[clang] [clang-tools-extra] [Clang] Use TargetInfo when deciding is an address space is compatible (PR #115777)

[John McCall via cfe-commits]

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@@ -697,45 +699,21 @@ class Qualifiers {
   ///   every address space is a superset of itself.
   /// CL2.0 adds:
   ///   __generic is a superset of any address space except for __constant.
-  static bool isAddressSpaceSupersetOf(LangAS A, LangAS B) {
-    // Address spaces must match exactly.
-    return A == B ||
-           // Otherwise in OpenCLC v2.0 s6.5.5: every address space except
-           // for __constant can be used as __generic.
-           (A == LangAS::opencl_generic && B != LangAS::opencl_constant) ||
-           // We also define global_device and global_host address spaces,
-           // to distinguish global pointers allocated on host from pointers
-           // allocated on device, which are a subset of __global.
-           (A == LangAS::opencl_global && (B == LangAS::opencl_global_device ||
-                                           B == LangAS::opencl_global_host)) ||
-           (A == LangAS::sycl_global && (B == LangAS::sycl_global_device ||
-                                         B == LangAS::sycl_global_host)) ||
-           // Consider pointer size address spaces to be equivalent to default.
-           ((isPtrSizeAddressSpace(A) || A == LangAS::Default) &&
-            (isPtrSizeAddressSpace(B) || B == LangAS::Default)) ||
-           // Default is a superset of SYCL address spaces.
-           (A == LangAS::Default &&
-            (B == LangAS::sycl_private || B == LangAS::sycl_local ||
-             B == LangAS::sycl_global || B == LangAS::sycl_global_device ||
-             B == LangAS::sycl_global_host)) ||
-           // In HIP device compilation, any cuda address space is allowed
-           // to implicitly cast into the default address space.
-           (A == LangAS::Default &&
-            (B == LangAS::cuda_constant || B == LangAS::cuda_device ||
-             B == LangAS::cuda_shared));
-  }
+  static bool isAddressSpaceSupersetOf(LangAS A, LangAS B,
+                                       const ASTContext &Ctx);
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rjmccall wrote:

Sorry for being picky here, but could you *only* leave the equality check inline?  That will make this function very likely to be inlined, which is great because "both of the address spaces are DefaultAS" is like the 99.9999% case here, and then "the address space is something else but it's still the same on both sides" is probably another 0.00009%.  Once we're in the vanishingly small case where we're not only using address spaces but actually have different ones, the overhead of a function call barely registers and we might as well write the code in a nice, well-organized way. (I won't ask you to do that, I'm just noting that it's currently a huge mess.)

https://github.com/llvm/llvm-project/pull/115777