Handle AR_FULL vs. AR_FULL in dependency checking.

Previously, handling of full vs. full references failed to take
AR_FULL vs. AR_FULL into account.  A change in dependency
checking in gcc 10 created a code path that could lead there;
with this patch, this is now correctly handled.

gcc/fortran/ChangeLog:

2020-06-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/95812
	* dependency.c (ref_same_as_full_array): Handle case of AR_FULL
	vs. AR_FULL.

gcc/testsuite/ChangeLog:

2020-06-23  Thomas Koenig  <tkoenig@gcc.gnu.org>

	PR fortran/95812
	* gfortran.dg/dependency_59.f90: New test.

(cherry picked from commit abcde0a658e17dbbabcb396eaae5a3612e07d401)

gcc/fortran/dependency.c

@@ -2033,6 +2033,8 @@ ref_same_as_full_array (gfc_ref *full_ref, gfc_ref *ref)
     return false;
   if (ref->type != REF_ARRAY)
     return false;
+  if (ref->u.ar.type == AR_FULL)
+    return true;
   if (ref->u.ar.type != AR_SECTION)
     return false;
 

gcc/testsuite/gfortran.dg/dependency_59.f90

+! { dg-do compile }
+! PR 95812 - this caused an ICE.
+! Test case by Jakub Jelinek.
+
+module test
+contains
+  subroutine foo()
+    integer :: a(3)
+    a = 1
+    print *, matmul(1*reshape(a,(/3,1/)), reshape((/1,1,1/),(/1,3/)))
+  end subroutine foo
+  subroutine bar()
+    call foo()
+  end subroutine bar
+end module test