c++: local class memfn synth from uneval context [PR113063]
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Commit Message
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk?
-- >8 --
Here we first use and therefore synthesize the local class operator<=>
from an unevaluated context, which inadvertently affects synthesization
by causing functions used within the definition (such as the copy
constructor of std::strong_ordering) to not get marked as odr-used.
This patch fixes this by using maybe_push_to_top_level in synthesize_method
which ensures that cp_unevaluated_operand is cleared even in the
function-local case.
PR c++/113063
gcc/cp/ChangeLog:
* method.cc (synthesize_method): Use maybe_push_to_top_level
and maybe_pop_from_top_level.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/spaceship-synth16.C: New test.
---
gcc/cp/method.cc | 12 ++----------
gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C | 13 +++++++++++++
2 files changed, 15 insertions(+), 10 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C
Comments
On 12/18/23 14:50, Patrick Palka wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk?
OK.
> -- >8 --
>
> Here we first use and therefore synthesize the local class operator<=>
> from an unevaluated context, which inadvertently affects synthesization
> by causing functions used within the definition (such as the copy
> constructor of std::strong_ordering) to not get marked as odr-used.
>
> This patch fixes this by using maybe_push_to_top_level in synthesize_method
> which ensures that cp_unevaluated_operand is cleared even in the
> function-local case.
>
> PR c++/113063
>
> gcc/cp/ChangeLog:
>
> * method.cc (synthesize_method): Use maybe_push_to_top_level
> and maybe_pop_from_top_level.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/spaceship-synth16.C: New test.
> ---
> gcc/cp/method.cc | 12 ++----------
> gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C | 13 +++++++++++++
> 2 files changed, 15 insertions(+), 10 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C
>
> diff --git a/gcc/cp/method.cc b/gcc/cp/method.cc
> index 26e6eb79946..f645066077f 100644
> --- a/gcc/cp/method.cc
> +++ b/gcc/cp/method.cc
> @@ -1770,8 +1770,6 @@ decl_remember_implicit_trigger_p (tree decl)
> void
> synthesize_method (tree fndecl)
> {
> - bool nested = (current_function_decl != NULL_TREE);
> - tree context = decl_function_context (fndecl);
> bool need_body = true;
> tree stmt;
> location_t save_input_location = input_location;
> @@ -1795,10 +1793,7 @@ synthesize_method (tree fndecl)
> it now. */
> push_deferring_access_checks (dk_no_deferred);
>
> - if (! context)
> - push_to_top_level ();
> - else if (nested)
> - push_function_context ();
> + bool push_to_top = maybe_push_to_top_level (fndecl);
>
> input_location = DECL_SOURCE_LOCATION (fndecl);
>
> @@ -1843,10 +1838,7 @@ synthesize_method (tree fndecl)
>
> input_location = save_input_location;
>
> - if (! context)
> - pop_from_top_level ();
> - else if (nested)
> - pop_function_context ();
> + maybe_pop_from_top_level (push_to_top);
>
> pop_deferring_access_checks ();
>
> diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C
> new file mode 100644
> index 00000000000..8e59f7d2e46
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth16.C
> @@ -0,0 +1,13 @@
> +// PR c++/113063
> +// { dg-do link { target c++20 } }
> +
> +#include <compare>
> +
> +int main() {
> + struct X {
> + auto operator<=>(const X&) const = default;
> + };
> + X x;
> + static_assert(noexcept(x <=> x));
> + static_cast<void>(x <=> x);
> +}
@@ -1770,8 +1770,6 @@ decl_remember_implicit_trigger_p (tree decl)
void
synthesize_method (tree fndecl)
{
- bool nested = (current_function_decl != NULL_TREE);
- tree context = decl_function_context (fndecl);
bool need_body = true;
tree stmt;
location_t save_input_location = input_location;
@@ -1795,10 +1793,7 @@ synthesize_method (tree fndecl)
it now. */
push_deferring_access_checks (dk_no_deferred);
- if (! context)
- push_to_top_level ();
- else if (nested)
- push_function_context ();
+ bool push_to_top = maybe_push_to_top_level (fndecl);
input_location = DECL_SOURCE_LOCATION (fndecl);
@@ -1843,10 +1838,7 @@ synthesize_method (tree fndecl)
input_location = save_input_location;
- if (! context)
- pop_from_top_level ();
- else if (nested)
- pop_function_context ();
+ maybe_pop_from_top_level (push_to_top);
pop_deferring_access_checks ();
new file mode 100644
@@ -0,0 +1,13 @@
+// PR c++/113063
+// { dg-do link { target c++20 } }
+
+#include <compare>
+
+int main() {
+ struct X {
+ auto operator<=>(const X&) const = default;
+ };
+ X x;
+ static_assert(noexcept(x <=> x));
+ static_cast<void>(x <=> x);
+}