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

[via flang-commits]

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@@ -797,8 +797,70 @@ 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(sym);
+    const auto *details =
+        sym.detailsIf<Fortran::semantics::ObjectEntityDetails>();
+    if (details && !Fortran::semantics::IsPolymorphic(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 = fir::NameUniquer::doGenerated(
+          (converter.mangleName(*declTy->AsDerived()) + fir::kNameSeparator +
+           fir::kDerivedTypeInitSuffix)
+              .str());
+      mlir::Location loc = genLocation(converter, sym);
+      mlir::StringAttr linkage = builder.createInternalLinkage();
+      cuf::DataAttributeAttr dataAttr =
+          Fortran::lower::translateSymbolCUFDataAttribute(builder.getContext(),
+                                                          sym);
+      fir::GlobalOp global = builder.getNamedGlobal(globalName);
+      if (!global && details->init()) {
+        global = builder.createGlobal(
+            loc, symTy, globalName, linkage, mlir::Attribute{},
+            /*isConst=*/true,
+            sym.GetUltimate().attrs().test(Fortran::semantics::Attr::TARGET),
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jeanPerier wrote:

Why are you setting the TARGET attribute here?
I do not think that is relevant for the read only global with the initial value, it is not being used in a Fortran pointer assignment as far as I can tell.

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