[AArch64][SVE] Add intrinsics for bitwise permute instructions

[dancgr]

Summary

Add instrinsics and patterns for the following instructions:

• bext, bdep, bgrp

[dancgr]

llvm/test/CodeGen/AArch64/sve2-bit-perm.ll

1

Not sure I should keep both +sve2 and +sve2-bitperm or not.

[c-rhodes]

Thanks for the patch @dancgr but these intrinsics have already been implemented in D74912. @sdesmalen shared a spreadsheet [1] with the mailing list to coordinate the intrinsics upstreaming, it's probably not as useful now given they're almost all implemented but you might find it useful if you haven't seen it already.

[1] https://docs.google.com/spreadsheets/d/1leug3a0eHhi_bWtKJOR0MeZHvfQLoIPtP-um7AWafRM

llvm/test/CodeGen/AArch64/sve2-bit-perm.ll

1

+sve2-bitperm implies +sve2 so only the former is required.

[dancgr]

In D75197#1894971, @c-rhodes wrote:

Thanks for the patch @dancgr but these intrinsics have already been implemented in D74912. @sdesmalen shared a spreadsheet [1] with the mailing list to coordinate the intrinsics upstreaming, it's probably not as useful now given they're almost all implemented but you might find it useful if you haven't seen it already.

[1] https://docs.google.com/spreadsheets/d/1leug3a0eHhi_bWtKJOR0MeZHvfQLoIPtP-um7AWafRM

Thanks for the info @c-rhodes, it seems like we are done with codegen then.