[GSoC] A bug related to induction variables and blocks

[Roman Gareev]

If we try to generate code from the following ISL AST:

{
  for (int c1 = 0; c1 < k.3; c1 += 1) {
    S_21(c1);
    S_21(c1);
    S_4(c1);
    for (int c3 = 0; c3 < pretmp; c3 += 1)
      S_5(c1, c3);
    S_7(c1);
    S_26(c1);
    S_8(c1);
    S_8(c1);
    S_9(c1);
    for (int c3 = 0; c3 < pretmp; c3 += 1)
      S_10(c1, c3);
    S_11(c1);
    S_25(c1);
    S_13(c1);
    S_13(c1);
    S_14(c1);
    for (int c3 = 0; c3 < pretmp; c3 += 1)
      S_15(c1, c3);
    S_16(c1);
    S_24(c1);
    S_18(c1);
  }
  S_19();
}

we'll get the following error:

isl_ctx.c:172: isl_ctx freed, but some objects still reference it

If I'm not mistaken, it is caused by missing of isl_id_free functions,
which should be called in the same quantity as isl_ast_expr_get_id
because of the implementation of ISL.

I've attached the patch, which may fix the problem. It also contains a
corresponding test case. Is it fine for trunk?


--
                                   Cheers, Roman Gareev.

2014-07-23  Roman Gareev  <gareevro...@gmail.com>

[gcc/]

        * graphite-isl-ast-to-gimple.c:
        (graphite_create_new_loop): Add calling of isl_id_free.
        
[gcc/testsuite]

        * gcc.dg/graphite/isl-ast-gen-blocks-4.c: New testcase.

Index: gcc/graphite-isl-ast-to-gimple.c
===================================================================
--- gcc/graphite-isl-ast-to-gimple.c    (revision 212922)
+++ gcc/graphite-isl-ast-to-gimple.c    (working copy)
@@ -383,6 +383,10 @@
 
   isl_ast_expr *for_iterator = isl_ast_node_for_get_iterator (node_for);
   isl_id *id = isl_ast_expr_get_id (for_iterator);
+  std::map<isl_id *, tree>::iterator res;
+  res = ip.find (id);
+  if (res != ip.end ())
+    isl_id_free (res->first);
   ip[id] = iv;
   isl_ast_expr_free (for_iterator);
   return loop;

Index: gcc/testsuite/gcc.dg/graphite/isl-ast-gen-blocks-4.c
===================================================================
--- gcc/testsuite/gcc.dg/graphite/isl-ast-gen-blocks-4.c        (revision 0)
+++ gcc/testsuite/gcc.dg/graphite/isl-ast-gen-blocks-4.c        (working copy)
@@ -0,0 +1,37 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fgraphite-identity -fgraphite-code-generator=isl" } */
+
+int k = 4;
+int n1 = 50;
+int n2 = 50;
+int n3 = 50;
+
+static int __attribute__((noinline))
+foo ()
+{
+  int j, res = 0;
+  for (j = 0, res = 0; j < k; j++)
+    {
+      int i;
+      for (i = 0; i < n1; i++)
+        res += i;
+      for (i = 0; i < n2; i++)
+        res += i;
+      for (i = 0; i < n3; i++)
+        res += i;
+    }
+
+  return res;
+}
+
+extern void abort ();
+
+int
+main (void)
+{ 
+  int res = foo ();
+  if (res != 14700)
+    abort ();
+
+  return 0;
+}