[flang][hlfir] Lower parent component in constant structure constructors (llvm#71421)

Simply remove TODO. Since parent components are now fields of the
extended types fir.type<> in HLFIR, there is nothing specific to do to
deal with the appearance of a parent component value in a structure
constructor value that must be turned into a fir.global initial value:
it can simply be inserted as a normal field value.

Author: jeanPerier

flang/lib/Lower/ConvertConstant.cpp

@@ -476,10 +476,6 @@ static mlir::Value genInlinedStructureCtorLitImpl(
 
   const Fortran::semantics::DerivedTypeSpec *curentType = nullptr;
   for (const auto &[sym, expr] : ctor.values()) {
-    // This TODO is not needed here anymore, but should be removed in a separate
-    // patch.
-    if (sym->test(Fortran::semantics::Symbol::Flag::ParentComp))
-      TODO(loc, "parent component in structure constructor");
     const Fortran::semantics::DerivedTypeSpec *componentParentType =
         sym->owner().derivedTypeSpec();
     assert(componentParentType && "failed to retrieve component parent type");

flang/test/Lower/HLFIR/constant-derived.f90

@@ -24,6 +24,17 @@ subroutine test_constant_scalar_ptr_component()
 ! CHECK:  fir.address_of(@[[CST_TARGET:_QQro._QFtest_constant_scalar_ptr_componentTmyderived..*]])
 end subroutine
 
+subroutine test_comp_ref()
+  ! Test parent component value in an initial value structure constructor.
+  type t1
+    integer :: i
+  end type
+  type, extends(t1) :: t2
+    integer :: j
+  end type
+  type(t2) :: x = t2(t1=t1(1), j=2)
+end subroutine
+
 ! CHECK: fir.global internal @[[CST]] constant : !fir.type<[[DERIVED:_QFtest_constant_scalarTmyderived{i:i32,j:i32,x:!fir.array<2xf32>,c:!fir.char<1,10>}]]> {
 ! CHECK:   %[[VAL_0:.*]] = fir.undefined !fir.type<[[DERIVED]]>
 ! CHECK:   %[[VAL_1:.*]] = fir.field_index i, !fir.type<[[DERIVED]]>
@@ -69,3 +80,17 @@ subroutine test_constant_scalar_ptr_component()
 ! CHECK:   %[[VAL_20:.*]] = fir.insert_value %[[VAL_4]], %[[VAL_19]], ["y", !fir.type<[[DERIVED_2]]>] : (!fir.type<[[DERIVED_2]]>, !fir.box<!fir.ptr<!fir.array<?xf32>>>) -> !fir.type<[[DERIVED_2]]>
 ! CHECK:   fir.has_value %[[VAL_20]] : !fir.type<[[DERIVED_2]]>
 ! CHECK: }
+
+! CHECK-LABEL:   fir.global internal @_QFtest_comp_refEx : !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}> {
+! CHECK:   %[[VAL_0:.*]] = fir.undefined !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK:   %[[VAL_1:.*]] = fir.field_index t1, !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK:   %[[VAL_2:.*]] = fir.undefined !fir.type<_QFtest_comp_refTt1{i:i32}>
+! CHECK:   %[[VAL_3:.*]] = fir.field_index i, !fir.type<_QFtest_comp_refTt1{i:i32}>
+! CHECK:   %[[VAL_4:.*]] = arith.constant 1 : i32
+! CHECK:   %[[VAL_5:.*]] = fir.insert_value %[[VAL_2]], %[[VAL_4]], ["i", !fir.type<_QFtest_comp_refTt1{i:i32}>] : (!fir.type<_QFtest_comp_refTt1{i:i32}>, i32) -> !fir.type<_QFtest_comp_refTt1{i:i32}>
+! CHECK:   %[[VAL_6:.*]] = fir.insert_value %[[VAL_0]], %[[VAL_5]], ["t1", !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>] : (!fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>, !fir.type<_QFtest_comp_refTt1{i:i32}>) -> !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK:   %[[VAL_7:.*]] = fir.field_index j, !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK:   %[[VAL_8:.*]] = arith.constant 2 : i32
+! CHECK:   %[[VAL_9:.*]] = fir.insert_value %[[VAL_6]], %[[VAL_8]], ["j", !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>] : (!fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>, i32) -> !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK:   fir.has_value %[[VAL_9]] : !fir.type<_QFtest_comp_refTt2{t1:!fir.type<_QFtest_comp_refTt1{i:i32}>,j:i32}>
+! CHECK: }