[clang] [AMDGPU] Add builtin to test for constant memory (PR #209679)

[Yaxun Liu via cfe-commits]

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@@ -47,6 +50,95 @@ static Value *emitAMDGPUSBufferLoadBuiltin(CodeGenFunction &CGF,
                                     CGF.EmitScalarExpr(E->getArg(2))});
 }
 
+constexpr char AMDGPUConstantSectionMarker[] =
+    "__clang_amdgpu_constant_section_marker";
+
+static llvm::GlobalVariable *
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yxsamliu wrote:

Done. Factored this into a generic “pointer is inside named section” helper and used it for `__amdgpu_constant`.

https://github.com/llvm/llvm-project/pull/209679