* df.h (enum df_ref_flags.DF_REF_STRIPPED): New.
        (DF_FOR_REGALLOC): New.
        * df.c (df_ref_record): Set DF_REF_STRIPPED.
        (read_modify_subreg_p): Simplify.
        (df_def_record_1, df_uses_record): Set DF_REF_MODE_CHANGE more often.
        Use DF_FOR_REGALLOC.
        * ra.h (struct web): New member subreg_stripped.
        (invalid_mode_change_regs): Declare.
        * ra.c (invalid_mode_change_regs): New.
        (init_ra): Initialize it.
        * ra-build.c (init_one_web_common, remember_web_was_spilled): Use it.
        Use CANNOT_CHANGE_MODE_CLASS as ifdef guard.
        (reinit_one_web, parts_to_web_1): Deal with subreg_stripped.
        * ra-colorize.c (colorize_one_web): Use invalid_mode_change_regs.
        Use CANNOT_CHANGE_MODE_CLASS as ifdef guard.

From-SVN: r63952