[llvm-dev] [RFC] Upstream development of support for yet-to-be-ratified RISC-V extensions

[Simon Cook via llvm-dev]

> So based on feedback so far, I'd like to narrow the field to:
>
> Option 1)
> * Unratified extensions are not available through the ISA naming
> string and are enabled via `-riscv-experimental-foo` or similar
> * A warning is always emitted when enabling experimental extensions
> * Support is always compiled in, and the flags aren't ifdeffed out
>
> Option 2)
> * Unratified extensions can be enabled by passing a flag like
> -riscv-enable-experimental-extensions and additionally putting the
> extension name and version number in the ISA naming string (version
> number is always required, and we will only accept the 'current'
> version number).
> * A warning is always emitted when enabling experimental extensions
> * Support is always compiled in, and the flags aren't ifdeffed out

Option 2 is what I would opt for.

- Simon