postgresql/config
Heikki Linnakangas f044d71e33 Use ARMv8 CRC instructions where available.
ARMv8 introduced special CPU instructions for calculating CRC-32C. Use
them, when available, for speed.

Like with the similar Intel CRC instructions, several factors affect
whether the instructions can be used. The compiler intrinsics for them must
be supported by the compiler, and the instructions must be supported by the
target architecture. If the compilation target architecture does not
support the instructions, but adding "-march=armv8-a+crc" makes them
available, then we compile the code with a runtime check to determine if
the host we're running on supports them or not.

For the runtime check, use glibc getauxval() function. Unfortunately,
that's not very portable, but I couldn't find any more portable way to do
it. If getauxval() is not available, the CRC instructions will still be
used if the target architecture supports them without any additional
compiler flags, but the runtime check will not be available.

Original patch by Yuqi Gu, heavily modified by me. Reviewed by Andres
Freund, Thomas Munro.

Discussion: https://www.postgresql.org/message-id/HE1PR0801MB1323D171938EABC04FFE7FA9E3110%40HE1PR0801MB1323.eurprd08.prod.outlook.com
2018-04-04 12:22:45 +03:00
..
ac_func_accept_argtypes.m4 Remove some configure header-file checks that we weren't really using. 2017-02-25 18:10:09 -05:00
ax_prog_perl_modules.m4 Make configure check for IPC::Run when --enable-tap-tests is specified. 2017-06-15 15:56:12 -04:00
ax_pthread.m4 Update ax_pthread.m4 to an experimental draft version from upstream. 2015-07-30 14:14:50 +03:00
c-compiler.m4 Use ARMv8 CRC instructions where available. 2018-04-04 12:22:45 +03:00
c-library.m4 C comments: "a" <--> "an" corrections 2018-03-29 15:18:53 -04:00
config.guess Update config.guess and config.sub 2017-05-14 11:09:34 -04:00
config.sub Update config.guess and config.sub 2017-05-14 11:09:34 -04:00
docbook.m4 Convert documentation to DocBook XML 2017-11-23 09:44:28 -05:00
general.m4
install-sh Fix install-strip on Mac OS X 2012-08-21 23:42:43 -04:00
libtool.m4
llvm.m4 Add configure infrastructure (--with-llvm) to enable LLVM support. 2018-03-20 17:26:25 -07:00
Makefile Install our "missing" script where PGXS builds can find it. 2015-12-11 16:15:05 -05:00
missing
perl.m4 MSVC: Test whether 32-bit Perl needs -D_USE_32BIT_TIME_T. 2017-12-08 18:06:05 -08:00
pkg.m4 ICU support 2017-03-23 15:28:48 -04:00
prep_buildtree
programs.m4 Further improve consistency of configure's program searching. 2017-08-01 11:40:08 -04:00
python.m4 Teach configure --with-python to report the Python version number. 2018-04-02 12:26:12 -04:00
tcl.m4 Further improve consistency of configure's program searching. 2017-08-01 11:40:08 -04:00