https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117599
--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by LuluCheng <chengl...@gcc.gnu.org>: https://gcc.gnu.org/g:8079e96eb767851e8e061a13ecfb21aa1a2362de commit r16-3176-g8079e96eb767851e8e061a13ecfb21aa1a2362de Author: Yang Yujie <yangyu...@loongson.cn> Date: Sat Aug 2 17:16:23 2025 +0800 LoongArch: Add support for _BitInt [PR117599] This patch adds support for C23's _BitInt for LoongArch. From the LoongArch psABI[1]: > _BitInt(N) objects are stored in little-endian order in memory > and are signed by default. > > For N ⤠64, a _BitInt(N) object have the same size and alignment > of the smallest fundamental integral type that can contain it. > The unused high-order bits within this containing type are filled > with sign or zero extension of the N-bit value, depending on whether > the _BitInt(N) object is signed or unsigned. The _BitInt(N) object > propagates its signedness to the containing type and is laid out > in a register or memory as an object of this type. > > For N > 64, _BitInt(N) objects are implemented as structs of 64-bit > integer chunks. The number of chunks is the smallest even integer M > so that M * 64 ⥠N. These objects are of the same size of the struct > containing the chunks, but always have 16-byte alignment. If there > are unused bits in the highest-ordered chunk that contains used > bits, they are defined as the sign- or zero- extension of the used > bits depending on whether the _BitInt(N) object is signed or > unsigned. If an entire chunk is unused, its bits are undefined. [1] https://github.com/loongson/la-abi-specs PR target/117599 gcc/ChangeLog: * config/loongarch/loongarch.h: Define a PROMOTE_MODE case for small _BitInts. * config/loongarch/loongarch.cc (loongarch_promote_function_mode): Same. (loongarch_bitint_type_info): New function. (TARGET_C_BITINT_TYPE_INFO): Declare. libgcc/ChangeLog: * config/loongarch/t-softfp-tf: Enable _BitInt helper functions. * config/loongarch/t-loongarch: Same. * config/loongarch/libgcc-loongarch.ver: New file. gcc/testsuite/ChangeLog: * gcc.target/loongarch/bitint-alignments.c: New test. * gcc.target/loongarch/bitint-args.c: New test. * gcc.target/loongarch/bitint-sizes.c: New test.
