* gcc.c (getenv_spec_function): New function.

[pf3gnuchains/gcc-fork.git] / gcc / tree-loop-linear.c

diff --git a/gcc/tree-loop-linear.c b/gcc/tree-loop-linear.c
index a47981c..61fdee3 100644 (file)
--- a/gcc/tree-loop-linear.c
+++ b/gcc/tree-loop-linear.c
@@ -178,6 +178,9 @@ try_interchange_loops (lambda_trans_matrix trans,
   unsigned int nb_deps_not_carried_by_i, nb_deps_not_carried_by_j;
   struct data_dependence_relation *ddr;
 
+  if (VEC_length (ddr_p, dependence_relations) == 0)
+    return trans;
+
   /* When there is an unknown relation in the dependence_relations, we
      know that it is no worth looking at this loop nest: give up.  */
   ddr = VEC_index (ddr_p, dependence_relations, 0);
@@ -233,26 +236,26 @@ try_interchange_loops (lambda_trans_matrix trans,
   return trans;
 }
 
-/* Perform a set of linear transforms on LOOPS.  */
+/* Perform a set of linear transforms on loops.  */
 
 void
-linear_transform_loops (struct loops *loops)
+linear_transform_loops (void)
 {
-  unsigned int i;
+  bool modified = false;
+  loop_iterator li;
   VEC(tree,heap) *oldivs = NULL;
   VEC(tree,heap) *invariants = NULL;
+  struct loop *loop_nest;
   
-  for (i = 1; i < loops->num; i++)
+  FOR_EACH_LOOP (li, loop_nest, 0)
     {
       unsigned int depth = 0;
       VEC (ddr_p, heap) *dependence_relations;
       VEC (data_reference_p, heap) *datarefs;
-      struct loop *loop_nest = loops->parray[i];
       struct loop *temp;
       lambda_loopnest before, after;
       lambda_trans_matrix trans;
       bool problem = false;
-      bool need_perfect_nest = false;
       /* If it's not a loop nest, we don't want it.
          We also don't handle sibling loops properly, 
          which are loops of the following form:
@@ -262,12 +265,12 @@ linear_transform_loops (struct loops *loops)
                {
                ...
                }
-           for (j = 0; j < 50; j++)
+             for (j = 0; j < 50; j++)
                {
                 ...
                }
            } */
-      if (!loop_nest || !loop_nest->inner)
+      if (!loop_nest->inner || !single_exit (loop_nest))
        continue;
       VEC_truncate (tree, oldivs, 0);
       VEC_truncate (tree, invariants, 0);
@@ -275,7 +278,7 @@ linear_transform_loops (struct loops *loops)
       for (temp = loop_nest->inner; temp; temp = temp->inner)
        {
          /* If we have a sibling loop or multiple exit edges, jump ship.  */
-         if (temp->next || !temp->single_exit)
+         if (temp->next || !single_exit (temp))
            {
              problem = true;
              break;
@@ -289,8 +292,8 @@ linear_transform_loops (struct loops *loops)
  
       datarefs = VEC_alloc (data_reference_p, heap, 10);
       dependence_relations = VEC_alloc (ddr_p, heap, 10 * 10);
-      compute_data_dependences_for_loop (loop_nest, true, datarefs,
-                                        dependence_relations);
+      compute_data_dependences_for_loop (loop_nest, true, &datarefs,
+                                        &dependence_relations);
 
       if (dump_file && (dump_flags & TDF_DETAILS))
        dump_ddrs (dump_file, dependence_relations);
@@ -305,7 +308,7 @@ linear_transform_loops (struct loops *loops)
        {
          if (dump_file)
           fprintf (dump_file, "Won't transform loop. Optimal transform is the identity transform\n");
-         continue;
+         goto free_and_continue;
        }
 
       /* Check whether the transformation is legal.  */
@@ -313,19 +316,15 @@ linear_transform_loops (struct loops *loops)
        {
          if (dump_file)
            fprintf (dump_file, "Can't transform loop, transform is illegal:\n");
-         continue;
+         goto free_and_continue;
        }
 
-      if (!perfect_nest_p (loop_nest))
-       need_perfect_nest = true;
+      before = gcc_loopnest_to_lambda_loopnest (loop_nest, &oldivs,
+                                               &invariants);
 
-      before = gcc_loopnest_to_lambda_loopnest (loops,
-                                               loop_nest, &oldivs, 
-                                               &invariants,
-                                               need_perfect_nest);
       if (!before)
-       continue;
-            
+       goto free_and_continue;
+
       if (dump_file)
        {
          fprintf (dump_file, "Before:\n");
@@ -342,10 +341,12 @@ linear_transform_loops (struct loops *loops)
 
       lambda_loopnest_to_gcc_loopnest (loop_nest, oldivs, invariants,
                                       after, trans);
+      modified = true;
 
       if (dump_file)
        fprintf (dump_file, "Successfully transformed loop.\n");
 
+    free_and_continue:
       free_dependence_relations (dependence_relations);
       free_data_refs (datarefs);
     }
@@ -353,5 +354,7 @@ linear_transform_loops (struct loops *loops)
   VEC_free (tree, heap, oldivs);
   VEC_free (tree, heap, invariants);
   scev_reset ();
-  rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa_full_phi);
+
+  if (modified)
+    rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa_full_phi);
 }