[clang] [NVPTX] Support the OpenCL generic addrspace feature by default (PR #137940)

[Fraser Cormack via cfe-commits]

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@@ -170,6 +170,8 @@ class LLVM_LIBRARY_VISIBILITY NVPTXTargetInfo : public TargetInfo {
     Opts["cl_khr_global_int32_extended_atomics"] = true;
     Opts["cl_khr_local_int32_base_atomics"] = true;
     Opts["cl_khr_local_int32_extended_atomics"] = true;
+
+    Opts["__opencl_c_generic_address_space"] = true;
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frasercrmck wrote:

I think that approach makes sense for mandatory features. The generic address space is indeed mandatory in OpenCL 2.0 but not in OpenCL 3.0 (see the preprocessor guard around that line). For optional cases we want target-specific logic.

https://github.com/llvm/llvm-project/pull/137940