[PATCH] PR fortran/102287 - optional allocatable array arguments (intent out) of derived types with allocatable components are not properly passed to subroutines

[PATCH] PR fortran/102287 - optional allocatable array arguments (intent out) of derived types with allocatable components are not properly passed to subroutines

[Harald Anlauf]

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As nicely described in the PR, we mishandled the case of passing
optional allocatable DT arguments with allocatable components
when the INTENT was declared as INTENT(OUT), as we unconditionally
tried to deallocate these components even when the argument was not
present.  The obvious solution is to wrap the code for deallocation
by a check for presence.

Regtested on x86_64-pc-linux-gnu.  OK for mainline?

As this is a potentially nasty wrong-code bug, I'd like to backport
to at least 11-branch.

Thanks,
Harald


Fortran - fix handling of optional allocatable DT arguments with INTENT(OUT)

gcc/fortran/ChangeLog:

	PR fortran/102287
	* trans-expr.c (gfc_conv_procedure_call): Wrap deallocation of
	allocatable components of optional allocatable derived type
	procedure arguments with INTENT(OUT) into a presence check.

gcc/testsuite/ChangeLog:

	PR fortran/102287
	* gfortran.dg/intent_out_14.f90: New test.


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diff --git a/gcc/fortran/trans-expr.c b/gcc/fortran/trans-expr.c
index 18d665192f0..4a81f4695d9 100644
--- a/gcc/fortran/trans-expr.c
+++ b/gcc/fortran/trans-expr.c
@@ -6548,6 +6548,17 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol * sym,
 		    // deallocate the components first
 		    tmp = gfc_deallocate_alloc_comp (fsym->ts.u.derived,
 						     parmse.expr, e->rank);
+		    /* But check whether dummy argument is optional.  */
+		    if (tmp != NULL_TREE
+			&& fsym->attr.optional
+			&& e->expr_type == EXPR_VARIABLE
+			&& e->symtree->n.sym->attr.optional)
+		      {
+			tree present;
+			present = gfc_conv_expr_present (e->symtree->n.sym);
+			tmp = build3_v (COND_EXPR, present, tmp,
+					build_empty_stmt (input_location));
+		      }
 		    if (tmp != NULL_TREE)
 		      gfc_add_expr_to_block (&se->pre, tmp);
 		  }
diff --git a/gcc/testsuite/gfortran.dg/intent_out_14.f90 b/gcc/testsuite/gfortran.dg/intent_out_14.f90
new file mode 100644
index 00000000000..e5994635008
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/intent_out_14.f90
@@ -0,0 +1,24 @@
+! { dg-do run }
+! PR fortran/102287 - optional allocatable DT array arguments (intent out)
+
+module m
+  type t
+     integer, allocatable :: a
+  end type t
+contains
+  subroutine a (x, v)
+    type(t), optional, allocatable, intent(out) :: x(:)
+    type(t), optional,              intent(out) :: v(:)
+    call b (x, v)
+  end subroutine a
+
+  subroutine b (y, w)
+    type(t), optional, allocatable, intent(out) :: y(:)
+    type(t), optional,              intent(out) :: w(:)
+  end subroutine b
+end module m
+
+program p
+  use m
+  call a ()
+end

Re: [PATCH] PR fortran/102287 - optional allocatable array arguments (intent out) of derived types with allocatable components are not properly passed to subroutines

[Thomas Koenig]

Hello Harald,

> As nicely described in the PR, we mishandled the case of passing
> optional allocatable DT arguments with allocatable components
> when the INTENT was declared as INTENT(OUT), as we unconditionally
> tried to deallocate these components even when the argument was not
> present.  The obvious solution is to wrap the code for deallocation
> by a check for presence.

Looks good.

> Regtested on x86_64-pc-linux-gnu.  OK for mainline?

Sure!

> As this is a potentially nasty wrong-code bug, I'd like to backport
> to at least 11-branch.

OK for all open branches as far as you want to go.

Thanks for the patch!

Best regards

	Thomas