Ping Re: Fix IBM long double spurious overflows

David Edelsohn
Wed Jan 29 02:38:00 GMT 2014

On Tue, Jan 28, 2014 at 4:19 PM, Joseph S. Myers
<> 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).


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

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