[AArch64] Implement FP16FML intrinsics

Add LLVM intrinsics for the ARMv8.2-A FP16FML vector-form instructions. Add a
DAG pattern to define the indexed-form intrinsics in terms of the vector-form
ones, similarly to how the Dot Product intrinsics were implemented.

Based on a patch by Gao Yiling.

Differential Revision: https://reviews.llvm.org/D53632


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345337 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed