[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:

Still need some clarification. In my opinion the read only global relates more to the type than the symbol, and it is weird that it could carry the symbol attribute that may be meaningless/wrong for a global (given the symbol could be a dummy/local).

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