(add_label_notes): Don't add notes for references to dispatch tables because jump...

(add_label_notes): Don't add notes for references to
dispatch tables because jump doesn't.
(find_and_verify_loops): Invalidate loops that contain labels
whose address has been taken.

From-SVN: r3523

diff --git a/gcc/loop.c b/gcc/loop.c
index 11b7c96842aa90f7da048fc5d4004f3ffc1e4461..03458ee59598eb9af69e1a46047fae3adfb03622 100644 (file)
--- a/gcc/loop.c
+++ b/gcc/loop.c
@@ -1476,10 +1476,21 @@ add_label_notes (x, insns)
 
   if (code == LABEL_REF && !LABEL_REF_NONLOCAL_P (x))
     {
-      for (insn = insns; insn; insn = NEXT_INSN (insn))
-       if (reg_mentioned_p (XEXP (x, 0), insn))
-         REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_LABEL, XEXP (x, 0),
-                                     REG_NOTES (insn));
+      rtx next = next_real_insn (XEXP (x, 0));
+
+      /* Don't record labels that refer to dispatch tables.
+        This is not necessary, since the tablejump references the same label.
+        And if we did record them, flow.c would make worse code.  */
+      if (next == 0
+         || ! (GET_CODE (next) == JUMP_INSN
+               && (GET_CODE (PATTERN (next)) == ADDR_VEC
+                   || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)))
+       {
+         for (insn = insns; insn; insn = NEXT_INSN (insn))
+           if (reg_mentioned_p (XEXP (x, 0), insn))
+             REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_LABEL, XEXP (x, 0),
+                                         REG_NOTES (insn));
+       }
       return;
     }
 
@@ -2167,7 +2178,7 @@ static void
 find_and_verify_loops (f)
      rtx f;
 {
-  rtx insn;
+  rtx insn, label;
   int current_loop = -1;
   int next_loop = -1;
   int loop;
@@ -2222,8 +2233,24 @@ find_and_verify_loops (f)
       uid_loop_num[INSN_UID (insn)] = current_loop;
     }
 
-  /* Now scan all JUMP_INSN's in the function.  If any branches into a loop
-     that it is not contained within, that loop is marked invalid.
+  /* Any loop containing a label used in an initializer must be invalidated,
+     because it can be jumped into from anywhere.  */
+
+  for (label = forced_labels; label; label = XEXP (label, 1))
+    {
+      int loop_num;
+
+      for (loop_num = uid_loop_num[INSN_UID (XEXP (label, 0))];
+          loop_num != -1;
+          loop_num = loop_outer_loop[loop_num])
+       loop_invalid[loop_num] = 1;
+    }
+
+  /* Now scan all insn's in the function.  If any JUMP_INSN branches into a
+     loop that it is not contained within, that loop is marked invalid.
+     If any INSN or CALL_INSN uses a label's address, then the loop containing
+     that label is marked invalid, because it could be jumped into from
+     anywhere.
 
      Also look for blocks of code ending in an unconditional branch that
      exits the loop.  If such a block is surrounded by a conditional 
@@ -2233,10 +2260,27 @@ find_and_verify_loops (f)
      possible second cse pass.  */
 
   for (insn = f; insn; insn = NEXT_INSN (insn))
-    if (GET_CODE (insn) == JUMP_INSN)
+    if (GET_RTX_CLASS (GET_CODE (insn)) == 'i')
       {
        int this_loop_num = uid_loop_num[INSN_UID (insn)];
 
+       if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN)
+         {
+           rtx note = find_reg_note (insn, REG_LABEL, NULL_RTX);
+           if (note)
+             {
+               int loop_num;
+
+               for (loop_num = uid_loop_num[INSN_UID (XEXP (note, 0))];
+                    loop_num != -1;
+                    loop_num = loop_outer_loop[loop_num])
+                 loop_invalid[loop_num] = 1;
+             }
+         }
+
+       if (GET_CODE (insn) != JUMP_INSN)
+         continue;
+
        mark_loop_jump (PATTERN (insn), this_loop_num);
 
        /* See if this is an unconditional branch outside the loop.  */