Re: [PATCH v2 0/2] Basic support for the Ventana VT1 w/ instruction fusion

[Palmer Dabbelt <palmer@rivosinc.com>]

On Sun, 13 Nov 2022 12:48:22 PST (-0800), philipp.tomsich@vrull.eu wrote:
>
> This series provides support for the Ventana VT1 (a 4-way superscalar
> rv64gc_zba_zbb_zbc_zbs_zifenci_xventanacondops core) including support
> for the supported instruction fusion patterns.
>
> This includes the addition of the fusion-aware scheduling
> infrastructure for RISC-V and implements idiom recognition for the
> fusion patterns supported by VT1.
>
> Note that we don't signal support for XVentanaCondOps at this point,
> as the XVentanaCondOps support is in-flight separately.  Changing the
> defaults for VT1 can happen late in the cycle, so no need to link the
> two different changesets.
>
> Changes in v2:
> - Rebased and changed over to .rst-based documentation
> - Updated to catch more fusion cases
> - Signals support for Zifencei
>
> Philipp Tomsich (2):
>   RISC-V: Add basic support for the Ventana-VT1 core
>   RISC-V: Add instruction fusion (for ventana-vt1)
>
>  gcc/config/riscv/riscv-cores.def              |   3 +
>  gcc/config/riscv/riscv-opts.h                 |   2 +-
>  gcc/config/riscv/riscv.cc                     | 233 ++++++++++++++++++
>  .../risc-v-options.rst                        |   5 +-
>  4 files changed, 240 insertions(+), 3 deletions(-)

I guess we never really properly talked about this on the GCC mailing 
lists, but IMO it's fine to start taking code for designs that have been 
announced under the assumption that if the hardware doesn't actually 
show up according to those timelines that it will be assumed to have 
never existed and thus be removed more quickly than usual.

That said, I can't find anything describing that the VT-1 exists aside 
from these patches.  Is there anything that describes this design and 
when it's expected to be available?