[Bug rtl-optimization/104405] Inefficient register allocation on complex arithmetic

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104405

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Eric Botcazou from comment #6)
> > But seems to me a simple enough thing that we should be able to handle.
> 
> Register allocation is a global problem though, so what happens on toy
> examples is not always representative of what happens in real world code
> because there is a lot of heuristics involved and you want to tune it for
> the latter case, not for the former case.

There is of course the option to switch to alternate heuristics if, by
heuristic, the argument/return part of the function is a big part of it (aka
for toy examples or small functions which do happen in real-life).

Also toy examples can highlight issues that also exist in the real world.