The xxeval instruction was intorduced in Power PC in Power 10.
The instruction accepts three vector registers and an immediate.
Depending on the value of the immediate the instruction can be used
to perform certain bitwise boolean operations (and, or, xor, ...) on
the given vector registers.
This patch implements the AND and NAND patterns that can be used by
the instruction.
Reviewed By: nemanjai, #powerpc, bsaleil, NeHuang, jsji
Differential Revision: https://reviews.llvm.org/D92420
Stefan Pintilie