This patch adds the beginnings of more thorough support in the
legalizers for vector-predicated (VP) operations.
The first step is the ability to widen illegal vectors. The more
complicated scenario in which the result/operands need widening but the
mask doesn't has not been handled here. That would require a lot of code
without an in-tree target on which to test it.
Reviewed By: RKSimon
Differential Revision: https://reviews.llvm.org/D107904
With the exception of `frem`, this patch supports the current set of VP
floating-point binary intrinsics by lowering them to to RVV instructions. It
does so by using the existing `RISCVISD *_VL` custom nodes as an intermediate
layer. Both scalable and fixed-length vectors are supported by using this
method.
The `frem` node is unsupported due to a lack of available instructions. For
fixed-length vectors we could scalarize but that option is not (currently)
available for scalable-vector types. The support is intentionally left out so
it equivalent for both vector types.
The matching of vector/scalar forms is currently lacking, as scalable vector
types do not lower to the custom `VFMV_V_F_VL` node. We could either make
floating-point scalable vector splats lower to this node, or support the
matching of multiple kinds of splat via a `ComplexPattern`, much like we do for
integer types.
Reviewed By: rogfer01
Differential Revision: https://reviews.llvm.org/D104237
Fraser Cormack