[LLVMdev] More AVX Advice Needed
dag at cray.com
Wed Dec 2 15:08:09 PST 2009
On Wednesday 02 December 2009 16:51, Eli Friedman wrote:
> On Wed, Dec 2, 2009 at 2:44 PM, David Greene <dag at cray.com> wrote:
> > I'm working on some of the AVX insert/extract instructions. They're
> > stupid. They do not operate on ymm registers, meaning we have to
> > use VINSERTF128/VEXTRACTF128 and then do the real operation.
> > Anyway, I'm looking at how INSERTPS and friends work and noticed that
> > there are special SelectionDAG nodes for them and corresponding TableGen
> > dag operators (X86insrtps, for example).
> > What's the reason for using special dag operators as opposed to
> > intrinsics?
> INSERTPS isn't an intrinsic because there's a standard way to
> represent the operation, and we try to avoid adding intrinsics when
I don't get it. How is X86insrtps "standard?" It looks just like an
intrinsic to me.
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