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Re: [PING^3] PR 21438 : Warning about division by zero depends on lexical form

From: Andrew Haley <aph at redhat dot com>
To: "Manuel López-Ibáñez" <lopezibanez at gmail dot com>
Cc: "Mark Mitchell" <mark at codesourcery dot com>, "Joseph S. Myers" <joseph at codesourcery dot com>, gcc-patches <gcc-patches at gcc dot gnu dot org>
Date: Fri, 2 Mar 2007 19:48:22 +0000
Subject: Re: [PING^3] PR 21438 : Warning about division by zero depends on lexical form
References: <6c33472e0702100802v4469d3dehd49655d67a552da9@mail.gmail.com> <6c33472e0702180347x367cd15pa77c9d24143e0e24@mail.gmail.com> <6c33472e0703011018m3b24fd6by68723c3d8191b983@mail.gmail.com> <Pine.LNX.4.64.0703012009460.5655@digraph.polyomino.org.uk> <45E7A930.2080205@codesourcery.com> <6c33472e0703021140v2feadbebl14cf1e9eb7e61b23@mail.gmail.com>

Manuel López-Ibáñez writes:
 > On 02/03/07, Mark Mitchell <mark@codesourcery.com> wrote:
 > > Joseph S. Myers wrote:
 > >
 > > I don't know that I entirely agree that we should not warn about
 > > 1.0/0.0.  In particular, if doing that division would generate a SIGFPE
 > > on the target, were it not folded, then it seems reasonable to warn
 > > about it.
 > >
 > 
 > I think that if it generates a SIGFPE, then it is not a legitimate way
 > to generate infinities and NaNs.
 > 
 > Can I detect that from the front-end? How?

I doubt it.  Is a target that generates SIGFPE from 1.0/0.0
IEEE-754(etc) compliant?  I would not have thought so, but it can be
hard to be certain.

Andrew.

References:
- [PING^3] PR 21438 : Warning about division by zero depends on lexical form
  - From: Manuel López-Ibáñez
- Re: [PING^3] PR 21438 : Warning about division by zero depends on lexical form
  - From: Joseph S. Myers
- Re: [PING^3] PR 21438 : Warning about division by zero depends on lexical form
  - From: Mark Mitchell
- Re: [PING^3] PR 21438 : Warning about division by zero depends on lexical form
  - From: Manuel López-Ibáñez

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