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[GSoC] generation of Gimple loops with empty bodies

Message ID CABGF_gc3-gg4cmLuRhq4pHanPE2icUXKSmvjyWtPqK6SkTP6pg@mail.gmail.com
State New
Headers show

Commit Message

Roman Gareev July 11, 2014, 9:01 a.m. UTC
> I would use -x to see the headers. This should tell you if it is defined
> or only used there.

It gives the following output:

roman@roman-System-Product-Name:~/isl-0.12.2/lib$ objdump -x
libisl.so.10.2.2 | grep isl_ast_expr_get_val
0000000000060380 g     F .text 0000000000000053
isl_ast_expr_get_val

> Sorry, but this still needs to be debugged. :-( I am too busy to do it
> myself, so i am afraid you may just need to dig into it yourself. :-(

I've found the reason of this error. Somehow cc1 used an older version
of isl provided by the package from the standard repository in spite
of manually selected paths to isl 0.12.2. I think it is better to move
on and not to concentrate on this.

>> +#include "graphite-htab.h"
>
> Is this still needed?

No, this is redundant.

>> +/* IVS_PARAMS_MAP maps ISL's scattering and parameter identifiers
>> +   to corresponding trees.  */
>> +typedef struct ivs_params {
>> +  std::map<isl_id *, tree, id_comp> ivs_params_map;
>
> What about calling it isl_id_to_tree?

Maybe it would be better to call it tree_from_isl_id (because it would
help to avoid confusion with definitions from isl)?

>> +  sese region;
>
> Is this region needed?

No, this is redundant.

>> +   We create a new if region protecting the loop to be executed, if
>> +   the execution count is zero (lower bound > upper bound). In this case,
>> +   it is subsequently removed by dead code elimination.  */
>
>
> The last sentence is unclear. Are you saying the loop will be removed or
> that the condition will be removed in case it is always true. Also, what
> about cases where the condition remains?

I wanted to say that the loop will be removed. Maybe it would be
better to remove the last sentence at all (because the previous
sentence already explains the motivation)?

> Those changes are unrelated and are part of the other patch, right?

Yes, these changes were made in the revision under No. 212361.

>> +  ip.region = region;
>
> Is this needed? ip.region seems unused.

Yes, this is redundant.


I tried to incorporate all your comments in the attached patch.

--
                                   Cheers, Roman Gareev.

Comments

Tobias Grosser July 11, 2014, 9:18 a.m. UTC | #1
> I tried to incorporate all your comments in the attached patch.

Nice. It looks now very good to me. One final and last detail:


+/* TREE_FROM_ISL_ID maps ISL's scattering and parameter identifiers
+   to corresponding trees.  */
+
+typedef struct ivs_params {
+  std::map<isl_id *, tree> tree_from_isl_id;
+} *ivs_params_p;

The struct now contains only a single element such that there seems to 
be no need for it anymore. Should we remove it? (We could still use a 
typedef if you believe the datatype is too long).

Cheers,
Tobias
Roman Gareev July 11, 2014, 11:11 a.m. UTC | #2
> The struct now contains only a single element such that there seems to be no
> need for it anymore. Should we remove it? (We could still use a typedef if
> you believe the datatype is too long).

I don't mind removing it. However I think that we should choose the
way of transferring of sese region, which is used for translation of
an isl_ast_node_user to Gimple code. Should we transfer it separately
or restore ivs_params later? What do you think?

--
                                   Cheers, Roman Gareev.
Tobias Grosser July 11, 2014, 11:15 a.m. UTC | #3
On 11/07/2014 13:11, Roman Gareev wrote:
>> The struct now contains only a single element such that there seems to be no
>> need for it anymore. Should we remove it? (We could still use a typedef if
>> you believe the datatype is too long).
>
> I don't mind removing it. However I think that we should choose the
> way of transferring of sese region, which is used for translation of
> an isl_ast_node_user to Gimple code. Should we transfer it separately
> or restore ivs_params later? What do you think?

Sorry, I currently don't see why sese region is needed later. In case it
is, we may keep it, but this would require to pull more code in the 
review. I personally would just remove it to finish this review.

Feel free to commit after applying this change.

Cheers,
Tobias
diff mbox

Patch

Index: gcc/graphite-isl-ast-to-gimple.c
===================================================================
--- gcc/graphite-isl-ast-to-gimple.c	(revision 212361)
+++ gcc/graphite-isl-ast-to-gimple.c	(working copy)
@@ -25,7 +25,14 @@ 
 #include <isl/map.h>
 #include <isl/union_map.h>
 #include <isl/ast_build.h>
+#if defined(__cplusplus)
+extern "C" {
 #endif
+#include <isl/val_gmp.h>
+#if defined(__cplusplus)
+}
+#endif
+#endif
 
 #include "system.h"
 #include "coretypes.h"
@@ -42,6 +49,9 @@ 
 #include "cfgloop.h"
 #include "tree-data-ref.h"
 #include "sese.h"
+#include "tree-ssa-loop-manip.h"
+#include "tree-scalar-evolution.h"
+#include <map>
 
 #ifdef HAVE_cloog
 #include "graphite-poly.h"
@@ -52,6 +62,517 @@ 
 
 static bool graphite_regenerate_error;
 
+/* We always use signed 128, until isl is able to give information about
+types  */
+
+static tree *graphite_expression_size_type = &int128_integer_type_node;
+
+/* Converts a GMP constant VAL to a tree and returns it.  */
+
+static tree
+gmp_cst_to_tree (tree type, mpz_t val)
+{
+  tree t = type ? type : integer_type_node;
+  mpz_t tmp;
+
+  mpz_init (tmp);
+  mpz_set (tmp, val);
+  wide_int wi = wi::from_mpz (t, tmp, true);
+  mpz_clear (tmp);
+
+  return wide_int_to_tree (t, wi);
+}
+
+/* Verifies properties that GRAPHITE should maintain during translation.  */
+
+static inline void
+graphite_verify (void)
+{
+#ifdef ENABLE_CHECKING
+  verify_loop_structure ();
+  verify_loop_closed_ssa (true);
+#endif
+}
+
+/* TREE_FROM_ISL_ID maps ISL's scattering and parameter identifiers
+   to corresponding trees.  */
+
+typedef struct ivs_params {
+  std::map<isl_id *, tree> tree_from_isl_id;
+} *ivs_params_p;
+
+/* Free all memory allocated for ISL's identifiers.  */
+
+void ivs_params_clear (ivs_params_p ip)
+{
+  std::map<isl_id *, tree>::iterator it;
+  for (it = ip->tree_from_isl_id.begin ();
+       it != ip->tree_from_isl_id.end (); it++)
+    {
+      isl_id_free (it->first);
+    }
+}
+
+static tree
+gcc_expression_from_isl_expression (tree type, __isl_take isl_ast_expr *,
+				    ivs_params_p ip);
+
+/* Return the tree variable that corresponds to the given isl ast identifier
+ expression (an isl_ast_expr of type isl_ast_expr_id).  */
+
+static tree
+gcc_expression_from_isl_ast_expr_id (__isl_keep isl_ast_expr *expr_id,
+				     ivs_params_p ip)
+{
+  gcc_assert (isl_ast_expr_get_type (expr_id) == isl_ast_expr_id);
+  isl_id *tmp_isl_id = isl_ast_expr_get_id (expr_id);
+  std::map<isl_id *, tree>::iterator res;
+  res = ip->tree_from_isl_id.find (tmp_isl_id);
+  isl_id_free (tmp_isl_id);
+  gcc_assert (res != ip->tree_from_isl_id.end () &&
+              "Could not map isl_id to tree expression");
+  isl_ast_expr_free (expr_id);
+  return res->second;
+}
+
+/* Converts an isl_ast_expr_int expression E to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+gcc_expression_from_isl_expr_int (tree type, __isl_take isl_ast_expr *expr)
+{
+  gcc_assert (isl_ast_expr_get_type (expr) == isl_ast_expr_int);
+  isl_val *val = isl_ast_expr_get_val (expr);
+  mpz_t val_mpz_t;
+  mpz_init (val_mpz_t);
+  tree res;
+  if (isl_val_get_num_gmp (val, val_mpz_t) == -1)
+    res = NULL_TREE;
+  else
+    res = gmp_cst_to_tree (type, val_mpz_t);
+  isl_val_free (val);
+  isl_ast_expr_free (expr);
+  mpz_clear (val_mpz_t);
+  return res;
+}
+
+/* Converts a binary isl_ast_expr_op expression E to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+binary_op_to_tree (tree type, __isl_take isl_ast_expr *expr, ivs_params_p ip)
+{
+  isl_ast_expr *arg_expr = isl_ast_expr_get_op_arg (expr, 0);
+  tree tree_lhs_expr = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  arg_expr = isl_ast_expr_get_op_arg (expr, 1);
+  tree tree_rhs_expr = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  enum isl_ast_op_type expr_type = isl_ast_expr_get_op_type (expr);
+  isl_ast_expr_free (expr);
+  switch (expr_type)
+    {
+    case isl_ast_op_add:
+      return fold_build2 (PLUS_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_sub:
+      return fold_build2 (MINUS_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_mul:
+      return fold_build2 (MULT_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_div:
+      return fold_build2 (EXACT_DIV_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_fdiv_q:
+      return fold_build2 (FLOOR_DIV_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_and:
+      return fold_build2 (TRUTH_ANDIF_EXPR, type,
+			  tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_or:
+      return fold_build2 (TRUTH_ORIF_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_eq:
+      return fold_build2 (EQ_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_le:
+      return fold_build2 (LE_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_lt:
+      return fold_build2 (LT_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_ge:
+      return fold_build2 (GE_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    case isl_ast_op_gt:
+      return fold_build2 (GT_EXPR, type, tree_lhs_expr, tree_rhs_expr);
+
+    default:
+      gcc_unreachable ();
+    }
+}
+
+/* Converts a ternary isl_ast_expr_op expression E to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+ternary_op_to_tree (tree type, __isl_take isl_ast_expr *expr, ivs_params_p ip)
+{
+  gcc_assert (isl_ast_expr_get_op_type (expr) == isl_ast_op_minus);
+  isl_ast_expr *arg_expr = isl_ast_expr_get_op_arg (expr, 0);
+  tree tree_first_expr
+    = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  arg_expr = isl_ast_expr_get_op_arg (expr, 1);
+  tree tree_second_expr
+    = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  arg_expr = isl_ast_expr_get_op_arg (expr, 2);
+  tree tree_third_expr
+    = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  isl_ast_expr_free (expr);
+  return fold_build3 (COND_EXPR, type, tree_first_expr,
+		      tree_second_expr, tree_third_expr);
+}
+
+/* Converts a unary isl_ast_expr_op expression E to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+unary_op_to_tree (tree type, __isl_take isl_ast_expr *expr, ivs_params_p ip)
+{
+  gcc_assert (isl_ast_expr_get_op_type (expr) == isl_ast_op_minus);
+  isl_ast_expr *arg_expr = isl_ast_expr_get_op_arg (expr, 0);
+  tree tree_expr = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  isl_ast_expr_free (expr);
+  return fold_build1 (NEGATE_EXPR, type, tree_expr);
+}
+
+/* Converts an isl_ast_expr_op expression E with unknown number of arguments
+   to a GCC expression tree of type TYPE.  */
+
+static tree
+nary_op_to_tree (tree type, __isl_take isl_ast_expr *expr, ivs_params_p ip)
+{
+  enum tree_code op_code;
+  switch (isl_ast_expr_get_op_type (expr))
+    {
+    case isl_ast_op_max:
+      op_code = MAX_EXPR;
+      break;
+
+    case isl_ast_op_min:
+      op_code = MIN_EXPR;
+      break;
+
+    default:
+      gcc_unreachable ();    
+    }
+  isl_ast_expr *arg_expr = isl_ast_expr_get_op_arg (expr, 0);
+  tree res = gcc_expression_from_isl_expression (type, arg_expr, ip);
+  int i;
+  for (i = 1; i < isl_ast_expr_get_op_n_arg (expr); i++)
+    {
+      arg_expr = isl_ast_expr_get_op_arg (expr, i);
+      tree t = gcc_expression_from_isl_expression (type, arg_expr, ip);
+      res = fold_build2 (op_code, type, res, t);
+    }
+  isl_ast_expr_free (expr);
+  return res;
+}
+
+
+/* Converts an isl_ast_expr_op expression E to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+gcc_expression_from_isl_expr_op (tree type, __isl_take isl_ast_expr *expr,
+				 ivs_params_p ip)
+{
+  gcc_assert (isl_ast_expr_get_type (expr) == isl_ast_expr_op);
+  switch (isl_ast_expr_get_op_type (expr))
+    {
+    /* These isl ast expressions are not supported yet.  */
+    case isl_ast_op_error:
+    case isl_ast_op_call:
+    case isl_ast_op_and_then:
+    case isl_ast_op_or_else:
+    case isl_ast_op_pdiv_q:
+    case isl_ast_op_pdiv_r:
+    case isl_ast_op_select:
+      gcc_unreachable ();
+
+    case isl_ast_op_max:
+    case isl_ast_op_min:
+      return nary_op_to_tree (type, expr, ip);
+
+    case isl_ast_op_add:
+    case isl_ast_op_sub:
+    case isl_ast_op_mul:
+    case isl_ast_op_div:
+    case isl_ast_op_fdiv_q:
+    case isl_ast_op_and:
+    case isl_ast_op_or:
+    case isl_ast_op_eq:
+    case isl_ast_op_le:
+    case isl_ast_op_lt:
+    case isl_ast_op_ge:
+    case isl_ast_op_gt:
+      return binary_op_to_tree (type, expr, ip);
+
+    case isl_ast_op_minus:
+      return unary_op_to_tree (type, expr, ip);
+
+    case isl_ast_op_cond:
+      return ternary_op_to_tree (type, expr, ip);
+
+    default:
+      gcc_unreachable ();
+    }
+
+  return NULL_TREE;
+}
+
+/* Converts an ISL AST expression E back to a GCC expression tree of
+   type TYPE.  */
+
+static tree
+gcc_expression_from_isl_expression (tree type, __isl_take isl_ast_expr *expr,
+				    ivs_params_p ip)
+{
+  switch (isl_ast_expr_get_type (expr))
+    {
+    case isl_ast_expr_id:
+      return gcc_expression_from_isl_ast_expr_id (expr, ip);
+
+    case isl_ast_expr_int:
+      return gcc_expression_from_isl_expr_int (type, expr);
+
+    case isl_ast_expr_op:
+      return gcc_expression_from_isl_expr_op (type, expr, ip);
+
+    default:
+      gcc_unreachable ();
+    }
+
+  return NULL_TREE;
+}
+
+/* Creates a new LOOP corresponding to isl_ast_node_for.  Inserts an
+   induction variable for the new LOOP.  New LOOP is attached to CFG
+   starting at ENTRY_EDGE.  LOOP is inserted into the loop tree and
+   becomes the child loop of the OUTER_LOOP.  NEWIVS_INDEX binds
+   ISL's scattering name to the induction variable created for the
+   loop of STMT.  The new induction variable is inserted in the NEWIVS
+   vector and is of type TYPE.  */
+
+static struct loop *
+graphite_create_new_loop (edge entry_edge, __isl_keep isl_ast_node *node_for,
+			  loop_p outer, tree type, tree lb, tree ub,
+			  ivs_params_p ip)
+{
+  isl_ast_expr *for_inc = isl_ast_node_for_get_inc (node_for);
+  tree stride = gcc_expression_from_isl_expression (type, for_inc, ip);
+  tree ivvar = create_tmp_var (type, "graphite_IV");
+  tree iv, iv_after_increment;
+  loop_p loop = create_empty_loop_on_edge
+    (entry_edge, lb, stride, ub, ivvar, &iv, &iv_after_increment,
+     outer ? outer : entry_edge->src->loop_father);
+
+  isl_ast_expr *for_iterator = isl_ast_node_for_get_iterator (node_for);
+  isl_id *id = isl_ast_expr_get_id (for_iterator);
+  ip->tree_from_isl_id[id] = iv;
+  isl_ast_expr_free (for_iterator);
+  return loop;
+}
+
+static edge
+translate_isl_ast (loop_p context_loop, __isl_keep isl_ast_node *node,
+		   edge next_e, ivs_params_p ip);
+
+/* Create the loop for a isl_ast_node_for.
+
+   - NEXT_E is the edge where new generated code should be attached.  */
+
+static edge
+translate_isl_ast_for_loop (loop_p context_loop,
+			    __isl_keep isl_ast_node *node_for, edge next_e,
+			    tree type, tree lb, tree ub,
+			    ivs_params_p ip)
+{
+  gcc_assert (isl_ast_node_get_type (node_for) == isl_ast_node_for);
+  struct loop *loop = graphite_create_new_loop (next_e, node_for, context_loop,
+						type, lb, ub, ip);
+  edge last_e = single_exit (loop);
+  edge to_body = single_succ_edge (loop->header);
+  basic_block after = to_body->dest;
+
+  /* Create a basic block for loop close phi nodes.  */
+  last_e = single_succ_edge (split_edge (last_e));
+
+  /* Translate the body of the loop.  */
+  isl_ast_node *for_body = isl_ast_node_for_get_body (node_for);
+  next_e = translate_isl_ast (loop, for_body, to_body, ip);
+  isl_ast_node_free (for_body);
+  redirect_edge_succ_nodup (next_e, after);
+  set_immediate_dominator (CDI_DOMINATORS, next_e->dest, next_e->src);
+
+  /* TODO: Add checking for the loop parallelism.  */
+
+  return last_e;
+}
+
+/* We use this function to get the upper bound because of the form,
+   which is used by isl to represent loops:
+
+   for (iterator = init; cond; iterator += inc)
+
+   {
+
+     ...
+
+   }
+
+   The loop condition is an arbitrary expression, which contains the
+   current loop iterator.
+
+   (e.g. iterator + 3 < B && C > iterator + A)
+
+   We have to know the upper bound of the iterator to generate a loop
+   in Gimple form. It can be obtained from the special representation
+   of the loop condition, which is generated by isl,
+   if the ast_build_atomic_upper_bound option is set. In this case,
+   isl generates a loop condition that consists of the current loop
+   iterator, + an operator (< or <=) and an expression not involving
+   the iterator, which is processed and returned by this function.
+
+   (e.g iterator <= upper-bound-expression-without-iterator)  */
+
+static __isl_give isl_ast_expr *
+get_upper_bound (__isl_keep isl_ast_node *node_for)
+{
+  gcc_assert (isl_ast_node_get_type (node_for) == isl_ast_node_for);
+  isl_ast_expr *for_cond = isl_ast_node_for_get_cond (node_for);
+  gcc_assert (isl_ast_expr_get_type (for_cond) == isl_ast_expr_op);
+  isl_ast_expr *res;
+  switch (isl_ast_expr_get_op_type (for_cond))
+    {
+    case isl_ast_op_le:
+      res = isl_ast_expr_get_op_arg (for_cond, 1);
+      break;
+
+    case isl_ast_op_lt:
+      {
+        // (iterator < ub) => (iterator <= ub - 1)
+        isl_val *one = isl_val_int_from_si (isl_ast_expr_get_ctx (for_cond), 1);
+        isl_ast_expr *ub = isl_ast_expr_get_op_arg (for_cond, 1);
+        res = isl_ast_expr_sub (ub, isl_ast_expr_from_val (one));
+        break;
+      }
+
+    default:
+      gcc_unreachable ();
+    }
+  isl_ast_expr_free (for_cond);
+  return res;
+}
+
+/* All loops generated by create_empty_loop_on_edge have the form of
+   a post-test loop:
+
+   do
+
+   {
+     body of the loop;
+   } while (lower bound < upper bound);
+
+   We create a new if region protecting the loop to be executed, if
+   the execution count is zero (lower bound > upper bound).  */
+
+static edge
+graphite_create_new_loop_guard (edge entry_edge,
+				__isl_keep isl_ast_node *node_for, tree *type,
+				tree *lb, tree *ub, ivs_params_p ip)
+{
+  gcc_assert (isl_ast_node_get_type (node_for) == isl_ast_node_for);
+  tree cond_expr;
+  edge exit_edge;
+
+  *type = *graphite_expression_size_type;
+  isl_ast_expr *for_init = isl_ast_node_for_get_init (node_for);
+  *lb = gcc_expression_from_isl_expression (*type, for_init, ip);
+  isl_ast_expr *upper_bound = get_upper_bound (node_for);
+  *ub = gcc_expression_from_isl_expression (*type, upper_bound, ip);
+  
+  /* When ub is simply a constant or a parameter, use lb <= ub.  */
+  if (TREE_CODE (*ub) == INTEGER_CST || TREE_CODE (*ub) == SSA_NAME)
+    cond_expr = fold_build2 (LE_EXPR, boolean_type_node, *lb, *ub);
+  else
+    {
+      tree one = (POINTER_TYPE_P (*type)
+		  ? convert_to_ptrofftype (integer_one_node)
+		  : fold_convert (*type, integer_one_node));
+      /* Adding +1 and using LT_EXPR helps with loop latches that have a
+	 loop iteration count of "PARAMETER - 1".  For PARAMETER == 0 this
+	 becomes 2^k-1 due to integer overflow, and the condition lb <= ub
+	 is true, even if we do not want this.  However lb < ub + 1 is false,
+	 as expected.  */
+      tree ub_one = fold_build2 (POINTER_TYPE_P (*type) ? POINTER_PLUS_EXPR
+				 : PLUS_EXPR, *type, *ub, one);
+
+      cond_expr = fold_build2 (LT_EXPR, boolean_type_node, *lb, ub_one);
+    }
+
+  exit_edge = create_empty_if_region_on_edge (entry_edge, cond_expr);
+
+  return exit_edge;
+}
+
+/* Translates an isl_ast_node_for to Gimple. */
+
+static edge
+translate_isl_ast_node_for (loop_p context_loop, __isl_keep isl_ast_node *node,
+			    edge next_e, ivs_params_p ip)
+{
+  gcc_assert (isl_ast_node_get_type (node) == isl_ast_node_for);
+  tree type, lb, ub;
+  edge last_e = graphite_create_new_loop_guard (next_e, node, &type,
+						&lb, &ub, ip);
+  edge true_e = get_true_edge_from_guard_bb (next_e->dest);
+
+  translate_isl_ast_for_loop (context_loop, node, true_e,
+			      type, lb, ub, ip);
+  return last_e;
+}
+
+/* Translates an ISL AST node NODE to GCC representation in the
+   context of a SESE.  */
+
+static edge
+translate_isl_ast (loop_p context_loop, __isl_keep isl_ast_node *node,
+		   edge next_e, ivs_params_p ip)
+{
+  switch (isl_ast_node_get_type (node))
+    {
+    case isl_ast_node_error:
+      gcc_unreachable ();
+
+    case isl_ast_node_for:
+      return translate_isl_ast_node_for (context_loop, node,
+					 next_e, ip);
+
+    case isl_ast_node_if:
+      return next_e;
+
+    case isl_ast_node_user:
+      return next_e;
+
+    case isl_ast_node_block:
+      return next_e;
+
+    default:
+      gcc_unreachable ();
+    }
+}
+
 /* Prints NODE to FILE.  */
 
 void
@@ -65,6 +586,23 @@ 
   isl_printer_free (prn);
 }
 
+/* Add ISL's parameter identifiers and corresponding.trees to ivs_params  */
+
+static void
+add_parameters_to_ivs_params (scop_p scop, ivs_params_p ip)
+{
+  sese region = SCOP_REGION (scop);
+  unsigned nb_parameters = isl_set_dim (scop->context, isl_dim_param);
+  gcc_assert (nb_parameters == SESE_PARAMS (region).length ());
+  unsigned i;
+  for (i = 0; i < nb_parameters; i++)
+    {
+      isl_id *tmp_id = isl_set_get_dim_id (scop->context, isl_dim_param, i);
+      ip->tree_from_isl_id[tmp_id] = SESE_PARAMS (region)[i];
+    }
+}
+
+
 /* Generates a build, which specifies the constraints on the parameters.  */
 
 static __isl_give isl_ast_build *
@@ -103,8 +641,15 @@ 
 }
 
 static __isl_give isl_ast_node *
-scop_to_isl_ast (scop_p scop)
+scop_to_isl_ast (scop_p scop, ivs_params_p ip)
 {
+  /* Generate loop upper bounds that consist of the current loop iterator,
+  an operator (< or <=) and an expression not involving the iterator.
+  If this option is not set, then the current loop iterator may appear several
+  times in the upper bound. See the isl manual for more details.  */
+  isl_options_set_ast_build_atomic_upper_bound (scop->ctx, true);
+
+  add_parameters_to_ivs_params (scop, ip);
   isl_union_map *schedule_isl = generate_isl_schedule (scop);
   isl_ast_build *context_isl = generate_isl_context (scop);
   isl_ast_node *ast_isl = isl_ast_build_ast_from_schedule (context_isl,
@@ -117,21 +662,59 @@ 
    the given SCOP.  Return true if code generation succeeded.
 
    FIXME: This is not yet a full implementation of the code generator
-          with ISL ASTs. Generation of GIMPLE code is have to be added.  */
+          with ISL ASTs. Generation of GIMPLE code has to be completed.  */
 
 bool
 graphite_regenerate_ast_isl (scop_p scop)
 {
+  loop_p context_loop;
+  sese region = SCOP_REGION (scop);
+  ifsese if_region = NULL;
+  isl_ast_node *root_node;
+  struct ivs_params ip;
+
   timevar_push (TV_GRAPHITE_CODE_GEN);
   graphite_regenerate_error = false;
-  isl_ast_node *root_node = scop_to_isl_ast (scop);
+  root_node = scop_to_isl_ast (scop, &ip);
+
   if (dump_file && (dump_flags & TDF_DETAILS))
     {
       fprintf (dump_file, "\nISL AST generated by ISL: \n");
       print_isl_ast_node (dump_file, root_node, scop->ctx);
+      fprintf (dump_file, "\n");
     }
+
+  recompute_all_dominators ();
+  graphite_verify ();
+
+  if_region = move_sese_in_condition (region);
+  sese_insert_phis_for_liveouts (region,
+				 if_region->region->exit->src,
+				 if_region->false_region->exit,
+				 if_region->true_region->exit);
+  recompute_all_dominators ();
+  graphite_verify ();
+
+  context_loop = SESE_ENTRY (region)->src->loop_father;
+
+  translate_isl_ast (context_loop, root_node, if_region->true_region->entry,
+		     &ip);
+  graphite_verify ();
+  scev_reset ();
+  recompute_all_dominators ();
+  graphite_verify ();
+
+  if (graphite_regenerate_error)
+    set_ifsese_condition (if_region, integer_zero_node);
+
+  free (if_region->true_region);
+  free (if_region->region);
+  free (if_region);
+
+  ivs_params_clear (&ip);
   isl_ast_node_free (root_node);
   timevar_pop (TV_GRAPHITE_CODE_GEN);
+  /* TODO: Add dump  */
   return !graphite_regenerate_error;
 }
 #endif