ARM64 builds fails if Neon is enabled on MSVC

[sylveon]

When building rapidjson for ARM64 with RAPIDJSON_NEON defined on MSVC, it will fail to build, because it includes <arm_neon.h>, but this is for ARM 32-bits only on Microsoft's compiler. The right file to include is <arm64_neon.h>

Apparently a fix is incoming, but this was posted in April and we're in June now... https://developercommunity.visualstudio.com/content/problem/201662/arm-neonh-doenst-support-arm64-compiler.html

[sylveon]

This got fixed in the latest VS 2019, but now when compiling with NEON on, there's a bunch of errors pertaining to __builtin_clzll and uint64x2_t

  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(446,24): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(446,24): error C2440:         uint64_t low = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 0);   // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(446,24): error C2440:                        ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(447,25): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(447,25): error C2440:         uint64_t high = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 1);  // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(447,25): error C2440:                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(451,25): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(451,25): error C3861:                 int lz =__builtin_clzll(high);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(451,25): error C3861:                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(455,22): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(455,22): error C3861:             int lz = __builtin_clzll(low);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(455,22): error C3861:                      ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(482,24): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(482,24): error C2440:         uint64_t low = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 0);   // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(482,24): error C2440:                        ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(483,25): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(483,25): error C2440:         uint64_t high = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 1);  // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(483,25): error C2440:                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(487,26): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(487,26): error C3861:                 int lz = __builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(487,26): error C3861:                          ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(491,22): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(491,22): error C3861:             int lz = __builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(491,22): error C3861:                      ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C2065:                     unsigned lz = (unsigned)__builtin_clzll(high);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C2065:                                             ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C3861:                     unsigned lz = (unsigned)__builtin_clzll(high);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1254,45): error C3861:                                             ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C2065:                 unsigned lz = (unsigned)__builtin_clzll(low);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C2065:                                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C3861:                 unsigned lz = (unsigned)__builtin_clzll(low);; [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1259,41): error C3861:                                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C2065:                     unsigned lz = (unsigned)__builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C2065:                                             ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C3861:                     unsigned lz = (unsigned)__builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1324,45): error C3861:                                             ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C2065:                 unsigned lz = (unsigned)__builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C2065:                                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C3861:                 unsigned lz = (unsigned)__builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1329,41): error C3861:                                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C2065:                     int lz = __builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C2065:                              ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C3861:                     int lz = __builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1378,30): error C3861:                              ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C2065:  '__builtin_clzll': undeclared identifier [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C2065:                 int lz = __builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C2065:                          ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C3861:                 int lz = __builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\reader.h(1383,26): error C3861:                          ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(671,1): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(671,1): error C2440:         uint64_t low = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 0);   // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(671,1): error C2440: ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(672,1): error C2440:  'reinterpret_cast': cannot convert from 'uint8x16_t' to 'uint64x2_t' [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(672,1): error C2440:         uint64_t high = vgetq_lane_u64(reinterpret_cast<uint64x2_t>(x), 1);  // extract [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(672,1): error C2440: ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(678,41): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(678,41): error C3861:                 unsigned lz = (unsigned)__builtin_clzll(high); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(678,41): error C3861:                                         ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
  T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(683,37): error C3861:  '__builtin_clzll': identifier not found [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(683,37): error C3861:             unsigned lz = (unsigned)__builtin_clzll(low); [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]
T:\Projects\vcpkg\installed\arm64-windows\include\rapidjson\writer.h(683,37): error C3861:                                     ^ (compiling source file main.cpp) [T:\Projects\TranslucentTB\TranslucentTB\TranslucentTB.vcxproj]

[sylveon]

clzll can be replaced with https://docs.microsoft.com/en-us/cpp/intrinsics/bitscanreverse-bitscanreverse64

The casts can be replaced by vreinterpretq_u64_u8