To POD or not to POD

[Johannes Pfau]

Am Wed, 13 Feb 2013 14:10:26 +0000
schrieb Iain Buclaw <ibuclaw at ubuntu.com>:

> On 13 February 2013 13:26, Johannes Pfau <nospam at example.com> wrote:
> 
> > Am Tue, 12 Feb 2013 18:16:31 +0000
> > schrieb Iain Buclaw <ibuclaw at ubuntu.com>:
> >
> > > TREE_ADDRESSABLE should be sufficient.  I can't think any reason
> > > off the top of my head why not.
> > >
> >
> > maybe TREE_ADDRESSABLE is too strong: It generates errors in the
> > backend if the frontend produces non-lvalues:
> > ---
> >     auto b = Date();
> >     a(b);
> > ---
> >
> > works, but
> > ---
> >     a(Date());
> > ---
> >
> > fails in gimplify.c. Do we really have to rewrite such cases so that
> > non-PODs get a temporary variable? And how would this be done? It
> > seems we would have to use the frontend for this, as maybeMakeTemp
> > and makeTemp refuse to work for TREE_ADDRESSABLE types.
> >
> 
> Don't set it on the variable, set it on the type.
> 
> TypeStruct::toCtype()
> {
>     TYPE_ADDRESSABLE(ctype) = !isPOD();
> }

That's actually what I did. But the backend wants to create a copy of
the Date type which then fails as create_tmp_var fails for
TREE_ADDRESSABLE types.

Complete test case:
https://gist.github.com/jpf91/4944999

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../../objdir-4.7/x86_64-unknown-linux-gnu/libphobos/dm-test.reduced/datetime2.d:22:
internal compiler error: in create_tmp_var, at gimplify.c:479 0x804509
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