Crash in process_regs_for_copy

[Jeff Law]

Andreas Schwab wrote:
> I'm testing IRA on m68k (with IRA_COVER_CLASSES defined to {
> GENERAL_REGS, FP_REGS, LIM_REG_CLASSES }) and get a crash in
> process_regs_for_copy.  It is called with
>
> (insn 22 17 28 4 /cvs/gcc/libgcc/../gcc/libgcc2.c:169 (set (reg/i:SI 0 %d0)
>         (subreg:SI (reg/v:DI 30 [ w ]) 4)) 36 {*movsi_m68k2} (expr_list:REG_DEAD (reg/v:DI 30 [ w ])
>         (nil)))
>
> and hard_regno becomes -1 due to offset2 == 1.  I don't understand how
> substracting offset2 from REGNO (reg1) can make sense here.
>
> Andreas.
>
>   
Do you have a testcase handy?  I just started looking at the m68k as 
well....

Jeff