[PATCH] i386, expand: Optimize also 256-bit and 512-bit permutatations as vpmovzx if possible [PR95905]

[Richard Biener]

On Wed, 13 Jan 2021, Jakub Jelinek wrote:

> On Wed, Jan 13, 2021 at 08:26:49AM +0100, Richard Biener wrote:
> > +  if (op1 && op0 != op1)
> > +    op1 = force_reg (vmode, op1);
> > 
> > code (presumably to handle RTX sharing here)?
> 
> That could be actually simplified, incrementally e.g. to:
>    if (op0)
>      {
>        rtx nop0 = force_reg (vmode, op0);
>        if (op0 == op1)
>          op1 = nop0;
>        op0 = nop0;
>      }
> -  if (op1 && op0 != op1)
> +  if (op1)
>      op1 = force_reg (vmode, op1);
> 
> (because the outer force_reg in force_reg (vmode, force_reg (vmode, X))
> just returns its argument).

I see.  Thanks for clarifying in the earlier mail - the non-x86
parts of the patch are OK.

Thanks,
Richard.