Fix PR 93956, wrong pointer when returned via function.

Backport from trunk.

This one took a bit of detective work.  When array pointers point
to components of derived types, we currently set the span field
and then create an array temporary when we pass the array
pointer to a procedure as a non-pointer or non-target argument.
(This is inefficient, but that's for another release).

Now, the compiler detected this case when there was a direct assignment
like p => a%b, but not when p was returned either as a function result
or via an argument.  This patch fixes that.

2020-04-24  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/93956
	* expr.c (gfc_check_pointer_assign): Also set subref_array_pointer
	when a function returns a pointer.
	* interface.c (gfc_set_subref_array_pointer_arg): New function.
	(gfc_procedure_use): Call it.

2020-04-24  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/93956
	* gfortran.dg/pointer_assign_13.f90: New test.

diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 03193c2f9d7c4176bd1547aef2b12beb359a5bd3..787a7d57f79651a03751d4fc13a0778da1a333a5 100644 (file)
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,12 @@
+2020-04-24  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       Backport from trunk
+       PR fortran/93956
+       * expr.c (gfc_check_pointer_assign): Also set subref_array_pointer
+       when a function returns a pointer.
+       * interface.c (gfc_set_subref_array_pointer_arg): New function.
+       (gfc_procedure_use): Call it.
+
 2020-04-20  Harald Anlauf  <anlauf@gmx.de>
 
        Backport from mainline.

diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 94f9eb00f71c951af936e19c7af776457e2ccc52..deba751fe227ef4135087f873b0f93af98811c95 100644 (file)
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -4196,8 +4196,11 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_expr *rvalue,
   if (rvalue->expr_type == EXPR_NULL)
     return true;
 
-  if (rvalue->expr_type == EXPR_VARIABLE && is_subref_array (rvalue))
-    lvalue->symtree->n.sym->attr.subref_array_pointer = 1;
+  /* A function may also return subref arrray pointer.  */
+
+  if ((rvalue->expr_type == EXPR_VARIABLE && is_subref_array (rvalue))
+      || rvalue->expr_type == EXPR_FUNCTION)
+      lvalue->symtree->n.sym->attr.subref_array_pointer = 1;
 
   attr = gfc_expr_attr (rvalue);
 

diff --git a/gcc/fortran/interface.c b/gcc/fortran/interface.c
index b5701b1a59a1f7074ab7e2843550eed734813903..76bd1afd9c4d729a8ce0e296b73ed71a951b1959 100644 (file)
--- a/gcc/fortran/interface.c
+++ b/gcc/fortran/interface.c
@@ -3654,6 +3654,36 @@ check_intents (gfc_formal_arglist *f, gfc_actual_arglist *a)
   return true;
 }
 
+/* Go through the argument list of a procedure and look for
+   pointers which may be set, possibly introducing a span.  */
+
+static void
+gfc_set_subref_array_pointer_arg (gfc_formal_arglist *dummy_args,
+                                 gfc_actual_arglist *actual_args)
+{
+  gfc_formal_arglist *f;
+  gfc_actual_arglist *a;
+  gfc_symbol *a_sym;
+  for (f = dummy_args, a = actual_args; f && a ; f = f->next, a = a->next)
+    {
+
+      if (f->sym == NULL)
+       continue;
+
+      if (!f->sym->attr.pointer || f->sym->attr.intent == INTENT_IN)
+       continue;
+
+      if (a->expr == NULL || a->expr->expr_type != EXPR_VARIABLE)
+       continue;
+      a_sym = a->expr->symtree->n.sym;
+
+      if (!a_sym->attr.pointer)
+       continue;
+
+      a_sym->attr.subref_array_pointer = 1;
+    }
+  return;
+}
 
 /* Check how a procedure is used against its interface.  If all goes
    well, the actual argument list will also end up being properly
@@ -3805,6 +3835,10 @@ gfc_procedure_use (gfc_symbol *sym, gfc_actual_arglist **ap, locus *where)
   if (warn_aliasing)
     check_some_aliasing (dummy_args, *ap);
 
+  /* Set the subref_array_pointer_arg if needed.  */
+  if (dummy_args)
+    gfc_set_subref_array_pointer_arg (dummy_args, *ap);
+
   return true;
 }
 

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4bfeef9ea6b56a22b8604388455fbb1609bddcca..ec3b39c1dbdd7151386ba7571735bd1eb2ebdfea 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,17 @@
+2020-04-24  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+       Backport from trunk
+       PR fortran/93956
+       * gfortran.dg/pointer_assign_13.f90: New test.
+
+2020-04-23 Iain Sandoe <iain@sandoe.co.uk>
+
+       * g++.dg/coroutines/coro-bad-alloc-00-bad-op-new.C: Adjust for
+       changed inline namespace.
+       * g++.dg/coroutines/coro-bad-alloc-01-bad-op-del.C: Likewise.
+       * g++.dg/coroutines/coro-bad-alloc-02-no-op-new-nt.C: Likewise
+       * g++.dg/coroutines/coro.h: Likewise
+
 2020-04-21  Martin Sebor  <msebor@redhat.com>
 
        PR c++/94510

diff --git a/gcc/testsuite/gfortran.dg/pointer_assign_13.f90 b/gcc/testsuite/gfortran.dg/pointer_assign_13.f90
new file mode 100644 (file)
index 0000000..b3f2cd9
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pointer_assign_13.f90
@@ -0,0 +1,47 @@
+! { dg-do run }
+! PR 93956 - span was set incorrectly, leading to wrong code.
+! Original test case by "martin".
+program array_temps
+  implicit none
+  
+  type :: tt
+     integer :: u = 1
+     integer :: v = 2
+  end type tt
+
+  type(tt), dimension(:), pointer :: r
+  integer :: n
+  integer, dimension(:), pointer :: p, q, u
+
+  n = 10
+  allocate(r(1:n))
+  call foo(r%v,n)
+  p => get(r(:))
+  call foo(p, n)
+  call get2(r,u)
+  call foo(u,n)
+  q => r%v
+  call foo(q, n)
+
+deallocate(r)
+
+contains
+
+   subroutine foo(a, n)
+      integer, dimension(:), intent(in) :: a
+      integer, intent(in) :: n
+      if (sum(a(1:n)) /= 2*n) stop 1
+   end subroutine foo
+
+   function get(x) result(q)
+      type(tt), dimension(:), target, intent(in) :: x
+      integer, dimension(:), pointer :: q
+      q => x(:)%v
+   end function get
+
+   subroutine get2(x,q)
+      type(tt), dimension(:), target, intent(in) :: x
+      integer, dimension(:), pointer, intent(out) :: q
+      q => x(:)%v
+    end subroutine get2
+end program array_temps