28-01-2010 Razya Ladelsky <razya@il.ibm.com>

        * tree-parloops.c (transform_to_exit_first_loop): Update the basic 
        block list passed to gimple_duplicate_sese_tail.
        (parallelize_loops): Avoid parallelization when the function
        has_nonlocal_label.
        Avoid parallelization when the preheader is IRREDUCIBLE.
        Try to optimize when estimated_loop_iterations_int is unresolved.
        Add the loop's location to the dump file.
        * tree-cfg.c(add_phi_args_after_redirect): Remove.
        (gimple_duplicate_sese_tail): Remove the check for the latch.
        Redirect nexits to the exit block.
        Remove handling of the incoming edges to the latch.
        Redirect the backedge from the copied latch to the exit bb.

From-SVN: r156321

1 files changed, 24 insertions, 101 deletions

diff --git a/gcc/tree-cfg.c b/gcc/tree-cfg.c
index d927698..361b46e 100644
--- a/gcc/tree-cfg.c
+++ b/gcc/tree-cfg.c
@@ -4927,31 +4927,6 @@ gimple_duplicate_bb (basic_block bb)
   return new_bb;
 }
 
-/* Add phi arguments to the phi nodes in E_COPY->dest according to
-   the phi arguments coming from the equivalent edge at
-   the phi nodes of DEST.  */
-
-static void
-add_phi_args_after_redirect (edge e_copy, edge orig_e)
-{
-   gimple_stmt_iterator psi, psi_copy;
-   gimple phi, phi_copy;
-   tree def;
-
-    for (psi = gsi_start_phis (orig_e->dest),
-       psi_copy = gsi_start_phis (e_copy->dest);
-       !gsi_end_p (psi);
-       gsi_next (&psi), gsi_next (&psi_copy))
-    {
-
-      phi = gsi_stmt (psi);
-      phi_copy = gsi_stmt (psi_copy);
-      def = PHI_ARG_DEF_FROM_EDGE (phi, orig_e);
-      add_phi_arg (phi_copy, def, e_copy,
-                   gimple_phi_arg_location_from_edge (phi, orig_e));
-    }
-}
-
 /* Adds phi node arguments for edge E_COPY after basic block duplication.  */
 
 static void
@@ -5235,12 +5210,13 @@ gimple_duplicate_sese_tail (edge entry ATTRIBUTE_UNUSED, edge exit ATTRIBUTE_UNU
   edge exits[2], nexits[2], e;
   gimple_stmt_iterator gsi,gsi1;
   gimple cond_stmt;
-  edge sorig, snew, orig_e;
+  edge sorig, snew;
   basic_block exit_bb;
-  edge_iterator ei;
-  VEC (edge, heap) *redirect_edges;
-  basic_block iters_bb, orig_src;
+  basic_block iters_bb;
   tree new_rhs;
+  gimple_stmt_iterator psi;
+  gimple phi;
+  tree def;
 
   gcc_assert (EDGE_COUNT (exit->src->succs) == 2);
   exits[0] = exit;
@@ -5249,17 +5225,6 @@ gimple_duplicate_sese_tail (edge entry ATTRIBUTE_UNUSED, edge exit ATTRIBUTE_UNU
   if (!can_copy_bbs_p (region, n_region))
     return false;
 
-  /* Some sanity checking.  Note that we do not check for all possible
-     missuses of the functions.  I.e. if you ask to copy something weird
-     (e.g., in the example, if there is a jump from inside to the middle
-     of some_code, or come_code defines some of the values used in cond)
-     it will work, but the resulting code will not be correct.  */
-  for (i = 0; i < n_region; i++)
-    {
-      if (region[i] == orig_loop->latch)
-	return false;
-    }
-
   initialize_original_copy_tables ();
   set_loop_copy (orig_loop, loop);
   duplicate_subloops (orig_loop, loop);
@@ -5377,72 +5342,30 @@ gimple_duplicate_sese_tail (edge entry ATTRIBUTE_UNUSED, edge exit ATTRIBUTE_UNU
   e = redirect_edge_and_branch (exits[0], exits[1]->dest);
   PENDING_STMT (e) = NULL;
 
-  /* If the block consisting of the exit condition has the latch as
-     successor, then the body of the loop is executed before
-     the exit condition is tested.
-
-     { body  }
-     { cond  } (exit[0])  -> { latch }
-        |
-	V (exit[1])
-
-     { exit_bb }
-
-
-     In such case, the equivalent copied edge nexits[1]
-     (for the peeled iteration) needs to be redirected to exit_bb.
-
-     Otherwise,
-
-     { cond  } (exit[0])  -> { body }
-        |
-	V (exit[1])
-
-     { exit_bb }
-
-
-     exit[0] is pointing to the body of the loop,
-     and the equivalent nexits[0] needs to be redirected to
-     the copied body (of the peeled iteration).  */
-
-  if (exits[1]->dest == orig_loop->latch)
-    e = redirect_edge_and_branch (nexits[1], nexits[0]->dest);
-  else
-    e = redirect_edge_and_branch (nexits[0], nexits[1]->dest);
-  PENDING_STMT (e) = NULL;
-
-  redirect_edges = VEC_alloc (edge, heap, 10);
-
-  for (i = 0; i < n_region; i++)
-    region_copy[i]->flags |= BB_DUPLICATED;
-
-  /* Iterate all incoming edges to latch.  All those coming from
-     copied bbs will be redirected to exit_bb.  */
-  FOR_EACH_EDGE (e, ei, orig_loop->latch->preds)
-    {
-      if (e->src->flags & BB_DUPLICATED)
-        VEC_safe_push (edge, heap, redirect_edges, e);
-    }
-
+  /* The latch of ORIG_LOOP was copied, and so was the backedge 
+     to the original header.  We redirect this backedge to EXIT_BB.  */
   for (i = 0; i < n_region; i++)
-    region_copy[i]->flags &= ~BB_DUPLICATED;
-
-  for (i = 0; VEC_iterate (edge, redirect_edges, i, e); ++i)
-    {
-      e = redirect_edge_and_branch (e, exit_bb);
-      PENDING_STMT (e) = NULL;
-      orig_src = get_bb_original (e->src);
-      orig_e = find_edge (orig_src, orig_loop->latch);
-      add_phi_args_after_redirect (e, orig_e);
-    }
-
-  VEC_free (edge, heap, redirect_edges);
-
+    if (get_bb_original (region_copy[i]) == orig_loop->latch)
+      {
+	gcc_assert (single_succ_edge (region_copy[i]));
+	e = redirect_edge_and_branch (single_succ_edge (region_copy[i]), exit_bb);
+	PENDING_STMT (e) = NULL;
+	for (psi = gsi_start_phis (exit_bb);
+	     !gsi_end_p (psi);
+	     gsi_next (&psi))
+	  {
+	    phi = gsi_stmt (psi);
+	    def = PHI_ARG_DEF (phi, nexits[0]->dest_idx);
+	    add_phi_arg (phi, def, e, gimple_phi_arg_location_from_edge (phi, e));
+	  }
+      }
+  e = redirect_edge_and_branch (nexits[0], nexits[1]->dest);
+  PENDING_STMT (e) = NULL;
+  
   /* Anything that is outside of the region, but was dominated by something
      inside needs to update dominance info.  */
   iterate_fix_dominators (CDI_DOMINATORS, doms, false);
   VEC_free (basic_block, heap, doms);
-
   /* Update the SSA web.  */
   update_ssa (TODO_update_ssa);