https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118940
--- Comment #11 from Hongtao Liu <liuhongt at gcc dot gnu.org> ---
(In reply to Miao Wang from comment #10)
> (In reply to Hongtao Liu from comment #9)
> > >
> > > > Because I think the operands usage is broken.
> > >
> > > Additionally, by removing the do{ ... } while(0) wrap from
> > > bigint_test_exec(), the issue disappears. I believe that if it is the
> > > operands usage issue, the result should be the same no matter whether it
> > > is
> > > wrapped in a do{ ... } while(0).
> >
> > I think it just happened to hit the RA limitation, and it doesn't look like
> > a performance/functionality regression either.
>
> But why the code compiles after removing the wrapping do {...} while(0)? I
> believe the functionality of the code remains equivalent, so why it does not
> hit the RA limitation without do {...} while(0), but hits with it?
The compiler IRs are different(with small difference), w/ different input, RA
behave differently.
