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From: Bruce Korb <bkorb@sco.COM>
To: Richard Kenner <kenner@vlsi1.ultra.nyu.edu>
Cc: mark@codesourcery.com, gcc@gcc.gnu.org
Subject: Re: SSA implementation
Date: Fri, 30 Jun 2000 08:38:00 -0000	[thread overview]
Message-ID: <395CBCE8.1EDD8994@sco.com> (raw)
In-Reply-To: <10006301052.AA25097@vlsi1.ultra.nyu.edu>

Richard Kenner wrote:
> 
>     We will be contributing a dead-code elimination pass in the very near
>     future that operates on the SSA form.  One big improvement is that
>     this algorithm is a) very fast and b) can eliminate loops in things
>     like:
> 
>   void f () {
>     int i;
>     for (i = 0; i < 100; ++i)
>       ;
>   }
> 
> We could always have eliminated such loops, but as I understood it, we
> chose not to under the assumption they were there for timing delay
> purposes.  Has this policy chaged?

This won't work for timing delay on advanced processors anyway.
You would have to make "i" be "volatile" or the processor itself
will optimize it away (essentially).

  reply	other threads:[~2000-06-30  8:38 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2000-06-30  3:39 Richard Kenner
2000-06-30  8:38 ` Bruce Korb [this message]
2000-06-30  9:14 ` Mark Mitchell
  -- strict thread matches above, loose matches on Subject: below --
2000-06-29  7:30 David Dolan
2000-06-29 11:59 ` Geoff Keating
2000-06-29 12:11   ` Mark Mitchell
2000-06-29 12:24     ` Gerald Pfeifer

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