Thanks for the help! When the optimize converts
(let-values ([(X ...) (values M ...)]) ....) to (let ([X M] ...) ....) it incorrectly attaches a virtual timestamp to each "[X M]" binding that corresponds to the timestamp after the whole `(values M ...)`. So, the optimizer loses the fact that in `(values (car xy) (cdr xy))` the `(cdr xy)` happens after the `(car xy)`. It later ends up swapping the order of those expressions, which is a particular problem when `(cdr xy)` was changed to `(unsafe-cdr xy)` on the grounds that it happens after `(car xy)`. At Sun, 13 Sep 2015 12:15:33 +0200, antoine wrote: > Bonjour, > > The bytecode generated is: > > (begin > (module test .... > (require (lib "racket/base.rkt")) > (provide) > (module configure-runtime .... > (require '#%kernel (lib "racket/runtime-config.rkt")) > (provide) > (print-as-expression '#t)) > (define-values > (_split&flip) > (begin > '%%inline-variant%% > (#%closed > split&flip28 > (lambda (arg0-30) > '#(split&flip #<path:/tmp/test.rkt> 3 0 20 90 #f) > (values (unsafe-cdr arg0-30) (car arg0-30)))) > (#%closed > split&flip27 > (lambda (arg0-35) > '#(split&flip #<path:/tmp/test.rkt> 3 0 20 90 #f) > (values (unsafe-cdr arg0-35) (car (#%sfs-clear arg0-35))))))) > (define-values > (_a _b) > (let ((local40 (cons '0 '1))) > (values (unsafe-cdr local40) (unsafe-car local40)))) > (#%apply-values > |_print-values:p@(lib "racket/private/modbeg.rkt")| > (values (unsafe-cdr _b) (car _b))))) > > > Not familiar with the bytecode but a quick look at > http://docs.racket-lang.org/raco/decompile.html about %%inline-variant%% make > me > think split&flip28 is over enthousiastic about > > (values (unsafe-cdr arg0-30) (car arg0-30)) > > and should have generated: > > (values (cdr arg0-30) (car arg0-30)) > > By the way it also segfault to me, 32bit, linux 6.2 release. > > -- > You received this message because you are subscribed to the Google Groups > "Racket Users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "Racket Users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
