From: Jeffrey A Law <law@cygnus.com>
Date: Thu, 4 May 2000 20:40:17 +0000 (+0000)
Subject: predict.c (estimate_probability): If no prediction was found...
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=926fd2e161ada3acf143b8c123b9237d53e3c27e;p=gcc.git

predict.c (estimate_probability): If no prediction was found...

        * predict.c (estimate_probability): If no prediction was found, then
        predict the successor that is the next physical block (if such a
        successor exists).

From-SVN: r33683
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fbab6406025..a1312d23b37 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+Thu May  4 14:37:23 2000  Jeffrey A Law  (law@cygnus.com)
+
+	* predict.c (estimate_probability): If no prediction was found, then
+	predict the successor that is the next physical block (if such a
+	successor exists).
+
 2000-05-04  Richard Henderson  <rth@cygnus.com>
 
 	* config/alpha/t-alpha (LIB2FUNCS_EXTRA): Use qrrnd.asm in place.
diff --git a/gcc/predict.c b/gcc/predict.c
index b957e5f6050..148d46bb1e6 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -202,6 +202,19 @@ estimate_probability (loops_info)
 	  break;
 	}
 
+      /* If one of the blocks already directly follows the current
+	 block, then predict it as the taken path.  This reduces
+	 random block movement.  */
+      for (e = BASIC_BLOCK (i)->succ; e; e = e->succ_next)
+        if (e->dest->index == i + 1)
+          {
+            if (e->flags & EDGE_FALLTHRU)
+              prob = 0;
+            else
+              prob = REG_BR_PROB_BASE;
+            goto emitnote;
+          }
+
       /* If we havn't chosen something by now, predict 50-50.  */
       prob = REG_BR_PROB_BASE / 2;