re PR tree-optimization/78788 (ICE (segfault) on s390x-linux-gnu)

2016-12-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78788
	* tree-vrp.c (set_value_range): Allow [-INF(OVF), +INF(OVF)].
	(set_and_canonicalize_value_range): Do not drop the above to
	VARYING.

	* gcc.dg/torture/pr78788.c: New testcase.

From-SVN: r243631

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dff1b829ce5f0db40482b6268bd3a93fab2ebfa3..17a33618b5ec06649afc093cc2d57c16a9c82519 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2016-12-14  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/78788
+       * tree-vrp.c (set_value_range): Allow [-INF(OVF), +INF(OVF)].
+       (set_and_canonicalize_value_range): Do not drop the above to
+       VARYING.
+
 2016-12-13  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
 
        * config/rs6000/rs600.c (rs6000_builtin_vectorization_cost):

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4378e36bbe7a9fb12e7f55190fda4cf7fa4f701e..2be6da24268a4c48054c97a2e01255ac00b2b8c2 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2016-12-14  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/78788
+       * gcc.dg/torture/pr78788.c: New testcase.
+
 2016-12-13  Nathan Sidwell  <nathan@acm.org>
 
        PR c++/69481

diff --git a/gcc/testsuite/gcc.dg/torture/pr78788.c b/gcc/testsuite/gcc.dg/torture/pr78788.c
new file mode 100644 (file)
index 0000000..9861260
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr78788.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+
+int a;
+long b;
+long c;
+void d()
+{
+  int e = 0;
+  for (; b; b++)
+    if (c)
+      {
+       e++;
+       e++;
+      }
+  while (e)
+    a = e -= 2;
+}

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index 600634d1804d37f3b307d0c1582db2ff83bb094e..3535d7a4d83f0a44c5715808b166298f4c8524fd 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -365,10 +365,6 @@ set_value_range (value_range *vr, enum value_range_type t, tree min,
 
       cmp = compare_values (min, max);
       gcc_assert (cmp == 0 || cmp == -1 || cmp == -2);
-
-      if (needs_overflow_infinity (TREE_TYPE (min)))
-       gcc_assert (!is_overflow_infinity (min)
-                   || !is_overflow_infinity (max));
     }
 
   if (flag_checking
@@ -506,14 +502,9 @@ set_and_canonicalize_value_range (value_range *vr, enum value_range_type t,
         }
     }
 
-  /* Drop [-INF(OVF), +INF(OVF)] to varying.  */
-  if (needs_overflow_infinity (TREE_TYPE (min))
-      && is_overflow_infinity (min)
-      && is_overflow_infinity (max))
-    {
-      set_value_range_to_varying (vr);
-      return;
-    }
+  /* Do not drop [-INF(OVF), +INF(OVF)] to varying.  (OVF) has to be sticky
+     to make sure VRP iteration terminates, otherwise we can get into
+     oscillations.  */
 
   set_value_range (vr, t, min, max, equiv);
 }