On 5/16/22 11:36, 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);
Hmm, how do we get a COMPOUND_EXPR around a CONSTRUCTOR?
+ 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
