[Patch 0/4] [ARM] Enable _Float16 on ARM

[James Greenhalgh]

Hi,

This patch set builds on the AArch64 support for _Float16 that will be added
once the patch set starting at
https://gcc.gnu.org/ml/gcc-patches/2016-09/msg02383.html is accepted.

Unlike the AArch64 support, we've not got too much to do, outside of setting
up a single step conversions between HFmode and DFmode.

Patches 1-3 (co-authored with Matthew Wahab) add this support, by refactoring
__gnu_f2h_internal, then expanding it to support 16-bit to 64-bit conversions,
then removing TARGET_CONVERT_TO_TYPE and wiring up truncdfhf2 and
extendhfdf2 for ARM.

Patch 4 adds the requisite wiring to enable the _Float16 type on ARM.

I've bootstrapped the patch set on ARMv8-A hardware, and cross-tested it
with appropriate multilibs.

OK once the AArch64 support is in?

Thanks,
James