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Re: [PATCH] Document arithmetic overflow semantics
- From: Richard Earnshaw <rearnsha at arm dot com>
- To: Richard Henderson <rth at redhat dot com>
- Cc: Roger Sayle <roger at www dot eyesopen dot com>, Richard Kenner <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc-patches at gcc dot gnu dot org, gcc at gcc dot gnu dot org, Richard dot Earnshaw at arm dot com
- Date: Thu, 13 Feb 2003 18:04:55 +0000
- Subject: Re: [PATCH] Document arithmetic overflow semantics
- Organization: ARM Ltd.
- Reply-to: Richard dot Earnshaw at arm dot com
> On Thu, Feb 13, 2003 at 08:31:33AM -0700, Roger Sayle wrote:
> > At the GCC internal level there should be no such thing as undefined
> > behaviour, this is a front-end concept.
>
> I disagree. It's the undefinedness we want to take advantage of.
>
I think there is major confusion here between "undefined" in the
language-lawyer concept and "ambiguous" about what our internal nodes mean.
Yes, we want to take advantage of the former. But we need to try and
avoid the latter.
R.