Patch, Split powerpc -mfloat128 into 2 parts

Segher Boessenkool segher@kernel.crashing.org
Thu Oct 6 22:35:00 GMT 2016


On Thu, Oct 06, 2016 at 10:26:34PM +0000, Joseph Myers wrote:
> On Thu, 6 Oct 2016, Segher Boessenkool wrote:
> 
> > On Wed, Oct 05, 2016 at 06:18:50PM -0400, Michael Meissner wrote:
> > > I have removed the #define of __float128, and instead created a keyword that
> > > points to the _Float128 type.  I added a little commentary on the use of
> > > __ieee128 (which is needed to create the type when we aren't using __float128).
> > > 
> > > I did a bootstrap and test on a little endian power8 system with no
> > > regressions.  Can I install the patch on the trunk?
> > 
> > Not easy to read this patch :-)
> > 
> > It looks good; it is fine for trunk if Joseph thinks it is good, too.
> 
> I don't really understand the motivation for needing the extra options, 
> but I have no further comments provided __float128 is now the same type as 
> _Float128 when both are available (rather than being long double, even if 
> that also has binary128 format), as indicated above.

+; We want to enable the internal support for the IEEE 128-bit floating point
+; type without necessarily enabling the __float128 keyword.  This is to allow
+; Boost and other libraries that know about __float128 to work until the
+; official library support is finished.
+mfloat128-type
+Target Undocumented Mask(FLOAT128_TYPE) Var(rs6000_isa_flags)
+Allow the IEEE 128-bit types without requiring the __float128 keyword.

I think this is the motivation.

Hopefully one day we can remove this complexity again.


Segher



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