re PR c++/86184 (Conditional expression with omitted operand cannot use rvalue…

re PR c++/86184 (Conditional expression with omitted operand cannot use rvalue of type convertible to bool)

	PR c++/86184
	* tree.c (cp_save_expr): Don't call save_expr for TARGET_EXPRs.

	* g++.dg/ext/cond3.C: New test.

From-SVN: r262254

gcc/cp/ChangeLog

+2018-06-29  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/86184
+	* tree.c (cp_save_expr): Don't call save_expr for TARGET_EXPRs.
+
 2018-06-28  David Malcolm  <dmalcolm@redhat.com>
 
 	* parser.c (cp_parser_error_1): After issuing a conflict marker

gcc/cp/tree.c

@@ -4918,6 +4918,11 @@ cp_save_expr (tree expr)
      tree codes.  */
   if (processing_template_decl)
     return expr;
+
+  /* TARGET_EXPRs are only expanded once.  */
+  if (TREE_CODE (expr) == TARGET_EXPR)
+    return expr;
+
   return save_expr (expr);
 }
 

gcc/testsuite/ChangeLog

+2018-06-29  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/86184
+	* g++.dg/ext/cond3.C: New test.
+
 2018-06-29  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
 
 	* gcc.target/arm/arm-soft-strd-even.c: New test.

gcc/testsuite/g++.dg/ext/cond3.C

+// PR c++/86184
+// { dg-do run }
+// { dg-options "" }
+
+int j;
+struct X {
+  X() { j++; }
+  operator bool() { return true; }
+};
+
+/* Only create X once.  */
+bool b = X() ?: false;
+bool b2 = X() ? X() : false;
+
+int
+main ()
+{
+  if (j != 3)
+    __builtin_abort ();
+}