[PATCH] D64083: [OpenCL][Sema] Improve address space support for blocks

[John McCall via Phabricator via llvm-commits]

rjmccall added inline comments.


================
Comment at: cfe/trunk/lib/Sema/SemaExprCXX.cpp:4229
+    LangAS AddrSpaceR =
+        RHSType->getAs<BlockPointerType>()->getPointeeType().getAddressSpace();
+    CastKind Kind =
----------------
Anastasia wrote:
> rjmccall wrote:
> > All of this can be much simpler:
> > 
> > ```
> > LangAS AddrSpaceL = ToType->castAs<BlockPointerType>()->getPointeeType().getAddressSpace();
> > LangAS AddrSpaceR = FromType->castAs<BlockPointerType>()->getPointeeType().getAddressSpace();
> > ```
> > 
> > Is there something actually checking the validity of this address-space cast somewhere?
> > Is there something actually checking the validity of this address-space cast somewhere?
> 
> The address spaces for blocks are currently added by clang implicitly. It doesn't seem possible to write kernel code qualifying blocks with address spaces. Although I have to say the error is not given properly because the parser gets confused at least for the examples I have tried. The OpenCL spec doesn't detail much regarding this use case. Potentially this is the area for improvement.
> 
> So for now we can add an assert to check the cast validity if you think it makes sense and maybe a FIXME in the  code to explain that address spaces aren't working with blocks....
> The address spaces for blocks are currently added by clang implicitly. It doesn't seem possible to write kernel code qualifying blocks with address spaces.

There's no way that just fell out from the existing implementation; it was a change someone must have made for OpenCL.  Unless you care about blocks existing in multiple address spaces — which, given that you depend on eliminating them, I'm pretty sure you don't — the compiler just shouldn't do that if it's causing you problems.


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  https://reviews.llvm.org/D64083/new/

https://reviews.llvm.org/D64083