* acconfig.h (ENABLE_CHECKING): Undefine.
        * configure.in (--enable-checking): New option.
        * flow.c (reg_n_max): New global variable.
        * regclass.c (allocate_reg_info): Keep reg_n_max up to date.
        Delete regno_max variable.
        * regs.h (REG_N_CHECK): Define.
        (REG_N_REFS, REG_N_SETS, REG_N_DEATHS): Use REG_N_CHECK.
        (REG_N_CHANGES_SIZE, REG_N_CALLS_CROSSED, REG_LIVE_LENGTH): Likewise.
        (REGNO_FIRST_UID, REGNO_LAST_UID, REGNO_LAST_NOTE_UID): Likewise.

Co-Authored-By: Martin v. Loewis <martin@mira.isdn.cs.tu-berlin.de>

From-SVN: r19708