CC0 questions

[Richard Kenner]

     Can a jump_insn use cc0 but not actually jump?  The following
     instruction is found in the H8 port.

     (jump_insn 18 17 20
     	   (set (reg:HI 3 r3)
     		(eq:HI (cc0)
     		       (const_int 0))))

A jump_insn is supposed to modify the PC.  That one doesn't, so isn't a
legitimate jump_insn.
     
     Is there a requirement that every cc0 user must be a jump_insn?

No.

    Can there be two consecutive insns that use cc0 after cc0 is set? 

No.