* reorg.c (mostly_true_jump): Clean up code depending on

	LABEL_OUTSIDE_LOOP_P and loop notes.  Remove code doing
	poor man's branch prediction, instead rely on REG_BR_PROB
	notes to be available.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@108653 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f5e91e6..a73bcb4 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2005-12-16  Steven Bosscher  <stevenb@suse.de>
+
+       * reorg.c (mostly_true_jump): Clean up code depending on
+       LABEL_OUTSIDE_LOOP_P and loop notes.  Remove code doing
+       poor man's branch prediction, instead rely on REG_BR_PROB
+       notes to be available.
+
 2005-12-16  Jakub Jelinek  <jakub@redhat.com>
 
        PR rtl-optimization/24899

diff --git a/gcc/reorg.c b/gcc/reorg.c
index 46154f1..104ad8e 100644 (file)
--- a/gcc/reorg.c
+++ b/gcc/reorg.c
@@ -964,8 +964,7 @@ mostly_true_jump (rtx jump_insn, rtx condition)
 {
   rtx target_label = JUMP_LABEL (jump_insn);
   rtx insn, note;
-  int rare_dest = rare_destination (target_label);
-  int rare_fallthrough = rare_destination (NEXT_INSN (jump_insn));
+  int rare_dest, rare_fallthrough;
 
   /* If branch probabilities are available, then use that number since it
      always gives a correct answer.  */
@@ -984,32 +983,10 @@ mostly_true_jump (rtx jump_insn, rtx condition)
        return -1;
     }
 
-  /* ??? Ought to use estimate_probability instead.  */
-
-  /* If this is a branch outside a loop, it is highly unlikely.  */
-  if (GET_CODE (PATTERN (jump_insn)) == SET
-      && GET_CODE (SET_SRC (PATTERN (jump_insn))) == IF_THEN_ELSE
-      && ((GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 1)) == LABEL_REF
-          && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 1)))
-         || (GET_CODE (XEXP (SET_SRC (PATTERN (jump_insn)), 2)) == LABEL_REF
-             && LABEL_OUTSIDE_LOOP_P (XEXP (SET_SRC (PATTERN (jump_insn)), 2)))))
-    return -1;
-
-  if (target_label)
-    {
-      /* If this is the test of a loop, it is very likely true.  We scan
-        backwards from the target label.  If we find a NOTE_INSN_LOOP_BEG
-        before the next real insn, we assume the branch is to the top of
-        the loop.  */
-      for (insn = PREV_INSN (target_label);
-          insn && NOTE_P (insn);
-          insn = PREV_INSN (insn))
-       if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
-         return 2;
-    }
-
   /* Look at the relative rarities of the fallthrough and destination.  If
      they differ, we can predict the branch that way.  */
+  rare_dest = rare_destination (target_label);
+  rare_fallthrough = rare_destination (NEXT_INSN (jump_insn));
 
   switch (rare_fallthrough - rare_dest)
     {
@@ -1030,33 +1007,6 @@ mostly_true_jump (rtx jump_insn, rtx condition)
   if (condition == 0)
     return 0;
 
-  /* EQ tests are usually false and NE tests are usually true.  Also,
-     most quantities are positive, so we can make the appropriate guesses
-     about signed comparisons against zero.  */
-  switch (GET_CODE (condition))
-    {
-    case CONST_INT:
-      /* Unconditional branch.  */
-      return 1;
-    case EQ:
-      return 0;
-    case NE:
-      return 1;
-    case LE:
-    case LT:
-      if (XEXP (condition, 1) == const0_rtx)
-       return 0;
-      break;
-    case GE:
-    case GT:
-      if (XEXP (condition, 1) == const0_rtx)
-       return 1;
-      break;
-
-    default:
-      break;
-    }
-
   /* Predict backward branches usually take, forward branches usually not.  If
      we don't know whether this is forward or backward, assume the branch
      will be taken, since most are.  */