Bug#916066: csound regression: zir opcode appears entirely broken; hangs instrument

[Sam Hartman <hartmans@mit.edu>]

package: csound
version: 1:6.12.2~dfsg-1

I was experiencing strange failures with orchestras with csound 6.12 and
eventually I've tracked it down to the zir opcode to read a value from
zk-space at i-time.

It's fairly basic: the zir.csd from the csound examples fails to print
out anything  in the instrument that runs zir.
Based on what I've seen the instrument hangs (or aborts without a note
aborted message).

This is bad because it doesn't look like there's any way to read a
zk-value at I time without that opcode.
I guess you could play reinit games, but ugh.

Interestingly, Debian doesn't seem to be shipping zir.csd or really most
of the examples.
We used to, as I got them somewhere, and they're really useful.
I'm not seeing any license problems, so it would be cool if we either
shipped them or documented why not.
Anyway for completeness I'm attaching zir.csd.

This works on stretch.
<CsoundSynthesizer>
<CsOptions>
; Select audio/midi flags here according to platform
; Audio out   Audio in
-odac           -iadc    ;;;RT audio I/O
; For Non-realtime ouput leave only the line below:
; -o zir.wav -W ;;; for file output any platform
</CsOptions>
<CsInstruments>

; Initialize the global variables.
sr = 44100
kr = 4410
ksmps = 10
nchnls = 1

; Initialize the ZAK space.
; Create 1 a-rate variable and 1 k-rate variable.
zakinit 1, 1

; Instrument #1 -- a simple instrument.
instr 1
  ; Set the zk variable #1 to 32.594.
  ziw 32.594, 1
endin

; Instrument #2 -- prints out zk variable #1.
instr 2
  ; Read the zk variable #1 at i-rate.
  i1 zir 1

  ; Print out the value of zk variable #1.
  print i1
endin


</CsInstruments>
<CsScore>

; Play Instrument #1 for one second.
i 1 0 1
; Play Instrument #2 for one second.
i 2 0 1
e


</CsScore>
</CsoundSynthesizer>