threads: fix msvc build without openmp (#9615)

We're missing atomic_thread_fence() in MSVC builds when openmp is disabled.

diff --git a/ggml/src/ggml.c b/ggml/src/ggml.c
index 96c09ca897ee79f3865029df18dd2d860a22f95c..d4aa0a81bfae24a465c7520a4334f8b28a7e863f 100644 (file)
--- a/ggml/src/ggml.c
+++ b/ggml/src/ggml.c
@@ -135,6 +135,9 @@ static atomic_bool atomic_flag_test_and_set(atomic_flag * ptr) {
 static void atomic_flag_clear(atomic_flag * ptr) {
     InterlockedExchange(ptr, 0);
 }
+static void atomic_thread_fence(memory_order mo) {
+    MemoryBarrier();
+}
 #else // clang
 #include <stdatomic.h>
 #endif