passing _Float16 to printf where double is expected should raise a warning

[sh1boot]

Unlike __fp16, _Float16 is passed without conversion to double, and so it's an unexpected argument type at that position when used with %f and the like, and should raise a warning.

https://godbolt.org/z/r5o7djxbd

[sh1boot]

Demonstration showing how GCC gives the warning and Clang does not:
https://godbolt.org/z/b6dq9Mjae