From fdc3dd70c7304e1352201fee85429d07380a96bb Mon Sep 17 00:00:00 2001
From: Valentin Clement <clementval@gmail.com>
Date: Mon, 9 Jan 2023 17:53:16 +0100
Subject: [PATCH] [flang] Add runtime default initialization for polymorphic
 intent(out) dummy

This patch adds runtime default initialization for polymorphic
dummy argument. The dynamic type might require default initialization
but not the declared type.

Reviewed By: jeanPerier, PeteSteinfeld

Differential Revision: https://reviews.llvm.org/D141278
---
 flang/lib/Lower/ConvertVariable.cpp |  5 +++++
 flang/test/Lower/polymorphic.f90    | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/flang/lib/Lower/ConvertVariable.cpp b/flang/lib/Lower/ConvertVariable.cpp
index ad586ca..bc579a0 100644
--- a/flang/lib/Lower/ConvertVariable.cpp
+++ b/flang/lib/Lower/ConvertVariable.cpp
@@ -625,6 +625,11 @@ mustBeDefaultInitializedAtRuntime(const Fortran::lower::pft::Variable &var) {
     return false;
   if (Fortran::semantics::IsDummy(sym) && !Fortran::semantics::IsIntentOut(sym))
     return false;
+  // Polymorphic intent(out) dummy might need default initialization
+  // at runtime.
+  if (Fortran::semantics::IsPolymorphic(sym) &&
+      Fortran::semantics::IsDummy(sym) && Fortran::semantics::IsIntentOut(sym))
+    return true;
   // Local variables (including function results), and intent(out) dummies must
   // be default initialized at runtime if their type has default initialization.
   return hasDefaultInitialization(sym);
diff --git a/flang/test/Lower/polymorphic.f90 b/flang/test/Lower/polymorphic.f90
index bd31cc7..48c54a0 100644
--- a/flang/test/Lower/polymorphic.f90
+++ b/flang/test/Lower/polymorphic.f90
@@ -23,7 +23,7 @@ module polymorphic_test
   end type
 
   type, extends(p1) :: p2
-    real :: c
+    real :: c = 10.5
   end type
 
   type r1
@@ -738,6 +738,24 @@ module polymorphic_test
 ! CHECK: %[[RES:.*]] = fir.call @_QMpolymorphic_testPunlimited_polymorphic_alloc_array_ret() fastmath<contract> : () -> !fir.class<!fir.heap<!fir.array<?xnone>>>
 ! CHECK: fir.save_result %[[RES]] to %[[RES_TMP]] : !fir.class<!fir.heap<!fir.array<?xnone>>>, !fir.ref<!fir.class<!fir.heap<!fir.array<?xnone>>>>
 
+  subroutine test_unlimited_polymorphic_intentout(a)
+    class(*), intent(out) :: a
+  end subroutine
+
+! CHECK-LABEL: func.func @_QMpolymorphic_testPtest_unlimited_polymorphic_intentout(
+! CHECK-SAME: %[[ARG0:.*]]: !fir.class<none> {fir.bindc_name = "a"}) {
+! CHECK: %[[BOX_NONE:.*]] = fir.convert %[[ARG0]] : (!fir.class<none>) -> !fir.box<none>
+! CHECK: %{{.*}} = fir.call @_FortranAInitialize(%[[BOX_NONE]], %{{.*}}, %{{.*}}) {{.*}} : (!fir.box<none>, !fir.ref<i8>, i32) -> none
+
+  subroutine test_polymorphic_intentout(a)
+    class(p1), intent(out) :: a
+  end subroutine
+
+! CHECK-LABEL: func.func @_QMpolymorphic_testPtest_polymorphic_intentout(
+! CHECK-SAME: %[[ARG0:.*]]: !fir.class<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>> {fir.bindc_name = "a"}) {
+! CHECK: %[[BOX_NONE:.*]] = fir.convert %[[ARG0]] : (!fir.class<!fir.type<_QMpolymorphic_testTp1{a:i32,b:i32}>>) -> !fir.box<none>
+! CHECK: %{{.*}} = fir.call @_FortranAInitialize(%[[BOX_NONE]], %{{.*}}, %{{.*}}) {{.*}} : (!fir.box<none>, !fir.ref<i8>, i32) -> none
+
 end module
 
 program test
-- 
2.7.4