re PR c++/67364 ("accessing uninitialized member" error in constexpr context)

PR c++/67364

	* constexpr.c (cxx_eval_component_reference): Further tweak.

From-SVN: r233982
This commit is contained in:
Jason Merrill 2016-03-04 17:08:22 -05:00 committed by Jason Merrill
parent 39dce2b790
commit 188e53bd7e
3 changed files with 37 additions and 4 deletions

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@ -1,5 +1,8 @@
2016-03-04 Jason Merrill <jason@redhat.com>
PR c++/67364
* constexpr.c (cxx_eval_component_reference): Further tweak.
* constexpr.c (struct constexpr_ctx): Add save_exprs field.
(cxx_eval_loop_expr): Discard SAVE_EXPR values before looping.
(cxx_eval_constant_expression) [SAVE_EXPR]: Add it to the set.

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@ -1990,13 +1990,16 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t,
return t;
}
if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole)
&& !is_really_empty_class (TREE_TYPE (t)))
/* We only create a CONSTRUCTOR for a subobject when we modify it, so empty
classes never get represented; throw together a value now. */
if (is_really_empty_class (TREE_TYPE (t)))
return build_constructor (TREE_TYPE (t), NULL);
if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole))
{
/* 'whole' is part of the aggregate initializer we're currently
building; if there's no initializer for this member yet, that's an
error. But expand_aggr_init_1 doesn't bother to initialize really
empty classes, so ignore them here, too. */
error. */
if (!ctx->quiet)
error ("accessing uninitialized member %qD", part);
*non_constant_p = true;

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@ -0,0 +1,27 @@
// { dg-do compile { target c++14 } }
struct A
{
constexpr A(int) { }
};
struct B: A {
constexpr B(int i): A(i) { }
constexpr B(const B& b): A(b) { }
};
struct C {
B b;
constexpr C(int i): b(i) { }
constexpr C(const C&c): b(c.b) {}
};
constexpr int f()
{
C b1{42};
C b2{b1};
b2.b;
return 42;
}
constexpr int i = f();