[clang] [llvm] [clang][OpenMP][SPIR-V] Fix addrspace of globals and global constants (PR #134399)

[Alex Voicu via llvm-commits]

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@@ -5402,6 +5407,10 @@ LangAS CodeGenModule::GetGlobalConstantAddressSpace() const {
     // UniformConstant storage class is not viable as pointers to it may not be
     // casted to Generic pointers which are used to model HIP's "flat" pointers.
     return LangAS::cuda_device;
+  if (LangOpts.OpenMPIsTargetDevice && getTriple().isSPIRV())
+    // OpenMP SPIR-V global constants should map to UniformConstant, different
+    // from the HIPSPV case above.
+    return LangAS::opencl_constant;
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AlexVlx wrote:

I believe that whilst this makes sense you might run into obnoxious issues where valid source ends up generating a SPIR-V invalid cast to/from generic/constant, which will fail in the translator / fail SPIR-V validation (HIP code runs into this). I *think* we need to relax this restriction at least in the translator / BE, or potentially extend SPIR-V itself in this direction.

https://github.com/llvm/llvm-project/pull/134399