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Re: Dead-code elimination can't remove string copy insns?

From: Joe Buck <jbuck at synopsys dot com>
To: law at redhat dot com
Cc: Diego Novillo <dnovillo at redhat dot com>, Zack Weinberg <zack at codesourcery dot com>, Michael Matz <matz at suse dot de>, "gcc at gcc dot gnu dot org" <gcc at gcc dot gnu dot org>
Date: Tue, 13 May 2003 11:35:44 -0700
Subject: Re: Dead-code elimination can't remove string copy insns?
References: <1052848240.27232.407.camel@frodo.toronto.redhat.com> <200305131802.h4DI25Ea012586@speedy.slc.redhat.com>

On Tue, May 13, 2003 at 12:02:05PM -0600, law@redhat.com wrote:
> In message <1052848240.27232.407.camel@frodo.toronto.redhat.com>, Diego Novillo
>  writes:
>  >Now, if we could also get rid of those pesky labels.  You mentioned
>  >something about that, but I forget what.
> Well, it's simply a matter of building a use count for the labels.  As
> we remove GOTO_EXPRs we decrement the count.

I don't know anything about the code in question, but is it certain that
the cost of maintaining, incrementing, and decrementing reference counts
is less than the cost of doing a sweep at the end to clean up unused cruft?
Reference counting is not necessarily cheap.

References:
- Re: Dead-code elimination can't remove string copy insns?
  - From: Diego Novillo
- Re: Dead-code elimination can't remove string copy insns?
  - From: law

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