Hi, This is a proposition of a _BitInt(N) implementation for LoongArch, with the following psABI description:
``` === Fundamental types of N-bit integers `_BitInt(N)` (as proposed in ISO/IEC WG14 N2763) is a family of integer types where `N` specifies the exact number of bits used for its representation. * `_BitInt(N)` objects are stored in little-endian order in memory and are signed by default. * For N <= 64, `_BitInt(N)` objects have the same size and alignment of the smallest fundamental integral type that can contain them, and are always sign-extended or zero-extended to this size according its signedness. For instance, `_BitInt(8)`, `_BitInt(16)`, `_BitInt(32)` and `_BitInt(64)` behave exactly the same as the fundamental types of signed byte, half-word, word and double-word, respectively. * 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. If an entire chunk is unused, its bits are undefined. ``` The main differences from the existing implementations (x86_64 and aarch64) is that all partial limbs are extended for both small/middle and large/huge _BitInts. For this purpose, some changes needs to be made to gimple lowering and expand. This series has been bootstrapped and regtested with x86_64-linux-gnu and loongarch64-linux-gnu (against a version that leaves the partial limbs undefined). Please help us find if there's something we've missed. Thanks, Yujie Yang Yujie (3): bitint: Support ABI-extended _BitInt(N) bitint: Allow wider abi_limb_mode than limb_mode during layout LoongArch: Add support for _BitInt [PR117599] gcc/c-family/c-common.cc | 65 +++- gcc/config/loongarch/loongarch.cc | 31 +- gcc/config/loongarch/loongarch.h | 4 +- gcc/explow.cc | 32 +- gcc/expr.cc | 23 +- gcc/gimple-lower-bitint.cc | 365 ++++++++++++++++-- gcc/stor-layout.cc | 3 +- .../gcc.target/loongarch/bitint-alignments.c | 58 +++ .../gcc.target/loongarch/bitint-args.c | 93 +++++ .../gcc.target/loongarch/bitint-sizes.c | 60 +++ libgcc/config/loongarch/t-softfp-tf | 1 + 11 files changed, 690 insertions(+), 45 deletions(-) create mode 100644 gcc/testsuite/gcc.target/loongarch/bitint-alignments.c create mode 100644 gcc/testsuite/gcc.target/loongarch/bitint-args.c create mode 100644 gcc/testsuite/gcc.target/loongarch/bitint-sizes.c -- 2.34.1
