On Fri, May 24, 2024 at 10:44 AM Mariam Arutunian <mariamarutun...@gmail.com> wrote: > > This patch introduces new built-in functions to GCC for computing bit-forward > and bit-reversed CRCs. > These builtins aim to provide efficient CRC calculation capabilities. > When the target architecture supports CRC operations (as indicated by the > presence of a CRC optab), > the builtins will utilize the expander to generate CRC code. > In the absence of hardware support, the builtins default to generating code > for a table-based CRC calculation.
I wonder whether for embedded target use we should arrange for the table-based CRC calculation to be out-of-line and implemented in a way so uses across TUs can be merged? I guess a generic implementation inside libgcc is difficult? > > The builtins are defined as follows: > __builtin_rev_crc16_data8, > __builtin_rev_crc32_data8, __builtin_rev_crc32_data16, > __builtin_rev_crc32_data32 > __builtin_crc8_data8, > __builtin_crc16_data16, __builtin_crc16_data8, > __builtin_crc32_data8, __builtin_crc32_data16, __builtin_crc32_data32, > __builtin_crc64_data8, __builtin_crc64_data16, __builtin_crc64_data32, > __builtin_crc64_data64 > > Each builtin takes three parameters: > crc: The initial CRC value. > data: The data to be processed. > polynomial: The CRC polynomial without the leading 1. > > To validate the correctness of these builtins, this patch also includes > additions to the GCC testsuite. > This enhancement allows GCC to offer developers high-performance CRC > computation options > that automatically adapt to the capabilities of the target hardware. > > Co-authored-by: Joern Rennecke <joern.renne...@embecosm.com> > > Not complete. May continue the work if these built-ins are needed. > > gcc/ > > * builtin-types.def (BT_FN_UINT8_UINT8_UINT8_CONST_SIZE): Define. > (BT_FN_UINT16_UINT16_UINT8_CONST_SIZE): Likewise. > (BT_FN_UINT16_UINT16_UINT16_CONST_SIZE): Likewise. > (BT_FN_UINT32_UINT32_UINT8_CONST_SIZE): Likewise. > (BT_FN_UINT32_UINT32_UINT16_CONST_SIZE): Likewise. > (BT_FN_UINT32_UINT32_UINT32_CONST_SIZE): Likewise. > (BT_FN_UINT64_UINT64_UINT8_CONST_SIZE): Likewise. > (BT_FN_UINT64_UINT64_UINT16_CONST_SIZE): Likewise. > (BT_FN_UINT64_UINT64_UINT32_CONST_SIZE): Likewise. > (BT_FN_UINT64_UINT64_UINT64_CONST_SIZE): Likewise. > * builtins.cc (associated_internal_fn): Handle BUILT_IN_CRC8_DATA8, > BUILT_IN_CRC16_DATA8, BUILT_IN_CRC16_DATA16, > BUILT_IN_CRC32_DATA8, BUILT_IN_CRC32_DATA16, BUILT_IN_CRC32_DATA32, > BUILT_IN_CRC64_DATA8, BUILT_IN_CRC64_DATA16, BUILT_IN_CRC64_DATA32, > BUILT_IN_CRC64_DATA64, > BUILT_IN_REV_CRC8_DATA8, > BUILT_IN_REV_CRC16_DATA8, BUILT_IN_REV_CRC16_DATA16, > BUILT_IN_REV_CRC32_DATA8, BUILT_IN_REV_CRC32_DATA16, > BUILT_IN_REV_CRC32_DATA32. > (expand_builtin_crc_table_based): New function. > (expand_builtin): Handle BUILT_IN_CRC8_DATA8, > BUILT_IN_CRC16_DATA8, BUILT_IN_CRC16_DATA16, > BUILT_IN_CRC32_DATA8, BUILT_IN_CRC32_DATA16, BUILT_IN_CRC32_DATA32, > BUILT_IN_CRC64_DATA8, BUILT_IN_CRC64_DATA16, BUILT_IN_CRC64_DATA32, > BUILT_IN_CRC64_DATA64, > BUILT_IN_REV_CRC8_DATA8, > BUILT_IN_REV_CRC16_DATA8, BUILT_IN_REV_CRC16_DATA16, > BUILT_IN_REV_CRC32_DATA8, BUILT_IN_REV_CRC32_DATA16, > BUILT_IN_REV_CRC32_DATA32. > * builtins.def (BUILT_IN_CRC8_DATA8): New builtin. > (BUILT_IN_CRC16_DATA8): Likewise. > (BUILT_IN_CRC16_DATA16): Likewise. > (BUILT_IN_CRC32_DATA8): Likewise. > (BUILT_IN_CRC32_DATA16): Likewise. > (BUILT_IN_CRC32_DATA32): Likewise. > (BUILT_IN_CRC64_DATA8): Likewise. > (BUILT_IN_CRC64_DATA16): Likewise. > (BUILT_IN_CRC64_DATA32): Likewise. > (BUILT_IN_CRC64_DATA64): Likewise. > (BUILT_IN_REV_CRC8_DATA8): New builtin. > (BUILT_IN_REV_CRC16_DATA8): Likewise. > (BUILT_IN_REV_CRC16_DATA16): Likewise. > (BUILT_IN_REV_CRC32_DATA8): Likewise. > (BUILT_IN_REV_CRC32_DATA16): Likewise. > (BUILT_IN_REV_CRC32_DATA32): Likewise. > * builtins.h (expand_builtin_crc_table_based): New function > declaration. > * doc/extend.texti (__builtin_rev_crc16_data8, > (__builtin_rev_crc32_data32, __builtin_rev_crc32_data8, > __builtin_rev_crc32_data16, __builtin_crc8_data8, > __builtin_crc16_data16, __builtin_crc16_data8, > __builtin_crc32_data32, __builtin_crc32_data8, > __builtin_crc32_data16, __builtin_crc64_data64, > __builtin_crc64_data8, __builtin_crc64_data16, > __builtin_crc64_data32): Document. > > gcc/testsuite/ > > * gcc.c-torture/compile/crc-builtin-rev-target32.c > * gcc.c-torture/compile/crc-builtin-rev-target64.c > * gcc.c-torture/compile/crc-builtin-target32.c > * gcc.c-torture/compile/crc-builtin-target64.c > > Signed-off-by: Mariam Arutunian <mariamarutun...@gmail.com>
