https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114706
Bug ID: 114706 Summary: ICE - std::bit_cast in consteval function involving union Product: gcc Version: 14.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cuzdav at gmail dot com Target Milestone: --- ICE in a consteval function bit_casting an array of unions. The code isn't valid due to the union, but the compiler is not handling it properly (since gcc11...trunk). Reduced to the following program: CODE #include <bit> union U { int u; }; consteval void f() { U result[]{0, 0}; auto x = std::bit_cast<long>(result); } int main() { f(); } LIVE: https://godbolt.org/z/Y943bc5zK OUTPUT /opt/compiler-explorer/gcc-trunk-20240412/include/c++/14.0.1/bit:94:33: internal compiler error: in native_encode_initializer, at fold-const.cc:8468 94 | return __builtin_bit_cast(_To, __from); | ^~~ 0x267826c internal_error(char const*, ...) ???:0 0xa58c63 fancy_abort(char const*, int, char const*) ???:0 0xfa0eaf native_encode_initializer(tree_node*, unsigned char*, int, int, unsigned char*) ???:0 0xacf0f0 maybe_constant_value(tree_node*, tree_node*, mce_value) ???:0 0xd3a75f store_init_value(tree_node*, tree_node*, vec<tree_node*, va_gc, vl_embed>**, int) ???:0 0xb474fe cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int, cp_decomp*) ???:0 0xc5c81a c_parse_file() ???:0 0xdb1489 c_common_parse_file() ???:0 Please submit a full bug report, with preprocessed source (by using -freport-bug). Please include the complete backtrace with any bug report. See <https://gcc.gnu.org/bugs/> for instructions.