refactor: Some AArch64 specific NEON intrinsics was wrapped into macros.

[lordnn]

…code.

[kpchoi]

checking the following comment is required.

[kpchoi]

Can this work on non-GCC compiler?

[lordnn]

This works also on CLang and does nothing on MSVC, because of unknown pragma is not an error.
P.S. It may produce warning on MSVC, in dependency on warning level.

[kpchoi]

It means that the unrolling will not work properly on MSVC, and it can lead slow operation.

[lordnn]

It's hard to tell without measurement. Measure before Optimizing.

1. Small cycle will not flush instruction cache, so it may works faster without unrolling.
2. MSVC may unroll it without pragmas. Trust to compiler.
3. Do you really use MSVC to compile ARM project?

[lordnn]

Now it can be compiled for ARMv7 target, I hope.

[neergil]

The PR 1) proposes using several Macros, and 2) fixes minor typos, to refactor the ARM implementation. Please provide the following details:
a) Whether the bit-exactness is fully-tested
b) How the performance compared with the existing code (unit test and overall encode/decode time on ARM device)
c) Whether the PR maintains a fully clean build (without warnings) for all platforms including MS Visual Studio
Please provide the above information so we can decide on reviewing in detail.

[lordnn]

с) Currently muster brunch produce warnings during MSVC 2022 build. So, please clean it's first. And what's the "all platforms" you mention about? Please provide details.