On Thu, Feb 15, 2024 at 1:48 PM Patrick Palka <ppa...@redhat.com> wrote:
>
> On Thu, 15 Feb 2024, Ken Matsui wrote:
>
> > This patch implements built-in trait for std::rank.
> >
> > gcc/cp/ChangeLog:
> >
> > * cp-trait.def: Define __rank.
> > * semantics.cc (trait_expr_value): Handle CPTK_RANK.
> > (finish_trait_expr): Likewise.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * g++.dg/ext/has-builtin-1.C: Test existence of __rank.
> > * g++.dg/ext/rank.C: New test.
> >
> > Signed-off-by: Ken Matsui <kmat...@gcc.gnu.org>
> > ---
> > gcc/cp/cp-trait.def | 1 +
> > gcc/cp/semantics.cc | 18 ++++++++++++++++--
> > gcc/testsuite/g++.dg/ext/has-builtin-1.C | 3 +++
> > gcc/testsuite/g++.dg/ext/rank.C | 14 ++++++++++++++
> > 4 files changed, 34 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/g++.dg/ext/rank.C
> >
> > diff --git a/gcc/cp/cp-trait.def b/gcc/cp/cp-trait.def
> > index 11270f3ae6b..3d5a7970563 100644
> > --- a/gcc/cp/cp-trait.def
> > +++ b/gcc/cp/cp-trait.def
> > @@ -95,6 +95,7 @@ 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 (RANK, "__rank", 1)
> > DEFTRAIT_EXPR (REF_CONSTRUCTS_FROM_TEMPORARY,
> > "__reference_constructs_from_temporary", 2)
> > DEFTRAIT_EXPR (REF_CONVERTS_FROM_TEMPORARY,
> > "__reference_converts_from_temporary", 2)
> > DEFTRAIT_TYPE (REMOVE_ALL_EXTENTS, "__remove_all_extents", 1)
> > diff --git a/gcc/cp/semantics.cc b/gcc/cp/semantics.cc
> > index 256e7ef8166..4f285909b83 100644
> > --- a/gcc/cp/semantics.cc
> > +++ b/gcc/cp/semantics.cc
> > @@ -12538,6 +12538,9 @@ trait_expr_value (cp_trait_kind kind, tree type1,
> > tree type2)
> > case CPTK_IS_DEDUCIBLE:
> > return type_targs_deducible_from (type1, type2);
> >
> > + /* __rank is handled in finish_trait_expr. */
> > + case CPTK_RANK:
> > +
> > #define DEFTRAIT_TYPE(CODE, NAME, ARITY) \
> > case CPTK_##CODE:
> > #include "cp-trait.def"
> > @@ -12698,6 +12701,7 @@ finish_trait_expr (location_t loc, cp_trait_kind
> > kind, tree type1, tree type2)
> > case CPTK_IS_SAME:
> > case CPTK_IS_SCOPED_ENUM:
> > case CPTK_IS_UNION:
> > + case CPTK_RANK:
> > break;
> >
> > case CPTK_IS_LAYOUT_COMPATIBLE:
> > @@ -12729,8 +12733,18 @@ finish_trait_expr (location_t loc, cp_trait_kind
> > kind, tree type1, tree type2)
> > gcc_unreachable ();
> > }
> >
> > - tree val = (trait_expr_value (kind, type1, type2)
> > - ? boolean_true_node : boolean_false_node);
> > + tree val;
> > + if (kind == CPTK_RANK)
> > + {
> > + size_t rank = 0;
> > + for (; TREE_CODE (type1) == ARRAY_TYPE; type1 = TREE_TYPE (type1))
> > + ++rank;
> > + val = build_int_cst (size_type_node, rank);
>
> So this will be the first expression-yielding trait that's not a bool.
> That's no problem conceptually, but I think we hardcode their bool-ness
> near the top of finish_trait_expr when returning a templated version of
> the trait. We should instead give templated __rank the type size_type_node.
>
> > + }
> > + else
> > + val = (trait_expr_value (kind, type1, type2)
> > + ? boolean_true_node : boolean_false_node);
> > +
> > return maybe_wrap_with_location (val, loc);
> > }
> >
> > diff --git a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > index 5b590db1cf6..a00193c1a81 100644
> > --- a/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > +++ b/gcc/testsuite/g++.dg/ext/has-builtin-1.C
> > @@ -167,6 +167,9 @@
> > #if !__has_builtin (__is_union)
> > # error "__has_builtin (__is_union) failed"
> > #endif
> > +#if !__has_builtin (__rank)
> > +# error "__has_builtin (__rank) failed"
> > +#endif
> > #if !__has_builtin (__reference_constructs_from_temporary)
> > # error "__has_builtin (__reference_constructs_from_temporary) failed"
> > #endif
> > diff --git a/gcc/testsuite/g++.dg/ext/rank.C
> > b/gcc/testsuite/g++.dg/ext/rank.C
> > new file mode 100644
> > index 00000000000..bab062d776e
> > --- /dev/null
> > +++ b/gcc/testsuite/g++.dg/ext/rank.C
> > @@ -0,0 +1,14 @@
> > +// { dg-do compile { target c++11 } }
> > +
> > +#define SA(X) static_assert((X),#X)
> > +
> > +class ClassType { };
> > +
> > +SA(__rank(int) == 0);
> > +SA(__rank(int[2]) == 1);
> > +SA(__rank(int[][4]) == 2);
> > +SA(__rank(int[2][2][4][4][6][6]) == 6);
> > +SA(__rank(ClassType) == 0);
> > +SA(__rank(ClassType[2]) == 1);
> > +SA(__rank(ClassType[][4]) == 2);
> > +SA(__rank(ClassType[2][2][4][4][6][6]) == 6);
>
> We should have a test that the __rank inside a template has the correct
> type, something like (this should currently fail with your patch as-is
> due to the hardcoded bool type):
>
> template<class T> void f(T) = delete;
> void f(bool);
>
> template<class T>
> void g() { f(__rank(T)); }
>
> template void g<int>();
>
Thank you! I think this test should be the following, to fail with my
patch as-is:
- void f(bool);
+ void f(size_t);
since we are expecting size_t from __rank. The current patch passed
this test and failed with a test with change, and my updated patch
failed with this test and passed a test with this change.
I will submit the updated patch soon. Thank you for pointing this out!
> > --
> > 2.43.0
> >
> >
>
