* bug#9769: Misplaced tail call optimization
@ 2011-10-16 20:29 Ludovic Courtès
2011-10-17 8:33 ` Andy Wingo
2011-10-20 21:51 ` Andy Wingo
0 siblings, 2 replies; 3+ messages in thread
From: Ludovic Courtès @ 2011-10-16 20:29 UTC (permalink / raw)
To: 9769
(This is a copy of <http://savannah.gnu.org/bugs/?34300>, so it doesn't
get lost. :-))
Consider this example:
(define bar
(lambda ()
(let ((fail (lambda () 'fail)))
(let loop ((a (iota 3)))
(if (pair? a)
(loop (cdr a))
(fail)))
(pk 'done))))
This function should return 'done but it instead returns 'fail, because both
the call to `loop' and the call to `fail' are compiled as if they were tail
calls.
To reproduce the test, turn partial evaluation off---otherwise the call to
`fail' is inlined and the problem doesn't show up.
Ludo'.
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#9769: Misplaced tail call optimization
2011-10-16 20:29 bug#9769: Misplaced tail call optimization Ludovic Courtès
@ 2011-10-17 8:33 ` Andy Wingo
2011-10-20 21:51 ` Andy Wingo
1 sibling, 0 replies; 3+ messages in thread
From: Andy Wingo @ 2011-10-17 8:33 UTC (permalink / raw)
To: Ludovic Courtès; +Cc: 9769
The title of this bug isn't quite right. It's not that Guile is
intentionally treating the call to fail as a tail call; it's some
bug in the way that "labels allocated" procedures in compile-glil.scm
are called.
Andy
--
http://wingolog.org/
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#9769: Misplaced tail call optimization
2011-10-16 20:29 bug#9769: Misplaced tail call optimization Ludovic Courtès
2011-10-17 8:33 ` Andy Wingo
@ 2011-10-20 21:51 ` Andy Wingo
1 sibling, 0 replies; 3+ messages in thread
From: Andy Wingo @ 2011-10-20 21:51 UTC (permalink / raw)
To: Ludovic Courtès; +Cc: 9769-done
Fixed in git. Thanks for the report!
commit aa9c19858872a135ea959066fff26f86527a1bd0
Author: Andy Wingo <wingo@pobox.com>
Date: Thu Oct 20 23:50:05 2011 +0200
fix misallocation of some <fix> procedures
* module/language/tree-il/analyze.scm (analyze-lexicals): When stepping
into a non-tail form, we know that labels allocation will be invalid,
so use an empty labels set. Fixes http://debbugs.gnu.org/9769.
* test-suite/tests/tree-il.test ("labels allocation"): Add a test.
--
http://wingolog.org/
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2011-10-16 20:29 bug#9769: Misplaced tail call optimization Ludovic Courtès
2011-10-17 8:33 ` Andy Wingo
2011-10-20 21:51 ` Andy Wingo
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