[clang] [llvm] [AMDGPU] Enable OpenCL hostcall printf (WIP) (PR #72556)

[Matt Arsenault via cfe-commits]

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@@ -3616,6 +3617,12 @@ unsigned FunctionDecl::getBuiltinID(bool ConsiderWrapperFunctions) const {
   if (!ConsiderWrapperFunctions && getStorageClass() == SC_Static)
     return 0;
 
+  // AMDGCN implementation supports printf as a builtin
+  // for OpenCL
+  if (Context.getTargetInfo().getTriple().isAMDGCN() &&
+      Context.getLangOpts().OpenCL && BuiltinID == AMDGPU::BIprintf)
+    return BuiltinID;
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arsenm wrote:

The builtin specifications are also in terms of the lang address space, not the target address space (this was an ugly compromise to make builtins work at all in OpenCL)

https://github.com/llvm/llvm-project/pull/72556