[llvm] [RISCV] Add an initial set of InstAliases for P extension. (PR #180315)

[Christian Herber via llvm-commits]

christian-herber-nxp wrote:

> > > > Doesn't have to be in this PR, but you may want to have p.mv also with Zilsd when P extension is not present.
> > > 
> > > 
> > > Does this actually hold? `padd.*s` is doing a splat, I understand, so it's not a double word move?
> > > I was hoping that P has a GPR pair move of some kind, but I struggle with the P specs to understand what's actually there that might accomplish it. We do technically have a PGR Pair move in rv32 Zdinx, but having one with P would be useful.
> > 
> > 
> > In my original comment, I wanted to say Zfinx instead of Zilsd.
> 
> Did you mean Zdinx? Zfinx doesn't have pairs.
yes

https://github.com/llvm/llvm-project/pull/180315