* loop.h (struct induction): Add multi_insn_incr.
        * loop.c (basic_induction_var): New multi_insn_incr argument.
        Set it if we search back through previous insns for the biv.
        (record_biv): New multi_insn_incr argument; fill in struct induction.
        (strength_reduce): Discard an iv with multiple bivs, any of
        which require multiple insns to increment.

From-SVN: r30820