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| author | Andres Freund <andres@anarazel.de> | 2017-09-29 15:52:55 -0700 |
|---|---|---|
| committer | Andres Freund <andres@anarazel.de> | 2017-09-29 17:24:39 -0700 |
| commit | 510b8cbff15fcece246f66f2273ccf830a6c7e98 (patch) | |
| tree | 75dc05371931da2dfb72ba33084689658daa537c /config/c-compiler.m4 | |
| parent | 0008a106d4f84206a96fc1fb09a1e6b09f1627ec (diff) | |
| download | postgresql-510b8cbff15fcece246f66f2273ccf830a6c7e98.tar.gz | |
Extend & revamp pg_bswap.h infrastructure.
Upcoming patches are going to address performance issues that involve
slow system provided ntohs/htons etc. To address that expand
pg_bswap.h to provide pg_ntoh{16,32,64}, pg_hton{16,32,64} and
optimize their respective implementations by using compiler intrinsics
for gcc compatible compilers and msvc. Fall back to manual
implementations using shifts etc otherwise.
Additionally remove multiple evaluation hazards from the existing
BSWAP32/64 macros, by replacing them with inline functions when
necessary. In the course of that the naming scheme is changed to
pg_bswap16/32/64.
Author: Andres Freund
Discussion: https://postgr.es/m/20170927172019.gheidqy6xvlxb325@alap3.anarazel.de
Diffstat (limited to 'config/c-compiler.m4')
| -rw-r--r-- | config/c-compiler.m4 | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/config/c-compiler.m4 b/config/c-compiler.m4 index 7275ea69fe..6dcc790649 100644 --- a/config/c-compiler.m4 +++ b/config/c-compiler.m4 @@ -224,6 +224,23 @@ AC_DEFINE(HAVE__BUILTIN_TYPES_COMPATIBLE_P, 1, fi])# PGAC_C_TYPES_COMPATIBLE +# PGAC_C_BUILTIN_BSWAP16 +# ------------------------- +# Check if the C compiler understands __builtin_bswap16(), +# and define HAVE__BUILTIN_BSWAP16 if so. +AC_DEFUN([PGAC_C_BUILTIN_BSWAP16], +[AC_CACHE_CHECK(for __builtin_bswap16, pgac_cv__builtin_bswap16, +[AC_COMPILE_IFELSE([AC_LANG_SOURCE( +[static unsigned long int x = __builtin_bswap16(0xaabb);] +)], +[pgac_cv__builtin_bswap16=yes], +[pgac_cv__builtin_bswap16=no])]) +if test x"$pgac_cv__builtin_bswap16" = xyes ; then +AC_DEFINE(HAVE__BUILTIN_BSWAP16, 1, + [Define to 1 if your compiler understands __builtin_bswap16.]) +fi])# PGAC_C_BUILTIN_BSWAP16 + + # PGAC_C_BUILTIN_BSWAP32 # ------------------------- |