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Re: Ping Re: Fix IBM long double spurious overflows
- From: David Edelsohn <dje dot gcc at gmail dot com>
- To: "Joseph S. Myers" <joseph at codesourcery dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Adhemerval Zanella <azanella at linux dot vnet dot ibm dot com>
- Date: Tue, 28 Jan 2014 21:38:45 -0500
- Subject: Re: Ping Re: Fix IBM long double spurious overflows
- Authentication-results: sourceware.org; auth=none
- References: <Pine dot LNX dot 4 dot 64 dot 1401041314430 dot 23651 at digraph dot polyomino dot org dot uk> <CAGWvnykMLF=xsWKpw+rv3HyRCSH0ZDCPmin8J+RWE9x5d-HA6A at mail dot gmail dot com> <Pine dot LNX dot 4 dot 64 dot 1401281749340 dot 30131 at digraph dot polyomino dot org dot uk> <CAGWvnynQAsdBtK8ewqowY4F=Dq1FhNWj2WKj9p42khsE2cKmwA at mail dot gmail dot com> <Pine dot LNX dot 4 dot 64 dot 1401282108420 dot 2449 at digraph dot polyomino dot org dot uk>
On Tue, Jan 28, 2014 at 4:19 PM, Joseph S. Myers
<joseph@codesourcery.com> wrote:
> The glibc libm testsuite has much more thorough coverage (hopefully soon
> to include running all tests in all rounding modes by default) than it did
> two years ago, and it's a pain to keep test results clean across all
> architectures when the basic arithmetic operations for IBM long double do
> not follow the normal conventions as regards permitted errors for most
> glibc libm functions (results within a few ulps, no spurious overflows or
> underflows except possibly for exact underflowing results, no missing
> underflows), or as regards working in all rounding modes, making it hard
> to distinguish between libgcc and glibc bugs.
>
> Thus, if these issues are not to be fixed in libgcc, I think we need to
> seek FSF approval to use a copy of the current IBM long double libgcc code
> under LGPLv2.1+ in glibc, with a view to fixing the issues in that copy
> only and linking it directly into libc and libm (for their internal use
> rather than re-exporting symbols from it).
Joseph,
The testsuite can disable those tests or xfail them for IBM long double.
It is not appropriate for a GCC or GLIBC maintainer to impose behavior
or conformance on a specific target and port-specific code. I am sorry
that the failures bother you, but ports have the freedom to conform or
not conform with standards in target-specific code.
Thanks, David