altivec.md: Convert UNSPEC numerical values to define_constants.

altivec.md: Convert UNSPEC numerical values to define_constants.

        * config/rs6000/altivec.md: Convert UNSPEC numerical values to
        define_constants.  Change duplicate values to unassigned numbers.
        Change UNSPEC_SUBS to UNSPEC_VSUBS.
        (*altivec_vspltsf): New.
        (altivec_vperm_v4sf): Delete.
        (altivec_vperm_<mode>): Use mode macro V.
        (altivec_vsldoi_<mode>): Convert to mode macro pattern.
        (altivec_predicate_v4sf): Delete.
        (altivec_predicate_<mode>): Use mode macro V.
        (*altivec_lvesfx): New.
        (*altivec_stvesfx): New.
        (vec_realign_load_v4sf): Delete.
        (vec_realign_load_<mode>): Use mode macro V.
        * config/rs6000/rs6000.c (generate_set_vrsave): Use
        UNSPECV_SET_VRSAVE.

From-SVN: r102566