Subject: tree-il->bytecode compilation of (not (list …)) fails
From: Ludovic Courtès <[email-masked]>
To: [email-masked]
Date: Sat, 01 Oct 2022 12:27:30 +0200
List-Id: <debbugs-submit.debbugs.gnu.org>

Hi,

I stumbled upon this bug of the baseline compiler:

--8<---------------cut here---------------start------------->8---
scheme@(guile-user)> (compile '(not (list 1 2)) #:optimization-level 2)
$3 = #f
scheme@(guile-user)> (compile '(not (list 1 2)) #:optimization-level 1)
ice-9/boot-9.scm:1685:16: In procedure raise-exception:
In procedure struct-vtable: Wrong type argument in position 1 (expecting struct): #f

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
In system/base/compile.scm:
   352:28  5 (compile _ #:from _ #:to _ #:env _ #:optimization-level _ #:warning-level _ #:opts _)
   265:44  4 (_ _ _)
   261:27  3 (_ _ _)
In language/tree-il/compile-bytecode.scm:
  1386:14  2 (compile-bytecode #<tree-il (primcall not (primcall list (const 1) (const 2)))> #<module (#{ g446}#) …> …)
   412:30  1 (_ _)
In ice-9/boot-9.scm:
  1685:16  0 (raise-exception _ #:continuable? _)
scheme@(guile-user) [1]> (version)
$4 = "3.0.8"
--8<---------------cut here---------------end--------------->8---

The exception is raised in the ‘predicate?’ call below, where
(lookup-primitive 'list) returns #f:

  (define (finish-conditional exp)
    (define (true? x) (match x (($ <const> _ val) val) (_ #f)))
    (define (false? x) (match x (($ <const> _ val) (not val)) (_ #f)))
    (define (predicate? name) (primitive-predicate? (lookup-primitive name)))
    (match exp
      (($ <conditional> src ($ <conditional> _ test (? true?) (? false?))
          consequent alternate)
       (finish-conditional (make-conditional src test consequent alternate)))
      (($ <conditional> src ($ <conditional> _ test (? false?) (? true?))
          consequent alternate)
       (finish-conditional (make-conditional src test alternate consequent)))
      (($ <conditional> src ($ <primcall> _ (? predicate?)))
       exp)
      (($ <conditional> src test consequent alternate)
       (make-conditional src (make-primcall src 'false? (list test))
                         alternate consequent))))

I believe this is fixed by changing ‘predicate?’ to:

    (define (predicate? name)
      (and=> (lookup-primitive name) primitive-predicate?))

Thoughts?

Ludo’.