[clang] [Clang] Allow all address spaces to be converted to the default (PR #112248)

[Matt Arsenault via cfe-commits]

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@@ -721,7 +721,9 @@ class Qualifiers {
            // to implicitly cast into the default address space.
            (A == LangAS::Default &&
             (B == LangAS::cuda_constant || B == LangAS::cuda_device ||
-             B == LangAS::cuda_shared));
+             B == LangAS::cuda_shared)) ||
+           // Otherwise, assume the default address space is compatible.
+           (A == LangAS::Default);
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arsenm wrote:

Default is kind of broken, at least for OpenCL. Should avoid attaching any behavior to it 

https://github.com/llvm/llvm-project/pull/112248