re PR tree-optimization/80181 (ICE in set_lattice_value, at tree-ssa-ccp.c:505)

2017-03-27  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/80181
	* tree-ssa-ccp.c (likely_value): UNDEFINED ^ X is UNDEFINED.

	* gcc.dg/torture/pr80181.c: New testcase.

From-SVN: r246500

gcc/ChangeLog

+2017-03-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80181
+	* tree-ssa-ccp.c (likely_value): UNDEFINED ^ X is UNDEFINED.
+
 2017-03-27  Claudiu Zissulescu  <claziss@synopsys.com>
 
 	* config/arc/predicates.md (move_double_src_operand): Replace the

gcc/testsuite/ChangeLog

+2017-03-27  Richard Biener  <rguenther@suse.de>
+
+	PR tree-optimization/80181
+	* gcc.dg/torture/pr80181.c: New testcase.
+
 2017-03-27  Claudiu Zissulescu  <claziss@synopsys.com>
 
 	* testsuite/gcc.target/arc/interrupt-4.c: New file.

gcc/testsuite/gcc.dg/torture/pr80181.c

+/* { dg-do compile } */
+
+int
+nr (void)
+{
+}
+
+void
+it (int dl)
+{
+  int vp = 0;
+
+  for (;;)
+    {
+      dl = vp ^ nr ();
+      dl ^= vp;
+      vp = 1;
+    }
+}

gcc/tree-ssa-ccp.c

@@ -741,9 +741,11 @@ likely_value (gimple *stmt)
 	case PLUS_EXPR:
 	case MINUS_EXPR:
 	case POINTER_PLUS_EXPR:
+	case BIT_XOR_EXPR:
 	  /* Not MIN_EXPR, MAX_EXPR.  One VARYING operand may be selected.
 	     Not bitwise operators, one VARYING operand may specify the
-	     result completely.  Not logical operators for the same reason.
+	     result completely.
+	     Not logical operators for the same reason, apart from XOR.
 	     Not COMPLEX_EXPR as one VARYING operand makes the result partly
 	     not UNDEFINED.  Not *DIV_EXPR, comparisons and shifts because
 	     the undefined operand may be promoted.  */