[flang-commits] [flang] [flang] Rely on global initialization for simpler derived types (PR #114002)

[via flang-commits]

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@@ -797,8 +798,59 @@ void Fortran::lower::defaultInitializeAtRuntime(
         })
         .end();
   } else {
-    mlir::Value box = builder.createBox(loc, exv);
-    fir::runtime::genDerivedTypeInitialize(builder, loc, box);
+    /// For "simpler" types, relying on "_FortranAInitialize"
+    /// leads to poor runtime performance. Hence optimize
+    /// the same.
+    const Fortran::semantics::DeclTypeSpec *declTy = sym.GetType();
+    mlir::Type symTy = converter.genType(var);
+    const auto *details =
+        sym.detailsIf<Fortran::semantics::ObjectEntityDetails>();
+    if (details && Fortran::lower::hasDefaultInitialization(sym) &&
+        declTy->category() ==
+            Fortran::semantics::DeclTypeSpec::Category::TypeDerived &&
+        !mlir::isa<fir::SequenceType>(symTy) &&
+        !sym.test(Fortran::semantics::Symbol::Flag::OmpPrivate) &&
+        !sym.test(Fortran::semantics::Symbol::Flag::OmpFirstPrivate)) {
+      std::string globalName = converter.mangleName(*declTy->AsDerived());
+      mlir::Location loc = genLocation(converter, sym);
+      mlir::StringAttr linkage = builder.createInternalLinkage();
+      cuf::DataAttributeAttr dataAttr =
+          Fortran::lower::translateSymbolCUFDataAttribute(builder.getContext(),
+                                                          sym);
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jeanPerier wrote:

@clementval. I am not sure copying the CUDA data attributes from the local/dummy symbol that must be default initialized to the global makes sense. Are some attributes needed for the global if the dynamic initialization happens on the device, or will the global with the initial image be automatically cloned/mapped to the device if needed?

https://github.com/llvm/llvm-project/pull/114002