[PATCH] RISC-V: Add ZFINX support

[wangtao (CH)]

Hi,

This is the patch to support ZFINX of RISC-V, which option is like 
-march=rv32gc_zfinx. The ZFINX means f-registers in x-registers under RV-F and 
RV-D extension. For more details, please refer to 
https://github.com/riscv/riscv-zfinx/blob/master/Zfinx_spec.adoc.
This patch mainly adds the ZFINX option and abi constraints, and when it’s 
under ZFINX, makes the f-registers as FIXED_REGs to avoid allocating 
f-regsiters to pseudo registers.
And for binutils support, it has been done and I will send it to binutils-gdb 
community to review later.

Thanks,
Tao Wang

0001-RISC-V-Add-zfinx-support.patch
Description: 0001-RISC-V-Add-zfinx-support.patch