2007-04-24 Hui-May Chang <hm.chang@apple.com>

[pf3gnuchains/gcc-fork.git] / gcc / cfgrtl.c

diff --git a/gcc/cfgrtl.c b/gcc/cfgrtl.c
index 4424621..20b946d 100644 (file)
--- a/gcc/cfgrtl.c
+++ b/gcc/cfgrtl.c
@@ -1716,12 +1716,6 @@ rtl_verify_flow_info_1 (void)
                   bb->index);
            err = 1;
          }
-
-      if (bb->predictions)
-       {
-         error ("bb prediction set for block %d, but it is not used in RTL land", bb->index);
-         err = 1;
-       }
     }
 
   /* Now check the basic blocks (boundaries etc.) */
@@ -2519,10 +2513,11 @@ cfg_layout_can_merge_blocks_p (basic_block a, basic_block b)
          /* Must be simple edge.  */
          && !(single_succ_edge (a)->flags & EDGE_COMPLEX)
          && a != ENTRY_BLOCK_PTR && b != EXIT_BLOCK_PTR
-         /* If the jump insn has side effects,
-            we can't kill the edge.  */
+         /* If the jump insn has side effects, we can't kill the edge.
+            When not optimizing, try_redirect_by_replacing_jump will
+            not allow us to redirect an edge by replacing a table jump.  */
          && (!JUMP_P (BB_END (a))
-             || (reload_completed
+             || ((!optimize || reload_completed)
                  ? simplejump_p (BB_END (a)) : onlyjump_p (BB_END (a)))));
 }
 
@@ -2977,6 +2972,38 @@ insert_insn_end_bb_new (rtx pat, basic_block bb)
   return new_insn;
 }
 
+/* Returns true if it is possible to remove edge E by redirecting
+   it to the destination of the other edge from E->src.  */
+
+static bool
+rtl_can_remove_branch_p (edge e)
+{
+  basic_block src = e->src;
+  basic_block target = EDGE_SUCC (src, EDGE_SUCC (src, 0) == e)->dest;
+  rtx insn = BB_END (src), set;
+
+  /* The conditions are taken from try_redirect_by_replacing_jump.  */
+  if (target == EXIT_BLOCK_PTR)
+    return false;
+
+  if (e->flags & (EDGE_ABNORMAL_CALL | EDGE_EH))
+    return false;
+
+  if (find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX)
+      || BB_PARTITION (src) != BB_PARTITION (target))
+    return false;
+
+  if (!onlyjump_p (insn)
+      || tablejump_p (insn, NULL, NULL))
+    return false;
+
+  set = single_set (insn);
+  if (!set || side_effects_p (set))
+    return false;
+
+  return true;
+}
+
 /* Implementation of CFG manipulation for linearized RTL.  */
 struct cfg_hooks rtl_cfg_hooks = {
   "rtl",
@@ -2985,6 +3012,7 @@ struct cfg_hooks rtl_cfg_hooks = {
   rtl_create_basic_block,
   rtl_redirect_edge_and_branch,
   rtl_redirect_edge_and_branch_force,
+  rtl_can_remove_branch_p,
   rtl_delete_block,
   rtl_split_block,
   rtl_move_block_after,
@@ -3028,6 +3056,7 @@ struct cfg_hooks cfg_layout_rtl_cfg_hooks = {
   cfg_layout_create_basic_block,
   cfg_layout_redirect_edge_and_branch,
   cfg_layout_redirect_edge_and_branch_force,
+  rtl_can_remove_branch_p,
   cfg_layout_delete_block,
   cfg_layout_split_block,
   rtl_move_block_after,