On Mon, Jun 04, 2018 at 06:05:59PM -0400, Michael Meissner wrote:
> > > This
> > > allows templates to work again with those types (the template code aborts
> > > if
> > > you have two distinct types use the same mangling). However, overloaded
> > > types
> > > won't work, but I suspect these days people use templates over overloaded
> > > functions. I fixed up the test case for this (pr85657.C) so that it only
> > > tests
> > > for templates.
> >
> > If tests fail, do not delete the test. If we have a problem, we have
> > a problem, and it needs to be fixed (not necessarily today of course,
> > and there is xfail for long-standing problems).
>
> This is a fundamental detail of the current changes. There is no way it can
> be
> 'fixed'.
>
> If __float128/__ibm128 each use the long double type internally when long
> double uses that representation, then you cannot have overloaded functions
> that
> use the two types.
>
> I.e.
>
> class foo {
> // ...
> long double arith (long double);
> __float128 arith (__float128);
> __ibm128 arith (__ibm128);
> }
>
> In the previous changes that the test was written for, we had 3 types within
> the compiler. We had a __float128 type, we had a long double type, and we had
> an __ibm128 type. We had different manglings for each of the different types.
>
> Now that we only have two types, you can't have explicit overloading of the
> same type. You can have templates, because only one version of the template
> is
> created for the two types.
You can still have overloads, just not two between the same type. So you
can have both __ibm128 and __ieee128.
> The test in question was new and written when I did the previous changes. It
> is not a long standing problem. The test was explicitly written to make sure
> all three types were different. Since we now have only two types, we need to
> adjust the test.
The test currently ICEs. That needs to be fixed.
> > > +/* Generate old manged name, not new name. */
> > > +static bool old_mangling;
> >
> > As Andreas said, this is not a good name. Please at least mention for
> > what type this old mangling is.
>
> I will consider this.
Thanks. Naming is hard :-(
> > I wonder how hard it would be to alias the long double type to either
> > __ibm128 or __ieee128, instead of the other way around? This would
> > simplify code a lot. Esp. if we can do the same thing for the modes,
> > too.
>
> It depends on whether other parts of the compiler already have links to long
> double before the hook in rs6000.c gets called. I frankly don't see it as
> simplifying the code.
Not even if we can also get rid of TFmode as separate mode?
Segher
