On Tue, 5 Mar 2024, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
>
> -- >8 --
> Here we ICE because we call register_local_specialization while
> local_specializations is null, so
>
> local_specializations->put ();
>
> crashes on null this. It's null since maybe_instantiate_noexcept calls
> push_to_top_level which creates a new scope. Normally, I would have
> guessed that we need a new local_specialization_stack. But here we're
> dealing with an operand of a noexcept, which is an unevaluated operand,
> and those aren't registered in the hash map. maybe_instantiate_noexcept
> wasn't signalling that it's substituting an unevaluated operand though.
It thought it was noexcept-exprs rather than noexcept-specs that are
unevaluated contexts?
>
> PR c++/114114
>
> gcc/cp/ChangeLog:
>
> * pt.cc (maybe_instantiate_noexcept): Save/restore
> cp_unevaluated_operand, c_inhibit_evaluation_warnings, and
> cp_noexcept_operand around the tsubst_expr call.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp0x/noexcept84.C: New test.
> ---
> gcc/cp/pt.cc | 6 +++++
> gcc/testsuite/g++.dg/cpp0x/noexcept84.C | 32 +++++++++++++++++++++++++
> 2 files changed, 38 insertions(+)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept84.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index c4bc54a8fdb..11f7d33c766 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -26869,10 +26869,16 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t
> complain)
> if (orig_fn)
> ++processing_template_decl;
>
> + ++cp_unevaluated_operand;
> + ++c_inhibit_evaluation_warnings;
> + ++cp_noexcept_operand;
> /* Do deferred instantiation of the noexcept-specifier. */
> noex = tsubst_expr (DEFERRED_NOEXCEPT_PATTERN (noex),
> DEFERRED_NOEXCEPT_ARGS (noex),
> tf_warning_or_error, fn);
> + --cp_unevaluated_operand;
> + --c_inhibit_evaluation_warnings;
> + --cp_noexcept_operand;
>
> /* Build up the noexcept-specification. */
> spec = build_noexcept_spec (noex, tf_warning_or_error);
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> new file mode 100644
> index 00000000000..06f33264f77
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept84.C
> @@ -0,0 +1,32 @@
> +// PR c++/114114
> +// { dg-do compile { target c++11 } }
> +
> +template<bool B>
> +constexpr void
> +test ()
> +{
> + constexpr bool is_yes = B;
> + struct S {
> + constexpr S() noexcept(is_yes) { }
> + };
> + S s;
> +}
> +
> +constexpr bool foo() { return true; }
> +
> +template<typename T>
> +constexpr void
> +test2 ()
> +{
> + constexpr T (*pfn)() = &foo;
> + struct S {
> + constexpr S() noexcept(pfn()) { }
> + };
> + S s;
> +}
> +
> +int main()
> +{
> + test<true>();
> + test2<bool>();
> +}
>
> base-commit: 8776468d9e57ace5f832c1368243a6dbce9984d5
> --
> 2.44.0
>
>
