From: Marek Polacek <polacek@redhat.com>
Date: Thu, 4 Apr 2013 11:03:11 +0000 (+0000)
Subject: backport: re PR tree-optimization/48189 (ICE: SIGFPE (division by zero) in in predict... 
X-Git-Tag: releases/gcc-4.6.4~58
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f7c31f0d78918206f0ebaf512d7ba8b22efd33e9;p=thirdparty%2Fgcc.git

backport: re PR tree-optimization/48189 (ICE: SIGFPE (division by zero) in in predict_loops () at predict.c:991 with --param max-predicted-iterations=0)

        Backported from mainline
        2013-01-09  Steven Bosscher  <steven@gcc.gnu.org>
                    Jakub Jelinek  <jakub@redhat.com>

        PR tree-optimization/48189
        * predict.c (predict_loops): If max is 0, don't call compare_tree_int.
        If nitercst is 0, don't predict the exit edge.

From-SVN: r197478
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f5ddc786f7cf..f9b7ec9c8b58 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2013-04-04  Marek Polacek  <polacek@redhat.com>
+
+	Backported from mainline
+	2013-01-09  Steven Bosscher  <steven@gcc.gnu.org>
+		    Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/48189
+	* predict.c (predict_loops): If max is 0, don't call compare_tree_int.
+	If nitercst is 0, don't predict the exit edge.
+
 2013-04-03  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
diff --git a/gcc/predict.c b/gcc/predict.c
index f00424c3b1c0..18fda083da33 100644
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -1,6 +1,6 @@
 /* Branch prediction routines for the GNU compiler.
    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010
-   Free Software Foundation, Inc.
+   2011, 2012, 2013 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -966,7 +966,8 @@ predict_loops (void)
 	  if (TREE_CODE (niter) == INTEGER_CST)
 	    {
 	      if (host_integerp (niter, 1)
-		  && compare_tree_int (niter, max-1) == -1)
+		  && max
+		  && compare_tree_int (niter, max - 1) == -1)
 		nitercst = tree_low_cst (niter, 1) + 1;
 	      else
 		nitercst = max;
@@ -988,6 +989,11 @@ predict_loops (void)
 	  else
 	    continue;
 
+	  /* If the prediction for number of iterations is zero, do not
+	     predict the exit edges.  */
+	  if (nitercst == 0)
+	    continue;
+
 	  probability = ((REG_BR_PROB_BASE + nitercst / 2) / nitercst);
 	  predict_edge (ex, predictor, probability);
 	}
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index cd660f6e3fa0..80016c5622ff 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2013-04-04  Marek Polacek  <polacek@redhat.com>
+
+	Backported from mainline
+	2013-01-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/48189
+	* gcc.dg/pr48189.c: New test.
+
 2013-04-04  Tobias Burnus  <burnus@net-b.de>
 
 	Backport from mainline:
diff --git a/gcc/testsuite/gcc.dg/pr48189.c b/gcc/testsuite/gcc.dg/pr48189.c
new file mode 100644
index 000000000000..86b995dc9848
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr48189.c
@@ -0,0 +1,13 @@
+/* PR tree-optimization/48189 */
+/* { dg-do compile } */
+/* { dg-options "-O --param max-predicted-iterations=0" } */
+
+struct S { int s[8]; };
+  
+void
+foo (int *x, struct S *y)
+{
+  int i;
+  for (i = 0; y[i].s[i]; i++)
+    *x++ = y[i].s[i];
+}