cxx_eval_vec_init_1 was assuming that any CONSTRUCTOR would be for the
element type, which is silly in this context because an array
initializer is also a CONSTRUCTOR. Oops. While I was fixing this I
also changed value-initialization to be pre-evaluated like
default-initialization.
Tested x86_64-pc-linux-gnu, applying to trunk.
commit e421970c44311cf24389f8281f0e635523f9eea3
Author: Jason Merrill <ja...@redhat.com>
Date: Mon Aug 1 14:44:01 2011 -0400
PR c++/49924
* semantics.c (cxx_eval_vec_init_1): Fix logic.
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 47b714f..0b2a96f 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -6651,6 +6651,7 @@ cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
tree elttype = TREE_TYPE (atype);
int max = tree_low_cst (array_type_nelts (atype), 0);
VEC(constructor_elt,gc) *n = VEC_alloc (constructor_elt, gc, max + 1);
+ bool pre_init = false;
int i;
/* For the default constructor, build up a call to the default
@@ -6658,8 +6659,15 @@ cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
here, as for a constructor to be constexpr, all members must be
initialized, which for a defaulted default constructor means they must
be of a class type with a constexpr default constructor. */
- if (value_init)
- gcc_assert (!init);
+ if (TREE_CODE (elttype) == ARRAY_TYPE)
+ /* We only do this at the lowest level. */;
+ else if (value_init)
+ {
+ init = build_value_init (elttype, tf_warning_or_error);
+ init = cxx_eval_constant_expression
+ (call, init, allow_non_constant, addr, non_constant_p);
+ pre_init = true;
+ }
else if (!init)
{
VEC(tree,gc) *argvec = make_tree_vector ();
@@ -6669,6 +6677,7 @@ cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
release_tree_vector (argvec);
init = cxx_eval_constant_expression (call, init, allow_non_constant,
addr, non_constant_p);
+ pre_init = true;
}
if (*non_constant_p && !allow_non_constant)
@@ -6690,17 +6699,14 @@ cxx_eval_vec_init_1 (const constexpr_call *call, tree atype, tree init,
allow_non_constant, addr,
non_constant_p);
}
- else if (value_init)
+ else if (pre_init)
{
- eltinit = build_value_init (elttype, tf_warning_or_error);
- eltinit = cxx_eval_constant_expression
- (call, eltinit, allow_non_constant, addr, non_constant_p);
- }
- else if (TREE_CODE (init) == CONSTRUCTOR)
- {
- /* Initializing an element using the call to the default
- constructor we just built above. */
- eltinit = unshare_expr (init);
+ /* Initializing an element using value or default initialization
+ we just pre-built above. */
+ if (i == 0)
+ eltinit = init;
+ else
+ eltinit = unshare_expr (init);
}
else
{
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-array4.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-array4.C
new file mode 100644
index 0000000..9aeb75d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-array4.C
@@ -0,0 +1,14 @@
+// PR c++/49924
+// { dg-options -std=c++0x }
+
+struct A { constexpr A() { } };
+
+struct B {
+ A array[1]; //non-static member array of a literal type w constexpr ctor
+ constexpr B() : array{} { } // here is the problem
+};
+
+int main()
+{
+ constexpr B b{}; // won't compile
+}
