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Re: [PATCH]Incorrect TREE_OVERFLOW copying
- From: "Joseph S. Myers" <jsm at polyomino dot org dot uk>
- To: Nathan Sidwell <nathan at codesourcery dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 16 Aug 2004 15:05:34 +0000 (UTC)
- Subject: Re: [PATCH]Incorrect TREE_OVERFLOW copying
- References: <4120BF29.4010700@codesourcery.com>
On Mon, 16 Aug 2004, Nathan Sidwell wrote:
> I found some incorrect copying of TREE_OVERFLOW -- that flag is only
> valid on expr nodes, for a DECL node it means something else. whilst
> there I noticed IS_NON_TYPE_CODE_CLASS wasn't being very smart.
>
> Fixed thusly.
>
> booted & tested on i686-pc-linux-gnu, ok?
The c-typeck.c changes are OK. I'm not qualified to review the rest. (I
don't offhand see a testcase that would show any problem caused by this
incorrect copying.)
This seems illustrative of the problems of TREE_OVERFLOW and
TREE_CONSTANT_OVERFLOW - I don't have much more confidence in the accuracy
of their settings or uses after this patch than before it - and as I've
noted I'd like to get rid of them, leaving front ends to receive and track
flags from the middle-end when overflow occurs (C being covered by my
constant expressions proposal, C++ being only a minimal user and Ada
needing care to ensure it keeps the detection of overflow of TYPE_SIZE and
TYPE_SIZE_UNIT).
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=16437#c4
http://gcc.gnu.org/ml/gcc-patches/2004-07/msg01103.html
http://gcc.gnu.org/ml/gcc/2004-08/msg00608.html
http://www.srcf.ucam.org/~jsm28/gcc/#parsestruct
--
Joseph S. Myers http://www.srcf.ucam.org/~jsm28/gcc/
jsm@polyomino.org.uk (personal mail)
jsm28@gcc.gnu.org (Bugzilla assignments and CCs)