Unlike Neon, MVE does not have a way of duplicating from a vector lane,
so a VDUPLANE currently selects to a VDUP(move_from_lane(..)). This
forces that to be done earlier as a dag combine to allow other folds to
happen.
It converts to a VDUP(EXTRACT). On FP16 this is then folded to a
VGETLANEu to prevent it from creating a vmovx;vmovhr pair, using a
single move_from_reg instead.
Differential Revision: https://reviews.llvm.org/D79606
MVE doesn't have the range of shuffle instructions available in Neon. We
also cannot use the trick of cutting a difficult vector shuffle in half
to simplify things. Instead we need to be more careful about how we
lower shuffles.
This patch adds an extra combine that attempts to find "whole lane"
vmovs when lowering shuffles of smaller types. This helps us make some
shuffles a lot simpler, generating single lane movs for the parts that
can make use of it, falling back to the original shuffle for the rest.
Differential Revision: https://reviews.llvm.org/D69509
This adds support code for building and shuffling i1 predicate registers. It
generally uses two basic principles, either converting the predicate into an
scalar (through a PREDICATE_CAST) and doing scalar operations on it there, or
by converting the register to an full vector register and back.
Some of the code here is a not super efficient but will hopefully cover most
cases of moving i1 vectors around and can be improved in subsequent patches.
Some code by David Sherwood.
Differential Revision: https://reviews.llvm.org/D65052
llvm-svn: 366890
David Green