[Bug middle-end/78103] Failure to optimize with __builtin_clzl

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78103

--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> I wouldn't introduce a builtin, that would be user accessible, perhaps
> internal function + corresponding optab and just pattern match it.

Yeah, IFN + optab is now the canonical way of doing "instruction selection"
on GIMPLE.  [you could even have target dependent IFNs if you manage
to write a md define-insn to match.pd rule plus IFN generator skipping
the optab]