fix PR68976: only add loop close phi for names defined in loop

* graphite-isl-ast-to-gimple.c: Fix comment.
        * graphite-scop-detection.c (defined_in_loop_p): New.
        (canonicalize_loop_closed_ssa): Do not add close phi nodes for SSA
        names defined in loop.

gcc/testsuite

        * gcc.dg/graphite/pr68976.c: New test.

Co-Authored-By: Sebastian Pop <s.pop@samsung.com>

From-SVN: r232658

gcc/ChangeLog

@@ -1,3 +1,11 @@
+2016-01-21  Aditya Kumar  <aditya.k7@samsung.com>
+	    Sebastian Pop  <s.pop@samsung.com>
+
+        * graphite-isl-ast-to-gimple.c: Fix comment.
+        * graphite-scop-detection.c (defined_in_loop_p): New.
+        (canonicalize_loop_closed_ssa): Do not add close phi nodes for SSA
+        names defined in loop.
+
 2016-01-21  Aditya Kumar  <aditya.k7@samsung.com>
 	    Sebastian Pop  <s.pop@samsung.com>
 

gcc/graphite-isl-ast-to-gimple.c

@@ -507,8 +507,8 @@ private:
 /* Return the tree variable that corresponds to the given isl ast identifier
    expression (an isl_ast_expr of type isl_ast_expr_id).
 
-   FIXME: We should replace blind conversation of id's type with derivation
-   of the optimal type when we get the corresponding isl support. Blindly
+   FIXME: We should replace blind conversion of id's type with derivation
+   of the optimal type when we get the corresponding isl support.  Blindly
    converting type sizes may be problematic when we switch to smaller
    types.  */
 

gcc/graphite-scop-detection.c

@@ -336,6 +336,15 @@ make_close_phi_nodes_unique (basic_block bb)
     }
 }
 
+/* Return true when NAME is defined in LOOP.  */
+
+static bool
+defined_in_loop_p (tree name, loop_p loop)
+{
+  gcc_assert (TREE_CODE (name) == SSA_NAME);
+  return loop == loop_containing_stmt (SSA_NAME_DEF_STMT (name));
+}
+
 /* Transforms LOOP to the canonical loop closed SSA form.  */
 
 static void
@@ -376,7 +385,9 @@ canonicalize_loop_closed_ssa (loop_p loop)
 		use_operand_p use_p;
 		gphi *close_phi;
 
-		if (TREE_CODE (arg) != SSA_NAME)
+		/* Only add close phi nodes for SSA_NAMEs defined in LOOP.  */
+		if (TREE_CODE (arg) != SSA_NAME
+		    || !defined_in_loop_p (arg, loop))
 		  continue;
 
 		close_phi = create_phi_node (NULL_TREE, close);

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2016-01-21  Aditya Kumar  <aditya.k7@samsung.com>
+	    Sebastian Pop  <s.pop@samsung.com>
+
+        * gcc.dg/graphite/pr68976.c: New test.
+
 2016-01-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/67653

gcc/testsuite/gcc.dg/graphite/pr68976.c

@@ -0,0 +1,11 @@
+/* { dg-options "-O2 -floop-nest-optimize" } */
+
+int kw = -1, hv = -1, ju;
+int mc[1];
+void xx(void)
+{
+  for (; kw; ++kw)
+    for (; hv; ++hv)
+      for (ju = 0; ju < 2; ++ju)
+        mc[kw+1] = mc[0];
+}