Re: [PATCH] machine_mode type size: Extend enum size from 8-bit to 16-bit

[Richard Biener <rguenther@suse.de>]

On Thu, 13 Apr 2023, Richard Sandiford wrote:

> ??? <juzhe.zhong@rivai.ai> writes:
> > Yeah, like kito said.
> > Turns out the tuple type model in ARM SVE is the optimal solution for RVV.
> > And we like ARM SVE style implmentation.
> >
> > And now we see swapping rtx_code and mode in rtx_def can make rtx_def overal not exceed 64 bit.
> > But it seems that there is still problem in tree_type_common and tree_decl_common, is that right?
> 
> I thought upthread we had a way forward for tree_type_common and
> tree_decl_common too, but maybe I only convinced myself. :)
> 
> > After several trys (remove all redundant TI/TF vector modes and FP16 vector mode), now there are 252 modes
> > in RISC-V port. Basically, I can keep supporting new RVV intrinsisc features recently.
> > However, we can't support more in the future, for example, FP16 vector, BF16 vector, matrix modes, VLS modes,...etc.
> 
> I agree it doesn't make sense to try to squeeze modes out like this.
> It's a bit artificial, and like you say, it's likely only putting
> off the inevitable.

Agreed.  Let's do the proposed TYPE_PRECISION change first and then
see how bad 16bit mode will be.

Richard.