[PATCH] Add support to promote f16 to f32

[Ahmed Bougacha]

On Wed, Apr 1, 2015 at 10:07 AM, Pirama Arumuga Nainar
<pirama at google.com> wrote:
> I do not have a reasonable way of finding whether ISD::FP_TO_FP16, ISD::FP16_TO_FP are supported by the target. If unsupported, we have to fall back to making a libcall to gnu_h2f_ieee. Right now, this is a hard-coded branch in LegalizeFloatTypes.cpp:GetPromotedValue but I need suggestions on how to handle this.

Also, now that I think about it, isn't this already handled by ops
legalization?  I believe you shouldn't have to worry about unsupported
operations when legalizing types.

-Ahmed