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Re: Make max_align_t respect _Float128 [version 2]
- From: Florian Weimer <fweimer at redhat dot com>
- To: Bernd Edlinger <bernd dot edlinger at hotmail dot de>, Joseph Myers <joseph at codesourcery dot com>
- Cc: Richard Biener <rguenther at suse dot de>, Paul Eggert <eggert at cs dot ucla dot edu>, "gcc-patches at gcc dot gnu dot org" <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 8 Sep 2016 11:35:21 +0200
- Subject: Re: Make max_align_t respect _Float128 [version 2]
- Authentication-results: sourceware.org; auth=none
- References: <AM4PR0701MB21621ECE23D5802E2153DF30E4F80@AM4PR0701MB2162.eurprd07.prod.outlook.com>
On 09/07/2016 08:32 PM, Bernd Edlinger wrote:
interesting. I just tried the test case from PR 77330 with _Decimal128.
result: _Decimal128 did *not* trap with gcc4.8.4, but it does trap with
gcc-7.0.0.
Recent GCC versions rely on struct pointer alignment for struct member
access, older versions did less so.
For example, this tcsh bug flew under the radar for about two years:
<https://bugzilla.redhat.com/show_bug.cgi?id=1303323>
(glibc added 16-byte alignment to struct __dirstream as a side effect of
a change to help sparc in 2013, and this did not cause any trouble with
tcsh before.)
Florian