On Tue, Nov 24, 2015 at 09:17:18AM +0100, Hendrik Leppkes wrote: > On Sat, Nov 21, 2015 at 2:53 PM, Ganesh Ajjanagadde <gajja...@mit.edu> wrote: > > On Wed, Nov 18, 2015 at 3:04 PM, Ganesh Ajjanagadde <gajja...@mit.edu> > > wrote: > >> On Wed, Nov 18, 2015 at 2:58 PM, Michael Niedermayer <michae...@gmx.at> > >> wrote: > >>> On Tue, Nov 17, 2015 at 04:54:10PM -0500, Ganesh Ajjanagadde wrote: > >>>> isnan and isinf are actually macros as per the standard. In particular, > >>>> the existing implementation has incorrect signature. Furthermore, this > >>>> results in undefined behavior for e.g double values outside float range > >>>> as per the standard. > >>>> > >>>> This patch corrects the undefined behavior for all usage within FFmpeg. > >>>> > >>>> Note that long double is not handled as it is not used in FFmpeg. > >>>> Furthermore, even if at some point long double gets used, it is likely > >>>> not needed to modify the macro in practice for usage in FFmpeg. See > >>>> below for analysis. > >>>> > >>>> Getting long double to work strictly per the spec is significantly harder > >>>> since a long double may be an IEEE 128 bit quad (very rare), 80 bit > >>>> extended precision value (on GCC/Clang), or simply double (on recent > >>>> Microsoft). > >>>> On the other hand, any potential future usage of long double is likely > >>>> for precision (when a platform offers extra precision) and not for > >>>> range, since > >>>> the range anyway varies and is not as portable as IEEE 754 single/double > >>>> precision. In such cases, the implicit cast to a double is well defined > >>>> and isinf and isnan should work as intended. > >>>> > >>>> Reviewed-by: Michael Niedermayer <mich...@niedermayer.cc> > >>>> Signed-off-by: Ganesh Ajjanagadde <gajjanaga...@gmail.com> > >>>> --- > >>>> libavutil/libm.h | 34 ++++++++++++++++++++++++++++++++-- > >>>> 1 file changed, 32 insertions(+), 2 deletions(-) > >>> > >>> probably ok > >>> maybe wait a day or 2 before pushing so people can test it on more > >>> obscure platforms > >>> > >>> thx > >> > >> ok, will wait for 2 days for the hypot hack as well. Thanks. > > > > pushed, thanks > > > > nan/inf behavior on VS2012 seems to have broken with this (probably > nan, but as the patch touches both..) > Reverting this particular patch resolves the failures. > > http://fate.ffmpeg.org/report.cgi?time=20151124040137&slot=x86_32-msvc11-windows-native > (ebur128 was broken before)
heres a patch to reproduce these failures on linux
diff --git a/libavutil/libm.h b/libavutil/libm.h
index 9e5ec5d..1669970 100644
--- a/libavutil/libm.h
+++ b/libavutil/libm.h
@@ -82,6 +82,7 @@ static av_always_inline float cbrtf(float x)
#define exp2f(x) ((float)exp2(x))
#endif /* HAVE_EXP2F */
+#define HAVE_ISINF 0
#if !HAVE_ISINF
#undef isinf
/* Note: these do not follow the BSD/Apple/GNU convention of returning -1 for
@@ -109,6 +110,7 @@ static av_always_inline av_const int avpriv_isinf(double x)
: avpriv_isinf(x))
#endif /* HAVE_ISINF */
+#define HAVE_ISNAN 0
#if !HAVE_ISNAN
static av_always_inline av_const int avpriv_isnanf(float x)
{
[...]
--
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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