> On Aug 16, 2023, at 3:42 PM, Philipp Tomsich <philipp.toms...@vrull.eu> wrote:
>
> On Wed, 16 Aug 2023 at 21:10, Alexander Monakov <amona...@ispras.ru> wrote:
>>
>>
>> On Tue, 15 Aug 2023, Jeff Law wrote:
>>
>>> Because if the compiler can optimize it automatically, then the projects
>>> have
>>> to do literally nothing to take advantage of it. They just compile normally
>>> and their bitwise CRC gets optimized down to either a table lookup or a
>>> clmul
>>> variant. That's the real goal here.
>>
>> The only high-profile FOSS project that carries a bitwise CRC implementation
>> I'm aware of is the 'xz' compression library. There bitwise CRC is used for
>> populating the lookup table under './configure --enable-small':
>>
>> https://github.com/tukaani-project/xz/blob/2b871f4dbffe3801d0da3f89806b5935f758d5f3/src/liblzma/check/crc64_small.c
>>
>> It's a well-reasoned choice and your compiler would be undoing it
>> (reintroducing the table when the bitwise CRC is employed specifically
>> to avoid carrying the table).
Is that compiled with -Os? It would seem sensible for that to be the case, and
for the table optimization to be suppressed if that switch is used.
paul
