On 6/25/24 07:15, Jonathan Wakely wrote:
On Tue, 25 Jun 2024 at 03:12, Jason Merrill <ja...@redhat.com> wrote:
On 6/18/24 10:31, Marek Polacek wrote:
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk/14/13?
Makes sense to me, though probably the [meta.unary.prop] table should be
adjusted in the same way. Jonathan, what do you think?
Just to make sure I understand correctly, the suggestion is to change
the precondition for the trait to something like:
"remove_all_extents_t<T> shall be a complete type or cv void."
i.e. if T is incomplete then T[] cannot be used with the trait, right?
Yes.
Jason
-- >8 --
Here we started to ICE with r13-25: in check_trait_type, for "X[]" we
return true here:
if (kind == 1 && TREE_CODE (type) == ARRAY_TYPE && !TYPE_DOMAIN (type))
return true; // Array of unknown bound. Don't care about completeness.
and then end up crashing in record_has_unique_obj_representations:
4836 if (cur != wi::to_offset (sz))
because sz is null.
https://eel.is/c++draft/type.traits#tab:meta.unary.prop-row-47-column-3-sentence-1
says that the preconditions for __has_unique_object_representations are:
"T shall be a complete type, cv void, or an array of unknown bound" and
that "For an array type T, the same result as
has_unique_object_representations_v<remove_all_extents_t<T>>" so T[]
should be treated as T. So we should use kind==2 for the trait.
PR c++/115476
gcc/cp/ChangeLog:
* semantics.cc (finish_trait_expr)
<case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS>: Move below to call
check_trait_type with kind==2.
gcc/testsuite/ChangeLog:
* g++.dg/cpp1z/has-unique-obj-representations4.C: New test.
---
gcc/cp/semantics.cc | 2 +-
.../cpp1z/has-unique-obj-representations4.C | 16 ++++++++++++++++
2 files changed, 17 insertions(+), 1 deletion(-)
create mode 100644
gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C
diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
index 08f5f245e7d..42251b6764b 100644
--- a/gcc/cp/semantics.cc
+++ b/gcc/cp/semantics.cc
@@ -12966,7 +12966,6 @@ finish_trait_expr (location_t loc, cp_trait_kind kind,
tree type1, tree type2)
case CPTK_HAS_NOTHROW_COPY:
case CPTK_HAS_TRIVIAL_COPY:
case CPTK_HAS_TRIVIAL_DESTRUCTOR:
- case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
if (!check_trait_type (type1))
return error_mark_node;
break;
@@ -12976,6 +12975,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind,
tree type1, tree type2)
case CPTK_IS_STD_LAYOUT:
case CPTK_IS_TRIVIAL:
case CPTK_IS_TRIVIALLY_COPYABLE:
+ case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
if (!check_trait_type (type1, /* kind = */ 2))
return error_mark_node;
break;
diff --git a/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C
b/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C
new file mode 100644
index 00000000000..d6949dc7005
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/has-unique-obj-representations4.C
@@ -0,0 +1,16 @@
+// PR c++/115476
+// { dg-do compile { target c++11 } }
+
+struct X;
+static_assert(__has_unique_object_representations(X), ""); // { dg-error
"invalid use of incomplete type" }
+static_assert(__has_unique_object_representations(X[]), ""); // { dg-error
"invalid use of incomplete type" }
+static_assert(__has_unique_object_representations(X[1]), ""); // { dg-error
"invalid use of incomplete type" }
+static_assert(__has_unique_object_representations(X[][1]), ""); // { dg-error
"invalid use of incomplete type" }
+
+struct X {
+ int x;
+};
+static_assert(__has_unique_object_representations(X), "");
+static_assert(__has_unique_object_representations(X[]), "");
+static_assert(__has_unique_object_representations(X[1]), "");
+static_assert(__has_unique_object_representations(X[][1]), "");
base-commit: 7f9be55a4630134a237219af9cc8143e02080380
