Mark H Weaver <[email protected]> writes:
> It occurs to me that there's another problem with this optimization:
>
> scheme@(guile-user)> ,optimize (lambda (x y . z) (apply (lambda x x) x y z))
> $1 = (lambda x x)
>
> This optimization changes the arity of the procedure. The original
> version checks that at least 2 arguments are provided, and ensures that
> at least 2 arguments are passed to the inner procedure, which the code
> might depend on. The optimization effectively removes this check.
Here's an updated patch that fixes both issues.
Mark
diff --git a/module/language/tree-il/peval.scm
b/module/language/tree-il/peval.scm
index 993fa0ad6..13b7d9bc4 100644
--- a/module/language/tree-il/peval.scm
+++ b/module/language/tree-il/peval.scm
@@ -1585,11 +1585,15 @@ top-level bindings from ENV and return the resulting
expression."
(and (not opt) rest (not kw)
(match body
(($ <primcall> _ 'apply
- (($ <lambda> _ _ (and lcase ($ <lambda-case>)))
+ (($ <lambda> _ _ (and lcase ($ <lambda-case> _ req1)))
($ <lexical-ref> _ _ sym)
...))
(and (equal? sym gensyms)
(not (lambda-case-alternate lcase))
+ (<= (length req) (length req1))
+ (every (lambda (s)
+ (= (lexical-refcount s) 1))
+ sym)
lcase))
(_ #f))))
(let* ((vars (map lookup-var gensyms))
