Add 8-bit and 16-bit specialized NEON targets.

Like SSE4-8 and SSE4-16, these use 8-bit and 16-bit values for mask
elements, respectively, and thus should generate the best code when used
for computation with datatypes of those sizes.

module.cpp

@@ -1877,6 +1877,7 @@ Module::execPreprocessor(const char *infilename, llvm::raw_string_ostream *ostre
     char *p = targetMacro;
     while (*p) {
         *p = toupper(*p);
+        if (*p == '-') *p = '_';
         ++p;
     }
     opts.addMacroDef(targetMacro);