https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108883
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:6978df2c04df165eaa6aac9e17b6c770bed460e3 commit r13-6426-g6978df2c04df165eaa6aac9e17b6c770bed460e3 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Mar 3 00:34:59 2023 +0100 c++, v3: Emit fundamental tinfos for _Float16/decltype(0.0bf16) types on ia32 with -mno-sse2 [PR108883] _Float16 and decltype(0.0bf16) types are on x86 supported only with -msse2. On x86_64 that is the default, but on ia32 it is not. We should still emit fundamental type tinfo for those types in libsupc++.a/libstdc++.*, regardless of whether libsupc++/libstdc++ is compiled with -msse2 or not, as user programs can be compiled with different ISA flags from libsupc++/libstdc++ and if they are compiled with -msse2 and use std::float16_t or std::bfloat16_t and need RTTI for it, it should work out of the box. Furthermore, libstdc++ ABI on ia32 shouldn't depend on whether the library is compiled with -mno-sse or -msse2. Unfortunately, just hacking up libsupc++ Makefile/configure so that a single source is compiled with -msse2 isn't appropriate, because that TU emits also code and the code should be able to run on CPUs which libstdc++ supports. We could add [[gnu::attribute ("no-sse2")]] there perhaps conditionally, but it all gets quite ugly. The following patch instead adds a target hook which allows the backend to temporarily tweak registered types such that emit_support_tinfos emits whatever is needed. Additionally, it makes emit_support_tinfos_1 call emit_tinfo_decl immediately, so that temporarily created dummy types for emit_support_tinfo purposes only can be nullified again afterwards. And removes the previous fallback_* types used for dfloat*_type_node tinfos even when decimal types aren't supported. 2023-03-03 Jakub Jelinek <ja...@redhat.com> PR target/108883 gcc/ * target.h (emit_support_tinfos_callback): New typedef. * targhooks.h (default_emit_support_tinfos): Declare. * targhooks.cc (default_emit_support_tinfos): New function. * target.def (emit_support_tinfos): New target hook. * doc/tm.texi.in (emit_support_tinfos): Document it. * doc/tm.texi: Regenerated. * config/i386/i386.cc (ix86_emit_support_tinfos): New function. (TARGET_EMIT_SUPPORT_TINFOS): Redefine. gcc/cp/ * cp-tree.h (enum cp_tree_index): Remove CPTI_FALLBACK_DFLOAT*_TYPE enumerators. (fallback_dfloat32_type, fallback_dfloat64_type, fallback_dfloat128_type): Remove. * rtti.cc (emit_support_tinfo_1): If not emitted already, call emit_tinfo_decl and remove from unemitted_tinfo_decls right away. (emit_support_tinfos): Move &dfloat*_type_node from fundamentals array into new fundamentals_with_fallback array. Call emit_support_tinfo_1 on elements of that array too, with the difference that if the type is NULL, use a fallback REAL_TYPE for it temporarily. Drop the !targetm.decimal_float_supported_p () handling. Call targetm.emit_support_tinfos at the end. * mangle.cc (write_builtin_type): Remove references to fallback_dfloat*_type. Handle bfloat16_type_node mangling.
