diff options
Diffstat (limited to '')
| -rw-r--r-- | configure.ac | 59 |
1 files changed, 57 insertions, 2 deletions
diff --git a/configure.ac b/configure.ac index ddc82a3b..60a63825 100644 --- a/configure.ac +++ b/configure.ac @@ -370,6 +370,16 @@ esac AM_CONDITIONAL(COND_ASM_X86, test "x$enable_assembler" = xx86) +############# +# CLMUL CRC # +############# + +AC_ARG_ENABLE([clmul-crc], AS_HELP_STRING([--disable-clmul-crc], + [Do not use carryless multiplication for CRC calculation + even if support for it is detected.]), + [], [enable_clmul_crc=yes]) + + ##################### # Size optimization # ##################### @@ -733,8 +743,9 @@ AC_CHECK_HEADERS([fcntl.h limits.h sys/time.h], [], [AC_MSG_ERROR([Required header file(s) are missing.])]) -# This allows the use of the intrinsic functions if they are available. -AC_CHECK_HEADERS([immintrin.h]) +# immintrin.h allows the use of the intrinsic functions if they are available. +# cpuid.h may be used for detecting x86 processor features at runtime. +AC_CHECK_HEADERS([immintrin.h cpuid.h]) ############################################################################### @@ -874,6 +885,50 @@ AC_CHECK_DECL([_mm_movemask_epi8], #include <immintrin.h> #endif]) +# For faster CRC on 32/64-bit x86 and E2K (see also crc64_fast.c): +# +# - Check for the CLMUL intrinsic _mm_clmulepi64_si128 in <immintrin.h>. +# +# - Check that __attribute__((__target__("ssse3,sse4.1,pclmul"))) works +# together with _mm_clmulepi64_si128 from <immintrin.h>. The attribute +# was added in GCC 4.4 but some GCC 4.x versions don't allow intrinsics +# with it. Exception: it must be not be used with EDG-based compilers +# like ICC and the compiler on E2K. +# +# If everything above is supported, runtime detection will be used to keep the +# binaries working on systems that don't support the required extensions. +AC_MSG_CHECKING([if _mm_clmulepi64_si128 is usable]) +if test "x$enable_clmul_crc" = xno ; then + AC_MSG_RESULT([no, --disable-clmul-crc was used]) +else + AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ +#include <immintrin.h> + +// CLMUL works on older E2K instruction set but it is slow due to emulation. +#if defined(__e2k__) && __iset__ < 6 +# error +#endif + +// Intel's old compiler (ICC) can define __GNUC__ but the attribute must not +// be used with it. The new Clang-based ICX needs the attribute. +// Checking for !defined(__EDG__) catches ICC and other EDG-based compilers. +#if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__) +__attribute__((__target__("ssse3,sse4.1,pclmul"))) +#endif +__m128i my_clmul(__m128i a, __m128i b) +{ + return _mm_clmulepi64_si128(a, b, 0); +} + ]])], [ + AC_DEFINE([HAVE_USABLE_CLMUL], [1], + [Define to 1 if _mm_clmulepi64_si128 is usable. + See configure.ac for details.]) + AC_MSG_RESULT([yes]) + ], [ + AC_MSG_RESULT([no]) + ]) +fi + # Check for sandbox support. If one is found, set enable_sandbox=found. case $enable_sandbox in auto | capsicum) |