[ sisc-Bugs-1448235 ] non-functional procedures break unoptimisation

Bugs item #1448235, was opened at 2006-03-12 10:56
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 7
Submitted By: Matthias Radestock (mradestock)
Assigned to: Nobody/Anonymous (nobody)
Summary: non-functional procedures break unoptimisation

Initial Comment:
SISC (1.13.0-alpha)
#;> (define my+ +)
#;> (define (f l) (list (my+) (reverse! l)))
#;> (f (list 1 2 3))
(0 (3 2 1))
#;> (define (my+ . args) (apply + args))
#;> (f (list 1 2 3))
(0 (1))
#;> (f (list 1 2 3))
(0 (3 2 1))


The second result is clearly wrong and is caused by
AppExp re-executing the entire arg eval sequence when
one of the arg evals gets unoptimised.

Note though that even if AppExp were smarter about this
and only re-executed arg evals from the point it
failed, we would still run into problems when the
unoptimisation occurs at a deeper level, e.g. in one of
the args of a FixedAppExp.

I reckon the solution is to only permit inlining of
purely functional primitives.

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