How do I do a 64 bits mulhi in D?

[Vladimir Panteleev]

On Sunday, 27 November 2022 at 01:55:45 UTC, deadalnix wrote:
> That's a clever trick, but that only work on x86, but also will 
> blind the optimizer as to what's going on.

For DMD, yes. For GDC and LDC, this uses the syntax which 
declares input and output registers, so it's inlinable and should 
compile to one (inlined) instruction.