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Re: Code motion around labels
- To: kenner at vlsi1 dot ultra dot nyu dot edu (Richard Kenner)
- Subject: Re: Code motion around labels
- From: Fergus Henderson <fjh at cs dot mu dot oz dot au>
- Date: Sun, 15 Apr 2001 07:16:24 +1000
- Cc: gcc at gcc dot gnu dot org
- References: <10104141617.AA20810@vlsi1.ultra.nyu.edu>
On 20-May-2037, Richard Kenner, GNU C Maintainer <kenner@vlsi1.ultra.nyu.edu> wrote:
> Now, *maybe* it would be a good idea to make some guarantees along
> those lines, but you haven't really provided any argument for it.
>
> Sure I did. For one thing, it's the only way to do a zero-cost exception
> mechanism without using the one built in. The other related to external
> probing.
Preventing code motion across ordinary labels whose address is taken
is not the only way. For example, C-- has a different way, I think.
(I'm not going to check, since it's getting rather late, and the PC
I'm using doesn't have Ghostview installed, but the papers are
available from www.cminusminus.org.)
Also the alternative that I suggested of preventing code motion only
across `volatile' labels is another possibility.
--
Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit
| of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.