From baf16b2ea3a72d01712d4e16fae97606ac68dff0 Mon Sep 17 00:00:00 2001 From: Andrew Galante Date: Mon, 11 Jun 2018 15:05:25 -0700 Subject: [PATCH] configure.ac: Test for __atomic_add_fetch in atomic checks Some platforms have 64-bit __atomic_load_n but not 64-bit __atomic_add_fetch, so test for both of them. Bug: https://bugs.gentoo.org/655616 Reviewed-by: Matt Turner Reviewed-by: Eric Engestrom Reviewed-by: Dylan Baker --- configure.ac | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/configure.ac b/configure.ac index 75ee1a7c01c..3f747bf38cc 100644 --- a/configure.ac +++ b/configure.ac @@ -445,7 +445,8 @@ int main() { struct { uint64_t *v; } x; - return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE); + return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE) & + (int)__atomic_add_fetch(x.v, (uint64_t)1, __ATOMIC_ACQ_REL); }]])], GCC_ATOMIC_BUILTINS_SUPPORTED=yes, GCC_ATOMIC_BUILTINS_SUPPORTED=no) dnl If that didn't work, we try linking with -latomic, which is needed on some @@ -459,7 +460,8 @@ if test "x$GCC_ATOMIC_BUILTINS_SUPPORTED" != xyes; then struct { uint64_t *v; } x; - return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE); + return (int)__atomic_load_n(x.v, __ATOMIC_ACQUIRE) & + (int)__atomic_add_fetch(x.v, (uint64_t)1, __ATOMIC_ACQ_REL); }]])], GCC_ATOMIC_BUILTINS_SUPPORTED=yes LIBATOMIC_LIBS="-latomic", GCC_ATOMIC_BUILTINS_SUPPORTED=no) LDFLAGS=$save_LDFLAGS -- 2.30.2