* i386.md (testsi to testqi spliters): New.

	2002-01-14  Josef Zlomek  <zlomek@matfyz.cz>

	cfg.c (dump_edge_info): added dumping of EDGE_CAN_FALLTHRU.

	Wed Jan  9 2002  Josef Zlomek  <zlomj9am@artax.karlin.mff.cuni.cz>

	* basic-block.h: New flag EDGE_CAN_FALLTHRU
	* cfganal.c (set_edge_can_fallthru_flag): New function; marks the edges
	that can be made fallthru.

	Mon Nov 12 16:25:53 CET 2001  Jan Hubicka  <jh@suse.cz>

	* cfglayout.c (cleanup_unconditional_jumps): New static function.
	(cfg_layout_initialize): Use it.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@53383 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 36 insertions, 3 deletions

diff --git a/gcc/cfganal.c b/gcc/cfganal.c
index f70c6c7b2fc..a64124cfb79 100644
--- a/gcc/cfganal.c
+++ b/gcc/cfganal.c
@@ -189,6 +189,36 @@ mark_dfs_back_edges ()
   return found;
 }
 
+/* Set the flag EDGE_CAN_FALLTHRU for edges that can be fallthru.  */
+
+void
+set_edge_can_fallthru_flag ()
+{
+  int i;
+  for (i = 0; i < n_basic_blocks; i++)
+    {
+      basic_block bb = BASIC_BLOCK (i);
+      edge e;
+
+      /* The FALLTHRU edge is also CAN_FALLTHRU edge.  */
+      for (e = bb->succ; e; e = e->succ_next)
+	if (e->flags & EDGE_FALLTHRU)
+	  e->flags |= EDGE_CAN_FALLTHRU;
+
+      /* If the BB ends with an invertable condjump all (2) edges are
+	 CAN_FALLTHRU edges.  */
+      if (!bb->succ || !bb->succ->succ_next || bb->succ->succ_next->succ_next)
+	continue;
+      if (!any_condjump_p (bb->end))
+	continue;
+      if (!invert_jump (bb->end, JUMP_LABEL (bb->end), 0))
+	continue;
+      invert_jump (bb->end, JUMP_LABEL (bb->end), 0);
+      bb->succ->flags |= EDGE_CAN_FALLTHRU;
+      bb->succ->succ_next->flags |= EDGE_CAN_FALLTHRU;
+    }
+}
+
 /* Return true if we need to add fake edge to exit.
    Helper function for the flow_call_edges_add.  */
 
@@ -326,9 +356,12 @@ flow_call_edges_add (blocks)
 
 	      /* Note that the following may create a new basic block
 		 and renumber the existing basic blocks.  */
-	      e = split_block (bb, split_at_insn);
-	      if (e)
-		blocks_split++;
+	      if (split_at_insn != bb->end)
+		{
+		  e = split_block (bb, split_at_insn);
+		  if (e)
+		    blocks_split++;
+		}
 
 	      make_edge (bb, EXIT_BLOCK_PTR, EDGE_FAKE);
 	    }