re PR c++/92831 (CWG1299 extend_ref_init_temps_1 punts on COND_EXPRs)

	PR c++/92831
	* call.c (build_conditional_expr_1): For ?: with omitted middle
	operand use cp_stabilize_reference if arg1 is glvalue_p rather than
	just if it is lvalue_p.

	* g++.dg/ext/temp-extend1.C: New test.

From-SVN: r279069

gcc/cp/ChangeLog

+2019-12-07  Jason Merrill  <jason@redhat.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92831
+	* call.c (build_conditional_expr_1): For ?: with omitted middle
+	operand use cp_stabilize_reference if arg1 is glvalue_p rather than
+	just if it is lvalue_p.
+
 2019-12-06  Jakub Jelinek  <jakub@redhat.com>
 
 	* parser.c (cp_parser_diagnose_invalid_type_name): Mention

gcc/cp/call.c

@@ -5077,7 +5077,7 @@ build_conditional_expr_1 (const op_location_t &loc,
 	warn_for_omitted_condop (loc, arg1);
 
       /* Make sure that lvalues remain lvalues.  See g++.oliva/ext1.C.  */
-      if (lvalue_p (arg1))
+      if (glvalue_p (arg1))
 	arg2 = arg1 = cp_stabilize_reference (arg1);
       else
 	arg2 = arg1 = cp_save_expr (arg1);

gcc/testsuite/ChangeLog

+2019-12-07  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92831
+	* g++.dg/ext/temp-extend1.C: New test.
+
 2019-12-06  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/92451

gcc/testsuite/g++.dg/ext/temp-extend1.C

+// PR c++/92831
+// { dg-do run { target c++11 } }
+// { dg-options "" }
+
+template<typename T> using id = T;
+struct S { S () : s (false) { ++c; } S (bool x) : s (x) { ++c; } ~S () { --c; }; bool s; static int c; };
+int S::c = 0;
+
+void
+foo (int i)
+{
+  const bool&& a
+    = id<S[3]>{false, true, false}[i].s
+      ? id<S[2]>{true, false}[i].s : id<S[4]>{true, false, true, false}[i].s;
+  if (S::c != (i ? 2 : 4))
+    __builtin_abort ();
+}
+
+void
+baz (int i)
+{
+  const bool&& a = id<S[3]>{false, true, false}[i].s
+		   ? : id<S[4]>{true, false, true, false}[i].s;
+  if (S::c != (i ? 3 : 4))
+    __builtin_abort ();
+}
+
+int
+main ()
+{
+  foo (0);
+  if (S::c != 0)
+    __builtin_abort ();
+  foo (1);
+  if (S::c != 0)
+    __builtin_abort ();
+  baz (0);
+  if (S::c != 0)
+    __builtin_abort ();
+  baz (1);
+  if (S::c != 0)
+    __builtin_abort ();
+}