https://gcc.gnu.org/g:89c1412dfc26d141a6d8732b269c3e30eff44613
commit r17-3213-g89c1412dfc26d141a6d8732b269c3e30eff44613 Author: Jakub Jelinek <[email protected]> Date: Wed Aug 12 10:02:37 2026 +0200 c++: Change alignof (decltype (^^::)) from 1 to alignof (void *) We IMHO incorrectly leave TYPE_ALIGN of std::meta::info unset, so alignof on it is 1. We should change that to the same as decltype (nullptr) and void *. As C++26 is heavily experimental, this is changed unconditionally, without -fabi-version= checks, and only for 17, not for 16.x. 2026-08-12 Jakub Jelinek <[email protected]> * reflect.cc (init_reflection): Also initialize TYPE_UNSIGNED, TYPE_PRECISION, TYPE_MODE and TYPE_ALIGN of meta_info_type_node. * g++.dg/reflect/info1.C: New test. Reviewed-by: Jason Merrill <[email protected]> Diff: --- gcc/cp/reflect.cc | 4 ++++ gcc/testsuite/g++.dg/reflect/info1.C | 6 ++++++ 2 files changed, 10 insertions(+) diff --git a/gcc/cp/reflect.cc b/gcc/cp/reflect.cc index cfb9292849fc..be3c2c5f86cc 100644 --- a/gcc/cp/reflect.cc +++ b/gcc/cp/reflect.cc @@ -65,6 +65,10 @@ init_reflection () /* Make it a complete type. */ TYPE_SIZE (meta_info_type_node) = bitsize_int (GET_MODE_BITSIZE (ptr_mode)); TYPE_SIZE_UNIT (meta_info_type_node) = size_int (GET_MODE_SIZE (ptr_mode)); + TYPE_UNSIGNED (meta_info_type_node) = 1; + TYPE_PRECISION (meta_info_type_node) = GET_MODE_BITSIZE (ptr_mode); + SET_TYPE_MODE (meta_info_type_node, ptr_mode); + SET_TYPE_ALIGN (meta_info_type_node, GET_MODE_ALIGNMENT (ptr_mode)); /* Name it. */ record_builtin_type (RID_MAX, "decltype(^^int)", meta_info_type_node); diff --git a/gcc/testsuite/g++.dg/reflect/info1.C b/gcc/testsuite/g++.dg/reflect/info1.C new file mode 100644 index 000000000000..17d4d2f02288 --- /dev/null +++ b/gcc/testsuite/g++.dg/reflect/info1.C @@ -0,0 +1,6 @@ +// { dg-do compile { target c++26 } } +// { dg-additional-options "-freflection" } + +using info = decltype (^^::); +static_assert (sizeof (info) == sizeof (void *)); +static_assert (alignof (info) == alignof (void *));
