* combine.c (subst): Use CLASS_CANNOT_CHANGE_MODE and
        CLASS_CANNOT_CHANGE_MODE_P instead of CLASS_CANNOT_CHANGE_SIZE
        and hard-coded tests.
        (simplify_set): Likewise.
        (gen_lowpart_for_combine): Likewise.
        * emit-rtl.c (gen_lowpart_common): Likewise.
        * global.c (find_reg): Likewise.
        * local-alloc.c (find_free_reg): Likewise.
        * recog.c (register_operand): Likewise.
        * regclass.c (init_reg_sets_1): Likewise.
        (record_operand_costs, regclass): Likewise.
        * reload.c (push_reload): Likewise.
        * reload1.c (choose_reload_regs): Likewise.
        * flow.c (mark_used_regs): Conditionally set REG_CHANGES_MODE.
        * local-alloc.c (struct qty): Rename changes_size to changes_mode.
        Update all references.
        * regs.h (struct reg_info_def): Likewise.
        (REG_CHANGES_MODE): Rename from REG_CHANGES_SIZE.
        * tm.texi (CLASS_CANNOT_CHANGE_MODE): Document.
        (CLASS_CANNOT_CHANGE_MODE_P): Likewise.

        * config/alpha/alpha.h (CLASS_CANNOT_CHANGE_MODE): Rename.
        (CLASS_CANNOT_CHANGE_MODE_P): New.
        * config/mips/mips.h: Likewise.
        * config/pa/pa32-regs.h: Likewise.
        * config/pa/pa64-regs.h: Likewise.
        * config/rs6000/rs6000.h: Likewise.
        * config/sh/sh.h: Likewise.
        * config/ia64/ia64.h (CLASS_CANNOT_CHANGE_MODE): New.
        (CLASS_CANNOT_CHANGE_MODE_P): New.
        * config/avr/avr.h (CLASS_CANNOT_CHANGE_SIZE): Remove dead code.
        * config/d30v/d30v.h: Likewise.

From-SVN: r34526