cfgloop.c (update_latch_info): Update dominator of the new block.

	* cfgloop.c (update_latch_info): Update dominator of the new block.
	(canonicalize_loop_headers, flow_loops_find): Do not free dominance
	info.
	* dominance.c (verify_dominators): Check that the dominance tree is
	connected.
	(recount_dominator): Ignore unreachable blocks.
	(iterate_fix_dominators): Cleanup old dominance information before
	recomputing it.

From-SVN: r85307

3 files changed, 45 insertions, 12 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 1d17875..c66a8d0 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2004-07-29  Zdenek Dvorak  <rakdver@atrey.karlin.mff.cuni.cz>
+
+	* cfgloop.c (update_latch_info): Update dominator of the new block.
+	(canonicalize_loop_headers, flow_loops_find): Do not free dominance
+	info.
+	* dominance.c (verify_dominators): Check that the dominance tree is
+	connected.
+	(recount_dominator): Ignore unreachable blocks.
+	(iterate_fix_dominators): Cleanup old dominance information before
+	recomputing it.
+
 2004-07-29  Diego Novillo  <dnovillo@redhat.com>
 
 	* tree-ssa-operands.c (get_expr_operands): Revert changes
diff --git a/gcc/cfgloop.c b/gcc/cfgloop.c
index 50f31e6..58d9dd0 100644
--- a/gcc/cfgloop.c
+++ b/gcc/cfgloop.c
@@ -575,6 +575,7 @@ update_latch_info (basic_block jump)
   HEADER_BLOCK (jump) = 0;
   alloc_aux_for_edge (jump->pred, sizeof (int));
   LATCH_EDGE (jump->pred) = 0;
+  set_immediate_dominator (CDI_DOMINATORS, jump, jump->pred->src);
 }
 
 /* A callback for make_forwarder block, to redirect all edges except for
@@ -606,9 +607,6 @@ canonicalize_loop_headers (void)
   basic_block header;
   edge e;
 
-  /* Compute the dominators.  */
-  calculate_dominance_info (CDI_DOMINATORS);
-
   alloc_aux_for_blocks (sizeof (int));
   alloc_aux_for_edges (sizeof (int));
 
@@ -638,8 +636,6 @@ canonicalize_loop_headers (void)
 	HEADER_BLOCK (header) = num_latches;
     }
 
-  free_dominance_info (CDI_DOMINATORS);
-
   if (HEADER_BLOCK (ENTRY_BLOCK_PTR->succ->dest))
     {
       basic_block bb;
@@ -711,6 +707,10 @@ canonicalize_loop_headers (void)
 
   free_aux_for_blocks ();
   free_aux_for_edges ();
+
+#ifdef ENABLE_CHECKING
+  verify_dominators (CDI_DOMINATORS);
+#endif
 }
 
 /* Find all the natural loops in the function and save in LOOPS structure and
@@ -747,12 +747,12 @@ flow_loops_find (struct loops *loops, int flags)
   dfs_order = NULL;
   rc_order = NULL;
 
+  /* Ensure that the dominators are computed.  */
+  calculate_dominance_info (CDI_DOMINATORS);
+
   /* Join loops with shared headers.  */
   canonicalize_loop_headers ();
 
-  /* Compute the dominators.  */
-  calculate_dominance_info (CDI_DOMINATORS);
-
   /* Count the number of loop headers.  This should be the
      same as the number of natural loops.  */
   headers = sbitmap_alloc (last_basic_block);
@@ -880,10 +880,6 @@ flow_loops_find (struct loops *loops, int flags)
 
       loops->num = num_loops;
     }
-  else
-    {
-      free_dominance_info (CDI_DOMINATORS);
-    }
 
   sbitmap_free (headers);
 
diff --git a/gcc/dominance.c b/gcc/dominance.c
index 156fc98..d46d8f5 100644
--- a/gcc/dominance.c
+++ b/gcc/dominance.c
@@ -824,6 +824,20 @@ verify_dominators (enum cdi_direction dir)
 	  err = 1;
 	}
     }
+
+  if (dir == CDI_DOMINATORS
+      && dom_computed[dir] >= DOM_NO_FAST_QUERY)
+    {
+      FOR_EACH_BB (bb)
+	{
+	  if (!dominated_by_p (dir, bb, ENTRY_BLOCK_PTR))
+	    {
+	      error ("ENTRY does not dominate bb %d", bb->index);
+	      err = 1;
+	    }
+	}
+    }
+
   if (err)
     abort ();
 }
@@ -846,6 +860,11 @@ recount_dominator (enum cdi_direction dir, basic_block bb)
     {
       for (e = bb->pred; e; e = e->pred_next)
 	{
+	  /* Ignore the predecessors that either are not reachable from
+	     the entry block, or whose dominator was not determined yet.  */
+	  if (!dominated_by_p (dir, e->src, ENTRY_BLOCK_PTR))
+	    continue;
+
 	  if (!dominated_by_p (dir, e->src, bb))
 	    dom_bb = nearest_common_dominator (dir, dom_bb, e->src);
 	}
@@ -873,6 +892,9 @@ iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n)
   if (!dom_computed[dir])
     abort ();
 
+  for (i = 0; i < n; i++)
+    set_immediate_dominator (dir, bbs[i], NULL);
+
   while (changed)
     {
       changed = 0;
@@ -887,6 +909,10 @@ iterate_fix_dominators (enum cdi_direction dir, basic_block *bbs, int n)
 	    }
 	}
     }
+
+  for (i = 0; i < n; i++)
+    if (!get_immediate_dominator (dir, bbs[i]))
+      abort ();
 }
 
 void