* [PATCH] c++: ICE with deferred noexcept when deducing targs [PR82099]
@ 2021-01-05 1:31 Marek Polacek
2021-01-05 16:02 ` Jason Merrill
0 siblings, 1 reply; 2+ messages in thread
From: Marek Polacek @ 2021-01-05 1:31 UTC (permalink / raw)
To: Jason Merrill, GCC Patches
In this test we ICE in type_throw_all_p because it got a deferred
noexcept which it shouldn't. Here's the story:
In noexcept61.C, we call bar, so we perform overload resolution. When
adding the (only) candidate, we need to deduce template arguments, so
call fn_type_unification as usually. That deduces U to
void (*) (int &, int &)
which is correct, but its noexcept-spec is deferred_noexcept. Then
we call add_function_candidate (bar), wherein we try to create an
implicit conversion sequence for every argument. Since baz<int> is
of unknown type, we instantiate_type it; it is a TEMPLATE_ID_EXPR
so that calls resolve_address_of_overloaded_function. But we crash
there, because target_type contains the deferred_noexcept.
So we need to maybe_instantiate_noexcept before we can compare types.
resolve_overloaded_unification seemed like the appropriate spot, now
fn_type_unification produces the function type with its noexcept-spec
instantiated. This shouldn't go against CWG 1330 because here we
really need to instantiate the noexcept-spec.
This also fixes class-deduction76.C, a dg-ice test I recently added,
therefore this fix also fixes c++/90799, yay.
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
gcc/cp/ChangeLog:
PR c++/82099
* pt.c (resolve_overloaded_unification): Call
maybe_instantiate_noexcept after instantiating the function
decl.
gcc/testsuite/ChangeLog:
PR c++/82099
* g++.dg/cpp1z/class-deduction76.C: Remove dg-ice.
* g++.dg/cpp0x/noexcept61.C: New test.
---
gcc/cp/pt.c | 3 +++
gcc/testsuite/g++.dg/cpp0x/noexcept61.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/cpp1z/class-deduction76.C | 1 -
3 files changed, 20 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept61.C
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 062ef858501..0d061adc2ed 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -22373,6 +22373,9 @@ resolve_overloaded_unification (tree tparms,
--function_depth;
}
+ if (flag_noexcept_type)
+ maybe_instantiate_noexcept (fn, tf_none);
+
elem = TREE_TYPE (fn);
if (try_one_overload (tparms, targs, tempargs, parm,
elem, strict, sub_strict, addr_p, explain_p)
diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept61.C b/gcc/testsuite/g++.dg/cpp0x/noexcept61.C
new file mode 100644
index 00000000000..653cd7e6680
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/noexcept61.C
@@ -0,0 +1,17 @@
+// PR c++/82099
+// { dg-do compile { target c++11 } }
+
+template <typename T, typename U>
+void bar (T &x, T &y, U u)
+{
+ u (x, y);
+}
+
+template <typename T>
+void baz (T &x, T &y) noexcept (noexcept (x == y));
+
+void
+foo (int x, int y)
+{
+ bar (x, y, baz<int>);
+}
diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
index 23bb6e8fa9a..a131a386baa 100644
--- a/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
+++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
@@ -1,6 +1,5 @@
// PR c++/90799
// { dg-do compile { target c++17 } }
-// { dg-ice "unify" }
template<class T>
void foo() noexcept(T::value);
base-commit: f262a3518877ccce9ed41b2e152c3a3564727bd6
--
2.29.2
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] c++: ICE with deferred noexcept when deducing targs [PR82099]
2021-01-05 1:31 [PATCH] c++: ICE with deferred noexcept when deducing targs [PR82099] Marek Polacek
@ 2021-01-05 16:02 ` Jason Merrill
0 siblings, 0 replies; 2+ messages in thread
From: Jason Merrill @ 2021-01-05 16:02 UTC (permalink / raw)
To: Marek Polacek, GCC Patches
On 1/4/21 8:31 PM, Marek Polacek wrote:
> In this test we ICE in type_throw_all_p because it got a deferred
> noexcept which it shouldn't. Here's the story:
>
> In noexcept61.C, we call bar, so we perform overload resolution. When
> adding the (only) candidate, we need to deduce template arguments, so
> call fn_type_unification as usually. That deduces U to
>
> void (*) (int &, int &)
>
> which is correct, but its noexcept-spec is deferred_noexcept. Then
> we call add_function_candidate (bar), wherein we try to create an
> implicit conversion sequence for every argument. Since baz<int> is
> of unknown type, we instantiate_type it; it is a TEMPLATE_ID_EXPR
> so that calls resolve_address_of_overloaded_function. But we crash
> there, because target_type contains the deferred_noexcept.
>
> So we need to maybe_instantiate_noexcept before we can compare types.
> resolve_overloaded_unification seemed like the appropriate spot, now
> fn_type_unification produces the function type with its noexcept-spec
> instantiated. This shouldn't go against CWG 1330 because here we
> really need to instantiate the noexcept-spec.
>
> This also fixes class-deduction76.C, a dg-ice test I recently added,
> therefore this fix also fixes c++/90799, yay.
>
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK.
> gcc/cp/ChangeLog:
>
> PR c++/82099
> * pt.c (resolve_overloaded_unification): Call
> maybe_instantiate_noexcept after instantiating the function
> decl.
>
> gcc/testsuite/ChangeLog:
>
> PR c++/82099
> * g++.dg/cpp1z/class-deduction76.C: Remove dg-ice.
> * g++.dg/cpp0x/noexcept61.C: New test.
> ---
> gcc/cp/pt.c | 3 +++
> gcc/testsuite/g++.dg/cpp0x/noexcept61.C | 17 +++++++++++++++++
> gcc/testsuite/g++.dg/cpp1z/class-deduction76.C | 1 -
> 3 files changed, 20 insertions(+), 1 deletion(-)
> create mode 100644 gcc/testsuite/g++.dg/cpp0x/noexcept61.C
>
> diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
> index 062ef858501..0d061adc2ed 100644
> --- a/gcc/cp/pt.c
> +++ b/gcc/cp/pt.c
> @@ -22373,6 +22373,9 @@ resolve_overloaded_unification (tree tparms,
> --function_depth;
> }
>
> + if (flag_noexcept_type)
> + maybe_instantiate_noexcept (fn, tf_none);
> +
> elem = TREE_TYPE (fn);
> if (try_one_overload (tparms, targs, tempargs, parm,
> elem, strict, sub_strict, addr_p, explain_p)
> diff --git a/gcc/testsuite/g++.dg/cpp0x/noexcept61.C b/gcc/testsuite/g++.dg/cpp0x/noexcept61.C
> new file mode 100644
> index 00000000000..653cd7e6680
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/cpp0x/noexcept61.C
> @@ -0,0 +1,17 @@
> +// PR c++/82099
> +// { dg-do compile { target c++11 } }
> +
> +template <typename T, typename U>
> +void bar (T &x, T &y, U u)
> +{
> + u (x, y);
> +}
> +
> +template <typename T>
> +void baz (T &x, T &y) noexcept (noexcept (x == y));
> +
> +void
> +foo (int x, int y)
> +{
> + bar (x, y, baz<int>);
> +}
> diff --git a/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C b/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
> index 23bb6e8fa9a..a131a386baa 100644
> --- a/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
> +++ b/gcc/testsuite/g++.dg/cpp1z/class-deduction76.C
> @@ -1,6 +1,5 @@
> // PR c++/90799
> // { dg-do compile { target c++17 } }
> -// { dg-ice "unify" }
>
> template<class T>
> void foo() noexcept(T::value);
>
> base-commit: f262a3518877ccce9ed41b2e152c3a3564727bd6
>
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