This patch removes force_fit_type in favor of force_fit_type_double that
takes a double-int and a type argument.  This reduces intermediate types
created and cleans up the source as all uses left of force_fit_type are of
the form

   t = build_int_cst_wide (type, low, high);
   t = force_fit_type (t, -1, overflow | TREE_OVERFLOW (arg1),
                     TREE_CONSTANT_OVERFLOW (arg1));

which first creates a shared integer node (of possibly uncanonicalized form)
and then truncates it properly and propagates overflow flags.  Combining
this two steps also allows to adjust int_const_binop to produce less garbage
on overflow.

Bootstrapped and tested on i686-pc-linux-gnu, another on on
x86_64-unknown-linux-gnu for all languages still running.

Is the new name ok or should I re-use the old one, force_fit_type?
I also thought of build_and_force_fit_and_propagate_overflow_int_wide (),
but that's ugly ;)  Suggestions?

Thanks,
Richard.

2007-01-08  Richard Guenther  <rguenther@suse.de>

        * tree.h (force_fit_type_double): Export.
        (force_fit_type): Remove.
        * fold-const.c (force_fit_type_double): New function.
        (force_fit_type): Remove.
        (int_const_binop): Use it.
        (fold_convert_const_int_from_int): Likewise.
        (fold_convert_const_int_from_real): Likewise.
        (fold_div_compare): Likewise.
        (fold_sign_changed_comparison): Likewise.
        (fold_unary): Likewise.
        (fold_negate_const): Likewise.
        (fold_abs_const): Likewise.
        (fold_not_const): Likewise.
        * c-common.c (shorten_compare): Use force_fit_type_double.
        * convert.c (convert_to_pointer): Likewise.