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Re: wip-cse
From: |
Ludovic Courtès |
Subject: |
Re: wip-cse |
Date: |
Tue, 17 Apr 2012 14:42:36 +0200 |
User-agent: |
Gnus/5.110018 (No Gnus v0.18) Emacs/24.0.93 (gnu/linux) |
Hi!
Andy Wingo <address@hidden> skribis:
> This pass does a few related things:
>
> * Replacement of an expression with a reference to a lexical
> identifier.
>
> * Inferring the boolean value of an expression, given previous
> expressions that were true.
>
> * Eliminating an expression where it can cause no effect.
OK, excellent.
> It does not name new values, however. If we switched to CPS as our IR,
> then we would have a lot more names, and CSE could be more effective.
OK.
> Sure. In these I just replaced some of the calls to "log" with "pk".
> The "inferring" lines indicate boolean-valued expressions that were
> folded. The "elided" lines indicate useless expressions in effect
> context. The "propagate-value" lines... hm, there aren't any. They
> would correspond to replacing expressions with lexical-refs.
Nice, understood!
>> What impact does it have on compilation time in module/?
>
> Dunno. It almost doubles the fresh recompilation of of peval, though
> (1.3s to 2.3s).
So it’s probably safe to assume that the overall compilation time
doubles as well?
>>> seeing that lookup in vhashes is fairly slow. Dunno. If we can speed
>>> up vhashes somehow then we win in CSE, peval, and other passes, so
>>> probably it's best to focus there.
>>
>> I think we’ll need C-level profiling to see what’s going on. Do you
>> have such info already? Otherwise I can look into it.
>
> I don't have any such info yet.
BTW, you may also want to try with a higher value of
‘block-growth-factor’. With a factor of 2, roughly half of the values
are found in the first vlist block; with a higher value, you would
increase that ratio, at the expense of increased memory consumption.
Thanks,
Ludo’.
- wip-cse, Andy Wingo, 2012/04/16
- Re: wip-cse, Ludovic Courtès, 2012/04/16
- Re: wip-cse, Andy Wingo, 2012/04/16
- Re: wip-cse, Andy Wingo, 2012/04/16
- Re: wip-cse,
Ludovic Courtès <=
- Re: wip-cse, Andy Wingo, 2012/04/24
- Re: wip-cse, Ludovic Courtès, 2012/04/24
- Re: wip-cse, Andy Wingo, 2012/04/24
- Re: wip-cse, Ludovic Courtès, 2012/04/24
- Re: wip-cse, Andy Wingo, 2012/04/25
- Re: wip-cse, Ludovic Courtès, 2012/04/25
- Re: wip-cse, Andy Wingo, 2012/04/25