re PR tree-optimization/48189 (ICE: SIGFPE (division by zero) in in…

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

	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.

	* gcc.dg/pr48189.c: New test.

From-SVN: r195046

gcc/ChangeLog

+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.
+
 2013-01-08  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	* config/pa/pa.h (VAL_U6_BITS_P): Define.

gcc/predict.c

 /* Branch prediction routines for the GNU compiler.
    Copyright (C) 2000, 2001, 2002, 2003, 2004, 2005, 2007, 2008, 2009, 2010,
-   2011, 2012 Free Software Foundation, Inc.
+   2011, 2012, 2013 Free Software Foundation, Inc.
 
 This file is part of GCC.
 
@@ -1434,7 +1434,8 @@ 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;
@@ -1456,6 +1457,11 @@ 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);
 	}

gcc/testsuite/ChangeLog

+2013-01-09  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/48189
+	* gcc.dg/pr48189.c: New test.
+
 2013-01-04  Jan Hubicka  <jh@suse.cz>
 
 	PR tree-optimization/55823

gcc/testsuite/gcc.dg/pr48189.c

+/* 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];
+}