[llvm-dev] [SVE][AArch64] Codegen for a scalable vector splat

[Graham Hunter via llvm-dev]

Hi Renato,

> On 29 Aug 2019, at 14:00, Renato Golin <rengolin at gmail.com> wrote:
> 
> Hi Graham,
> 
> I'm not a big fan of boolean flags on related concepts because the API
> becomes brittle. In this case, BUILD_VECTOR-splat would need an assert
> to make sure there's only one element.

Ok.

> Can we reuse the SPLAT_VECTOR node for predicated fixed width vectors?
> This would simplify a bit the tail of the loop in AVX, for example,
> but would also make sure we treat similar patterns in the same way,
> and add to the list of reasons why to add a new node.

If we introduce the new node, I certainly expect it to be used for
fixed width vectors as well (though possibly not right away). Is there
anything special about predication in this use case, or is a simple
splat sufficient?

-Graham