[Chicken-janitors] #1317: fibc hangs when compiled with -O3 or -O4

[Chicken Trac]

#1317: fibc hangs when compiled with -O3 or -O4
------------------------+--------------------
 Reporter:  mario       |      Owner:
     Type:  defect      |     Status:  new
 Priority:  major       |  Milestone:  4.12.0
Component:  compiler    |    Version:  4.11.0
 Keywords:  fibc, hang  |
------------------------+--------------------
 The program below hangs eating CPU when compiled with -O3 or -O4:

 {{{
 (define (addc x y k)
   (if (zero? y)
     (k x)
     (addc (add1 x) (sub1 y) k)))

 (define (fibc x c)
   (if (zero? x)
     (c 0)
     (if (zero? (sub1 x))
       (c 1)
       (addc (call-with-current-continuation (lambda (c) (fibc (sub1 x)
 c)))
             (call-with-current-continuation (lambda (c) (fibc (sub1 (sub1
 x)) c)))
             c))))

 (let ((x (time (fibc 30 (lambda (n) n)))))
   (if (not (equal? x 832040))
       (error "wrong result" x) ) )
 }}}

 {{{
 $ csc fibc.scm
 $ ./fibc
 0.412s CPU time, 12/4237 GCs (major/minor)
 }}}

 {{{
 $ csc -O3 fibc.scm
 $ ./fibc
 <hangs>
 }}}

 Also hangs when compiled with -O4.  It works as expected (i.e., doesn't
 hang) when compiled with -O5.

 I could reproduce this behavior with 4.11.0 and master (as of 724f6866b).
 I could **not** reproduce the problem with 4.10.0, so the bug has been
 introduced at some point between 4.10.0 and 4.11.0. The issue doesn't seem
 to be related to the C compiler.  I could reproduce it with GCC 4.9.2, GCC
 6.1.1 and clang 3.6.2.

 This issue was caught while trying csc options for [https://github.com
 /mario-goulart/chicken-benchmarks chicken-benchmarks] (fibc is one of the
 benchmark programs).

--
Ticket URL: <http://bugs.call-cc.org/ticket/1317>
CHICKEN Scheme <https://www.call-cc.org/>
CHICKEN Scheme is a compiler for the Scheme programming language.