cfgcleanup.c (first_pass): New static variable.

	* cfgcleanup.c (first_pass): New static variable.
	(try_forward_edges):  Add work limiting check for threading.
	(try_crossjump_bb):  Add work limiting check for crossjumping.
	(try_optimize_cfg):  Maintain first pass variable.

From-SVN: r76375

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 6c632630aa2c10745ba99ff0d5f78e1262942464..6e361e776bcdf05cf412fa8b7ca6abac1c8f8467 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2004-01-22  Jan Hubicka  <jh@suse.cz>
+
+       * cfgcleanup.c (first_pass): New static variable.
+       (try_forward_edges):  Add work limiting check for threading.
+       (try_crossjump_bb):  Add work limiting check for crossjumping.
+       (try_optimize_cfg):  Maintain first pass variable.
+
 2004-01-22  Bob Wilson  <bob.wilson@acm.org>
 
        * config/xtensa/xtensa.c (function_arg): Generalize logic so that it

diff --git a/gcc/cfgcleanup.c b/gcc/cfgcleanup.c
index 3365a78c35571f1492ed3285c839cf8746191f85..ad44cbb446749ffb1645236c50bbebb7ba74045b 100644 (file)
--- a/gcc/cfgcleanup.c
+++ b/gcc/cfgcleanup.c
@@ -67,6 +67,8 @@ enum bb_flags
 
 #define FORWARDER_BLOCK_P(BB) (BB_FLAGS (BB) & BB_FORWARDER_BLOCK)
 
+/* Set to true when we are running first pass of try_optimize_cfg loop.  */
+static bool first_pass;
 static bool try_crossjump_to_edge (int, edge, edge);
 static bool try_crossjump_bb (int, basic_block);
 static bool outgoing_edges_match (int, basic_block, basic_block);
@@ -429,6 +431,7 @@ try_forward_edges (int mode, basic_block b)
       int counter;
       bool threaded = false;
       int nthreaded_edges = 0;
+      bool may_thread = first_pass | (b->flags & BB_DIRTY);
 
       next = e->succ_next;
 
@@ -447,6 +450,7 @@ try_forward_edges (int mode, basic_block b)
        {
          basic_block new_target = NULL;
          bool new_target_threaded = false;
+         may_thread |= target->flags & BB_DIRTY;
 
          if (FORWARDER_BLOCK_P (target)
              && target->succ->dest != EXIT_BLOCK_PTR)
@@ -459,7 +463,7 @@ try_forward_edges (int mode, basic_block b)
 
          /* Allow to thread only over one edge at time to simplify updating
             of probabilities.  */
-         else if (mode & CLEANUP_THREADING)
+         else if ((mode & CLEANUP_THREADING) && may_thread)
            {
              edge t = thread_jump (mode, e, target);
              if (t)
@@ -1573,6 +1577,12 @@ try_crossjump_bb (int mode, basic_block bb)
             If there is a match, we'll do it the other way around.  */
          if (e == fallthru)
            continue;
+         /* If nothing changed since the last attempt, there is nothing
+            we can do.  */
+         if (!first_pass
+             && (!(e->src->flags & BB_DIRTY)
+                 && !(fallthru->src->flags & BB_DIRTY)))
+           continue;
 
          if (try_crossjump_to_edge (mode, e, fallthru))
            {
@@ -1615,6 +1625,13 @@ try_crossjump_bb (int mode, basic_block bb)
          if (e->src->index > e2->src->index)
            continue;
 
+         /* If nothing changed since the last attempt, there is nothing
+            we can do.  */
+         if (!first_pass
+             && (!(e->src->flags & BB_DIRTY)
+                 && !(e2->src->flags & BB_DIRTY)))
+           continue;
+
          if (try_crossjump_to_edge (mode, e, e2))
            {
              changed = true;
@@ -1644,11 +1661,12 @@ try_optimize_cfg (int mode)
   FOR_EACH_BB (bb)
     update_forwarder_flag (bb);
 
-  if (mode & CLEANUP_UPDATE_LIFE)
+  if (mode & (CLEANUP_UPDATE_LIFE | CLEANUP_CROSSJUMP | CLEANUP_THREADING))
     clear_bb_flags ();
 
   if (! (* targetm.cannot_modify_jumps_p) ())
     {
+      first_pass = true;
       /* Attempt to merge blocks as made possible by edge removal.  If
         a block has only one successor, and the successor has only
         one predecessor, they may be combined.  */
@@ -1824,6 +1842,7 @@ try_optimize_cfg (int mode)
 #endif
 
          changed_overall |= changed;
+         first_pass = false;
        }
       while (changed);
     }