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Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570
From: |
Mark H Weaver |
Subject: |
Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570 |
Date: |
Fri, 13 Apr 2012 10:22:56 -0400 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/24.0.92 (gnu/linux) |
Hi Andy,
> commit 59c557056cff1ce6146b4d689eeee922300b6278
> Author: Andy Wingo <address@hidden>
> Date: Tue Apr 10 15:56:23 2012 -0700
>
> peval: elide redundant predicates; eliminate some common subexpressions
>
> * module/language/tree-il/peval.scm (fold-constants): Returns #f instead
> of the expression, as all continuations handle #f themselves.
> (negate, bailout?, extract-facts, infer, infer-defined?)
> (infer-struct-vtable): New helpers.
I haven't looked at the code, but it sounds like you are trying to
eliminate redundant 'struct-vtable' checks. Unfortunately, it seems to
me that this cannot be done safely. In practice, the checks look like:
(eq? (struct-vtable s) <foo>)
Both of the values being compared here are fetched from mutable
locations. The 'struct-vtable' field is mutable, and <foo> is usually a
top-level variable that is also mutable. Furthermore, both of these
things are mutated in practice when a GOOPS class is redefined, IIUC.
Am I missing something?
Thanks,
Mark
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570,
Mark H Weaver <=
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, Noah Lavine, 2012/04/13
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, Andy Wingo, 2012/04/13
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, Mark H Weaver, 2012/04/13
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, Andy Wingo, 2012/04/14
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, David Kastrup, 2012/04/15
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, Ludovic Courtès, 2012/04/15
- Re: GNU Guile branch, wip-peval-predicates, created. v2.0.5-100-g59c5570, David Kastrup, 2012/04/16