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

[via flang-commits]

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@@ -793,11 +794,35 @@ 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);
+    if (!var.isAlias() && !hasAllocatableDirectComponent(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(sym) + "_globalinit";
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jeanPerier wrote:

This is not a good name, it could conflict with user defined symbols since the user can define another symbol ending with "_globalinit" leading to weird bugs.

The name should also be from the type, not the variable, otherwise, you may end up redefining the global many times for nothing.

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