[LLVMdev] AArch64 codegen question

[Tim Northover]

Hi Sanjay,

On 10 December 2014 at 19:47, Sanjay Patel <spatel at rotateright.com> wrote:
> We're generating this:
>    ext    v0.16b, v1.16b, v1.16b, #8
>
> Rather than this:
>    mov    d0, v1.d[1]
>
> Are those logically equivalent? Is one form preferred over the other?

They're certainly semantically equivalent, and I'd expect the
performance to be the same too. I wouldn't worry about a change like
that if it was me. What's the DAG change that causes it?

Cheers.

Tim.