* doc/tm.texi (Register Classes): Remove
CLASS_CANNOT_CHANGE_MODE and CLASS_CANNOT_CHANGE_MODE_P.
Document CANNOT_CHANGE_MODE_CLASS.
* reload.c (push_reload): Use CANNOT_CHANGE_MODE_CLASS.
(push_reload): Same.
* simplify-rtx.c (simplify_subreg): Same.
* reload1.c (choose_reload_regs): Same.
* recog.c (register_operand): Same.
* regrename.c (mode_change_ok): Change to use new
CANNOT_CHANGE_MODE_CLASS infrastructure.
* regclass.c (cannot_change_mode_set_regs): New.
Declare subregs_of_mode.
(regclass): Use subregs_of_mode.
Remove references to reg_changes_mode.
(init_reg_sets_1): Remove class_can_change_mode and
reg_changes_mode code.
(invalid_mode_change_p): New.
(dump_regclass): Use invalid_mode_change_p instead of
class_can_change_mode.
(regclass): Same.
(record_operand_costs): Do not set reg_changes_mode.
* local-alloc.c (struct qty): Remove changes_mode field.
(alloc_qty): Remove changes_mode initialization.
(update_qty_class): Remove set of changes_mode.
(find_free_reg): Use subregs_of_mode.
* global.c (find_reg): Use subregs_of_mode info.
* rtl.h (cannot_change_mode_set_regs): New prototype.
(invalid_mode_change_p): Same.
(REG_CANNOT_CHANGE_MODE_P): New macro.
* combine.c (subst): Pass class to CLASS_CANNOT_CHANGE_MODE_P.
Remove use of CLASS_CANNOT_CHANGE_MODE.
(simplify_set): Same.
(gen_lowpart_for_combine): Calculate subregs_of_mode. Remove
REG_CHANGES_MODE.
* regs.h: Add extern for subregs_of_mode;
Include hard-reg-set and basic-block.
(REG_CHANGES_MODE): Delete.