Ping.
On Mon, May 16, 2022 at 11:36:27AM -0400, Marek Polacek wrote:
> On Sat, May 14, 2022 at 11:13:28PM -0400, Jason Merrill wrote:
> > On 5/13/22 19:41, Marek Polacek wrote:
> > > --- a/gcc/cp/typeck2.cc
> > > +++ b/gcc/cp/typeck2.cc
> > > @@ -1371,6 +1371,70 @@ digest_init_flags (tree type, tree init, int
> > > flags, tsubst_flags_t complain)
> > > return digest_init_r (type, init, 0, flags, complain);
> > > }
> > > +/* Return true if a prvalue is used as an initializer rather than for
> > > + temporary materialization. For instance:
> >
> > I might say "if SUBOB initializes the same object as FULL_EXPR"; the
> > full-expression could still end up initializing a temporary.
>
> Fixed.
>
> > > + A a = A{}; // initializer
> > > + A a = (A{}); // initializer
> > > + A a = (1, A{}); // initializer
> > > + A a = true ? A{} : A{}; // initializer
> > > + auto x = A{}.x; // temporary materialization
> > > + auto x = foo(A{}); // temporary materialization
> > > +
> > > + FULL_EXPR is the whole expression, SUBOB is its TARGET_EXPR
> > > subobject. */
> > > +
> > > +static bool
> > > +potential_prvalue_result_of (tree subob, tree full_expr)
> > > +{
> > > + if (subob == full_expr)
> > > + return true;
> > > + else if (TREE_CODE (full_expr) == TARGET_EXPR)
> > > + {
> > > + tree init = TARGET_EXPR_INITIAL (full_expr);
> > > + if (TREE_CODE (init) == COND_EXPR)
> > > + return (potential_prvalue_result_of (subob, TREE_OPERAND (init, 1))
> > > + || potential_prvalue_result_of (subob, TREE_OPERAND (init, 2)));
> > > + else if (TREE_CODE (init) == COMPOUND_EXPR)
> > > + return (potential_prvalue_result_of (subob, TREE_OPERAND (init, 0))
> >
> > We shouldn't recurse into the LHS of the comma, only the RHS.
>
> Fixed.
>
> > > + || potential_prvalue_result_of (subob, TREE_OPERAND (init, 1)));
> > > + /* ??? I don't know if this can be hit. If so, look inside the ( )
> > > + instead of the assert. */
> > > + else if (TREE_CODE (init) == PAREN_EXPR)
> > > + gcc_checking_assert (false);
> >
> > It seems trivial enough to recurse after the assert, in case it does happen
> > in the wild.
>
> OK, adjusted. Thanks!
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> -- >8 --
> Consider
>
> struct A {
> int x;
> int y = x;
> };
>
> struct B {
> int x = 0;
> int y = A{x}.y; // #1
> };
>
> where for #1 we end up with
>
> {.x=(&<PLACEHOLDER_EXPR struct B>)->x, .y=(&<PLACEHOLDER_EXPR struct A>)->x}
>
> that is, two PLACEHOLDER_EXPRs for different types on the same level in
> a {}. This crashes because our CONSTRUCTOR_PLACEHOLDER_BOUNDARY mechanism to
> avoid replacing unrelated PLACEHOLDER_EXPRs cannot deal with it.
>
> Here's why we wound up with those PLACEHOLDER_EXPRs: When we're performing
> cp_parser_late_parsing_nsdmi for "int y = A{x}.y;" we use
> finish_compound_literal
> on type=A, compound_literal={((struct B *) this)->x}. When digesting this
> initializer, we call get_nsdmi which creates a PLACEHOLDER_EXPR for A -- we
> don't
> have any object to refer to yet. After digesting, we have
>
> {.x=((struct B *) this)->x, .y=(&<PLACEHOLDER_EXPR struct A>)->x}
>
> and since we've created a PLACEHOLDER_EXPR inside it, we marked the whole ctor
> CONSTRUCTOR_PLACEHOLDER_BOUNDARY. f_c_l creates a TARGET_EXPR and returns
>
> TARGET_EXPR <D.2384, {.x=((struct B *) this)->x, .y=(&<PLACEHOLDER_EXPR
> struct A>)->x}>
>
> Then we get to
>
> B b = {};
>
> and call store_init_value, which digests the {}, which produces
>
> {.x=NON_LVALUE_EXPR <0>, .y=(TARGET_EXPR <D.2395, {.x=(&<PLACEHOLDER_EXPR
> struct B>)->x, .y=(&<PLACEHOLDER_EXPR struct A>)->x}>).y}
>
> lookup_placeholder in constexpr won't find an object to replace the
> PLACEHOLDER_EXPR for B, because ctx->object will be D.2395 of type A, and we
> cannot search outward from D.2395 to find 'b'.
>
> The call to replace_placeholders in store_init_value will not do anything:
> we've marked the inner { } CONSTRUCTOR_PLACEHOLDER_BOUNDARY, and it's only
> a sub-expression, so replace_placeholders does nothing, so the <P_E struct B>
> stays even though now is the perfect time to replace it because we have an
> object for it: 'b'.
>
> Later, in cp_gimplify_init_expr the *expr_p is
>
> D.2395 = {.x=(&<PLACEHOLDER_EXPR struct B>)->x, .y=(&<PLACEHOLDER_EXPR
> struct A>)->x}
>
> where D.2395 is of type A, but we crash because we hit <P_E struct B>, which
> has a different type.
>
> My idea was to replace <P_E struct A> with D.2384 after creating the
> TARGET_EXPR because that means we have an object we can refer to.
> Then clear CONSTRUCTOR_PLACEHOLDER_BOUNDARY because we no longer have
> a PLACEHOLDER_EXPR in the {}. Then store_init_value will be able to
> replace <P_E struct B> with 'b', and we should be good to go. We must
> be careful not to break guaranteed copy elision, so this replacement
> happens in digest_nsdmi_init where we can see the whole initializer,
> and avoid replacing any placeholders in TARGET_EXPRs used in the context
> of initialization/copy elision. This is achieved via the new function
> called potential_prvalue_result_of.
>
> While fixing this problem, I found PR105550, thus the FIXMEs in the
> tests.
>
> PR c++/100252
>
> gcc/cp/ChangeLog:
>
> * typeck2.cc (potential_prvalue_result_of): New.
> (replace_placeholders_for_class_temp_r): New.
> (digest_nsdmi_init): Call it.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp1y/nsdmi-aggr14.C: New test.
> * g++.dg/cpp1y/nsdmi-aggr15.C: New test.
> * g++.dg/cpp1y/nsdmi-aggr16.C: New test.
> * g++.dg/cpp1y/nsdmi-aggr17.C: New test.
> * g++.dg/cpp1y/nsdmi-aggr18.C: New test.
> * g++.dg/cpp1y/nsdmi-aggr19.C: New test.
> ---
> gcc/cp/typeck2.cc | 91 ++++++++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr14.C | 131 ++++++++++++++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr15.C | 80 +++++++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr16.C | 58 +++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr17.C | 138 ++++++++++++++++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr18.C | 56 +++++++++
> gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr19.C | 28 +++++
> 7 files changed, 582 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr14.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr15.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr16.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr17.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr18.C
> create mode 100644 gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr19.C
>
> diff --git a/gcc/cp/typeck2.cc b/gcc/cp/typeck2.cc
> index 1d92310edd0..1a96be3d412 100644
> --- a/gcc/cp/typeck2.cc
> +++ b/gcc/cp/typeck2.cc
> @@ -1371,6 +1371,71 @@ digest_init_flags (tree type, tree init, int flags,
> tsubst_flags_t complain)
> return digest_init_r (type, init, 0, flags, complain);
> }
>
> +/* Return true if SUBOB initializes the same object as FULL_EXPR.
> + For instance:
> +
> + A a = A{}; // initializer
> + A a = (A{}); // initializer
> + A a = (1, A{}); // initializer
> + A a = true ? A{} : A{}; // initializer
> + auto x = A{}.x; // temporary materialization
> + auto x = foo(A{}); // temporary materialization
> +
> + FULL_EXPR is the whole expression, SUBOB is its TARGET_EXPR subobject. */
> +
> +static bool
> +potential_prvalue_result_of (tree subob, tree full_expr)
> +{
> + if (subob == full_expr)
> + return true;
> + else if (TREE_CODE (full_expr) == TARGET_EXPR)
> + {
> + tree init = TARGET_EXPR_INITIAL (full_expr);
> + if (TREE_CODE (init) == COND_EXPR)
> + return (potential_prvalue_result_of (subob, TREE_OPERAND (init, 1))
> + || potential_prvalue_result_of (subob, TREE_OPERAND (init, 2)));
> + else if (TREE_CODE (init) == COMPOUND_EXPR)
> + return potential_prvalue_result_of (subob, TREE_OPERAND (init, 1));
> + /* ??? I don't know if this can be hit. */
> + else if (TREE_CODE (init) == PAREN_EXPR)
> + {
> + gcc_checking_assert (false);
> + return potential_prvalue_result_of (subob, TREE_OPERAND (init, 0));
> + }
> + }
> + return false;
> +}
> +
> +/* Callback to replace PLACEHOLDER_EXPRs in a TARGET_EXPR (which isn't used
> + in the context of guaranteed copy elision). */
> +
> +static tree
> +replace_placeholders_for_class_temp_r (tree *tp, int *, void *data)
> +{
> + tree t = *tp;
> + tree full_expr = *static_cast<tree *>(data);
> +
> + /* We're looking for a TARGET_EXPR nested in the whole expression. */
> + if (TREE_CODE (t) == TARGET_EXPR
> + && !potential_prvalue_result_of (t, full_expr))
> + {
> + tree init = TARGET_EXPR_INITIAL (t);
> + while (TREE_CODE (init) == COMPOUND_EXPR)
> + init = TREE_OPERAND (init, 1);
> + if (TREE_CODE (init) == CONSTRUCTOR
> + && CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init))
> + {
> + tree obj = TARGET_EXPR_SLOT (t);
> + replace_placeholders (init, obj);
> + /* We should have dealt with all PLACEHOLDER_EXPRs. */
> + CONSTRUCTOR_PLACEHOLDER_BOUNDARY (init) = false;
> + gcc_checking_assert (!find_placeholders (init));
> + }
> + }
> +
> + return NULL_TREE;
> +}
> +
> /* Process the initializer INIT for an NSDMI DECL (a FIELD_DECL). */
> tree
> digest_nsdmi_init (tree decl, tree init, tsubst_flags_t complain)
> @@ -1390,6 +1455,32 @@ digest_nsdmi_init (tree decl, tree init,
> tsubst_flags_t complain)
> && CP_AGGREGATE_TYPE_P (type))
> init = reshape_init (type, init, complain);
> init = digest_init_flags (type, init, flags, complain);
> +
> + /* We may have temporary materialization in a NSDMI, if the initializer
> + has something like A{} in it. Digesting the {} could have introduced
> + a PLACEHOLDER_EXPR referring to A. Now that we've got a TARGET_EXPR,
> + we have an object we can refer to. The reason we bother doing this
> + here is for code like
> +
> + struct A {
> + int x;
> + int y = x;
> + };
> +
> + struct B {
> + int x = 0;
> + int y = A{x}.y; // #1
> + };
> +
> + where in #1 we don't want to end up with two PLACEHOLDER_EXPRs for
> + different types on the same level in a {} when lookup_placeholder
> + wouldn't find a named object for the PLACEHOLDER_EXPR for A. Note,
> + temporary materialization does not occur when initializing an object
> + from a prvalue of the same type, therefore we must not replace the
> + placeholder with a temporary object so that it can be elided. */
> + cp_walk_tree (&init, replace_placeholders_for_class_temp_r, &init,
> + nullptr);
> +
> return init;
> }
>
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr14.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr14.C
> new file mode 100644
> index 00000000000..28b908a0a1a
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr14.C
> @@ -0,0 +1,131 @@
> +// PR c++/100252
> +// { dg-do run { target c++14 } }
> +
> +#define SA(X) static_assert ((X),#X)
> +
> +struct A {
> + int x;
> + int y = x;
> +};
> +
> +struct B {
> + int x = 0;
> + int y = A{x}.y;
> +};
> +
> +constexpr B csb1 = { };
> +SA(csb1.x == 0 && csb1.y == csb1.x);
> +constexpr B csb2 = { 1 };
> +SA(csb2.x == 1 && csb2.y == csb2.x);
> +constexpr B csb3 = { 1, 2 };
> +SA(csb3.x == 1 && csb3.y == 2);
> +
> +B sb1 = { };
> +B sb2 = { 1 };
> +B sb3 = { 1, 2};
> +
> +struct C {
> + int x = 0;
> + int y = (true, A{x}.y) + (A{x}.y, 0);
> +};
> +
> +constexpr C csc1 = { };
> +SA(csc1.x == 0 && csc1.y == csc1.x);
> +constexpr C csc2 = { 1 };
> +SA(csc2.x == 1 && csc2.y == csc2.x);
> +constexpr C csc3 = { 1, 2 };
> +SA(csc3.x == 1 && csc3.y == 2);
> +
> +C sc1 = { };
> +C sc2 = { 1 };
> +C sc3 = { 1, 2};
> +
> +struct D {
> + int x = 0;
> + int y = (A{x}.y);
> +};
> +
> +constexpr D csd1 = { };
> +SA(csd1.x == 0 && csd1.y == csd1.x);
> +constexpr D csd2 = { 1 };
> +SA(csd2.x == 1 && csd2.y == csd2.x);
> +constexpr D csd3 = { 1, 2 };
> +SA(csd3.x == 1 && csd3.y == 2);
> +
> +D sd1 = { };
> +D sd2 = { 1 };
> +D sd3 = { 1, 2};
> +
> +struct E {
> + int x = 0;
> + int y = x ? A{x}.y : A{x}.y;
> +};
> +
> +constexpr E cse1 = { };
> +SA(cse1.x == 0 && cse1.y == cse1.x);
> +constexpr E cse2 = { 1 };
> +SA(cse2.x == 1 && cse2.y == cse2.x);
> +constexpr E cse3 = { 1, 2 };
> +SA(cse3.x == 1 && cse3.y == 2);
> +
> +E se1 = { };
> +E se2 = { 1 };
> +E se3 = { 1, 2};
> +
> +int
> +main ()
> +{
> + if (sb1.x != 0 || sb1.x != sb1.y)
> + __builtin_abort();
> + if (sb2.x != 1 || sb2.x != sb2.y)
> + __builtin_abort();
> + if (sb3.x != 1 || sb3.y != 2)
> + __builtin_abort();
> +
> + if (sc1.x != 0 || sc1.x != sc1.y)
> + __builtin_abort();
> + if (sc2.x != 1 || sc2.x != sc2.y)
> + __builtin_abort();
> + if (sc3.x != 1 || sc3.y != 2)
> + __builtin_abort();
> +
> + B b1 = { };
> + B b2 = { 1 };
> + B b3 = { 1, 2};
> + if (b1.x != 0 || b1.x != b1.y)
> + __builtin_abort();
> + if (b2.x != 1 || b2.x != b2.y)
> + __builtin_abort();
> + if (b3.x != 1 || b3.y != 2)
> + __builtin_abort();
> +
> + C c1 = { };
> + C c2 = { 1 };
> + C c3 = { 1, 2};
> + if (c1.x != 0 || c1.x != c1.y)
> + __builtin_abort();
> + if (c2.x != 1 || c2.x != c2.y)
> + __builtin_abort();
> + if (c3.x != 1 || c3.y != 2)
> + __builtin_abort();
> +
> + D d1 = { };
> + D d2 = { 1 };
> + D d3 = { 1, 2};
> + if (d1.x != 0 || d1.x != d1.y)
> + __builtin_abort();
> + if (d2.x != 1 || d2.x != d2.y)
> + __builtin_abort();
> + if (d3.x != 1 || d3.y != 2)
> + __builtin_abort();
> +
> + E e1 = { };
> + E e2 = { 1 };
> + E e3 = { 1, 2};
> + if (e1.x != 0 || e1.x != e1.y)
> + __builtin_abort();
> + if (e2.x != 1 || e2.x != e2.y)
> + __builtin_abort();
> + if (e3.x != 1 || e3.y != 2)
> + __builtin_abort();
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr15.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr15.C
> new file mode 100644
> index 00000000000..d091d693042
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr15.C
> @@ -0,0 +1,80 @@
> +// PR c++/100252
> +// { dg-do run { target c++14 } }
> +
> +struct A {
> + int x;
> + int y = x;
> +};
> +
> +struct B {
> + int x = 0;
> + int y = A{x}.y;
> +};
> +
> +static void
> +test_b (B b1 = B{}, B b2 = B{1}, B b3 = B{1, 2})
> +{
> + if (b1.x != 0 || b1.y != b1.x)
> + __builtin_abort();
> + if (b2.x != 1 || b2.y != b2.x)
> + __builtin_abort();
> + if (b3.x != 1 || b3.y != 2)
> + __builtin_abort();
> +}
> +
> +struct C {
> + int x = 0;
> + int y = (true, A{x}.y) + (A{x}.y, 0);
> +};
> +
> +static void
> +test_c (C c1 = C{}, C c2 = C{1}, C c3 = C{1, 2})
> +{
> + if (c1.x != 0 || c1.y != c1.x)
> + __builtin_abort();
> + if (c2.x != 1 || c2.y != c2.x)
> + __builtin_abort();
> + if (c3.x != 1 || c3.y != 2)
> + __builtin_abort();
> +}
> +
> +struct D {
> + int x = 0;
> + int y = (A{x}.y);
> +};
> +
> +static void
> +test_d (D d1 = D{}, D d2 = D{1}, D d3 = D{1, 2})
> +{
> + if (d1.x != 0 || d1.y != d1.x)
> + __builtin_abort();
> + if (d2.x != 1 || d2.y != d2.x)
> + __builtin_abort();
> + if (d3.x != 1 || d3.y != 2)
> + __builtin_abort();
> +}
> +
> +struct E {
> + int x = 0;
> + int y = x ? A{x}.y : A{x}.y;
> +};
> +
> +static void
> +test_e (E e1 = E{}, E e2 = E{1}, E e3 = E{1, 2})
> +{
> + if (e1.x != 0 || e1.y != e1.x)
> + __builtin_abort();
> + if (e2.x != 1 || e2.y != e2.x)
> + __builtin_abort();
> + if (e3.x != 1 || e3.y != 2)
> + __builtin_abort();
> +}
> +
> +int
> +main ()
> +{
> + test_b ();
> + test_c ();
> + test_d ();
> + test_e ();
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr16.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr16.C
> new file mode 100644
> index 00000000000..dc6492c1b0b
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr16.C
> @@ -0,0 +1,58 @@
> +// PR c++/100252
> +// { dg-do compile { target c++14 } }
> +
> +#define SA(X) static_assert ((X),#X)
> +
> +struct A {
> + const A* p = this;
> +};
> +
> +struct B {
> + A a = A{};
> +};
> +
> +constexpr B b;
> +SA(b.a.p == &b.a);
> +B b1 = { };
> +
> +struct C {
> + A a = (true, A{});
> +};
> +
> +constexpr C c;
> +SA(c.a.p == &c.a);
> +C c1 = { };
> +
> +struct D {
> + A a = (A{});
> +};
> +
> +constexpr D d;
> +SA(d.a.p == &d.a);
> +D d1 = { };
> +
> +static constexpr A global_a;
> +
> +struct E {
> + A a = true ? A{} : A{};
> + A b = true ? global_a : (false ? A{} : A{});
> + A c = true ? (false ? A{} : A{}) : global_a;
> + A d = true ? (false ? A{} : A{}) : (false ? A{} : A{});
> +};
> +
> +// FIXME: When fixing this, also fix nsdmi-aggr17.C.
> +constexpr E e; // { dg-bogus "" "PR105550" { xfail *-*-* } }
> +SA (e.a.p == &e.a); // { dg-bogus "" "PR105550" { xfail *-*-* } }
> +
> +E e1 = { };
> +
> +struct F {
> + bool b = (A{}, true);
> +};
> +
> +constexpr F f;
> +
> +void
> +g (B b2 = B{}, C c2 = C{}, D d2 = D{}, E e2 = E{})
> +{
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr17.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr17.C
> new file mode 100644
> index 00000000000..fc27a2cdac7
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr17.C
> @@ -0,0 +1,138 @@
> +// PR c++/100252
> +// { dg-do run { target c++14 } }
> +
> +#define SA(X) static_assert ((X),#X)
> +
> +struct A {
> + int x;
> + int y = x;
> + const A* p = this;
> +};
> +
> +struct B {
> + int x = 42;
> + A a = A{x};
> +};
> +
> +constexpr B b;
> +SA(b.a.p == &b.a);
> +SA(b.x == 42);
> +B b2 = { };
> +B b3 = { 42 };
> +
> +struct C {
> + int x = 42;
> + B b = B{x};
> +};
> +
> +constexpr C c;
> +C c2;
> +C c3;
> +
> +struct D {
> + int x = 42;
> + A a = (true, A{x});
> +};
> +
> +constexpr D d;
> +SA(d.a.p == &d.a);
> +SA(d.x == 42);
> +D d2 = { };
> +D d3 = { 42 };
> +
> +struct E {
> + int x = 42;
> + A a = (A{x});
> +};
> +
> +constexpr E e;
> +SA(e.a.p == &e.a);
> +SA(e.x == 42);
> +E e2 = { };
> +E e3 = { 42 };
> +
> +struct F {
> + int x = 42;
> + A a = true ? A{x} : A{x};
> +};
> +
> +// FIXME: Doesn't work due to PR105550.
> +//constexpr F f;
> +//SA (f.a.p == &f.a);
> +SA (e.x == 42);
> +F f2 = { };
> +F f3 = { 42 };
> +
> +static void
> +test_b (B b4 = B{}, B b5 = B{ 42 })
> +{
> + if (b2.x != 42 || b2.a.x != 42 || b2.a.y != b2.a.x)
> + __builtin_abort ();
> + if (b3.x != 42 || b3.a.x != 42 || b3.a.y != b3.a.x)
> + __builtin_abort ();
> + if (b4.x != 42 || b4.a.x != 42 || b4.a.y != b4.a.x)
> + __builtin_abort ();
> + if (b5.x != 42 || b5.a.x != 42 || b5.a.y != b5.a.x)
> + __builtin_abort ();
> +}
> +
> +static void
> +test_c (C c4 = C{}, C c5 = C{ 42 })
> +{
> + if (c2.b.x != 42 || c2.b.a.x != 42 || c2.b.a.y != c2.b.a.x)
> + __builtin_abort ();
> + if (c3.b.x != 42 || c3.b.a.x != 42 || c3.b.a.y != c3.b.a.x)
> + __builtin_abort ();
> + if (c4.b.x != 42 || c4.b.a.x != 42 || c4.b.a.y != c4.b.a.x)
> + __builtin_abort ();
> + if (c5.b.x != 42 || c5.b.a.x != 42 || c5.b.a.y != c5.b.a.x)
> + __builtin_abort ();
> +}
> +
> +static void
> +test_d (D d4 = D{}, D d5 = D{ 42 })
> +{
> + if (d2.x != 42 || d2.a.x != 42 || d2.a.y != d2.a.x)
> + __builtin_abort ();
> + if (d3.x != 42 || d3.a.x != 42 || d3.a.y != d3.a.x)
> + __builtin_abort ();
> + if (d4.x != 42 || d4.a.x != 42 || d4.a.y != d4.a.x)
> + __builtin_abort ();
> + if (d5.x != 42 || d5.a.x != 42 || d5.a.y != d5.a.x)
> + __builtin_abort ();
> +}
> +
> +static void
> +test_e (E e4 = E{}, E e5 = E{ 42 })
> +{
> + if (e2.x != 42 || e2.a.x != 42 || e2.a.y != e2.a.x)
> + __builtin_abort ();
> + if (e3.x != 42 || e3.a.x != 42 || e3.a.y != e3.a.x)
> + __builtin_abort ();
> + if (e4.x != 42 || e4.a.x != 42 || e4.a.y != e4.a.x)
> + __builtin_abort ();
> + if (e5.x != 42 || e5.a.x != 42 || e5.a.y != e5.a.x)
> + __builtin_abort ();
> +}
> +
> +static void
> +test_f (F f4 = F{}, F f5 = F{ 42 })
> +{
> + if (f2.x != 42 || f2.a.x != 42 || f2.a.y != f2.a.x)
> + __builtin_abort ();
> + if (f3.x != 42 || f3.a.x != 42 || f3.a.y != f3.a.x)
> + __builtin_abort ();
> + if (f4.x != 42 || f4.a.x != 42 || f4.a.y != f4.a.x)
> + __builtin_abort ();
> + if (f5.x != 42 || f5.a.x != 42 || f5.a.y != f5.a.x)
> + __builtin_abort ();
> +}
> +int
> +main ()
> +{
> + test_b ();
> + test_c ();
> + test_d ();
> + test_e ();
> + test_f ();
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr18.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr18.C
> new file mode 100644
> index 00000000000..567b8ee96d9
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr18.C
> @@ -0,0 +1,56 @@
> +// PR c++/100252
> +// { dg-do compile { target c++14 } }
> +
> +struct B { };
> +
> +struct A {
> + int x;
> + int y = x;
> + constexpr operator B() { return B{}; }
> +};
> +
> +struct C {
> + int x = 42;
> + B b = A{x};
> +};
> +
> +C c1 = {};
> +C c2 = { 42 };
> +constexpr C c3 = {};
> +constexpr C c4 = { 42 };
> +
> +struct D {
> + int x = 42;
> + B b = (true, A{x});
> +};
> +
> +D d1 = {};
> +D d2 = { 42 };
> +constexpr D d3 = {};
> +constexpr D d4 = { 42 };
> +
> +struct E {
> + int x = 42;
> + B b = (A{x});
> +};
> +
> +E e1 = {};
> +E e2 = { 42 };
> +constexpr E e3 = {};
> +constexpr E e4 = { 42 };
> +
> +struct F {
> + int x = 42;
> + B b = (A{x});
> +};
> +
> +F f1 = {};
> +F f2 = { 42 };
> +constexpr F f3 = {};
> +constexpr F f4 = { 42 };
> +
> +void
> +g (C c5 = C{}, C c6 = C{ 42 }, D d5 = D{}, D d6 = D{ 42 },
> + E e5 = E{}, E e6 = E{ 42 }, F f5 = F{}, F f6 = F{ 42 })
> +{
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr19.C
> b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr19.C
> new file mode 100644
> index 00000000000..f4892e3379b
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp1y/nsdmi-aggr19.C
> @@ -0,0 +1,28 @@
> +// PR c++/100252
> +// { dg-do compile { target c++14 } }
> +
> +#define SA(X) static_assert ((X),#X)
> +
> +struct A {
> + const A* p = this;
> +};
> +
> +struct B {
> + A a = (A{}, A{});
> +};
> +
> +constexpr B b;
> +SA(b.a.p == &b.a);
> +
> +struct C {
> + int x;
> + int y = x;
> +};
> +
> +struct D {
> + int x = 0;
> + int y = (C{x}.y, C{x}.y);
> +};
> +
> +constexpr D d = { };
> +D d2 = {};
>
> base-commit: 682e587f1021241758f7dfe0b22651008622a312
> --
> 2.36.1
>
Marek
