basic-block.h: Document BB_* flags.

        * basic-block.h: Document BB_* flags.
        * regrename.c (copyprop_hardreg_forward): Don't use BB_VISITED,
        use an sbitmap instead.
        * sched-rgn.c (compute_trg_info): Likewise.

From-SVN: r93779

gcc/ChangeLog

+2005-01-17  Steven Bosscher  <stevenb@suse.de>
+
+	* basic-block.h: Document BB_* flags.
+	* regrename.c (copyprop_hardreg_forward): Don't use BB_VISITED,
+	use an sbitmap instead.
+	* sched-rgn.c (compute_trg_info): Likewise.
+
 2005-01-17  Richard Sandiford  <rsandifo@redhat.com>
 
 	* config.gcc (mips64*-*-linux*): Set the default abi to n32.  Remove

gcc/basic-block.h

@@ -285,17 +285,47 @@ typedef struct reorder_block_def
 
 #define BB_FREQ_MAX 10000
 
-/* Masks for basic_block.flags.  */
+/* Masks for basic_block.flags.
+
+   BB_VISITED should not be used by passes, it is used internally by
+   dfs_enumerate_from.
+
+   BB_HOT_PARTITION and BB_COLD_PARTITION should be preserved throughout
+   the compilation, so they are never cleared.
+
+   All other flags may be cleared by clear_bb_flags().  It is generally
+   a bad idea to rely on any flags being up-to-date.  */
+
+/* Set if insns in BB have are modified.  Used for updating liveness info.  */
 #define BB_DIRTY		1
+
+/* Only set on blocks that have just been created by create_bb.  */
 #define BB_NEW			2
+
+/* Set by find_unreachable_blocks.  Do not rely on this being set in any
+   pass.  */
 #define BB_REACHABLE		4
+
+/* Used by dfs_enumerate_from to keep track of visited basic blocks.  */
 #define BB_VISITED		8
+
+/* Set for blocks in an irreducible loop by loop analysis.  */
 #define BB_IRREDUCIBLE_LOOP	16
+
+/* Set on blocks that may actually not be single-entry single-exit block.  */
 #define BB_SUPERBLOCK		32
-#define BB_DISABLE_SCHEDULE     64
 
+/* Set on basic blocks that the scheduler should not touch.  This is used
+   by SMS to prevent other schedulers from messing with the loop schedule.  */
+#define BB_DISABLE_SCHEDULE	64
+
+/* Set on blocks that should be put in a hot section.  */
 #define BB_HOT_PARTITION	128
+
+/* Set on blocks that should be put in a cold section.  */
 #define BB_COLD_PARTITION	256
+
+/* Dummy flag for convenience in the hot/cold partitioning code.  */
 #define BB_UNPARTITIONED	0
 
 /* Partitions, to be used when partitioning hot and cold basic blocks into

gcc/regrename.c

@@ -1746,29 +1746,26 @@ copyprop_hardreg_forward (void)
   struct value_data *all_vd;
   bool need_refresh;
   basic_block bb;
+  sbitmap visited;
 
   need_refresh = false;
 
   all_vd = xmalloc (sizeof (struct value_data) * last_basic_block);
 
-  /* Clear all BB_VISITED flags.  We use BB_VISITED flags to indicate
-     whether we have processed a given basic block or not.  Note that
-     we never put BB_VISITED flag on ENTRY_BLOCK_PTR throughout this
-     function because we want to call init_value_data for all
-     successors of ENTRY_BLOCK_PTR.  */
-  FOR_ALL_BB (bb)
-    bb->flags &= ~BB_VISITED;
+  visited = sbitmap_alloc (last_basic_block - (INVALID_BLOCK + 1));
+  sbitmap_zero (visited);
 
   FOR_EACH_BB (bb)
     {
-      bb->flags |= BB_VISITED;
+      SET_BIT (visited, bb->index - (INVALID_BLOCK + 1));
 
       /* If a block has a single predecessor, that we've already
 	 processed, begin with the value data that was live at
 	 the end of the predecessor block.  */
       /* ??? Ought to use more intelligent queuing of blocks.  */
       if (EDGE_COUNT (bb->preds) == 1
-	  && ((EDGE_PRED (bb, 0)->src->flags & BB_VISITED) != 0)
+	  && TEST_BIT (visited,
+		       EDGE_PRED (bb, 0)->src->index - (INVALID_BLOCK + 1))
 	  && ! (EDGE_PRED (bb, 0)->flags & (EDGE_ABNORMAL_CALL | EDGE_EH)))
 	all_vd[bb->index] = all_vd[EDGE_PRED (bb, 0)->src->index];
       else
@@ -1778,11 +1775,7 @@ copyprop_hardreg_forward (void)
 	need_refresh = true;
     }
 
-  /* Clear BB_VISITED flag on each basic block.  We do not need to
-     clear the one on ENTRY_BLOCK_PTR because it's already cleared
-     above.  */
-  FOR_EACH_BB (bb)
-    bb->flags &= ~BB_VISITED;
+  sbitmap_free (visited);  
 
   if (need_refresh)
     {

gcc/sched-rgn.c

@@ -997,6 +997,7 @@ compute_trg_info (int trg)
   edgelst el;
   int i, j, k, update_idx;
   basic_block block;
+  sbitmap visited;
   edge_iterator ei;
   edge e;
 
@@ -1006,6 +1007,8 @@ compute_trg_info (int trg)
   sp->is_speculative = 0;
   sp->src_prob = 100;
 
+  visited = sbitmap_alloc (last_basic_block - (INVALID_BLOCK + 1));
+
   for (i = trg + 1; i < current_nr_blocks; i++)
     {
       sp = candidate_table + i;
@@ -1043,12 +1046,14 @@ compute_trg_info (int trg)
 	     overrunning the end of the bblst_table.  */
 
 	  update_idx = 0;
+	  sbitmap_zero (visited);
 	  for (j = 0; j < el.nr_members; j++)
 	    {
 	      block = el.first_member[j]->src;
 	      FOR_EACH_EDGE (e, ei, block->succs)
 		{
-		  if (!(e->dest->flags & BB_VISITED))
+		  if (!TEST_BIT (visited,
+				 e->dest->index - (INVALID_BLOCK + 1)))
 		    {
 		      for (k = 0; k < el.nr_members; k++)
 			if (e == el.first_member[k])
@@ -1057,7 +1062,8 @@ compute_trg_info (int trg)
 		      if (k >= el.nr_members)
 			{
 			  bblst_table[bblst_last++] = e->dest;
-			  e->dest->flags |= BB_VISITED;
+			  SET_BIT (visited,
+				   e->dest->index - (INVALID_BLOCK + 1));
 			  update_idx++;
 			}
 		    }
@@ -1065,9 +1071,6 @@ compute_trg_info (int trg)
 	    }
 	  sp->update_bbs.nr_members = update_idx;
 
-	  FOR_ALL_BB (block)
-	    block->flags &= ~BB_VISITED;
-
 	  /* Make sure we didn't overrun the end of bblst_table.  */
 	  gcc_assert (bblst_last <= bblst_size);
 	}
@@ -1079,6 +1082,8 @@ compute_trg_info (int trg)
 	  sp->src_prob = 0;
 	}
     }
+
+  sbitmap_free (visited);
 }
 
 /* Print candidates info, for debugging purposes.  Callable from debugger.  */