[LLVMdev] Selecting Vector Shuffle of Different Types
dag at cray.com
Thu Dec 3 09:22:32 PST 2009
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.
More information about the llvm-dev