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Re: Value Range Propagation Patch (Version 4)
- To: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- Subject: Re: Value Range Propagation Patch (Version 4)
- From: Jeffrey A Law <law at cygnus dot com>
- Date: Mon, 24 Jul 2000 14:15:38 -0600
- cc: John Wehle <john at feith dot com>, gcc-patches at gcc dot gnu dot org
- Reply-To: law at cygnus dot com
In message <397C8BAA.C17B3DEB@moene.indiv.nluug.nl>you write:
> There is a interesting irony about value range propagation: It tends to
> spend most of its time on routines/code that ultimately will take the
> least time to execute anyway ;-)
> [ Mainly because, as the human programmer knows - they won't take long
> to execute, so why should _he_ spend any time to optimize them ? ]
>
> I just saw it spend 5:26 minutes on a routine that will take care of the
> initialisation of some arrays in a split second when executing :-)
> [ That 5+ minutes is without array bounds checking ]
>
> How do you get it to focus its efforts on code that really matters ?
Profiling :-) Seriously though we could look at running VRP over subgraphs
and just do it for nested loops.
jeff