[PATCH] D53705: [OpenCL] Postpone PSV address space diagnostic

[John McCall via Phabricator via cfe-commits]

rjmccall added a comment.

In https://reviews.llvm.org/D53705#1284734, @keryell wrote:

> In https://reviews.llvm.org/D53705#1284268, @rjmccall wrote:
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> > Okay.  So the purpose of OpenCL C++ is to provide a non-unified model that allows you to easily run C++ code on the CPU.
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> It is just the second-order purpose.
>  A C++-based kernel language to program accelerators without C++ language extension, so that the code could also mostly run on a CPU without a specific compiler.


So, as a C++ language expert, I don't think this is actually possible without major compromises (e.g. preventing users from using `struct`s in non-generic address spaces), and I think you're being somewhat willfully blind about the extent to which you are going to be relying on language extensions — in ways that are unavoidably exposed in the language, and which therefore can change the well-formedness or dynamic behavior of the program — to make this work on a GPU (or any other device with interesting address spaces).  If your plan is to compile code for the CPU with a normal C++ compiler but for the GPU with an OpenCL-aware compiler, you are going to have significantly divergent behavior between the CPU and GPU language dialects because of the non-standardness of the GPU dialect.


Repository:
  rC Clang

https://reviews.llvm.org/D53705