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Re: [PATCH] [PR86397] set p_t_decl while canonicalizing eh specs for mangling


OK, thanks.
On Wed, Dec 5, 2018 at 1:32 AM Alexandre Oliva <aoliva@redhat.com> wrote:
>
> On Nov 29, 2018, Jason Merrill <jason@redhat.com> wrote:
>
> > Let's go with this.  And remove the comment.
>
> > And the !processing_template_decl is also redundant, since that's
> > checked at the top of value_dependent_expression_p.
>
> I've tested this on i686- and x86_64-linux-gnu.  Ok to install?
>
>
> [PR86397] resolve nondependent noexcept specs early in C++1[14]
>
> From: Alexandre Oliva <aoliva@redhat.com>
>
> build_noexcept_spec refrained from resolving nondependent noexcept
> expressions when they were not part of the function types (C++ 11 and
> 14).  This caused problems during mangling: canonical_eh_spec, when
> called on the template function type, would find an unresolved but not
> explicitly deferred expression, and nothrow_spec_p would reject it.
>
> We could relax the mangling logic to skip canonical_eh_spec, but since
> -Wnoexcept-type warns when mangling function names that change as
> noexcept specs become part of types and of mangling in C++17, and the
> test at mangling time may give incorrect results if the spec is not
> resolved, we might as well keep things simple and resolve nondependent
> noexcept specs sooner rather than later.  This is what this patch does.
>
>
> for  gcc/cp/ChangeLog
>
>         PR c++/86397
>         * except.c (build_noexcept_spec): Resolve nondependent
>         expressions.
>
> for gcc/testsuite/ChangeLog
>
>         PR c++/86397
>         * g++.dg/cpp0x/pr86397-1.C: New.
>         * g++.dg/cpp0x/pr86397-2.C: New.
> ---
>  gcc/cp/except.c                        |    5 +----
>  gcc/testsuite/g++.dg/cpp0x/pr86397-1.C |    4 ++++
>  gcc/testsuite/g++.dg/cpp0x/pr86397-2.C |    4 ++++
>  3 files changed, 9 insertions(+), 4 deletions(-)
>  create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr86397-1.C
>  create mode 100644 gcc/testsuite/g++.dg/cpp0x/pr86397-2.C
>
> diff --git a/gcc/cp/except.c b/gcc/cp/except.c
> index 3449b59b3cc0..a6951baa35c6 100644
> --- a/gcc/cp/except.c
> +++ b/gcc/cp/except.c
> @@ -1189,11 +1189,8 @@ type_throw_all_p (const_tree type)
>  tree
>  build_noexcept_spec (tree expr, tsubst_flags_t complain)
>  {
> -  /* This isn't part of the signature, so don't bother trying to evaluate
> -     it until instantiation.  */
>    if (TREE_CODE (expr) != DEFERRED_NOEXCEPT
> -      && (!processing_template_decl
> -         || (flag_noexcept_type && !value_dependent_expression_p (expr))))
> +      && !value_dependent_expression_p (expr))
>      {
>        expr = perform_implicit_conversion_flags (boolean_type_node, expr,
>                                                 complain,
> diff --git a/gcc/testsuite/g++.dg/cpp0x/pr86397-1.C b/gcc/testsuite/g++.dg/cpp0x/pr86397-1.C
> new file mode 100644
> index 000000000000..4f9f5fa7e4c8
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/pr86397-1.C
> @@ -0,0 +1,4 @@
> +// { dg-do compile { target c++11 } }
> +void e();
> +template <bool> void f(int() noexcept(e)) {}
> +template void f<false>(int()); // { dg-error "does not match" "" { target c++17 } }
> diff --git a/gcc/testsuite/g++.dg/cpp0x/pr86397-2.C b/gcc/testsuite/g++.dg/cpp0x/pr86397-2.C
> new file mode 100644
> index 000000000000..fb43499526e8
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/pr86397-2.C
> @@ -0,0 +1,4 @@
> +// { dg-do compile { target c++11 } }
> +void e();
> +template <bool> void f(int() noexcept(e)) {}
> +template void f<false>(int() noexcept);
>
>
> --
> Alexandre Oliva, freedom fighter   https://FSFLA.org/blogs/lxo
> Be the change, be Free!         FSF Latin America board member
> GNU Toolchain Engineer                Free Software Evangelist
> Hay que enGNUrecerse, pero sin perder la terGNUra jamás-GNUChe


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