Jakub Jelinek
6978df2c04
_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 <jakub@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.
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