[flang] Do not initialize intent(out) polymorphic pointer or allocatable

[clementval]

Summary

Calling the runtime on disassociated pointer or unallocated
allocatable will trigger a segfault.

[PeteSteinfeld]

All builds and tests successfully and looks good.

flang/lib/Lower/ConvertVariable.cpp

mustBeDefaultInitializedAtRuntime(const Fortran::lower::pft::Variable &var) {
   if (var.isGlobal())
     // Global variables are statically initialized.
     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))
+      Fortran::semantics::IsDummy(sym) &&
+      Fortran::semantics::IsIntentOut(sym) &&
+      !Fortran::semantics::IsAllocatable(sym) &&
+      !Fortran::semantics::IsPointer(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);
 }
 
 /// Call default initialization runtime routine to initialize \p var.
 static void

flang/test/Lower/default-initialization.f90

 ! Test default initialization of local and dummy variables (dynamic initialization)
-! RUN: bbc -emit-fir %s -o - | FileCheck %s
+! RUN: bbc -emit-fir -polymorphic-type %s -o - | FileCheck %s
 
 module test_dinit
   type t
     integer :: i = 42 
   end type
   type t_alloc_comp
     real, allocatable :: i(:)
   end type
! -----------------------------------------------------------------------------
 
   ! CHECK-LABEL: func @_QMtest_dinitPnoinit_intentinout_dummy
   subroutine noinit_intentinout_dummy(x)
     ! CHECK-NOT: fir.call @_FortranAInitialize
     type(t), intent(inout) :: x
     ! CHECK: return
   end subroutine 
 
+
+  subroutine test_pointer_intentout(a, b)
+    type(t), pointer, intent(out) :: a
+    class(t), pointer, intent(out) :: b
+  end subroutine
+
+! CHECK-LABEL: func.func @_QMtest_dinitPtest_pointer_intentout(
+! CHECK-NOT: fir.call @_FortranAInitialize
+
 end module
 
+! CHECK-LABEL: func.func @_QQmain
+
 ! End-to-end test for debug pruposes.
   use test_dinit
   type(t) :: at
   call local()
   call local_array()
   at%i = 66
   call intent_out(at)
   print *, at%i
   at%i = 66
   call intent_out_optional(at)
   print *, at%i
   call intent_out_optional()
   call local_eq()
   call local_eq2()
 end