[Openmcl-devel] tail calls in 1.3 IDE?

Brian Hayes bhayes at amsci.org
Thu Aug 13 13:35:00 PDT 2009

As far as I can tell, tail-call optimization has stopped working in  
1.3 versions of CCL when running under the IDE. Are others seeing this  
same change in behavior? Was the change deliberate? Is there some  
setting that controls it?


(defun tail-test (n)
  (if (zerop n)
    (tail-test (1- n))))

(tail-test 1000000)

This succeeds under CCL 1.2 in the IDE (I've tested PPC and x8664  
versions). It also succeeds in 1.3 when running in the terminal. But  
it fails with a stack overflow in 1.3 under the IDE. The backtrace  
shows some 60,000 stack frames. (I've tested fresh downloads of the  
prepackaged .dmg for PPC and x8664 as well as a newly svn-updated 1.3- 
r12575M  (DarwinX8664). )

It looks as if a tracing or debugging facility may have been turned on  
by default in the IDE. If so, can someone show me the magic switch  
that turns it off?


Brian Hayes

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