re PR tree-optimization/54647 (Segmentation fault in get_expr_value_id with -O2)

2012-09-21  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/54647
	* tree-ssa-pre.c (compute_avail): Do not put COND_EXPR
	or VEC_COND_EXPR into EXP_GEN again.

	* g++.dg/torture/pr54647.C: New testcase.

From-SVN: r191613

gcc/ChangeLog

+2012-09-21  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54647
+	* tree-ssa-pre.c (compute_avail): Do not put COND_EXPR
+	or VEC_COND_EXPR into EXP_GEN again.
+
 2012-09-21  Jakub Jelinek  <jakub@redhat.com>
 
 	PR tree-optimization/54629

gcc/testsuite/ChangeLog

+2012-09-21  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/54647
+	* g++.dg/torture/pr54647.C: New testcase.
+
 2012-09-21  Marc Glisse  <marc.glisse@inria.fr>
 
 	PR c++/54427

gcc/testsuite/g++.dg/torture/pr54647.C

+// { dg-do compile }
+
+class A
+{
+};
+template <class type> struct D:A
+{
+  type & operator[](int);
+};
+struct B
+{
+  typedef D <int *>Row;
+  struct C
+    {
+      Row *row;
+    };
+};
+B::C a;
+B::Row & b = *a.row;
+void
+fn1 ()
+{
+  while (1)
+    b[0] = b[0] ? (int *) -1 : 0;
+}

gcc/tree-ssa-pre.c

@@ -3981,9 +3981,18 @@ compute_avail (void)
 		  {
 		  case VN_NARY:
 		    {
+		      enum tree_code code = gimple_assign_rhs_code (stmt);
 		      vn_nary_op_t nary;
+
+		      /* COND_EXPR and VEC_COND_EXPR are awkward in
+			 that they contain an embedded complex expression.
+			 Don't even try to shove those through PRE.  */
+		      if (code == COND_EXPR
+			  || code == VEC_COND_EXPR)
+			continue;
+
 		      vn_nary_op_lookup_pieces (gimple_num_ops (stmt) - 1,
-						gimple_assign_rhs_code (stmt),
+						code,
 						gimple_expr_type (stmt),
 						gimple_assign_rhs1_ptr (stmt),
 						&nary);