simple question: what constraint does one use for mask registers in inline-asm? "k" does not work and "r" would be wrong.
More specific question: How does one efficiently test whether a mask returned from a __m512d compare is all true? ICC generates quite a lot of code for either the use of the _m512_kortestc intrinsic or a simple compare to 0xff. That's why I wanted to wrap this into a function that does the right thing via inline-asm, but without the constraint... (I still could make use of the constraint even if there is a good solution here that doesn't involve inline-asm.)