Add Neon implementation of find_last

[hazzlim]

This PR adds a Neon implementation of find_last.

Performance numbers (values are speedup figures relative to existing code; values greater than 1 indicate that the new code is faster):

	MSVC SU	Clang  SU
bm<uint8_t, not_highly_aligned_allocator, Op::FindLast>/8021/3056	12.571	12.453
bm<uint8_t, not_highly_aligned_allocator, Op::FindLast>/63/62	4.229	3.882
bm<uint8_t, not_highly_aligned_allocator, Op::FindLast>/31/30	2.118	2.333
bm<uint8_t, not_highly_aligned_allocator, Op::FindLast>/15/14	1.441	1.309
bm<uint8_t, not_highly_aligned_allocator, Op::FindLast>/7/6	0.842	0.636
bm<char, not_highly_aligned_allocator, Op::StringRFind>/8021/3056	12.571	12.585
bm<char, not_highly_aligned_allocator, Op::StringRFind>/63/62	3.115	4.045
bm<char, not_highly_aligned_allocator, Op::StringRFind>/31/30	1.872	2.437
bm<char, not_highly_aligned_allocator, Op::StringRFind>/15/14	1.071	1.378
bm<char, not_highly_aligned_allocator, Op::StringRFind>/7/6	0.647	0.667
bm<char, not_highly_aligned_allocator, Op::StringFindNotLastOne>/8021/3056	11.727	12.279
bm<char, not_highly_aligned_allocator, Op::StringFindNotLastOne>/63/62	3.147	3.405
bm<char, not_highly_aligned_allocator, Op::StringFindNotLastOne>/31/30	1.891	2.083
bm<char, not_highly_aligned_allocator, Op::StringFindNotLastOne>/15/14	1.155	1.202
bm<char, not_highly_aligned_allocator, Op::StringFindNotLastOne>/7/6	0.642	0.667
bm<uint16_t, not_highly_aligned_allocator, Op::FindLast>/8021/3056	7.371	8.036
bm<uint16_t, not_highly_aligned_allocator, Op::FindLast>/63/62	3.472	3.583
bm<uint16_t, not_highly_aligned_allocator, Op::FindLast>/31/30	2.492	2.613
bm<uint16_t, not_highly_aligned_allocator, Op::FindLast>/15/14	1.438	1.502
bm<uint16_t, not_highly_aligned_allocator, Op::FindLast>/7/6	0.976	0.947
bm<wchar_t, not_highly_aligned_allocator, Op::StringRFind>/8021/3056	7.703	7.679
bm<wchar_t, not_highly_aligned_allocator, Op::StringRFind>/63/62	3.267	3.6
bm<wchar_t, not_highly_aligned_allocator, Op::StringRFind>/31/30	2.358	2.435
bm<wchar_t, not_highly_aligned_allocator, Op::StringRFind>/15/14	1.515	1.413
bm<wchar_t, not_highly_aligned_allocator, Op::StringRFind>/7/6	0.913	0.927
bm<wchar_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/8021/3056	5.972	6.099
bm<wchar_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/63/62	2.777	3.13
bm<wchar_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/31/30	1.917	2.062
bm<wchar_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/15/14	1.218	1.266
bm<wchar_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/7/6	0.759	0.766
bm<uint32_t, not_highly_aligned_allocator, Op::FindLast>/8021/3056	4.027	3.921
bm<uint32_t, not_highly_aligned_allocator, Op::FindLast>/63/62	2.821	2.875
bm<uint32_t, not_highly_aligned_allocator, Op::FindLast>/31/30	2.437	2.513
bm<uint32_t, not_highly_aligned_allocator, Op::FindLast>/15/14	1.623	1.867
bm<uint32_t, not_highly_aligned_allocator, Op::FindLast>/7/6	0.985	1.148
bm<char32_t, not_highly_aligned_allocator, Op::StringRFind>/8021/3056	3.921	4
bm<char32_t, not_highly_aligned_allocator, Op::StringRFind>/63/62	2.829	2.99
bm<char32_t, not_highly_aligned_allocator, Op::StringRFind>/31/30	2.288	2.414
bm<char32_t, not_highly_aligned_allocator, Op::StringRFind>/15/14	1.636	1.688
bm<char32_t, not_highly_aligned_allocator, Op::StringRFind>/7/6	1.048	1.067
bm<char32_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/8021/3056	3.244	3.158
bm<char32_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/63/62	2.28	2.451
bm<char32_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/31/30	1.828	1.923
bm<char32_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/15/14	1.256	1.357
bm<char32_t, not_highly_aligned_allocator, Op::StringFindNotLastOne>/7/6	0.779	0.857
bm<uint64_t, not_highly_aligned_allocator, Op::FindLast>/8021/3056	1.934	1.934
bm<uint64_t, not_highly_aligned_allocator, Op::FindLast>/63/62	2.188	1.88
bm<uint64_t, not_highly_aligned_allocator, Op::FindLast>/31/30	1.6	1.686
bm<uint64_t, not_highly_aligned_allocator, Op::FindLast>/15/14	1.424	1.505
bm<uint64_t, not_highly_aligned_allocator, Op::FindLast>/7/6	1.003	1.158

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

🦾 🕵️ 🔍