The NEON_2_SSE.h file is intended to simplify ARM->IA32 porting. It makes the correspondence (or a real porting) of ARM NEON intrinsics as defined in "arm_neon.h" header and x86 SIMD (up to AVX2) intrinsic functions as defined in corresponding x86 compilers headers files.
To take advantage of this file just include it in your project that uses ARM NEON intinsics instead of "arm_neon.h", compile it as usual and enjoy the result.
Considering 64-128 bit width of the NEON istructions AVX usage in x86 implementaion is litited, SSE is used in more than 90% of functions. For significant performance improvement in some cases you might need to define USE_SSE4 or USE_AVX2 in your project settings. Otherwise by default SIMD up to SSSE3 to be used.
If NEON2SSE_DISABLE_PERFORMANCE_WARNING macro is defined, then the performance warnings for serial functions implementaions are disabled.
For more information and license please read the NEON_2_SSE.h content.
The unit tests set used for ARM NEON - x86 SSE conformance verification is https://github.com/christophe-lyon/arm-neon-tests