bb-reorder.c AIX bootstrap failure

[David Edelsohn]

	The recent bb-reorder.c change is causing a bootstrap failure on
AIX (powerpc-ibm-aix4.3.3.0) building libobjc/encoding.o for the POWER
architecture (-mcpu=power).

/gcc/dje/src/libobjc/encoding.c: In function `objc_aligned_size':
/gcc/dje/src/libobjc/encoding.c:387: error: unrecognizable insn:
(insn 123 122 124 3022d9c0 (parallel [
            (set (reg:SI 29 r29 [140])
                (div:SI (reg:SI 29 r29 [137])
                    (reg/v:SI 3 r3 [orig:121 align ] [121])))
            (set (reg:SI 64 mq [141])
                (mod:SI (reg:SI 29 r29 [137])
                    (reg/v:SI 3 r3 [orig:121 align ] [121])))
        ]) -1 (nil)
    (expr_list:REG_UNUSED (reg:SI 64 mq [141])
        (nil)))
/gcc/dje/src/libobjc/encoding.c:387: internal compiler error: in insn_default_length, at insn-attrtab.c:834


	Only the bb-reorder.c change creates the failure, not the
cfgcleanup.c change in the same patch.

David