* [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
@ 2022-02-03 19:58 Patrick Palka
2022-02-03 20:26 ` Jason Merrill
0 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2022-02-03 19:58 UTC (permalink / raw)
To: gcc-patches
When synthesizing a defaulted comparison op from
maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
noexcept-spec afterwards.
Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
trunk and perhaps 11?
PR c++/96242
gcc/cp/ChangeLog:
* pt.cc (maybe_instantiate_noexcept): Keep going after
successfully synthesizing a DECL_MAYBE_DELETED fn.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/spaceship-synth15.C: New test.
---
gcc/cp/pt.cc | 3 ++-
.../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
2 files changed, 24 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index 6dd64101ced..03345ed3ed3 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -25986,7 +25986,8 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
++function_depth;
maybe_synthesize_method (fn);
--function_depth;
- return !DECL_MAYBE_DELETED (fn);
+ if (DECL_MAYBE_DELETED (fn))
+ return false;
}
tree fntype = TREE_TYPE (fn);
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
new file mode 100644
index 00000000000..00ea6c10474
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
@@ -0,0 +1,22 @@
+// PR c++/96242
+// { dg-do compile { target c++20 } }
+
+#include <compare>
+
+template<bool B>
+struct X {
+ auto operator<=>(const X&) const noexcept(B) = default;
+ bool operator==(const X&) const noexcept(!B) = default;
+};
+
+X<true> x_t;
+static_assert(noexcept(x_t <=> x_t));
+static_assert(noexcept(x_t < x_t));
+static_assert(!noexcept(x_t == x_t));
+static_assert(!noexcept(x_t != x_t));
+
+X<false> x_f;
+static_assert(!noexcept(x_f <=> x_f));
+static_assert(!noexcept(x_f < x_f));
+static_assert(noexcept(x_f == x_f));
+static_assert(noexcept(x_f != x_f));
--
2.35.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
2022-02-03 19:58 [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242] Patrick Palka
@ 2022-02-03 20:26 ` Jason Merrill
2022-02-03 21:06 ` Patrick Palka
0 siblings, 1 reply; 6+ messages in thread
From: Jason Merrill @ 2022-02-03 20:26 UTC (permalink / raw)
To: Patrick Palka, gcc-patches
On 2/3/22 14:58, Patrick Palka wrote:
> When synthesizing a defaulted comparison op from
> maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
> noexcept-spec afterwards.
Hmm, there shouldn't be any need to instantiate the noexcept-spec
afterwards, it should have been set by ~comp_info.
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk and perhaps 11?
>
> PR c++/96242
>
> gcc/cp/ChangeLog:
>
> * pt.cc (maybe_instantiate_noexcept): Keep going after
> successfully synthesizing a DECL_MAYBE_DELETED fn.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/spaceship-synth15.C: New test.
> ---
> gcc/cp/pt.cc | 3 ++-
> .../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
> 2 files changed, 24 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 6dd64101ced..03345ed3ed3 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -25986,7 +25986,8 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
> ++function_depth;
> maybe_synthesize_method (fn);
> --function_depth;
> - return !DECL_MAYBE_DELETED (fn);
> + if (DECL_MAYBE_DELETED (fn))
> + return false;
> }
>
> tree fntype = TREE_TYPE (fn);
> diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> new file mode 100644
> index 00000000000..00ea6c10474
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> @@ -0,0 +1,22 @@
> +// PR c++/96242
> +// { dg-do compile { target c++20 } }
> +
> +#include <compare>
> +
> +template<bool B>
> +struct X {
> + auto operator<=>(const X&) const noexcept(B) = default;
> + bool operator==(const X&) const noexcept(!B) = default;
> +};
> +
> +X<true> x_t;
> +static_assert(noexcept(x_t <=> x_t));
> +static_assert(noexcept(x_t < x_t));
> +static_assert(!noexcept(x_t == x_t));
> +static_assert(!noexcept(x_t != x_t));
> +
> +X<false> x_f;
> +static_assert(!noexcept(x_f <=> x_f));
> +static_assert(!noexcept(x_f < x_f));
> +static_assert(noexcept(x_f == x_f));
> +static_assert(noexcept(x_f != x_f));
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
2022-02-03 20:26 ` Jason Merrill
@ 2022-02-03 21:06 ` Patrick Palka
2022-02-03 21:38 ` Jason Merrill
0 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2022-02-03 21:06 UTC (permalink / raw)
To: Jason Merrill; +Cc: Patrick Palka, gcc-patches
On Thu, 3 Feb 2022, Jason Merrill wrote:
> On 2/3/22 14:58, Patrick Palka wrote:
> > When synthesizing a defaulted comparison op from
> > maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
> > noexcept-spec afterwards.
>
> Hmm, there shouldn't be any need to instantiate the noexcept-spec afterwards,
> it should have been set by ~comp_info.
It appears the comp_info class sets the noexcept-spec only if the
comparison function hasn't been declared with an explicit noexcept-spec.
Otherwise the class doesn't touch the noexcept-spec, and it remains a
DEFERRED_NOEXCEPT with non-NULL DEFERRED_NOEXCEPT_PATTERN.
>
> > Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> > trunk and perhaps 11?
> >
> > PR c++/96242
> >
> > gcc/cp/ChangeLog:
> >
> > * pt.cc (maybe_instantiate_noexcept): Keep going after
> > successfully synthesizing a DECL_MAYBE_DELETED fn.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/cpp2a/spaceship-synth15.C: New test.
> > ---
> > gcc/cp/pt.cc | 3 ++-
> > .../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
> > 2 files changed, 24 insertions(+), 1 deletion(-)
> > create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> >
> > diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> > index 6dd64101ced..03345ed3ed3 100644
> > --- a/gcc/cp/pt.cc
> > +++ b/gcc/cp/pt.cc
> > @@ -25986,7 +25986,8 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t
> > complain)
> > ++function_depth;
> > maybe_synthesize_method (fn);
> > --function_depth;
> > - return !DECL_MAYBE_DELETED (fn);
> > + if (DECL_MAYBE_DELETED (fn))
> > + return false;
> > }
> > tree fntype = TREE_TYPE (fn);
> > diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> > b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> > new file mode 100644
> > index 00000000000..00ea6c10474
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> > @@ -0,0 +1,22 @@
> > +// PR c++/96242
> > +// { dg-do compile { target c++20 } }
> > +
> > +#include <compare>
> > +
> > +template<bool B>
> > +struct X {
> > + auto operator<=>(const X&) const noexcept(B) = default;
> > + bool operator==(const X&) const noexcept(!B) = default;
> > +};
> > +
> > +X<true> x_t;
> > +static_assert(noexcept(x_t <=> x_t));
> > +static_assert(noexcept(x_t < x_t));
> > +static_assert(!noexcept(x_t == x_t));
> > +static_assert(!noexcept(x_t != x_t));
> > +
> > +X<false> x_f;
> > +static_assert(!noexcept(x_f <=> x_f));
> > +static_assert(!noexcept(x_f < x_f));
> > +static_assert(noexcept(x_f == x_f));
> > +static_assert(noexcept(x_f != x_f));
>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
2022-02-03 21:06 ` Patrick Palka
@ 2022-02-03 21:38 ` Jason Merrill
2022-02-04 17:04 ` Patrick Palka
0 siblings, 1 reply; 6+ messages in thread
From: Jason Merrill @ 2022-02-03 21:38 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches
On 2/3/22 16:06, Patrick Palka wrote:
> On Thu, 3 Feb 2022, Jason Merrill wrote:
>
>> On 2/3/22 14:58, Patrick Palka wrote:
>>> When synthesizing a defaulted comparison op from
>>> maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
>>> noexcept-spec afterwards.
>>
>> Hmm, there shouldn't be any need to instantiate the noexcept-spec afterwards,
>> it should have been set by ~comp_info.
>
> It appears the comp_info class sets the noexcept-spec only if the
> comparison function hasn't been declared with an explicit noexcept-spec.
> Otherwise the class doesn't touch the noexcept-spec, and it remains a
> DEFERRED_NOEXCEPT with non-NULL DEFERRED_NOEXCEPT_PATTERN.
Ah, I see. So perhaps we should entirely skip the current
DECL_MAYBE_DELETED handling in maybe_instantiate_noexcept if we have
DEFERRED_NOEXCEPT with non-null DEFERRED_NOEXCEPT_PATTERN (which seems
to want another macro)?
>>> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
>>> trunk and perhaps 11?
>>>
>>> PR c++/96242
>>>
>>> gcc/cp/ChangeLog:
>>>
>>> * pt.cc (maybe_instantiate_noexcept): Keep going after
>>> successfully synthesizing a DECL_MAYBE_DELETED fn.
>>>
>>> gcc/testsuite/ChangeLog:
>>>
>>> * g++.dg/cpp2a/spaceship-synth15.C: New test.
>>> ---
>>> gcc/cp/pt.cc | 3 ++-
>>> .../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
>>> 2 files changed, 24 insertions(+), 1 deletion(-)
>>> create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>>>
>>> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
>>> index 6dd64101ced..03345ed3ed3 100644
>>> --- a/gcc/cp/pt.cc
>>> +++ b/gcc/cp/pt.cc
>>> @@ -25986,7 +25986,8 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t
>>> complain)
>>> ++function_depth;
>>> maybe_synthesize_method (fn);
>>> --function_depth;
>>> - return !DECL_MAYBE_DELETED (fn);
>>> + if (DECL_MAYBE_DELETED (fn))
>>> + return false;
>>> }
>>> tree fntype = TREE_TYPE (fn);
>>> diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>>> b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>>> new file mode 100644
>>> index 00000000000..00ea6c10474
>>> --- /dev/null
>>> +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>>> @@ -0,0 +1,22 @@
>>> +// PR c++/96242
>>> +// { dg-do compile { target c++20 } }
>>> +
>>> +#include <compare>
>>> +
>>> +template<bool B>
>>> +struct X {
>>> + auto operator<=>(const X&) const noexcept(B) = default;
>>> + bool operator==(const X&) const noexcept(!B) = default;
>>> +};
>>> +
>>> +X<true> x_t;
>>> +static_assert(noexcept(x_t <=> x_t));
>>> +static_assert(noexcept(x_t < x_t));
>>> +static_assert(!noexcept(x_t == x_t));
>>> +static_assert(!noexcept(x_t != x_t));
>>> +
>>> +X<false> x_f;
>>> +static_assert(!noexcept(x_f <=> x_f));
>>> +static_assert(!noexcept(x_f < x_f));
>>> +static_assert(noexcept(x_f == x_f));
>>> +static_assert(noexcept(x_f != x_f));
>>
>>
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
2022-02-03 21:38 ` Jason Merrill
@ 2022-02-04 17:04 ` Patrick Palka
2022-02-04 22:00 ` Jason Merrill
0 siblings, 1 reply; 6+ messages in thread
From: Patrick Palka @ 2022-02-04 17:04 UTC (permalink / raw)
To: Jason Merrill; +Cc: Patrick Palka, gcc-patches
On Thu, 3 Feb 2022, Jason Merrill wrote:
> On 2/3/22 16:06, Patrick Palka wrote:
> > On Thu, 3 Feb 2022, Jason Merrill wrote:
> >
> > > On 2/3/22 14:58, Patrick Palka wrote:
> > > > When synthesizing a defaulted comparison op from
> > > > maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
> > > > noexcept-spec afterwards.
> > >
> > > Hmm, there shouldn't be any need to instantiate the noexcept-spec
> > > afterwards,
> > > it should have been set by ~comp_info.
> >
> > It appears the comp_info class sets the noexcept-spec only if the
> > comparison function hasn't been declared with an explicit noexcept-spec.
> > Otherwise the class doesn't touch the noexcept-spec, and it remains a
> > DEFERRED_NOEXCEPT with non-NULL DEFERRED_NOEXCEPT_PATTERN.
>
> Ah, I see. So perhaps we should entirely skip the current DECL_MAYBE_DELETED
> handling in maybe_instantiate_noexcept if we have DEFERRED_NOEXCEPT with
> non-null DEFERRED_NOEXCEPT_PATTERN (which seems to want another macro)?
Hmm, I tried something to that effect but it looks like mark_used relies
solely on the DECL_MAYBE_DELETED handling in maybe_instantiate_noexcept
to determine deletedness of a defaulted comparison operator (via trying
to synthesize it). So by sometimes sidestepping this handling, we end
up failing to diagnose the use of the deleted defaulted <=> in e.g.:
#include <compare>
struct A { };
template<bool B>
struct X {
auto operator<=>(const X&) const noexcept(B) = default;
A a;
};
X<true> x_t;
auto c = x_t <=> x_t; // should be error: use of deleted <=> b/c A lacks <=>
In light of this, I suppose mark_used should directly perform
DECL_MAYBE_DELETED synthesization of its own?
And it looks like DECL_MAYBE_DELETED is always false after doing
maybe_synthesize_method, so I think maybe_instantiate_noexcept should
return !DECL_DELETED_FN instead of !DECL_MAYBE_DELETED after synthesization.
How does this look? Lightly tested so far, bootstrap and regtesting in progress.
-- >8 --
PR c++/96242
gcc/cp/ChangeLog:
* decl2.cc (mark_used): Directly synthesize a DECL_MAYBE_DELETED
fn by calling maybe_synthesize_method instead of relying on
maybe_instantiate_noexcept.
* pt.cc (maybe_instantiate_noexcept): Restrict DECL_MAYBE_DELETED
synthesization to only fns with an implicit noexcept-spec, and
return !DECL_DELETED_FN instead of !DECL_MAYBE_DELETED afteward.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/spaceship-synth15.C: New test.
---
gcc/cp/decl2.cc | 17 ++++++++++----
gcc/cp/pt.cc | 11 +++++-----
.../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
3 files changed, 41 insertions(+), 9 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
index a2aa5f1de4e..4d3798d02fe 100644
--- a/gcc/cp/decl2.cc
+++ b/gcc/cp/decl2.cc
@@ -5772,10 +5772,19 @@ mark_used (tree decl, tsubst_flags_t complain)
if (TREE_CODE (decl) == CONST_DECL)
used_types_insert (DECL_CONTEXT (decl));
- if (TREE_CODE (decl) == FUNCTION_DECL
- && !DECL_DELETED_FN (decl)
- && !maybe_instantiate_noexcept (decl, complain))
- return false;
+ if (TREE_CODE (decl) == FUNCTION_DECL)
+ {
+ if (DECL_MAYBE_DELETED (decl))
+ {
+ ++function_depth;
+ maybe_synthesize_method (decl);
+ --function_depth;
+ }
+
+ if (!DECL_DELETED_FN (decl)
+ && !maybe_instantiate_noexcept (decl, complain))
+ return false;
+ }
if (TREE_CODE (decl) == FUNCTION_DECL
&& DECL_DELETED_FN (decl))
diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
index d219bba6ac1..584c752529b 100644
--- a/gcc/cp/pt.cc
+++ b/gcc/cp/pt.cc
@@ -25982,7 +25982,11 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
&& (!flag_noexcept_type || type_dependent_expression_p (fn)))
return true;
- if (DECL_MAYBE_DELETED (fn))
+ tree fntype = TREE_TYPE (fn);
+ tree spec = TYPE_RAISES_EXCEPTIONS (fntype);
+
+ if (DECL_MAYBE_DELETED (fn)
+ && (!spec || UNEVALUATED_NOEXCEPT_SPEC_P (spec)))
{
if (fn == current_function_decl)
/* We're in start_preparsed_function, keep going. */
@@ -25991,12 +25995,9 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
++function_depth;
maybe_synthesize_method (fn);
--function_depth;
- return !DECL_MAYBE_DELETED (fn);
+ return !DECL_DELETED_FN (fn);
}
- tree fntype = TREE_TYPE (fn);
- tree spec = TYPE_RAISES_EXCEPTIONS (fntype);
-
if (!spec || !TREE_PURPOSE (spec))
return true;
diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
new file mode 100644
index 00000000000..00ea6c10474
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
@@ -0,0 +1,22 @@
+// PR c++/96242
+// { dg-do compile { target c++20 } }
+
+#include <compare>
+
+template<bool B>
+struct X {
+ auto operator<=>(const X&) const noexcept(B) = default;
+ bool operator==(const X&) const noexcept(!B) = default;
+};
+
+X<true> x_t;
+static_assert(noexcept(x_t <=> x_t));
+static_assert(noexcept(x_t < x_t));
+static_assert(!noexcept(x_t == x_t));
+static_assert(!noexcept(x_t != x_t));
+
+X<false> x_f;
+static_assert(!noexcept(x_f <=> x_f));
+static_assert(!noexcept(x_f < x_f));
+static_assert(noexcept(x_f == x_f));
+static_assert(noexcept(x_f != x_f));
--
2.35.0
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242]
2022-02-04 17:04 ` Patrick Palka
@ 2022-02-04 22:00 ` Jason Merrill
0 siblings, 0 replies; 6+ messages in thread
From: Jason Merrill @ 2022-02-04 22:00 UTC (permalink / raw)
To: Patrick Palka; +Cc: gcc-patches
On 2/4/22 12:04, Patrick Palka wrote:
> On Thu, 3 Feb 2022, Jason Merrill wrote:
>
>> On 2/3/22 16:06, Patrick Palka wrote:
>>> On Thu, 3 Feb 2022, Jason Merrill wrote:
>>>
>>>> On 2/3/22 14:58, Patrick Palka wrote:
>>>>> When synthesizing a defaulted comparison op from
>>>>> maybe_instantiate_noexcept, we seem to be forgetting to instantiate the
>>>>> noexcept-spec afterwards.
>>>>
>>>> Hmm, there shouldn't be any need to instantiate the noexcept-spec
>>>> afterwards,
>>>> it should have been set by ~comp_info.
>>>
>>> It appears the comp_info class sets the noexcept-spec only if the
>>> comparison function hasn't been declared with an explicit noexcept-spec.
>>> Otherwise the class doesn't touch the noexcept-spec, and it remains a
>>> DEFERRED_NOEXCEPT with non-NULL DEFERRED_NOEXCEPT_PATTERN.
>>
>> Ah, I see. So perhaps we should entirely skip the current DECL_MAYBE_DELETED
>> handling in maybe_instantiate_noexcept if we have DEFERRED_NOEXCEPT with
>> non-null DEFERRED_NOEXCEPT_PATTERN (which seems to want another macro)?
>
> Hmm, I tried something to that effect but it looks like mark_used relies
> solely on the DECL_MAYBE_DELETED handling in maybe_instantiate_noexcept
> to determine deletedness of a defaulted comparison operator (via trying
> to synthesize it). So by sometimes sidestepping this handling, we end
> up failing to diagnose the use of the deleted defaulted <=> in e.g.:
>
> #include <compare>
>
> struct A { };
>
> template<bool B>
> struct X {
> auto operator<=>(const X&) const noexcept(B) = default;
> A a;
> };
>
> X<true> x_t;
> auto c = x_t <=> x_t; // should be error: use of deleted <=> b/c A lacks <=>
>
> In light of this, I suppose mark_used should directly perform
> DECL_MAYBE_DELETED synthesization of its own?
>
> And it looks like DECL_MAYBE_DELETED is always false after doing
> maybe_synthesize_method, so I think maybe_instantiate_noexcept should
> return !DECL_DELETED_FN instead of !DECL_MAYBE_DELETED after synthesization.
>
> How does this look? Lightly tested so far, bootstrap and regtesting in progress.
>
> -- >8 --
>
> PR c++/96242
>
> gcc/cp/ChangeLog:
>
> * decl2.cc (mark_used): Directly synthesize a DECL_MAYBE_DELETED
> fn by calling maybe_synthesize_method instead of relying on
> maybe_instantiate_noexcept.
> * pt.cc (maybe_instantiate_noexcept): Restrict DECL_MAYBE_DELETED
> synthesization to only fns with an implicit noexcept-spec, and
> return !DECL_DELETED_FN instead of !DECL_MAYBE_DELETED afteward.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/cpp2a/spaceship-synth15.C: New test.
> ---
> gcc/cp/decl2.cc | 17 ++++++++++----
> gcc/cp/pt.cc | 11 +++++-----
> .../g++.dg/cpp2a/spaceship-synth15.C | 22 +++++++++++++++++++
> 3 files changed, 41 insertions(+), 9 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
>
> diff --git a/gcc/cp/decl2.cc b/gcc/cp/decl2.cc
> index a2aa5f1de4e..4d3798d02fe 100644
> --- a/gcc/cp/decl2.cc
> +++ b/gcc/cp/decl2.cc
> @@ -5772,10 +5772,19 @@ mark_used (tree decl, tsubst_flags_t complain)
> if (TREE_CODE (decl) == CONST_DECL)
> used_types_insert (DECL_CONTEXT (decl));
>
> - if (TREE_CODE (decl) == FUNCTION_DECL
> - && !DECL_DELETED_FN (decl)
> - && !maybe_instantiate_noexcept (decl, complain))
> - return false;
> + if (TREE_CODE (decl) == FUNCTION_DECL)
> + {
> + if (DECL_MAYBE_DELETED (decl))
> + {
> + ++function_depth;
> + maybe_synthesize_method (decl);
> + --function_depth;
> + }
> +
> + if (!DECL_DELETED_FN (decl)
> + && !maybe_instantiate_noexcept (decl, complain))
> + return false;
At this point we might move the call to maybe_instantiate_noexcept after
the DECL_DELETED_FN handling just below. OK either way.
> + }
>
> if (TREE_CODE (decl) == FUNCTION_DECL
> && DECL_DELETED_FN (decl))
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index d219bba6ac1..584c752529b 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -25982,7 +25982,11 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
> && (!flag_noexcept_type || type_dependent_expression_p (fn)))
> return true;
>
> - if (DECL_MAYBE_DELETED (fn))
> + tree fntype = TREE_TYPE (fn);
> + tree spec = TYPE_RAISES_EXCEPTIONS (fntype);
> +
> + if (DECL_MAYBE_DELETED (fn)
> + && (!spec || UNEVALUATED_NOEXCEPT_SPEC_P (spec)))
> {
> if (fn == current_function_decl)
> /* We're in start_preparsed_function, keep going. */
> @@ -25991,12 +25995,9 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain)
> ++function_depth;
> maybe_synthesize_method (fn);
> --function_depth;
> - return !DECL_MAYBE_DELETED (fn);
> + return !DECL_DELETED_FN (fn);
> }
>
> - tree fntype = TREE_TYPE (fn);
> - tree spec = TYPE_RAISES_EXCEPTIONS (fntype);
> -
> if (!spec || !TREE_PURPOSE (spec))
> return true;
>
> diff --git a/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> new file mode 100644
> index 00000000000..00ea6c10474
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp2a/spaceship-synth15.C
> @@ -0,0 +1,22 @@
> +// PR c++/96242
> +// { dg-do compile { target c++20 } }
> +
> +#include <compare>
> +
> +template<bool B>
> +struct X {
> + auto operator<=>(const X&) const noexcept(B) = default;
> + bool operator==(const X&) const noexcept(!B) = default;
> +};
> +
> +X<true> x_t;
> +static_assert(noexcept(x_t <=> x_t));
> +static_assert(noexcept(x_t < x_t));
> +static_assert(!noexcept(x_t == x_t));
> +static_assert(!noexcept(x_t != x_t));
> +
> +X<false> x_f;
> +static_assert(!noexcept(x_f <=> x_f));
> +static_assert(!noexcept(x_f < x_f));
> +static_assert(noexcept(x_f == x_f));
> +static_assert(noexcept(x_f != x_f));
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-02-04 22:00 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-03 19:58 [PATCH] c++: conditional noexcept-spec on defaulted comparison op [PR96242] Patrick Palka
2022-02-03 20:26 ` Jason Merrill
2022-02-03 21:06 ` Patrick Palka
2022-02-03 21:38 ` Jason Merrill
2022-02-04 17:04 ` Patrick Palka
2022-02-04 22:00 ` Jason Merrill
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