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Re: [PATCH][4.3] Deprecate -ftrapv

From: Mark Mitchell <mark at codesourcery dot com>
To: "Joseph S. Myers" <joseph at codesourcery dot com>
Cc: Richard Guenther <rguenther at suse dot de>, gcc-patches at gcc dot gnu dot org, gcc at gcc dot gnu dot org
Date: Fri, 29 Feb 2008 17:53:59 -0800
Subject: Re: [PATCH][4.3] Deprecate -ftrapv
References: <Pine.LNX.4.64.0803010041110.4133@zhemvz.fhfr.qr> <47C89DB1.6030200@codesourcery.com> <Pine.LNX.4.64.0803010109540.4133@zhemvz.fhfr.qr> <47C8AB88.10503@codesourcery.com> <Pine.LNX.4.64.0803010144400.21300@digraph.polyomino.org.uk>

Joseph S. Myers wrote:

You also need to deal with fold, which will optimize away potentially trapping computations with -ftrapv and runs before gimplification (possibly in association with making fold run at gimplification time and not before).

Indeed. However, errors missed due to fold eliminating them before gimplification would be a false negative, so less of a problem. Since this feature is designed to crash your program when it has a bug, crashing your program somewhat less often doesn't make the feature useless; just less useful.

--
Mark Mitchell
CodeSourcery
mark@codesourcery.com
(650) 331-3385 x713

References:
- Re: [PATCH][4.3] Deprecate -ftrapv
  - From: Mark Mitchell
- Re: [PATCH][4.3] Deprecate -ftrapv
  - From: Richard Guenther
- Re: [PATCH][4.3] Deprecate -ftrapv
  - From: Mark Mitchell
- Re: [PATCH][4.3] Deprecate -ftrapv
  - From: Joseph S. Myers

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