diff --git a/libc/arch-arm64/bionic/__bionic_clone.S b/libc/arch-arm64/bionic/__bionic_clone.S
index 499a6cc..c49782c 100644
--- a/libc/arch-arm64/bionic/__bionic_clone.S
+++ b/libc/arch-arm64/bionic/__bionic_clone.S
@@ -40,9 +40,6 @@
     # Copy 'fn' and 'arg' onto the child stack.
     stp     x5, x6, [x1, #-16]
 
-    # Zero out the top 32 bits of 'flags'. (Is this necessary?)
-    uxtw    x0, w0
-
     # Make the system call.
     mov     x8, __NR_clone
     svc     #0