Re: [PATCH] c++: implement __is_reference built-in trait

[Ken Matsui <kmatsui@cs.washington.edu>]

I created new patches which is a series, but I couldn't figure out how
to associate them with this email and another email. Please disregard
this email.

On Sun, Mar 19, 2023 at 1:19 PM Ken Matsui <kmatsui@cs.washington.edu> wrote:
>
> * cp-trait.def (names_builtin_p): Define __is_reference.
>
> This changelog should be the following.
>
> * cp-trait.def: Define __is_reference.
>
> I am sorry for the confusion.
>
> On Sat, Mar 18, 2023 at 9:07 PM Ken Matsui <kmatsui@cs.washington.edu> wrote:
> >
> > This patch implements built-in trait for std::is_reference.
> >
> > gcc/cp/ChangeLog:
> >
> > * cp-trait.def (names_builtin_p): Define __is_reference.
> > * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_REFERENCE.
> > * semantics.cc (trait_expr_value): Likewise.
> > (finish_trait_expr): Likewise.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/ext/has-builtin-1.C: Test existence of __is_reference.
> > * g++.dg/ext/is_reference.C: New test.
> >
> > ---
> > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > index 273d15ab097..23e5bc24dbb 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -3701,6 +3701,9 @@ diagnose_trait_expr (tree expr, tree args)
> >      case CPTK_HAS_VIRTUAL_DESTRUCTOR:
> >        inform (loc, "  %qT does not have a virtual destructor", t1);
> >        break;
> > +    case CPTK_IS_REFERENCE:
> > +      inform (loc, "  %qT is not a reference", t1);
> > +      break;
> >      case CPTK_IS_ABSTRACT:
> >        inform (loc, "  %qT is not an abstract class", t1);
> >        break;
> > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > index bac593c0094..63a64152ce6 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -67,6 +67,7 @@ DEFTRAIT_EXPR (IS_CONVERTIBLE, "__is_convertible", 2)
> >  DEFTRAIT_EXPR (IS_EMPTY, "__is_empty", 1)
> >  DEFTRAIT_EXPR (IS_ENUM, "__is_enum", 1)
> >  DEFTRAIT_EXPR (IS_FINAL, "__is_final", 1)
> > +DEFTRAIT_EXPR (IS_REFERENCE, "__is_reference", 1)
> >  DEFTRAIT_EXPR (IS_LAYOUT_COMPATIBLE, "__is_layout_compatible", 2)
> >  DEFTRAIT_EXPR (IS_LITERAL_TYPE, "__is_literal_type", 1)
> >  DEFTRAIT_EXPR (IS_NOTHROW_ASSIGNABLE, "__is_nothrow_assignable", 2)
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index 87c2e8a7111..dce98af4f72 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -11995,6 +11995,9 @@ trait_expr_value (cp_trait_kind kind, tree
> > type1, tree type2)
> >      case CPTK_IS_FINAL:
> >        return CLASS_TYPE_P (type1) && CLASSTYPE_FINAL (type1);
> >
> > +    case CPTK_IS_REFERENCE:
> > +      return type_code1 == REFERENCE_TYPE;
> > +
> >      case CPTK_IS_LAYOUT_COMPATIBLE:
> >        return layout_compatible_type_p (type1, type2);
> >
> > @@ -12139,6 +12142,7 @@ finish_trait_expr (location_t loc,
> > cp_trait_kind kind, tree type1, tree type2)
> >      case CPTK_HAS_TRIVIAL_COPY:
> >      case CPTK_HAS_TRIVIAL_DESTRUCTOR:
> >      case CPTK_HAS_UNIQUE_OBJ_REPRESENTATIONS:
> > +    case CPTK_IS_REFERENCE:
> >        if (!check_trait_type (type1))
> >   return error_mark_node;
> >        break;
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index f343e153e56..b697673790c 100644
> > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > @@ -146,3 +146,6 @@
> >  #if !__has_builtin (__remove_cvref)
> >  # error "__has_builtin (__remove_cvref) failed"
> >  #endif
> > +#if !__has_builtin (__is_reference)
> > +# error "__has_builtin (__is_reference) failed"
> > +#endif
> > diff --git a/gcc/testsuite/g++.dg/ext/is_reference.C
> > b/gcc/testsuite/g++.dg/ext/is_reference.C
> > new file mode 100644
> > index 00000000000..b4f048538e5
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_reference.C
> > @@ -0,0 +1,26 @@
> > +// { dg-do compile { target c++11 } }
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +SA(!__is_reference(void));
> > +SA(!__is_reference(int*));
> > +
> > +SA(__is_reference(int&));
> > +SA(__is_reference(const int&));
> > +SA(__is_reference(volatile int&));
> > +SA(__is_reference(const volatile int&));
> > +
> > +SA(__is_reference(int&&));
> > +SA(__is_reference(const int&&));
> > +SA(__is_reference(volatile int&&));
> > +SA(__is_reference(const volatile int&&));
> > +
> > +SA(!__is_reference(int[3]));
> > +SA(!__is_reference(const int[3]));
> > +SA(!__is_reference(volatile int[3]));
> > +SA(!__is_reference(const volatile int[3]));
> > +
> > +SA(!__is_reference(int(int)));
> > +SA(!__is_reference(int(*const)(int)));
> > +SA(!__is_reference(int(*volatile)(int)));
> > +SA(!__is_reference(int(*const volatile)(int)));