[Bug c/52592] New: mplayer compilation failure with undefined reference to `__builtin_iround'

["ojab at ojab dot ru" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52592

             Bug #: 52592
           Summary: mplayer compilation failure with undefined reference
                    to `__builtin_iround'
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: ojab@ojab.ru


MPlayer build fails with gcc-4.7.0rc2 (see
http://bugzilla.mplayerhq.hu/show_bug.cgi?id=2047 ):

gcc -o mencoder mencoder.o parser-mecmd.o â -lfribidi -lass -lz -lbz2 -lmad
-lvpx -lpthread -ldl -rdynamic   -lmp3lame
ffmpeg/libavcodec/libavcodec.a(ffv1.o): In function `encode_init':
ffv1.c:(.text.unlikely+0x16a1): undefined reference to `__builtin_iround'
collect2: error: ld returned 1 exit status
make: *** [mencoder] Error 1
make: *** Waiting for unfinished jobs....
ffmpeg/libavcodec/libavcodec.a(ffv1.o): In function `encode_init':
ffv1.c:(.text.unlikely+0x16a1): undefined reference to `__builtin_iround'
collect2: error: ld returned 1 exit status
make: *** [mplayer] Error 1


Looks like related to http://gcc.gnu.org/ml/gcc-patches/2011-08/msg01001.html
and 
>Please document those in doc/extend.texi and make sure they do not leak into the global namespace as ifloor, etc., but are only available as __builtin_ifloor, etc..
from http://gcc.gnu.org/ml/gcc-patches/2011-08/msg01003.html

mplayer builds fine with CFLAGS=-ffast-math, I think that it can be gcc bug.

Please tell me what additional info is needed.