[clang] [CLANG][AArch64]Add Neon vectors for mfloat8_t (PR #99865)

[Paul Walker via cfe-commits]

================
@@ -2580,6 +2580,8 @@ void NeonEmitter::runVectorTypes(raw_ostream &OS) {
   OS << "typedef __fp16 float16_t;\n";
 
   OS << "#if defined(__aarch64__) || defined(__arm64ec__)\n";
+  OS << "typedef __MFloat8x8_t mfloat8x8_t;\n";
+  OS << "typedef __MFloat8x16_t mfloat8x16_t;\n";
----------------
paulwalker-arm wrote:

Is there a reason for the new types to be guarded?  When looking at `arm_vector_types.h` the guards are only used for `float64` based types, with the other vector types unguarded.

Also, and this might necessitate reintroducing some of the code you were asked to remove, I'd rather `emitNeonTypeDefs` have the capability to emit the typedefs because that'll verify we have the necessary `TypeSpec` plumbing required to add the builtins.

https://github.com/llvm/llvm-project/pull/99865