scheduling insn on none

scheduling insn on none

[Tabony, Charles]

Hi,

I am trying to add instruction scheduling to a machine description.  I
added everything I think I need and the .dfa looks right to me, but when
I compile with -fsched-verbose=10 I get something that looks like this:

;;   ======================================================
;;   -- basic block 0 from 9 to 83 -- before reload
;;   ======================================================

;;   --------------- forward dependences: ------------ 

;;   --- Region Dependences --- b 0 bb 0 
;;      insn  code    bb   dep  prio  cost   blockage units
;;      ----  ----    --   ---  ----  ----   -------- -----
;;        9    17     0     0    12     1    0 -  0   none	: 83 10 
;;       10    62     0     1    11     1    0 -  0   none	: 83 33
32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 
;;       12    36     0     1    10     1    0 -  0   none	: 83 13 
;;       13    17     0     2     9     1    0 -  0   none	: 83 33 
;;       14    36     0     1    10     1    0 -  0   none	: 83 15 
;;       15    17     0     2     9     1    0 -  0   none	: 83 33 
;;       16    36     0     1    10     1    0 -  0   none	: 83 17

(snip)

;;		Ready list after queue_to_ready:    19  32  17  15  13
30  28  26  24  22  20
;;		Ready list after ready_sort:    32  19  17  15  13  30
28  26  24  22  20
;;	Ready list (t =  6):    32  19  17  15  13  30  28  26  24  22
20
;;		--> scheduling insn <<<20>>> on unit none
;;		dependences resolved: insn 21 into queue with cost=1
;;		Ready-->Q: insn 21: queued for 1 cycles.
;;	Ready list (t =  6):    32  19  17  15  13  30  28  26  24  22
;;		Q-->Ready: insn 21: moving to ready without stalls
;;		Ready list after queue_to_ready:    21  32  19  17  15
13  30  28  26  24  22
;;		Ready list after ready_sort:    32  21  19  17  15  13
30  28  26  24  22
;;	Ready list (t =  7):    32  21  19  17  15  13  30  28  26  24
22
;;		--> scheduling insn <<<22>>> on unit none
;;		dependences resolved: insn 23 into queue with cost=1
;;		Ready-->Q: insn 23: queued for 1 cycles.
;;	Ready list (t =  7):    32  21  19  17  15  13  30  28  26  24
;;		Q-->Ready: insn 23: moving to ready without stalls

(snip)

What does it mean by "unit none"?  Has anyone else encountered this
problem?  What more information do you think you would need to diagnose
it?  The port I am working on came from gcc 3.4.2.

Thank you,
Charles

Re: scheduling insn on none

[Ian Lance Taylor]

"Tabony, Charles" <ctabony@qualcomm.com> writes:

> What does it mean by "unit none"?

First I'll note that you shouldn't see this when using the DFA
scheduler (define_insn_reservation, etc.).  You should only see it
when using the old pipeline description (define_function_unit, etc.).
The old pipeline description has been removed from the current
sources, but it was still present in 3.4.

"unit none" simply means that the scheduler doesn't know which
functional unit(s) are used by the insn.  The insn did not match any
of the tests in the various define_function_unit clauses.

If you actually wrote define_insn_reservation clauses, then see
TARGET_SCHED_USE_DFA_PIPELINE_INTERFACE.

Ian