GCC pending_chain contains only (nil)

[Hsin-Hsien Wu]

Hello,
        I am currently porting gcc to a new target. After I write my own
machine description,
I got a ICE (segmentation fault) . So, I use GDB to debug, and what I got is
shown bellow,

(gdb) l emit_queue
502
503     /* Perform all the pending incrementations.  */
504
505     void
506     emit_queue ()
507     {
508       rtx p;
509       while ((p = pending_chain))
510         {
511           rtx body = QUEUED_BODY (p);
(gdb) l
512
513           switch (GET_CODE (body))                     <------ 
*SEGEMENTATION FLAULT
514             {
515             case INSN:
516             case JUMP_INSN:
517             case CALL_INSN:
518             case CODE_LABEL:
519             case BARRIER:
520             case NOTE:
521               QUEUED_INSN (p) = body;
(gdb) call debug_rtx(p)
(queued:SI (mem/s:SI (reg:SI 53) [20 <variable>.count+0 S4 A32])
    (nil)
    (nil)
    (nil)
    (nil))
(gdb)

The pending_chain contains only (nil).

What would cause the pending_chain containg only (nil) ?



Thanks

Mike Wu