iasm, lzcnt and tznct are not recognized

[kinke]

On Tuesday, 25 February 2020 at 21:18:48 UTC, Basile B. wrote:
> lzcnt and tznct are not recognized.
> DMD accept them.

I guess you mean in DMD-style inline asm; that part doesn't see 
much love. LDC-style __asm provides all of them, at least as long 
as using appropriate -mcpu/-mattr switches.

Looks like you're trying to manually optimize bsf/bsr; I'd advise 
against that, standard core.bitop generates exactly these 2 
instructions: https://d.godbolt.org/z/PG8GiU