re PR c++/88977 (__builtin_is_constant_evaluated() as function template argument…

re PR c++/88977 (__builtin_is_constant_evaluated() as function template argument causes substitution failure)

	PR c++/88977
	* pt.c (convert_nontype_argument): Pass true as manifestly_const_eval
	to maybe_constant_value calls.

	* g++.dg/cpp2a/is-constant-evaluated7.C: New test.

From-SVN: r268780

gcc/cp/ChangeLog

+2019-02-11  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/88977
+	* pt.c (convert_nontype_argument): Pass true as manifestly_const_eval
+	to maybe_constant_value calls.
+
 2019-02-11  Marek Polacek  <polacek@redhat.com>
 
 	* typeck2.c (digest_init_r): Remove commented code.

gcc/cp/pt.c

@@ -6821,12 +6821,14 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
 	    /* Make sure we return NULL_TREE only if we have really issued
 	       an error, as described above.  */
 	    return (complain & tf_error) ? NULL_TREE : error_mark_node;
-	  expr = maybe_constant_value (expr);
+	  expr = maybe_constant_value (expr, NULL_TREE,
+				       /*manifestly_const_eval=*/true);
 	  expr = convert_from_reference (expr);
 	}
       else if (TYPE_PTR_OR_PTRMEM_P (type))
 	{
-	  tree folded = maybe_constant_value (expr);
+	  tree folded = maybe_constant_value (expr, NULL_TREE,
+					      /*manifestly_const_eval=*/true);
 	  if (TYPE_PTR_P (type) ? integer_zerop (folded)
 	      : null_member_pointer_value_p (folded))
 	    expr = folded;

gcc/testsuite/ChangeLog

+2019-02-11  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/88977
+	* g++.dg/cpp2a/is-constant-evaluated7.C: New test.
+
 2019-02-12  Wilco Dijkstra  <wdijkstr@arm.com>
 
 	PR tree-optimization/86637

gcc/testsuite/g++.dg/cpp2a/is-constant-evaluated7.C

+// P0595R2
+// PR c++/88977
+// { dg-do compile { target c++11 } }
+
+namespace std {
+  constexpr inline bool
+  is_constant_evaluated () noexcept
+  {
+    return __builtin_is_constant_evaluated ();
+  }
+}
+
+template<bool B> constexpr bool foo () { return B; }
+
+constexpr bool x = foo<std::is_constant_evaluated ()> ();
+constexpr bool y = foo<__builtin_is_constant_evaluated ()> ();
+static_assert (x, "");
+static_assert (y, "");