Re: [PATCH 1/2] c++: implement __is_const built-in trait

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

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Sure. Thank you.

On Sat, Jun 24, 2023 at 5:14 AM Xi Ruoyao <xry111@xry111.site> wrote:

> Please use [PATCH v3 1/2] next time, now it's not easy to find the
> latest version of the series (I'm not sure if the number "3" is
> correct).
>
> On Sat, 2023-06-24 at 03:38 -0700, Ken Matsui via Gcc-patches wrote:
> > This patch implements built-in trait for std::is_const.
> >
> > gcc/cp/ChangeLog:
> >
> >         * cp-trait.def: Define __is_const.
> >         * constraint.cc (diagnose_trait_expr): Handle CPTK_IS_CONST.
> >         * semantics.cc (trait_expr_value): Likewise.
> >         (finish_trait_expr): Likewise.
> >
> > gcc/testsuite/ChangeLog:
> >
> >         * g++.dg/ext/has-builtin-1.C: Test existence of __is_const.
> >         * g++.dg/ext/is_const.C: New test.
> >
> > Signed-off-by: Ken Matsui <kmatsui@cs.washington.edu>
> > ---
> >  gcc/cp/constraint.cc                     |  3 +++
> >  gcc/cp/cp-trait.def                      |  1 +
> >  gcc/cp/semantics.cc                      |  4 ++++
> >  gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
> >  gcc/testsuite/g++.dg/ext/is_const.C      | 19 +++++++++++++++++++
> >  5 files changed, 30 insertions(+)
> >  create mode 100644 gcc/testsuite/g++.dg/ext/is_const.C
> >
> > diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> > index 8cf0f2d0974..ff4ae831def 100644
> > --- a/gcc/cp/constraint.cc
> > +++ b/gcc/cp/constraint.cc
> > @@ -3751,6 +3751,9 @@ diagnose_trait_expr (tree expr, tree args)
> >      case CPTK_IS_UNION:
> >        inform (loc, "  %qT is not a union", t1);
> >        break;
> > +    case CPTK_IS_CONST:
> > +      inform (loc, "  %qT is not a const type", t1);
> > +      break;
> >      case CPTK_IS_AGGREGATE:
> >        inform (loc, "  %qT is not an aggregate", t1);
> >        break;
> > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > index 8b7fece0cc8..b40b475b86d 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -82,6 +82,7 @@ DEFTRAIT_EXPR (IS_TRIVIALLY_ASSIGNABLE,
> > "__is_trivially_assignable", 2)
> >  DEFTRAIT_EXPR (IS_TRIVIALLY_CONSTRUCTIBLE,
> > "__is_trivially_constructible", -1)
> >  DEFTRAIT_EXPR (IS_TRIVIALLY_COPYABLE, "__is_trivially_copyable", 1)
> >  DEFTRAIT_EXPR (IS_UNION, "__is_union", 1)
> > +DEFTRAIT_EXPR (IS_CONST, "__is_const", 1)
> >  DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY,
> > "__reference_constructs_from_temporary", 2)
> >  DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY,
> > "__reference_converts_from_temporary", 2)
> >  /* FIXME Added space to avoid direct usage in GCC 13.  */
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index 8fb47fd179e..011ba8e46e1 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -12079,6 +12079,9 @@ trait_expr_value (cp_trait_kind kind, tree
> > type1, tree type2)
> >      case CPTK_IS_ENUM:
> >        return type_code1 == ENUMERAL_TYPE;
> >
> > +    case CPTK_IS_CONST:
> > +      return CP_TYPE_CONST_P (type1);
> > +
> >      case CPTK_IS_FINAL:
> >        return CLASS_TYPE_P (type1) && CLASSTYPE_FINAL (type1);
> >
> > @@ -12296,6 +12299,7 @@ finish_trait_expr (location_t loc,
> > cp_trait_kind kind, tree type1, tree type2)
> >      case CPTK_IS_ENUM:
> >      case CPTK_IS_UNION:
> >      case CPTK_IS_SAME:
> > +    case CPTK_IS_CONST:
> >        break;
> >
> >      case CPTK_IS_LAYOUT_COMPATIBLE:
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index f343e153e56..965309a333a 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_const)
> > +# error "__has_builtin (__is_const) failed"
> > +#endif
> > diff --git a/gcc/testsuite/g++.dg/ext/is_const.C
> > b/gcc/testsuite/g++.dg/ext/is_const.C
> > new file mode 100644
> > index 00000000000..8f2d7c2fce9
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/is_const.C
> > @@ -0,0 +1,19 @@
> > +// { dg-do compile { target c++11 } }
> > +
> > +#include <testsuite_tr1.h>
> > +
> > +using namespace __gnu_test;
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +// Positive tests.
> > +SA(__is_const(const int));
> > +SA(__is_const(const volatile int));
> > +SA(__is_const(cClassType));
> > +SA(__is_const(cvClassType));
> > +
> > +// Negative tests.
> > +SA(!__is_const(int));
> > +SA(!__is_const(volatile int));
> > +SA(!__is_const(ClassType));
> > +SA(!__is_const(vClassType));
>
> --
> Xi Ruoyao <xry111@xry111.site>
> School of Aerospace Science and Technology, Xidian University
>
-- 
Sincerely,
Ken Matsui