[13/14] c++: Implement __is_scalar built-in trait

  This patch implements built-in trait for std::is_scalar.

gcc/cp/ChangeLog:

	* cp-trait.def: Define __is_scalar.
	* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_SCALAR.
	* semantics.cc (trait_expr_value): Likewise.
	(finish_trait_expr): Likewise.

gcc/testsuite/ChangeLog:

	* g++.dg/ext/has-builtin-1.C: Test existence of __is_scalar.
	* g++.dg/ext/is_scalar.C: New test.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
---
 gcc/cp/constraint.cc                     |  3 +++
 gcc/cp/cp-trait.def                      |  1 +
 gcc/cp/semantics.cc                      | 10 +++++++++
 gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
 gcc/testsuite/g++.dg/ext/is_scalar.C     | 28 ++++++++++++++++++++++++
 5 files changed, 45 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/ext/is_scalar.C
  

On 01-10 (01:23), Ken Matsui wrote:
> This patch implements built-in trait for std::is_scalar.
> 
> gcc/cp/ChangeLog:
> 
> 	* cp-trait.def: Define __is_scalar.
> 	* constraint.cc (diagnose_trait_expr): Handle CPTK_IS_SCALAR.
> 	* semantics.cc (trait_expr_value): Likewise.
> 	(finish_trait_expr): Likewise.
> 
> gcc/testsuite/ChangeLog:
> 
> 	* g++.dg/ext/has-builtin-1.C: Test existence of __is_scalar.
> 	* g++.dg/ext/is_scalar.C: New test.
> 
> Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
> ---
>  gcc/cp/constraint.cc                     |  3 +++
>  gcc/cp/cp-trait.def                      |  1 +
>  gcc/cp/semantics.cc                      | 10 +++++++++
>  gcc/testsuite/g++.dg/ext/has-builtin-1.C |  3 +++
>  gcc/testsuite/g++.dg/ext/is_scalar.C     | 28 ++++++++++++++++++++++++
>  5 files changed, 45 insertions(+)
>  create mode 100644 gcc/testsuite/g++.dg/ext/is_scalar.C
> 
> diff --git a/gcc/cp/constraint.cc b/gcc/cp/constraint.cc
> index d2e41aa053d..7293f33c676 100644
> --- a/gcc/cp/constraint.cc
> +++ b/gcc/cp/constraint.cc
> @@ -3810,6 +3810,9 @@ diagnose_trait_expr (tree expr, tree args)
>      case CPTK_IS_SAME:
>        inform (loc, "  %qT is not the same as %qT", t1, t2);
>        break;
> +    case CPTK_IS_SCALAR:
> +      inform (loc, "  %qT is not a scalar type", t1);
> +      break;
>      case CPTK_IS_SCOPED_ENUM:
>        inform (loc, "  %qT is not a scoped enum", t1);
>        break;
> diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> index 6dac7622a7c..48e195b4938 100644
> --- a/gcc/cp/cp-trait.def
> +++ b/gcc/cp/cp-trait.def
> @@ -87,6 +87,7 @@ DEFTRAIT_EXPR (IS_POD, "__is_pod", 1)
>  DEFTRAIT_EXPR (IS_POLYMORPHIC, "__is_polymorphic", 1)
>  DEFTRAIT_EXPR (IS_REFERENCE, "__is_reference", 1)
>  DEFTRAIT_EXPR (IS_SAME, "__is_same", 2)
> +DEFTRAIT_EXPR (IS_SCALAR, "__is_scalar", 1)
>  DEFTRAIT_EXPR (IS_SCOPED_ENUM, "__is_scoped_enum", 1)
>  DEFTRAIT_EXPR (IS_SIGNED, "__is_signed", 1)
>  DEFTRAIT_EXPR (IS_STD_LAYOUT, "__is_standard_layout", 1)
> diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> index c3d6fc2d10f..2426ba629d9 100644
> --- a/gcc/cp/semantics.cc
> +++ b/gcc/cp/semantics.cc
> @@ -12545,6 +12545,15 @@ trait_expr_value (cp_trait_kind kind, tree type1, tree type2)
>      case CPTK_IS_SAME:
>        return same_type_p (type1, type2);
>  
> +    case CPTK_IS_SCALAR:
> +      return (TYPE_PTRDATAMEM_P (type1)
> +	|| TREE_CODE (type1) == ENUMERAL_TYPE
> +	|| integral_type_p (type1)
> +	|| floating_point_type_p (type1)
> +	|| TYPE_PTR_P (type1)
> +	|| TYPE_PTRMEMFUNC_P (type1)
> +	|| NULLPTR_TYPE_P (type1));
> +

Hi Jonathan,

Related to this Bugzilla report:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96710

do we want to update the is_scalar behavior?  For this patch, I just
followed the current implementation.

>      case CPTK_IS_SCOPED_ENUM:
>        return SCOPED_ENUM_P (type1);
>  
> @@ -12744,6 +12753,7 @@ finish_trait_expr (location_t loc, cp_trait_kind kind, tree type1, tree type2)
>      case CPTK_IS_OBJECT:
>      case CPTK_IS_REFERENCE:
>      case CPTK_IS_SAME:
> +    case CPTK_IS_SCALAR:
>      case CPTK_IS_SCOPED_ENUM:
>      case CPTK_IS_SIGNED:
>      case CPTK_IS_UNION:
> diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> index e3d16add403..c860f7e12ca 100644
> --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> @@ -143,6 +143,9 @@
>  #if !__has_builtin (__is_same_as)
>  # error "__has_builtin (__is_same_as) failed"
>  #endif
> +#if !__has_builtin (__is_scalar)
> +# error "__has_builtin (__is_scalar) failed"
> +#endif
>  #if !__has_builtin (__is_scoped_enum)
>  # error "__has_builtin (__is_scoped_enum) failed"
>  #endif
> diff --git a/gcc/testsuite/g++.dg/ext/is_scalar.C b/gcc/testsuite/g++.dg/ext/is_scalar.C
> new file mode 100644
> index 00000000000..ad4c2d7ea05
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/ext/is_scalar.C
> @@ -0,0 +1,28 @@
> +// { dg-do compile { target c++11 } }
> +
> +#define SA(X) static_assert((X),#X)
> +
> +#define SA_TEST_FN(TRAIT, TYPE, EXPECT)		\
> +  SA(TRAIT(TYPE) == EXPECT);			\
> +  SA(TRAIT(const TYPE) == EXPECT)
> +
> +#define SA_TEST_CATEGORY(TRAIT, TYPE, EXPECT)	\
> +  SA(TRAIT(TYPE) == EXPECT);			\
> +  SA(TRAIT(const TYPE) == EXPECT);		\
> +  SA(TRAIT(volatile TYPE) == EXPECT);		\
> +  SA(TRAIT(const volatile TYPE) == EXPECT)
> +
> +class ClassType { };
> +enum EnumType { e0 };
> +
> +SA_TEST_CATEGORY(__is_scalar, int, true);
> +SA_TEST_CATEGORY(__is_scalar, float, true);
> +SA_TEST_CATEGORY(__is_scalar, EnumType, true);
> +SA_TEST_CATEGORY(__is_scalar, int*, true);
> +SA_TEST_FN(__is_scalar, int(*)(int), true);
> +SA_TEST_CATEGORY(__is_scalar, int (ClassType::*), true);
> +SA_TEST_FN(__is_scalar, int (ClassType::*) (int), true);
> +SA_TEST_CATEGORY(__is_scalar, decltype(nullptr), true);
> +
> +// Sanity check.
> +SA_TEST_CATEGORY(__is_scalar, ClassType, false);
> -- 
> 2.43.0
>