Do not look at _data component in gfc_dep_resolver.

2019-11-30  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/91783
	* dependency.c (gfc_dep_resolver): Do not look at _data
	component if present.

2019-11-30  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/91783
	* gfortran.dg/dependency_56.f90: New test.

From-SVN: r278873

gcc/fortran/ChangeLog

+2019-11-30  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/91783
+	* dependency.c (gfc_dep_resolver): Do not look at _data
+	component if present.
+
 2019-11-28  Jerry DeLisle  <jvdelisle@gcc.ngu.org>
 
 	PR fortran/90374

gcc/fortran/dependency.c

@@ -2098,6 +2098,18 @@ gfc_dep_resolver (gfc_ref *lref, gfc_ref *rref, gfc_reverse *reverse,
   gfc_dependency this_dep;
   bool same_component = false;
 
+  /* The refs might come in mixed, one with a _data component and one
+     without.  Look at their next reference in order to avoid an
+     ICE.  */
+
+  if (lref && lref->type == REF_COMPONENT && lref->u.c.component
+      && strcmp (lref->u.c.component->name, "_data") == 0)
+    lref = lref->next;
+
+  if (rref && rref->type == REF_COMPONENT && rref->u.c.component
+      && strcmp (rref->u.c.component->name, "_data") == 0)
+    rref = rref->next;
+
   this_dep = GFC_DEP_ERROR;
   fin_dep = GFC_DEP_ERROR;
   /* Dependencies due to pointers should already have been identified.

gcc/testsuite/ChangeLog

+2019-11-30  Thomas Koenig  <tkoenig@gcc.gnu.org>
+
+	PR fortran/91783
+	* gfortran.dg/dependency_56.f90: New test.
+
 2019-11-29  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/91003

gcc/testsuite/gfortran.dg/dependency_56.f90

+! { dg-do compile }
+! PR 91783 - used to cause an ICE in dependency checking.
+! Test case by Gerhard Steinmetz.
+program p
+   class(*), allocatable :: a(:)
+   a = [1, 2, 3]
+   a = f(a)
+contains
+   function f(x) result(y)
+      class(*), allocatable, intent(in) :: x(:)
+      class(*), allocatable :: y(:)
+      y = x
+   end
+end