[llvm-dev] RFC: Complex in LLVM

[David Greene via llvm-dev]

Tim Northover via llvm-dev <llvm-dev at lists.llvm.org> writes:

> On Tue, 2 Jul 2019 at 19:11, Finkel, Hal J. <hfinkel at anl.gov> wrote:
>> One option is to make the complex type a special kind of vector, or a
>> special kind of aggregate (I have a slight preference for the latter).
>> That gives us an existing set of accessors.
>
> I agree non-vector. If nothing else a vector of complexes seems like a
> sensible concept which would be harder if a complex was itself
> vectorial.
>
> Myself, I think I do favour insertvalue/extractvalue over intrinsics
> (which is probably a +1 for isAggregate too by extension).
>
> If the notation for the literal is especially re/im rather than 0/1 we
> might think about adding "extractvalue %v, real" as sugar (that last
> arg is already weird). All just things to think about right now
> though.

Great ideas.  Are there downsides to making complex a subclass of an
aggregate?  I am thinking mainly WRT vectorization.  Does the vectorizer
expect elements to be scalar/non-aggregate types?

                         -David