alias-access-path-6.c: New testcase.

	* gcc.dg/tree-ssa/alias-access-path-6.c: New testcase.
	* tree-ssa-alias.c (nonoverlapping_component_refs_p): Do not
	give up on bitfields; continue searching for different refs
	appearing later.

From-SVN: r272587

gcc/ChangeLog

+2019-06-22  Jan Hubicka  <jh@suse.cz>
+
+	* tree-ssa-alias.c (nonoverlapping_component_refs_p): Do not
+	give up on bitfields; continue searching for different refs
+	appearing later.
+
 2019-06-21  Jakub Jelinek  <jakub@redhat.com>
 
 	* tree-vect-data-refs.c (vect_find_stmt_data_reference): Handle

gcc/testsuite/ChangeLog

+2019-06-22  Jan Hubicka  <jh@suse.cz>
+
+	* gcc.dg/tree-ssa/alias-access-path-6.c: New testcase.
+
 2019-06-22  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/86476 - noexcept-specifier is a complete-class context.

gcc/testsuite/gcc.dg/tree-ssa/alias-access-path-6.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+/* This tests that nonoveralpping_component_refs does not give up
+   on field delcs and continues looking to find mismatch between
+   a1 and a2.  */
+struct a {
+	int a:3;
+	int b:3;
+};
+struct b {struct a a1,a2;};
+struct c {struct b b[10];} *cptr;
+struct d {struct c c;} *dptr;
+int
+test(int i,int j)
+{
+  cptr->b[i].a1.a=0;
+  dptr->c.b[j].a2.b=1;
+  return cptr->b[i].a1.a;
+}
+int
+test2(int i,int j)
+{
+  cptr->b[i].a1.a=1;
+  dptr->c.b[j].a1.a=0;
+  return cptr->b[i].a1.a;
+}
+/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized"} } */
+/* { dg-final { scan-tree-dump-not "return 1" "optimized"} } */

gcc/tree-ssa-alias.c

@@ -1350,19 +1350,16 @@ nonoverlapping_component_refs_p (const_tree x, const_tree y)
 		 same.  */
 	      if (DECL_BIT_FIELD_REPRESENTATIVE (fieldx) == fieldy
 		  || DECL_BIT_FIELD_REPRESENTATIVE (fieldy) == fieldx)
-		{
-		   ++alias_stats.nonoverlapping_component_refs_p_may_alias;
-		   return false;
-		}
+		;
 	      /* Different fields of the same record type cannot overlap.
 		 ??? Bitfields can overlap at RTL level so punt on them.  */
-	      if (DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy))
+	      else if (DECL_BIT_FIELD (fieldx) && DECL_BIT_FIELD (fieldy))
+		;
+	      else
 		{
-		   ++alias_stats.nonoverlapping_component_refs_p_may_alias;
-		   return false;
+		  ++alias_stats.nonoverlapping_component_refs_p_no_alias;
+		  return true;
 		}
-	      ++alias_stats.nonoverlapping_component_refs_p_no_alias;
-	      return true;
 	    }
 	}
       if (TYPE_UID (typex) < TYPE_UID (typey))