On 2015-04-02 20:57:24 +0530, Abhijit Menon-Sen wrote: > At 2015-04-02 17:58:23 +0300, hlinn...@iki.fi wrote: > > > > We're only using inline assembly to force producing SSE 4.2 code, even > > when -msse4.2 is not used. That feels wrong. > > Why? It feels OK to me (and to Andres, per earlier discussions about > exactly this topic). Doing it this way allows the binary to run on a > non-SSE4.2 platform (and not use the CRC instructions).
Right. And SSE4.2 isn't that widespread yet. > > I believe the GCC way to do this would be to put the SSE4.2-specific > > code into a separate source file, and compile that file with > > "-msse4.2". And when you compile with -msse4.2, gcc actually also > > supports the _mm_crc32_u8/u64 intrinsics. To me this seems like a somewhat pointless exercise. I actually think from a performance POV it's better to have all the functions in one source file, so the compiler can inline things into the trampoline if it feels like it. Greetings, Andres Freund -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
