re PR tree-optimization/80842 (ICE at -O3 on x86_64-linux-gnu in "set_lattice_value")

2017-05-26  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80842
	* tree-ssa-ccp.c (set_lattice_value): Always meet with the old
	value.

	* gcc.dg/torture/pr80842.c: New testcase.

From-SVN: r248482

gcc/ChangeLog

 2017-05-26  Richard Biener  <rguenther@suse.de>
 
+	PR tree-optimization/80842
+	* tree-ssa-ccp.c (set_lattice_value): Always meet with the old
+	value.
+
+2017-05-26  Richard Biener  <rguenther@suse.de>
+
 	PR tree-optimization/80844
 	* tree-vectorizer.c (adjust_simduid_builtins): Propagate
 	results.

gcc/testsuite/ChangeLog

+2017-05-26  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80842
+	* gcc.dg/torture/pr80842.c: New testcase.
+
 2017-05-25  Paolo Carlini  <paolo.carlini@oracle.com>
 
 	PR c++/79652

gcc/testsuite/gcc.dg/torture/pr80842.c

+/* { dg-do compile } */
+
+unsigned a;
+short b;
+char c, d, e;
+void fn1();
+void fn2() {
+    a++;
+    for (; a;)
+      fn1(0, 0);
+}
+void fn3() {
+    fn2();
+l1:;
+   unsigned char f;
+   short g;
+   unsigned char *h = &f;
+   g += &h ? e ? g = 1 : 0 : 0;
+   d = g;
+   c *f;
+   if (d & (b %= *h) < f * d / (d -= 0))
+     goto l1;
+}

gcc/tree-ssa-ccp.c

@@ -497,9 +497,7 @@ set_lattice_value (tree var, ccp_prop_value_t *new_val)
      use the meet operator to retain a conservative value.
      Missed optimizations like PR65851 makes this necessary.
      It also ensures we converge to a stable lattice solution.  */
-  if (new_val->lattice_val == CONSTANT
-      && old_val->lattice_val == CONSTANT
-      && TREE_CODE (new_val->value) != SSA_NAME)
+  if (old_val->lattice_val != UNINITIALIZED)
     ccp_lattice_meet (new_val, old_val);
 
   gcc_checking_assert (valid_lattice_transition (*old_val, *new_val));