===================================================================
*************** gfc_conv_procedure_call (gfc_se * se, gf
&& e->ts.type == BT_CLASS
&& !CLASS_DATA (e)->attr.dimension
&& !CLASS_DATA (e)->attr.codimension)
! parmse.expr = gfc_class_data_get (parmse.expr);
/* Wrap scalar variable in a descriptor. We need to convert
the address of a pointer back to the pointer itself before,
&& e->ts.type == BT_CLASS
&& !CLASS_DATA (e)->attr.dimension
&& !CLASS_DATA (e)->attr.codimension)
! {
! parmse.expr = gfc_class_data_get (parmse.expr);
! /* The result is a class temporary, whose _data component
! must be freed to avoid a memory leak. */
! if (e->expr_type == EXPR_FUNCTION
! && CLASS_DATA (e)->attr.allocatable)
! {
! tree zero;
! zero = build_int_cst (TREE_TYPE (parmse.expr), 0);
! tmp = fold_build2_loc (input_location, NE_EXPR,
! logical_type_node,
! parmse.expr, zero);
! tmp = build3_v (COND_EXPR, tmp,
! gfc_call_free (parmse.expr),
! build_empty_stmt (input_location));
! gfc_add_expr_to_block (&parmse.post, tmp);
! gfc_add_modify (&parmse.post, parmse.expr, zero);
! }
! }
/* Wrap scalar variable in a descriptor. We need to convert
the address of a pointer back to the pointer itself before,
===================================================================
***************
+ ! { dg-do compile }
+ ! { dg-options "-fdump-tree-original" }
+ !
+ ! Test the fix for PR80477
+ !
+ ! Contributed by Stefano Zaghi <stefano.zaghi@cnr.it>
+ !
+ module a_type_m
+ implicit none
+ type :: a_type_t
+ real :: x
+ endtype
+ contains
+ subroutine assign_a_type(lhs, rhs)
+ type(a_type_t), intent(inout) :: lhs
+ type(a_type_t), intent(in) :: rhs
+ lhs%x = rhs%x
+ end subroutine
+
+ function add_a_type(lhs, rhs) result( res )
+ type(a_type_t), intent(in) :: lhs
+ type(a_type_t), intent(in) :: rhs
+ class(a_type_t), allocatable :: res
+ allocate (a_type_t :: res)
+ res%x = lhs%x + rhs%x
+ end function
+ end module
+
+ program polymorphic_operators_memory_leaks
+ use a_type_m
+ implicit none
+ type(a_type_t) :: a = a_type_t(1) , b = a_type_t(2)
+ call assign_a_type (a, add_a_type(a,b)) ! generated a memory leak
+ end
+ ! { dg-final { scan-tree-dump-times "builtin_free" 1 "original" } }
+ ! { dg-final { scan-tree-dump-times "builtin_malloc" 1 "original" } }
===================================================================
Several attempts, including mine, were made to fix this bug since it was posted. They were all attacking the wrong place. Instead of providing the free of the class _data as part of the call to 'add_a_type' it should be included in the post block of the argument processing in the call to 'assign_a_type'. The comment in the patch says the rest. Bootstrapped and regtested on FC28/x86_64 - OK for trunk? Paul 2017-07-27 Paul Thomas <pault@gcc.gnu.org> PR fortran/80477 * trans-expr.c (gfc_conv_procedure_call): Allocatable class results being passed to a derived type formal argument must have the _data component deallocated after use. 2017-07-27 Paul Thomas <pault@gcc.gnu.org> PR fortran/80477 * gfortran.dg/class_result_7.f90: New test.