[MPlayer-dev-eng] [PATCH] Enable FTZ and DAZ w/ -ffast-math

[Diego Biurrun]

On Fri, Feb 13, 2009 at 02:08:23PM +0100, Piotr Kaczuba wrote:
> W dniu 2009-02-10 14:31, Diego Biurrun pisze:
> > On Tue, Feb 10, 2009 at 08:10:06PM +0800, Zuxy Meng wrote:
> >> 2009/2/10 Diego Biurrun <diego at biurrun.de>:
> >>> On Tue, Feb 10, 2009 at 12:12:23AM +0800, Zuxy Meng wrote:
> >>>> 2009/2/10 Diego Biurrun <diego at biurrun.de>:
> >>>>> On Sun, Feb 08, 2009 at 02:02:20PM +0800, Zuxy Meng wrote:
> >>>>>> 2009/2/8 Diego Biurrun <diego at biurrun.de>:
> >>>>>>> On Mon, Feb 02, 2009 at 09:33:08PM +0800, Zuxy Meng wrote:
> >>>>>>>> GCC does a trick to enable FTZ (flush to zero) and DAZ (denormals are
> >>>>>>>> zeroes) when either -ffast-math or -funsafe-math-optimizations is used
> >>>>>>>> by linking crtfastmath.o into the executive. It requires the presence
> >>>>>>>> of one of the options in the final linking stage.
> >>>>>>> I don't like CFLAGS being used during the linking stage.  Add those
> >>>>>>> options to the linker flags instead.
> >>>>>> Something like COMMON_LDFLAGS += $(findstr, -ffast-math, $CFLAGS)?
> >>>>> No, add it to LDFLAGS in configure in the same place where fast-math is
> >>>>> added to CFLAGS.
> >>>> Do we check user specified CFLAGS?
> >>> Somewhat.  But IMO users have to make sure they add it to LDFLAGS as
> >>> well then.
> >> Actually gcc may pay attention to other CFLAGS during linking. For
> >> example, if one wants to generate coverage info s/he must pass "-pg"
> >> to gcc both during compilation and linking. IMHO it's cleaner to just
> >> pass the whole CFLAGS in makefile. Anyway it doesn't do anything bad.
> > 
> > I don't like it and still think that those flags should then appear in
> > both CFLAGS and LDFLAGS.
> 
> What about the following patch then?

Applied.

Diego