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Re: ppc32: math failures - logb_downward (1) gives wrong result
- From: "Joseph S. Myers" <joseph at codesourcery dot com>
- To: Andreas Jaeger <aj at suse dot com>
- Cc: libc-alpha <libc-alpha at sourceware dot org>
- Date: Thu, 21 Jun 2012 21:09:08 +0000 (UTC)
- Subject: Re: ppc32: math failures - logb_downward (1) gives wrong result
- References: <4FE37E9A.7050609@suse.com>
On Thu, 21 Jun 2012, Andreas Jaeger wrote:
> Build current trunk (as of yesterday) on s390 with gcc 4.7, I see a couple of
> failures in the math testsuite:
ppc32 or s390? For ppc32 it's a known GCC bug (though there may not be an
entry in GCC Bugzilla for it): the code sequence generated for converting
integers to floating-point, on older processors, wrongly converts 0 to -0
in round-downwards mode (if -frounding-math, a more complicated sequence
should be used instead that temporarily sets round-to-nearest mode).
--
Joseph S. Myers
joseph@codesourcery.com