bug bootstrap/25589] New: can not configure CFLAGS_FOR_TARGET

["gcc-bugzilla at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

Flags that are passed to newly built gcc when compiling code for
target system during are determined by value of `CFLAGS_FOR_TARGET'
makefile variable as defined in top level `Makefile'.  `CFLAGS' in
that `Makefile' are passed on for use with old compiler used to
bootstrap gcc.

Can not configure `CFLAGS_FOR_TARGET' value at all, that is, can not
change its value and nothing more by passing arguments to / setting
variables in `configure'.  Top level `Makefile.in' just
unconditionally duplicates `$(CFLAGS)' into it.  Thus the same flags
are passed to completely different compilers.  If old compiler is not
a gnu one, its flags does not have to be recognized by newly built gcc
at all.  In this case target code does not build at all like this.

checking for C compiler default output file name... configure: error: C
compiler cannot create executables
See `config.log' for more details.
gmake: *** [configure-intl] Error 1
checking for suffix of object files... configure: error: cannot compute suffix
of object files: cannot compile
See `config.log' for more details.
gmake: *** [configure-libiberty] Error 1

The worst is sometimes gcc maintainers themselves tell users to
specify weird flags to native compiler - like pinskia at gcc dot gnu
dot org did on 2005-11-23 15:04 in
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25002>:

> the problem is that you need to supply -ieee to the
> compiler.

gcc does not recognize it.

How-To-Repeat:

That particular case of needing `-ieee' flag not recognized by gcc is
described in <http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16787>.


------- Comment #1 from gin at mo dot msk dot ru  2005-12-28 15:53 -------
Fix:

One workaround is described in that same
<http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16787#c6>: to put these
weird flags in `CC' value as passed to `configure', and leave in
`CFLAGS' only those recognized by gcc, if any.  If put all flags in
`CC', why have separate `CFLAGS' variable at all?

The other is explicitly set `CFLAGS_FOR_TARGET' in `make' command
line.

gmake CFLAGS_FOR_TARGET='-O2 -pthread -g  -mieee' bootstrap;


-- 
           Summary: can not configure CFLAGS_FOR_TARGET
           Product: gcc
           Version: 4.0.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: bootstrap
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: gin at mo dot msk dot ru


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25589