[PATCH] D31404: [OpenCL] Allow alloca return non-zero private pointer

[Tony Tye via Phabricator via cfe-commits]

t-tye added inline comments.


================
Comment at: include/clang/AST/Type.h:339-340
+    auto Addr = getAddressSpace();
+    if (Addr == 0)
+      return 0;
+    return Addr - LangAS::target_first;
----------------
Anastasia wrote:
> yaxunl wrote:
> > t-tye wrote:
> > > Since you mention this is only used for  `__attribute__((address_space(n)))`, why is this check for 0 needed?
> > > 
> > > If it is needed then to match other places should it simply be:
> > > 
> > > ```
> > > if (Addr)
> > >   return Addr - LangAS::target_first;
> > > return 0;
> > > ```
> > It is for `__attribute__((address_space(n)))` and the default addr space 0.
> > 
> > For the default addr space 0, we want to print 0 instead of `-LangAS::target_first`.
> > 
> > I will make the change for matching other places.
> Could we use LangAS::Count instead?
I do not think the address space 0 should be returned as 0 as then it is impossible to distinguish between a type that has no address space attribute, and one that has an explicit address space attribute with the value 0.

But that seems to be a bug in the original code so I would suggest leaving this for now and fixing it as a separate patch. The diagnostic message should really be checking if an address space attribute was present (by checking for 0), and changing the working of the message accordingly.

Suggest add a TODO here to mention this which can be fixed in a later patch.


https://reviews.llvm.org/D31404