From patchwork Sun Mar 25 09:28:20 2012
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Subject: [fortran] Fix PR 52668, bogus warning for only list
Date: Sat, 24 Mar 2012 23:28:20 -0000
From: Thomas Koenig <tkoenig@netcologne.de>
X-Patchwork-Id: 148554
Message-Id: <4F6EE534.8070502@netcologne.de>
To: "fortran@gcc.gnu.org" <fortran@gcc.gnu.org>,
 gcc-patches <gcc-patches@gcc.gnu.org>

Hello world,

this fixes a 4.7/4.8 regression with a bogus warning for variables
which were excluded from being imported by "use, only" if they
were in a common block inside the module.

Regression-tested.  OK for trunk and for 4.7 after a few days?

	Thomas

2012-03-25  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/52668
         * module.c:  Only mark symbols as use_only if they have been
         imported via an only list.

2012-03-25  Thomas Koenig  <tkoenig@gcc.gnu.org>

         PR fortran/52668
         * gfortran.dg/use_only_6.f90: New test.
! { dg-do compile }
! PR 52668 - there used to be a bogus warning about not using b.
! Original test case by Arnaud Desitter.
module mm
  integer :: a, b
  common /mm1/ a, b
end module mm

subroutine aa()
  use mm, only: a
  implicit none
  a = 1
end subroutine aa
! { dg-final { cleanup-modules "mm" } }


Index: module.c
===================================================================
--- module.c	(Revision 184854)
+++ module.c	(Arbeitskopie)
@@ -4389,9 +4389,24 @@ load_needed (pointer_info *p)
 
   /* Mark as only or rename for later diagnosis for explicitly imported
      but not used warnings; don't mark internal symbols such as __vtab,
-     __def_init etc.  */
+     __def_init etc. Only mark them if they have been explicitly loaded.  */
+
   if (only_flag && sym->name[0] != '_' && sym->name[1] != '_')
-    sym->attr.use_only = 1;
+    {
+      gfc_use_rename *u;
+
+      /* Search the use/rename list for the variable; if the variable is
+	 found, mark it.  */
+      for (u = gfc_rename_list; u; u = u->next)
+	{
+	  if (strcmp (u->use_name, sym->name) == 0)
+	    {
+	      sym->attr.use_only = 1;
+	      break;
+	    }
+	}
+    }
+
   if (p->u.rsym.renamed)
     sym->attr.use_rename = 1;