On Thu, Apr 2, 2015 at 5:33 PM, Heikki Linnakangas <hlinn...@iki.fi> wrote: > It was added in gcc 4.2. That's good enough for me.
I think it's fine to have optional optimizations that require gcc >= 4.2, as long as older platforms don't break outright. >>> We have a buildfarm animal that still uses gcc 2.95.3, which was >>> released in 2001. I don't have a compiler of that vintage to test >>> with, but I assume an old enough assembler would not know about the >>> crc32q instruction and fail to compile. >> >> >> GCC from <2002 wouldn't support the symbolic operand names in inline >> assembly. binutils from <2007 (IIRC) wouldn't support the assembler >> instructions themselves. >> >> We could work around the latter by using the appropriate sequence of >> bytes. We could work around the former by using the old syntax for >> operands. > > I'm OK with not supporting the new instructions when building with an old > compiler/assembler. But the build shouldn't fail with an old > compiler/assembler. Using old syntax or raw bytes just to avoid failing on > an ancient compiler seems ugly. I dunno about old syntax, but raw bytes seems like a bad idea, for sure. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
