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

	Backport from mainline
	2013-01-08  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.

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

From-SVN: r198085

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 92c1e2219dcec3cf6976ee1fc98ec2ee4fd76c59..713ececa0a83b808f6c776eef6c7d8b69ee90cb5 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,13 @@
+2013-04-19  Marek Polacek  <polacek@redhat.com>
+
+       Backport from mainline
+       2013-01-08  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.
+
 2013-04-16  Jack Howarth  <howarth@bromo.med.uc.edu>
 
        Backport from mainline

diff --git a/gcc/predict.c b/gcc/predict.c
index c12b45f12de9d9b8805593091a895336e4a3259c..2f550e74e18bbc11298aef5587151da8470aca65 100644 (file)
--- a/gcc/predict.c
+++ b/gcc/predict.c
@@ -983,7 +983,8 @@ 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;
@@ -1005,6 +1006,11 @@ 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 7fc674384d44749948499a059ed3347033369e76..a719d45e8f4a9701c3f4eea5213c00ac648deedb 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2013-04-19  Marek Polacek  <polacek@redhat.com>
+
+       Backport from mainline
+       2013-01-08  Steven Bosscher  <steven@gcc.gnu.org>
+                   Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/48189
+       * gcc.dg/pr48189.c: New test.
+
 2013-04-15  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
 
        * gcc.dg/torture/pr53922.c: Skip on alpha*-*-osf*.

diff --git a/gcc/testsuite/gcc.dg/pr48189.c b/gcc/testsuite/gcc.dg/pr48189.c
new file mode 100644 (file)
index 0000000..86b995d
--- /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];
+}