[Bug target/39501] -O -ffinite-math-only gets min(x,y) optimization wrong for SF on arm-*-gnueabi

["martinwguy at yahoo dot it" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #8 from martinwguy at yahoo dot it  2009-03-29 17:49 -------
A bit more info on the real-world cases that this bug bites.

1) libvorbis's testsuite (only in trunk) fails:

    svn co http://svn.xiph.org/trunk/vorbis
    cd vorbis; ./autogen.sh; ./configure; make
    test/test

complains that "max_abs (0.000000) too small."; it should say "ok"

It can be fixed by using "./configure CFLAGS=-fno-finite-math-only"

(Both of these utilities' build scripts append your CFLAGS settings to their
own default ones.)

2) LAME -V0 outputs silence

    wget http://downloads.sourceforge.net/lame/lame-398-2.tar.gz
    tar xzf lame-398-2.tar.gz
    cd lame-398-2
    ./configure && make
    wget http://martinwguy.co.uk/martin/test/Happy.wav
    frontend/lame --nohist -V0 Happy.wav Happy.mp3
    mpg123 -w Happy2.wav Happy.mp3
    # Or frontend/lame --quiet --decode Happy.mp3 Happy2.wav
    sox Happy2.wav -e stat | grep 'Maximum amplitude'

should say something like maxamp = 0.574310, not 0.000000

It can be fixed by using
        "./configure CFLAGS=-fno-finite-math-only"
and also with
        "./configure CFLAGS="-fno-schedule-insns -fno-schedule-insns2"
though this does not fix the libvorbis issue.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39501