[Patch soft-fp] Add support for various half-precision conversion routines

[Joseph Myers]

On Fri, 16 Sep 2016, James Greenhalgh wrote:

> Hi Joseph,
> 
> An initial draft of this patch did implement these conversions. I thought
> I had updated the ChangeLog, but clearly didn't. I pulled them out to get
> the minimum number of new functions I needed for AArch64 support. After
> https://gcc.gnu.org/ml/gcc-patches/2016-09/msg00704.html is approved,
> the DI to HF conversion routines will not require a libgcc call (for AArch64).
> Likewise DF to HF is handled by GCC proper.

But is DF to HF is handled *correctly* by GCC proper (avoiding double 
rounding), or is such a libgcc call actually needed to get correct 
conversions rather than going via SFmode (or is that double rounding issue 
only an issue for AArch32 or for older instruction set variants you're not 
dealing with in this patch)?

> However, as you've observed I will need to add more of these when I get on
> to enabling _Float16 for AArch32, so if proposing them now would be prefered,
> I'm happy to do that.

It's reasonable to include just the functions you need, as long as the 
write-up, the ChangeLog and the patch itself are consistent.

-- 
Joseph S. Myers
joseph@codesourcery.com