Patchwork [3/3] Fix PR47654: Compute LB and UB of a CLAST expression.

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Submitter Sebastian Pop
Date July 7, 2011, 6:07 p.m.
Message ID <1310062037-16618-4-git-send-email-sebpop@gmail.com>
Download mbox | patch
Permalink /patch/103715/
State New
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Sebastian Pop - July 7, 2011, 6:07 p.m.
2011-07-05  Sebastian Pop  <sebastian.pop@amd.com>

	PR tree-optimization/47654
	PR middle-end/49649
	* graphite-clast-to-gimple.c (struct clast_name_index): Add
	a level field.
	(new_clast_name_index): Add the level parameter.
	(clast_name_to_level): New.
	(save_clast_name_index): Add the level parameter.
	(save_clast_name_index): Adjust call to new_clast_name_index.
	(newivs_to_depth_to_newiv): Removed.
	(clast_name_to_gcc): Inline code of newivs_to_depth_to_newiv.
	(compute_bounds_for_level): Moved down.
	(compute_type_for_level): Renamed gcc_type_for_clast_expr_from_lb_ub.
	(clast_get_body_of_loop): Renamed clast_get_body_of.
	(gcc_type_for_iv_of_clast_loop): Removed.
	(graphite_create_new_loop): Add the level parameter.  Adjust call
	to save_clast_name_index.
	(compute_bounds_for_param): New.
	(lb_ub_for_name): New.
	(lb_ub_for_term): New.
	(lb_ub_for_red): New.
	(lb_ub_for_bin): New.
	(lb_ub_for_expr): New.
	(graphite_create_new_loop_guard): Do not pass in the level in
	parameter.  Compute type as the max_precision_type of lb_type and
	ub_type.  Call gcc_type_for_clast_expr_from_lb_ub.
	(translate_clast_for_loop): Adjust call to graphite_create_new_loop.
	(translate_clast_for): Adjust call to graphite_create_new_loop_guard.
	(create_params_index): Adjust call to save_clast_name_index.
	* graphite-ppl.h (value_min): New.

	* gcc.dg/graphite/run-id-pr47654.c
---
 gcc/ChangeLog                                  |   32 ++
 gcc/graphite-clast-to-gimple.c                 |  432 +++++++++++++++++-------
 gcc/graphite-ppl.h                             |   11 +
 gcc/testsuite/ChangeLog                        |    5 +
 gcc/testsuite/gcc.dg/graphite/run-id-pr47654.c |   24 ++
 5 files changed, 388 insertions(+), 116 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/graphite/run-id-pr47654.c

Patch

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 77cf1f6..b86c059 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,37 @@ 
 2011-07-05  Sebastian Pop  <sebastian.pop@amd.com>
 
+	PR tree-optimization/47654
+	PR middle-end/49649
+	* graphite-clast-to-gimple.c (struct clast_name_index): Add
+	a level field.
+	(new_clast_name_index): Add the level parameter.
+	(clast_name_to_level): New.
+	(save_clast_name_index): Add the level parameter.
+	(save_clast_name_index): Adjust call to new_clast_name_index.
+	(newivs_to_depth_to_newiv): Removed.
+	(clast_name_to_gcc): Inline code of newivs_to_depth_to_newiv.
+	(compute_bounds_for_level): Moved down.
+	(compute_type_for_level): Renamed gcc_type_for_clast_expr_from_lb_ub.
+	(clast_get_body_of_loop): Renamed clast_get_body_of.
+	(gcc_type_for_iv_of_clast_loop): Removed.
+	(graphite_create_new_loop): Add the level parameter.  Adjust call
+	to save_clast_name_index.
+	(compute_bounds_for_param): New.
+	(lb_ub_for_name): New.
+	(lb_ub_for_term): New.
+	(lb_ub_for_red): New.
+	(lb_ub_for_bin): New.
+	(lb_ub_for_expr): New.
+	(graphite_create_new_loop_guard): Do not pass in the level in
+	parameter.  Compute type as the max_precision_type of lb_type and
+	ub_type.  Call gcc_type_for_clast_expr_from_lb_ub.
+	(translate_clast_for_loop): Adjust call to graphite_create_new_loop.
+	(translate_clast_for): Adjust call to graphite_create_new_loop_guard.
+	(create_params_index): Adjust call to save_clast_name_index.
+	* graphite-ppl.h (value_min): New.
+
+2011-07-05  Sebastian Pop  <sebastian.pop@amd.com>
+
 	* graphite-clast-to-gimple.c (graphite_create_new_loop): Do not
 	recompute type, lb, and ub.  Get them from...
 	(graphite_create_new_loop_guard): ...here.  Pass in parameter
diff --git a/gcc/graphite-clast-to-gimple.c b/gcc/graphite-clast-to-gimple.c
index a8ac9c6..9f66edb 100644
--- a/gcc/graphite-clast-to-gimple.c
+++ b/gcc/graphite-clast-to-gimple.c
@@ -56,26 +56,55 @@  graphite_verify (void)
 #endif
 }
 
-/* Stores the INDEX in a vector for a given clast NAME.  */
+/* Stores the INDEX in a vector and the loop nesting LEVEL for a given
+   clast NAME.  */
 
 typedef struct clast_name_index {
   int index;
+  int level;
   const char *name;
 } *clast_name_index_p;
 
 /* Returns a pointer to a new element of type clast_name_index_p built
-   from NAME and INDEX.  */
+   from NAME, LEVEL, and INDEX.  */
 
 static inline clast_name_index_p
-new_clast_name_index (const char *name, int index)
+new_clast_name_index (const char *name, int index, int level)
 {
   clast_name_index_p res = XNEW (struct clast_name_index);
 
   res->name = name;
+  res->level = level;
   res->index = index;
   return res;
 }
 
+/* For a given clast NAME, returns -1 if NAME is not in the
+   INDEX_TABLE, otherwise returns the loop level for the induction
+   variable NAME, or if it is a parameter, the parameter number in the
+   vector of parameters.  */
+
+static inline int
+clast_name_to_level (clast_name_p name, htab_t index_table)
+{
+  struct clast_name_index tmp;
+  PTR *slot;
+
+#ifdef CLOOG_ORG
+  gcc_assert (name->type == clast_expr_name);
+  tmp.name = ((const struct clast_name *) name)->name;
+#else
+  tmp.name = name;
+#endif
+
+  slot = htab_find_slot (index_table, &tmp, NO_INSERT);
+
+  if (slot && *slot)
+    return ((struct clast_name_index *) *slot)->level;
+
+  return -1;
+}
+
 /* For a given clast NAME, returns -1 if it does not correspond to any
    parameter, or otherwise, returns the index in the PARAMS or
    SCATTERING_DIMENSIONS vector.  */
@@ -101,10 +130,11 @@  clast_name_to_index (clast_name_p name, htab_t index_table)
   return -1;
 }
 
-/* Records in INDEX_TABLE the INDEX for NAME.  */
+/* Records in INDEX_TABLE the INDEX and LEVEL for NAME.  */
 
 static inline void
-save_clast_name_index (htab_t index_table, const char *name, int index)
+save_clast_name_index (htab_t index_table, const char *name,
+		       int index, int level)
 {
   struct clast_name_index tmp;
   PTR *slot;
@@ -116,7 +146,7 @@  save_clast_name_index (htab_t index_table, const char *name, int index)
     {
       free (*slot);
 
-      *slot = new_clast_name_index (name, index);
+      *slot = new_clast_name_index (name, index, level);
     }
 }
 
@@ -139,15 +169,6 @@  eq_clast_name_indexes (const void *e1, const void *e2)
   return (elt1->name == elt2->name);
 }
 
-/* For a given scattering dimension, return the new induction variable
-   associated to it.  */
-
-static inline tree
-newivs_to_depth_to_newiv (VEC (tree, heap) *newivs, int depth)
-{
-  return VEC_index (tree, newivs, depth);
-}
-
 
 
 /* Returns the tree variable from the name NAME that was given in
@@ -172,7 +193,7 @@  clast_name_to_gcc (clast_name_p name, sese region, VEC (tree, heap) *newivs,
   index = clast_name_to_index (name, newivs_index);
   gcc_assert (index >= 0);
 
-  return newivs_to_depth_to_newiv (newivs, index);
+  return VEC_index (tree, newivs, index);
 }
 
 /* Returns the signed maximal precision type for expressions TYPE1 and TYPE2.  */
@@ -602,94 +623,6 @@  graphite_create_new_guard (sese region, edge entry_edge,
   return exit_edge;
 }
 
-/* Compute the lower bound LOW and upper bound UP for the induction
-   variable at LEVEL for the statement PBB, based on the transformed
-   scattering of PBB: T|I|G|Cst, with T the scattering transform, I
-   the iteration domain, and G the context parameters.  */
-
-static void
-compute_bounds_for_level (poly_bb_p pbb, int level, mpz_t low, mpz_t up)
-{
-  ppl_Pointset_Powerset_C_Polyhedron_t ps;
-  ppl_Linear_Expression_t le;
-
-  combine_context_id_scat (&ps, pbb, false);
-
-  /* Prepare the linear expression corresponding to the level that we
-     want to maximize/minimize.  */
-  {
-    ppl_dimension_type dim = pbb_nb_scattering_transform (pbb)
-      + pbb_dim_iter_domain (pbb) + pbb_nb_params (pbb);
-
-    ppl_new_Linear_Expression_with_dimension (&le, dim);
-    ppl_set_coef (le, psct_dynamic_dim (pbb, level), 1);
-  }
-
-  ppl_max_for_le_pointset (ps, le, up);
-  ppl_min_for_le_pointset (ps, le, low);
-  ppl_delete_Linear_Expression (le);
-  ppl_delete_Pointset_Powerset_C_Polyhedron (ps);
-}
-
-/* Compute the type for the induction variable at LEVEL for the
-   statement PBB, based on the transformed schedule of PBB.  */
-
-static tree
-compute_type_for_level (poly_bb_p pbb, int level)
-{
-  mpz_t low, up;
-  tree type;
-
-  mpz_init (low);
-  mpz_init (up);
-
-  compute_bounds_for_level (pbb, level, low, up);
-  type = gcc_type_for_interval (low, up);
-
-  mpz_clear (low);
-  mpz_clear (up);
-  return type;
-}
-
-/* Walks a CLAST and returns the first statement in the body of a
-   loop.  */
-
-static struct clast_user_stmt *
-clast_get_body_of_loop (struct clast_stmt *stmt)
-{
-  if (!stmt
-      || CLAST_STMT_IS_A (stmt, stmt_user))
-    return (struct clast_user_stmt *) stmt;
-
-  if (CLAST_STMT_IS_A (stmt, stmt_for))
-    return clast_get_body_of_loop (((struct clast_for *) stmt)->body);
-
-  if (CLAST_STMT_IS_A (stmt, stmt_guard))
-    return clast_get_body_of_loop (((struct clast_guard *) stmt)->then);
-
-  if (CLAST_STMT_IS_A (stmt, stmt_block))
-    return clast_get_body_of_loop (((struct clast_block *) stmt)->body);
-
-  gcc_unreachable ();
-}
-
-/* Returns the type for the induction variable for the loop translated
-   from STMT_FOR.  */
-
-static tree
-gcc_type_for_iv_of_clast_loop (struct clast_for *stmt_for, int level,
-			       tree lb_type, tree ub_type)
-{
-  struct clast_stmt *stmt = (struct clast_stmt *) stmt_for;
-  struct clast_user_stmt *body = clast_get_body_of_loop (stmt);
-  CloogStatement *cs = body->statement;
-  poly_bb_p pbb = (poly_bb_p) cloog_statement_usr (cs);
-
-  return max_signed_precision_type (lb_type, max_precision_type
-				    (ub_type, compute_type_for_level
-				     (pbb, level)));
-}
-
 /* Creates a new LOOP corresponding to Cloog's STMT.  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
@@ -703,7 +636,7 @@  graphite_create_new_loop (edge entry_edge,
 			  struct clast_for *stmt,
 			  loop_p outer, VEC (tree, heap) **newivs,
 			  htab_t newivs_index,
-			  tree type, tree lb, tree ub)
+			  tree type, tree lb, tree ub, int level)
 {
   tree stride = gmp_cst_to_tree (type, stmt->stride);
   tree ivvar = create_tmp_var (type, "graphite_IV");
@@ -715,7 +648,7 @@  graphite_create_new_loop (edge entry_edge,
   add_referenced_var (ivvar);
 
   save_clast_name_index (newivs_index, stmt->iterator,
-			 VEC_length (tree, *newivs));
+			 VEC_length (tree, *newivs), level);
   VEC_safe_push (tree, heap, *newivs, iv);
   return loop;
 }
@@ -872,6 +805,270 @@  translate_clast_user (sese region, struct clast_user_stmt *stmt, edge next_e,
   return next_e;
 }
 
+
+/* Compute the lower bound LOW and upper bound UP for the parameter
+   PARAM for the statement PBB, based on the transformed scattering of
+   PBB: T|I|G|Cst, with T the scattering transform, I the iteration
+   domain, and G the context parameters.  */
+
+static void
+compute_bounds_for_param (poly_bb_p pbb, int param, mpz_t low, mpz_t up)
+{
+  ppl_Pointset_Powerset_C_Polyhedron_t ps;
+  ppl_Linear_Expression_t le;
+
+  combine_context_id_scat (&ps, pbb, false);
+
+  /* Prepare the linear expression corresponding to the parameter that
+     we want to maximize/minimize.  */
+  {
+    ppl_dimension_type dim = pbb_nb_scattering_transform (pbb)
+      + pbb_dim_iter_domain (pbb) + pbb_nb_params (pbb);
+
+    ppl_new_Linear_Expression_with_dimension (&le, dim);
+    ppl_set_coef (le, psct_parameter_dim (pbb, param), 1);
+  }
+
+  ppl_max_for_le_pointset (ps, le, up);
+  ppl_min_for_le_pointset (ps, le, low);
+  ppl_delete_Linear_Expression (le);
+  ppl_delete_Pointset_Powerset_C_Polyhedron (ps);
+}
+
+/* Compute the lower bound LOW and upper bound UP for the induction
+   variable at LEVEL for the statement PBB, based on the transformed
+   scattering of PBB: T|I|G|Cst, with T the scattering transform, I
+   the iteration domain, and G the context parameters.  */
+
+static void
+compute_bounds_for_level (poly_bb_p pbb, int level, mpz_t low, mpz_t up)
+{
+  ppl_Pointset_Powerset_C_Polyhedron_t ps;
+  ppl_Linear_Expression_t le;
+
+  combine_context_id_scat (&ps, pbb, false);
+
+  /* Prepare the linear expression corresponding to the level that we
+     want to maximize/minimize.  */
+  {
+    ppl_dimension_type dim = pbb_nb_scattering_transform (pbb)
+      + pbb_dim_iter_domain (pbb) + pbb_nb_params (pbb);
+
+    ppl_new_Linear_Expression_with_dimension (&le, dim);
+    ppl_set_coef (le, psct_dynamic_dim (pbb, level), 1);
+  }
+
+  ppl_max_for_le_pointset (ps, le, up);
+  ppl_min_for_le_pointset (ps, le, low);
+  ppl_delete_Linear_Expression (le);
+  ppl_delete_Pointset_Powerset_C_Polyhedron (ps);
+}
+
+/* Return the lower bound LB and upper bound UB of the clast_name NAME.  */
+
+static void
+lb_ub_for_name (clast_name_p name, htab_t newivs_index, htab_t params_index,
+		mpz_t lb, mpz_t ub, poly_bb_p pbb)
+{
+  int level;
+
+  if (params_index)
+    {
+      int param = clast_name_to_level (name, params_index);
+
+      if (param >= 0)
+	{
+	  compute_bounds_for_param (pbb, param, lb, ub);
+	  return;
+	}
+    }
+
+  gcc_assert (newivs_index);
+  level = clast_name_to_level (name, newivs_index);
+  gcc_assert (level >= 0);
+  compute_bounds_for_level (pbb, level, lb, ub);
+}
+
+/* Return the lower bound LB and upper bound UB of the clast_term T.  */
+
+static void
+lb_ub_for_term (struct clast_term *t, htab_t newivs_index, htab_t params_index,
+		mpz_t lb, mpz_t ub, poly_bb_p pbb)
+{
+  gcc_assert (t->expr.type == clast_expr_term);
+
+  if (t->var)
+    {
+      mpz_t v;
+      lb_ub_for_name ((clast_name_p) (t->var),
+		      newivs_index, params_index, lb, ub, pbb);
+      mpz_init (v);
+      mpz_abs (v, t->val);
+      mpz_mul (lb, lb, v);
+      mpz_mul (ub, ub, v);
+      mpz_clear (v);
+    }
+  else
+    {
+      mpz_set (lb, t->val);
+      mpz_set (ub, t->val);
+    }
+}
+
+static void
+lb_ub_for_expr (struct clast_expr *, htab_t, htab_t, mpz_t, mpz_t, poly_bb_p);
+
+/* Return the lower bound LB and upper bound UB of the clast_reduction R.  */
+
+static void
+lb_ub_for_red (struct clast_reduction *r, htab_t newivs_index,
+	       htab_t params_index, mpz_t lb, mpz_t ub, poly_bb_p pbb)
+{
+  int i;
+  mpz_t l, u;
+
+  lb_ub_for_expr (r->elts[0], newivs_index, params_index, lb, ub, pbb);
+
+  if (r->n == 1)
+    return;
+
+  mpz_init (l);
+  mpz_init (u);
+
+  for (i = 1; i < r->n; i++)
+    {
+      lb_ub_for_expr (r->elts[i], newivs_index, params_index, l, u, pbb);
+
+      /* As the interval [LB, UB] is used to compute a type for the
+	 expression, it should include the bounds of each term of the
+	 reduction expression: so take the min of lower bounds and the
+	 max of upper bounds.  */
+      value_min (lb, lb, l);
+      value_max (ub, ub, u);
+
+      switch (r->type)
+	{
+	case clast_red_sum:
+	  /* The interval [LB, UB] should also include the result of
+	     the sum.  */
+	  mpz_add (l, lb, l);
+	  mpz_add (u, ub, u);
+	  value_min (lb, lb, l);
+	  value_max (ub, ub, u);
+	  break;
+
+	case clast_red_min:
+	case clast_red_max:
+	  break;
+
+	default:
+	  gcc_unreachable ();
+	}
+    }
+
+  mpz_clear (l);
+  mpz_clear (u);
+}
+
+/* Return the type for the clast_binary B used in STMT.  */
+
+static void
+lb_ub_for_bin (struct clast_binary *b, htab_t newivs_index,
+	       htab_t params_index, mpz_t lb, mpz_t ub, poly_bb_p pbb)
+{
+  lb_ub_for_expr ((struct clast_expr *) b->LHS, newivs_index, params_index,
+		  lb, ub, pbb);
+
+  switch (b->type)
+    {
+    case clast_bin_cdiv:
+    case clast_bin_fdiv:
+    case clast_bin_div:
+    case clast_bin_mod:
+      value_min (lb, lb, b->RHS);
+      value_max (ub, ub, b->RHS);
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+}
+
+/* Return the lower bound LB and upper bound UB of the clast_expr E.  */
+
+static void
+lb_ub_for_expr (struct clast_expr *e, htab_t newivs_index, htab_t params_index,
+		mpz_t lb, mpz_t ub, poly_bb_p pbb)
+{
+  switch (e->type)
+    {
+    case clast_expr_term:
+      lb_ub_for_term ((struct clast_term *) e,
+		      newivs_index, params_index, lb, ub, pbb);
+      break;
+
+    case clast_expr_red:
+      lb_ub_for_red ((struct clast_reduction *) e,
+		     newivs_index, params_index, lb, ub, pbb);
+      break;
+
+    case clast_expr_bin:
+      lb_ub_for_bin ((struct clast_binary *) e,
+		     newivs_index, params_index, lb, ub, pbb);
+      break;
+
+    case clast_expr_name:
+      lb_ub_for_name ((clast_name_p) e, 
+		      newivs_index, params_index, lb, ub, pbb);
+      break;
+
+    default:
+      gcc_unreachable ();
+    }
+}
+
+/* Returns the type for the CLAST expression E in REGION.  */
+
+static tree
+gcc_type_for_clast_expr_from_lb_ub (struct clast_expr *e, htab_t newivs_index,
+				    htab_t params_index, poly_bb_p pbb)
+{
+  mpz_t lb, ub;
+  tree type;
+
+  mpz_init (lb);
+  mpz_init (ub);
+
+  lb_ub_for_expr (e, newivs_index, params_index, lb, ub, pbb);
+  type = gcc_type_for_interval (lb, ub);
+
+  mpz_clear (lb);
+  mpz_clear (ub);
+  return type;
+}
+
+/* Walks a CLAST and returns the first statement in the body of a
+   loop.  */
+
+static struct clast_user_stmt *
+clast_get_body_of (struct clast_stmt *stmt)
+{
+  if (!stmt
+      || CLAST_STMT_IS_A (stmt, stmt_user))
+    return (struct clast_user_stmt *) stmt;
+
+  if (CLAST_STMT_IS_A (stmt, stmt_for))
+    return clast_get_body_of (((struct clast_for *) stmt)->body);
+
+  if (CLAST_STMT_IS_A (stmt, stmt_guard))
+    return clast_get_body_of (((struct clast_guard *) stmt)->then);
+
+  if (CLAST_STMT_IS_A (stmt, stmt_block))
+    return clast_get_body_of (((struct clast_block *) stmt)->body);
+
+  gcc_unreachable ();
+}
+
 /* Creates a new if region protecting the loop to be executed, if the execution
    count is zero (lb > ub).  */
 
@@ -880,16 +1077,19 @@  graphite_create_new_loop_guard (sese region, edge entry_edge,
 				struct clast_for *stmt,
 				VEC (tree, heap) *newivs,
 				htab_t newivs_index, htab_t params_index,
-				int level, tree *type, tree *lb, tree *ub)
+				tree *type, tree *lb, tree *ub)
 {
   tree cond_expr;
   edge exit_edge;
-  tree lb_type = gcc_type_for_clast_expr (stmt->LB, region, newivs,
-					  newivs_index, params_index);
-  tree ub_type = gcc_type_for_clast_expr (stmt->UB, region, newivs,
-					  newivs_index, params_index);
-
-  *type = gcc_type_for_iv_of_clast_loop (stmt, level, lb_type, ub_type);
+  struct clast_stmt *cstmt = (struct clast_stmt *) stmt;
+  struct clast_user_stmt *body = clast_get_body_of (cstmt);
+  CloogStatement *cs = body->statement;
+  poly_bb_p pbb = (poly_bb_p) cloog_statement_usr (cs);
+  tree lb_type = gcc_type_for_clast_expr_from_lb_ub (stmt->LB, newivs_index,
+						     params_index, pbb);
+  tree ub_type = gcc_type_for_clast_expr_from_lb_ub (stmt->UB, newivs_index,
+						     params_index, pbb);
+  *type = max_precision_type (lb_type, ub_type);
   *lb = clast_to_gcc_expression (*type, stmt->LB, region, newivs,
 				 newivs_index, params_index);
   *ub = clast_to_gcc_expression (*type, stmt->UB, region, newivs,
@@ -942,7 +1142,7 @@  translate_clast_for_loop (sese region, loop_p context_loop,
   struct loop *loop = graphite_create_new_loop (next_e, stmt,
  						context_loop, newivs,
 						newivs_index,
-						type, lb, ub);
+						type, lb, ub, level);
   edge last_e = single_exit (loop);
   edge to_body = single_succ_edge (loop->header);
   basic_block after = to_body->dest;
@@ -982,7 +1182,7 @@  translate_clast_for (sese region, loop_p context_loop, struct clast_for *stmt,
   tree type, lb, ub;
   edge last_e = graphite_create_new_loop_guard (region, next_e, stmt, *newivs,
 						newivs_index, params_index,
-						level, &type, &lb, &ub);
+						&type, &lb, &ub);
   edge true_e = get_true_edge_from_guard_bb (next_e->dest);
 
   translate_clast_for_loop (region, context_loop, stmt, true_e, newivs,
@@ -1423,7 +1623,7 @@  create_params_index (htab_t index_table, CloogProgram *prog) {
   int i;
 
   for (i = 0; i < nb_parameters; i++)
-    save_clast_name_index (index_table, parameters[i], i);
+    save_clast_name_index (index_table, parameters[i], i, i);
 }
 
 /* GIMPLE Loop Generator: generates loops from STMT in GIMPLE form for
diff --git a/gcc/graphite-ppl.h b/gcc/graphite-ppl.h
index 49bde61..5820e19 100644
--- a/gcc/graphite-ppl.h
+++ b/gcc/graphite-ppl.h
@@ -124,6 +124,17 @@  ppl_set_coef_tree (ppl_Linear_Expression_t e, ppl_dimension_type i, tree x)
   mpz_clear (v);
 }
 
+/* Sets RES to the min of V1 and V2.  */
+
+static inline void
+value_min (mpz_t res, mpz_t v1, mpz_t v2)
+{
+  if (mpz_cmp (v1, v2) < 0)
+    mpz_set (res, v1);
+  else
+    mpz_set (res, v2);
+}
+
 /* Sets RES to the max of V1 and V2.  */
 
 static inline void
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 282990f..8e08779 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@ 
 2011-07-05  Sebastian Pop  <sebastian.pop@amd.com>
 
 	PR tree-optimization/47654
+	* gcc.dg/graphite/run-id-pr47654.c
+
+2011-07-05  Sebastian Pop  <sebastian.pop@amd.com>
+
+	PR tree-optimization/47654
 	* gcc.dg/graphite/block-pr47654.c: New.
 
 2011-07-05  Jason Merrill  <jason@redhat.com>
diff --git a/gcc/testsuite/gcc.dg/graphite/run-id-pr47654.c b/gcc/testsuite/gcc.dg/graphite/run-id-pr47654.c
new file mode 100644
index 0000000..c257f58
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/graphite/run-id-pr47654.c
@@ -0,0 +1,24 @@ 
+/* { dg-options "-O -floop-block" } */
+
+int a[128][40];
+
+void __attribute__ ((noinline, noclone))
+foo (void)
+{
+  int i, j;
+  for (i = 0; i < 40; i++)
+    for (j = 0; j < 128; j++)
+      a[j][i] = 4;
+}
+
+int
+main ()
+{
+  int i, j;
+  foo ();
+  for (i = 0; i < 40; i++)
+    for (j = 0; j < 128; j++)
+      if (a[j][i] != 4)
+	__builtin_abort ();
+  return 0;
+}