diff options
Diffstat (limited to 'm4')
| -rw-r--r-- | m4/fp_gcc_supports__atomics.m4 | 52 |
1 files changed, 38 insertions, 14 deletions
diff --git a/m4/fp_gcc_supports__atomics.m4 b/m4/fp_gcc_supports__atomics.m4 index 81fc44c500..6aa3c9dc93 100644 --- a/m4/fp_gcc_supports__atomics.m4 +++ b/m4/fp_gcc_supports__atomics.m4 @@ -1,17 +1,41 @@ -# FP_GCC_SUPPORTS__ATOMICS -# ------------------------ -# Does gcc support the __atomic_* family of builtins? +dnl FP_GCC_SUPPORTS__ATOMICS +dnl ------------------------ +dnl Does gcc support the __atomic_* family of builtins? AC_DEFUN([FP_GCC_SUPPORTS__ATOMICS], [ - AC_REQUIRE([AC_PROG_CC]) - AC_MSG_CHECKING([whether GCC supports __atomic_ builtins]) - echo 'int test(int *x) { int y; __atomic_load(x, &y, __ATOMIC_SEQ_CST); return y; }' > conftest.c - if $CC -c conftest.c > /dev/null 2>&1; then - CONF_GCC_SUPPORTS__ATOMICS=YES - AC_MSG_RESULT([yes]) - else - CONF_GCC_SUPPORTS__ATOMICS=NO - AC_MSG_RESULT([no]) - fi - rm -f conftest.c conftest.o + AC_REQUIRE([AC_PROG_CC]) + AC_MSG_CHECKING([whether GCC supports __atomic_ builtins]) + AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[int x, y;]], [[__atomic_load(&x, &y, __ATOMIC_SEQ_CST); return y]])], + [ + AC_MSG_RESULT(yes) + AC_MSG_CHECKING(whether -latomic is needed for sub-word-sized atomic operations) + AC_LINK_IFELSE([AC_LANG_PROGRAM([[unsigned char a;]], [[__atomic_fetch_or(&a, 1, __ATOMIC_RELAXED);]])], + [ + AC_MSG_RESULT(no) + AC_SUBST([CabalNeedLibatomic],[False]) + need_latomic=0 + ], + [ + _save_LIBS=$LIBS + LIBS="-latomic" + AC_LINK_IFELSE([AC_LANG_PROGRAM([[unsigned char a;]], [[__atomic_fetch_or(&a, 1, __ATOMIC_RELAXED);]])], + [ + AC_MSG_RESULT(yes) + AC_SUBST([CabalNeedLibatomic],[True]) + need_latomic=1 + ], + [ + AC_MSG_RESULT(failed) + AC_MSG_ERROR([sub-word-sized atomic operations are not available.]) + ]) + LIBS=$_save_LIBS + ]) + ], + [ + AC_MSG_RESULT(no) + AC_MSG_ERROR([C compiler needs to support __atomic primitives.]) + ]) + AC_DEFINE([HAVE_C11_ATOMICS], [1], [Does GCC support __atomic primitives?]) + AC_DEFINE_UNQUOTED([NEED_ATOMIC_LIB], [$need_latomic], + [Define to 1 if we need -latomic for sub-word atomic operations.]) ]) |