Access numeric indices in openCL

Can someone point where is a test/s (or implementation) checking access to vector`s (scalar) components by specifying them:

float16 x;
x.sA // refers to the 11th element of the float16 variable x
x.sF // refers to the 16th element of the float16 variable x

In addition i am a bit conduced about vector size
AFAIK vector types with length >16 are not supported , but in Type.h there is a following ManyElementsThreshold definition
enum { ManyElementsThreshold = 1 << 8 };
does it meant that int128 etc. should work properly?

git grep \\.sF points to clang/test/Sema/ext_vector_components.c .

If you run clang -Xclang -ast-dump on the given example, you’ll see it’s parsed as an ExtVectorElementExpr.

git grep ManyElementsThreshold returns nothing.