diff --git a/src/fastmem.zig b/src/fastmem.zig
index 687c057af..bdea44155 100644
--- a/src/fastmem.zig
+++ b/src/fastmem.zig
@@ -2,13 +2,20 @@ const std = @import("std");
 const builtin = @import("builtin");
 const assert = std.debug.assert;
 
-/// Same as std.mem.copyForwards but prefers libc memmove if it is available
-/// because it is generally much faster.
+/// Same as std.mem.copyForwards/Backwards but prefers libc memmove if it is
+/// available because it is generally much faster.
 pub inline fn move(comptime T: type, dest: []T, source: []const T) void {
     if (builtin.link_libc) {
         _ = memmove(dest.ptr, source.ptr, source.len * @sizeOf(T));
     } else {
-        std.mem.copyForwards(T, dest, source);
+        // Depending on the ordering of the copy, we need to use the
+        // proper call here. Unfortunately this function call is
+        // too generic to know this at comptime.
+        if (@intFromPtr(dest.ptr) <= @intFromPtr(source.ptr)) {
+            std.mem.copyForwards(T, dest, source);
+        } else {
+            std.mem.copyBackwards(T, dest, source);
+        }
     }
 }