Bugzilla Bug 98685

Using CFLAGS="-ffast-math" in /etc/make.conf will cause screen corruption while
the user is drawing at 3:x or x:3 zoom levels in gimp 2.2.x (compiled with that
flag).  An example of this is at
http://bugzilla.gnome.org/show_bug.cgi?id=309978 (GNOMEbug 309978).

Reproducible: Always
Steps to Reproduce:
1.  Compile gimp with CFLAGS="-ffast-math"
2.  Run gimp, and create any image
3.  Zoom in 3:x or x:3, and draw!!!

Actual Results:  
Window corrupts.

Expected Results:  
Window should never corrupt

Portage 2.0.51.22-r1 (default-linux/x86/2005.0, gcc-3.3.5-20050130,
glibc-2.3.4.20041102-r1, 2.6.11.10 i686)
=================================================================
System uname: 2.6.11.10 i686 AMD Athlon(tm) 
Gentoo Base System version 1.6.12
distcc 2.18.3 i686-pc-linux-gnu (protocols 1 and 2) (default port 3632) [enabled]
ccache version 2.3 [enabled]
dev-lang/python:     2.3.5
sys-apps/sandbox:    1.2.10
sys-devel/autoconf:  2.13, 2.59-r6
sys-devel/automake:  1.4_p6, 1.5, 1.6.3, 1.7.9-r1, 1.8.5-r3, 1.9.5
sys-devel/binutils:  2.15.92.0.2-r10
sys-devel/libtool:   1.5.16
virtual/os-headers:  2.6.8.1-r2
ACCEPT_KEYWORDS="x86"
AUTOCLEAN="yes"
CBUILD="i686-pc-linux-gnu"
CFLAGS="-O2 -march=athlon-xp -fomit-frame-pointer -pipe"
CHOST="i686-pc-linux-gnu"
CONFIG_PROTECT="/etc /usr/kde/2/share/config /usr/kde/3.3/env
/usr/kde/3.3/share/config /usr/kde/3.3/shutdown /usr/kde/3.4/env
/usr/kde/3.4/share/config /usr/kde/3.4/shutdown /usr/kde/3/share/config
/usr/lib/X11/xkb /usr/lib/mozilla/defaults/pref /usr/share/config
/var/qmail/control"
CONFIG_PROTECT_MASK="/etc/gconf /etc/terminfo /etc/env.d"
CXXFLAGS="-O2 -march=athlon-xp -fomit-frame-pointer -pipe"
DISTDIR="/usr/portage/distfiles"
FEATURES="autoconfig ccache distcc distlocks sandbox sfperms strict"
GENTOO_MIRRORS="http://mirror.datapipe.net/gentoo http://gentoo.mirror.solnet.ch
http://mirror.datapipe.net/gentoo http://ftp.easynet.nl/mirror/gentoo/
http://www.gigaload.org/gentoo.org/ http://gentoo.chem.wisc.edu/gentoo/
ftp://gentoo.mirrors.pair.com/ http://gentoo.mirror.icd.hu/
http://open-systems.ufl.edu/mirrors/gentoo"
PKGDIR="/usr/portage/packages"
PORTAGE_TMPDIR="/var/tmp"
PORTDIR="/usr/portage"
PORTDIR_OVERLAY="/usr/local/portage"
SYNC="rsync://rsync.gentoo.org/gentoo-portage"
USE="x86 3dnow 3dnowex X acpi alsa arts avi berkdb bitmap-fonts bzlib cdparanoia
cdr crypt cups curl dvd dvdread emboss encode esd fam flac font-server
foomaticdb fortran gd gdbm gif gimpprint gpm gtk gtk2 imagemagick imlib ipv6
java jpeg kde libg++ libwww mad mbox mikmod mmx mozilla mp3 mpeg mysql ncurses
nomotif nvidia ogg oggvorbis opengl oss pdflib perl png ppds python qt quicktime
readline real rtc samba scanner sdl slang softmmu spell sqlite sse ssl svga
tcltk tcpd theora tiff truetype truetype-fonts type1-fonts usb vorbis xine xml2
xmms xv xvid zlib userland_GNU kernel_linux elibc_glibc"
Unset:  ASFLAGS, CTARGET, LANG, LC_ALL, LDFLAGS, LINGUAS, MAKEOPTS

So don't use it, it breaks a lot more apps, not just gimp.

fixed in cvs, heres reference link to another person on the gnome bugzilla that
had similar issues.

http://bugs.gnome.org/show_bug.cgi?id=150742

gimp now filters this flag.

Thanks!