[PATCH] c++: Fix ICE on defaulted spaceship with pointer return type [PR94162]

Jason Merrill jason@redhat.com
Wed Aug 11 17:43:31 GMT 2021


On 8/11/21 10:01 AM, Jakub Jelinek wrote:
> On Wed, Aug 11, 2021 at 09:42:56AM -0400, Jason Merrill wrote:
>> Checking CLASS_TYPE_P && decl_in_std_namespace (TYPE_MAIN_DECL) before
>> looking at the name makes sense to me.
> 
> CLASS_TYPE_P is cheap, but isn't decl_in_std_namespace, especially when
> it needs to walk inline namespaces, better done only if we get a match, so
> like below?
> 
> Though I can do it even in the first if if you think it is better...

Let's do it first; no need to micro-optimize this function.

OK with that change.

> 2021-08-11  Jakub Jelinek  <jakub@redhat.com>
> 
> gcc/cp/
> 	PR c++/94162
> 	* method.c (cat_tag_for): Return cc_last for !CLASS_TYPE_P
> 	or for classes not in std namespace.
> gcc/testsuite/
> 	PR c++/99429
> 	* g++.dg/cpp2a/spaceship-synth11.C: New test.
> 
> 	PR c++/94162
> 	* g++.dg/cpp2a/spaceship-synth-neg6.C: New test.
> 
> --- gcc/cp/method.c.jj	2021-08-09 15:03:00.923206463 +0200
> +++ gcc/cp/method.c	2021-08-11 15:52:27.157437691 +0200
> @@ -1029,10 +1029,13 @@ is_cat (tree type, comp_cat_tag tag)
>   static comp_cat_tag
>   cat_tag_for (tree type)
>   {
> +  if (!CLASS_TYPE_P (type))
> +    return cc_last;
>     for (int i = 0; i < cc_last; ++i)
>       {
>         comp_cat_tag tag = (comp_cat_tag)i;
> -      if (is_cat (type, tag))
> +      if (is_cat (type, tag)
> +	  && decl_in_std_namespace_p (TYPE_MAIN_DECL (type)))
>   	return tag;
>       }
>     return cc_last;
> --- gcc/testsuite/g++.dg/cpp2a/spaceship-synth11.C.jj	2021-08-11 15:49:05.267204333 +0200
> +++ gcc/testsuite/g++.dg/cpp2a/spaceship-synth11.C	2021-08-11 15:49:05.267204333 +0200
> @@ -0,0 +1,29 @@
> +// PR c++/99429
> +// { dg-do compile { target c++20 } }
> +
> +namespace std {
> +struct strong_ordering {
> +  int _v;
> +  constexpr strong_ordering (int v) :_v(v) {}
> +  constexpr operator int (void) const { return _v; }
> +  static const strong_ordering less;
> +  static const strong_ordering equal;
> +  static const strong_ordering greater;
> +};
> +constexpr strong_ordering strong_ordering::less = -1;
> +constexpr strong_ordering strong_ordering::equal = 0;
> +constexpr strong_ordering strong_ordering::greater = 1;
> +}
> +
> +template <unsigned long N>
> +struct duration {
> +  static constexpr const long period = N;
> +  constexpr duration (void) = default;
> +  constexpr duration (const duration& d) = default;
> +  constexpr bool operator== (const duration& d) const = default;
> +  constexpr bool operator<=> (const duration& d) const = default;
> +  long _d;
> +};
> +
> +using nanoseconds = duration<1>;
> +using microseconds = duration<nanoseconds::period * 1000>;
> --- gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg6.C.jj	2021-08-11 15:49:05.268204320 +0200
> +++ gcc/testsuite/g++.dg/cpp2a/spaceship-synth-neg6.C	2021-08-11 15:49:05.268204320 +0200
> @@ -0,0 +1,11 @@
> +// PR c++/94162
> +// { dg-do compile { target c++20 } }
> +
> +#include <compare>
> +
> +struct S {
> +  int a;			// { dg-error "three-way comparison of 'S::a' has type 'std::strong_ordering', which does not convert to 'int\\*'" }
> +  int *operator<=>(const S&) const = default;
> +};
> +
> +bool b = S{} < S{};		// { dg-error "use of deleted function 'constexpr int\\* S::operator<=>\\\(const S&\\\) const'" }
> 
> 	Jakub
> 



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