Revert "ensure fast thread local lookups occur once per access on macos"

This reverts commit d252f3b77f3b7d4cd59620588f9d026633c05816.

1 files changed, 0 insertions, 17 deletions

diff --git a/src/libstd/sys/unix/fast_thread_local.rs b/src/libstd/sys/unix/fast_thread_local.rs
index 28fb9800541..c34c2e6e786 100644
--- a/src/libstd/sys/unix/fast_thread_local.rs
+++ b/src/libstd/sys/unix/fast_thread_local.rs
@@ -82,20 +82,3 @@ pub unsafe fn register_dtor(t: *mut u8, dtor: unsafe extern fn(*mut u8)) {
         }
     }
 }
-
-#[cfg(not(target_os = "macos"))]
-pub unsafe fn lookup_once<T>(ptr: *const &T) -> &T {
-    *ptr
-}
-
-#[cfg(target_os = "macos")]
-pub unsafe fn lookup_once<T>(ptr: *const &T) -> &T {
-    // On macos, thread_local lookups can result in terrible code due to
-    // aggressive rerunning of the macos equivalent of `__tls_get_addr` - four
-    // lookups per actual reference in user code.
-    //
-    // Using a read_volatile on a value holding fast Key's address tricks the
-    // optimizer into only calling the macos get_addr equivalent once per time
-    // requested by the user.
-    crate::ptr::read_volatile(ptr)
-}