[PATCH 0/1] RISC-V: Make XVentanaCondOps RV64 only

[Tsukasa OI <research_trasio@irq.a4lg.com>]

Hello,

I noticed that two instructions in the XVentanaCondOps vendor extension --
"vt.maskc" and "vt.maskcn" -- are defined for all XLEN values.

This is against the manual and LLVM.


1. The instruction manual

<https://github.com/ventanamicro/ventana-custom-extensions/releases/download/v1.0.0/ventana-custom-extensions-v1.0.0.pdf>

Currently defines the instructions only for RV64.

> All current cores by Ventana Micro implement RV64 and are designed as
> 64-bit only, the RV32-column is marked "n/a".

But it also says it's (in theory) XLEN-agonistic.

> The instructions in the XVentanaCondOps extension are defined to operate
> on XLEN and would thus be directly applicable to RV32.


2. LLVM (llvm/lib/Target/RISCV/RISCVInstrInfoXVentana.td)

> let Predicates = [IsRV64, HasVendorXVentanaCondOps]

It indicates that XVentanaCondOps instructions are only enabled on RV64.



Unless Ventana is working on some RV32 processors (and soon to be released
), I think disabling XVentanaCondOps instructions on RV32 would be safer
(to prevent possible misuses).  I would like to hear thoughts especially
from Ventana employees since I am just a volunteer.

I also chose not to reject XVentanaCondOps + RV32 because it is not stated
that is illegal (unlike Zcf + RV64).  This patch set makes XVentanaCondOps
+ RV32 empty (yet legal).


Sincerely,
Tsukasa




Tsukasa OI (1):
  RISC-V: Make XVentanaCondOps RV64 only

 gas/testsuite/gas/riscv/x-ventana-condops-32.d | 3 +++
 gas/testsuite/gas/riscv/x-ventana-condops-32.l | 3 +++
 opcodes/riscv-opc.c                            | 4 ++--
 3 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 gas/testsuite/gas/riscv/x-ventana-condops-32.d
 create mode 100644 gas/testsuite/gas/riscv/x-ventana-condops-32.l


base-commit: 0637da3c7325b28a2c05f016d7f290513b1cd19b
-- 
2.42.0