[doc] invoke.texi: -mno-fancy-math-387 and FreeBSD

[Gerald Pfeifer <gerald at pfeifer dot com>]

Now that Andreas is on board, time to dust off some older issues 
of mine. :-)

I verified that current GCC HEAD generates fsincos on FreeBSD/i386
with -ffastmath (and no options otherwise), and generates a call
to a sin() function otherwise.

So, okay to apply this patch?  And if so, okay to push back to
GCC 5 and 4.9 as well?

Gerald

On Wed, 16 Feb 2011, Gerald Pfeifer wrote:
> The documentation indicates that -mno-fancy-math-387 is the default
> on FreeBSD, yet I do not see any code actually implementing that, and
> I verified that the following
> 
>   #include <math.h>
> 
>   double f(double d) {
>     return __builtin_sin(d);
>   }
> 
> did generate fsin with -ffast-math as the only option.
> 
> Richard, http://gcc.gnu.org/ml/gcc-patches/2002-03/msg02001.html was
> the last time someone really made changes in this area, though the
> reference to FreeBSD predates your patch where you added OpenBSD and
> NetBSD for both of which I _do_ see code in config/i386 to that extent,
> unlike FreeBSD.
> 
> Am I missing something obvious, or is the patch below okay?
> 
> Gerald
> 
> 
> 2011-02-16  Gerald Pfeifer  <gerald@pfeifer.com>
> 
> 	PR target/37072
> 	* doc/invoke.texi (i386 and x86-64 Options): -mno-fancy-math-387
> 	is not actually the default on FreeBSD.
> 	Uppercase CPU.
> 
> Index: doc/invoke.texi
> ===================================================================
> --- doc/invoke.texi	(revision 170120)
> +++ doc/invoke.texi	(working copy)
> @@ -12273,9 +12273,9 @@
>  @opindex mno-fancy-math-387
>  Some 387 emulators do not support the @code{sin}, @code{cos} and
>  @code{sqrt} instructions for the 387.  Specify this option to avoid
> -generating those instructions.  This option is the default on FreeBSD,
> +generating those instructions.  This option is the default on
>  OpenBSD and NetBSD@.  This option is overridden when @option{-march}
> -indicates that the target cpu will always have an FPU and so the
> +indicates that the target CPU will always have an FPU and so the
>  instruction will not need emulation.  As of revision 2.6.1, these
>  instructions are not generated unless you also use the
>  @option{-funsafe-math-optimizations} switch.
>