[LLVMdev] Selecting Vector Shuffle of Different Types

[David Greene]

On Wednesday 02 December 2009 18:26, Eli Friedman wrote:

> > Well, it's right!  So how do I express this kind of thing?  Since LLVM
> > 2.5 shufflevector supports creating a vector of a difference size than
> > the inputs.  Which is exactly what we need for VEXTRACTF128 and
> > VINSERTF128.
>
> Perhaps EXTRACT_SUBVECTOR would be more appropriate here?

Except there's no upper 128-bit subvector of a ymm register, which is why we 
need VEXTRACTF128 / VINSERTF128.  It's a big pain in the rear.

                           -Dave