diff options
| -rw-r--r-- | configure.ac | 11 | ||||
| -rw-r--r-- | src/util/u_atomic.h | 21 |
2 files changed, 32 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index 1bfac3b2912..421f4f3c801 100644 --- a/configure.ac +++ b/configure.ac @@ -387,6 +387,17 @@ fi AM_CONDITIONAL([SSE41_SUPPORTED], [test x$SSE41_SUPPORTED = x1]) AC_SUBST([SSE41_CFLAGS], $SSE41_CFLAGS) +dnl Check for new-style atomic builtins +AC_COMPILE_IFELSE([AC_LANG_SOURCE([[ +int main() { + int n; + return __atomic_load_n(&n, __ATOMIC_ACQUIRE); +}]])], GCC_ATOMIC_BUILTINS_SUPPORTED=1) +if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" = x1; then + DEFINES="$DEFINES -DUSE_GCC_ATOMIC_BUILTINS" +fi +AM_CONDITIONAL([GCC_ATOMIC_BUILTINS_SUPPORTED], [test x$GCC_ATOMIC_BUILTINS_SUPPORTED = x1]) + dnl Check for Endianness AC_C_BIGENDIAN( little_endian=no, diff --git a/src/util/u_atomic.h b/src/util/u_atomic.h index 867590391f4..2a5bbae295b 100644 --- a/src/util/u_atomic.h +++ b/src/util/u_atomic.h @@ -36,6 +36,20 @@ #define PIPE_ATOMIC "GCC Sync Intrinsics" +#if defined(USE_GCC_ATOMIC_BUILTINS) + +/* The builtins with explicit memory model are available since GCC 4.7. */ +#define p_atomic_set(_v, _i) __atomic_store_n((_v), (_i), __ATOMIC_RELEASE) +#define p_atomic_read(_v) __atomic_load_n((_v), __ATOMIC_ACQUIRE) +#define p_atomic_dec_zero(v) (__atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) == 0) +#define p_atomic_inc(v) (void) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL) +#define p_atomic_dec(v) (void) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) +#define p_atomic_add(v, i) (void) __atomic_add_fetch((v), (i), __ATOMIC_ACQ_REL) +#define p_atomic_inc_return(v) __atomic_add_fetch((v), 1, __ATOMIC_ACQ_REL) +#define p_atomic_dec_return(v) __atomic_sub_fetch((v), 1, __ATOMIC_ACQ_REL) + +#else + #define p_atomic_set(_v, _i) (*(_v) = (_i)) #define p_atomic_read(_v) (*(_v)) #define p_atomic_dec_zero(v) (__sync_sub_and_fetch((v), 1) == 0) @@ -44,6 +58,13 @@ #define p_atomic_add(v, i) (void) __sync_add_and_fetch((v), (i)) #define p_atomic_inc_return(v) __sync_add_and_fetch((v), 1) #define p_atomic_dec_return(v) __sync_sub_and_fetch((v), 1) + +#endif + +/* There is no __atomic_* compare and exchange that returns the current value. + * Also, GCC 5.4 seems unable to optimize a compound statement expression that + * uses an additional stack variable with __atomic_compare_exchange[_n]. + */ #define p_atomic_cmpxchg(v, old, _new) \ __sync_val_compare_and_swap((v), (old), (_new)) |