diff --git a/autoload/fugitive.vim b/autoload/fugitive.vim
index 6ebf080..bec6f57 100644
--- a/autoload/fugitive.vim
+++ b/autoload/fugitive.vim
@@ -4479,7 +4479,7 @@ function! fugitive#Diffsplit(autodir, keepfocus, mods, arg, args) abort
     exe pre
     let restore = s:diff_restore()
     let w:fugitive_diff_restore = restore
-    if s:CompareAge(commit, s:DirCommitFile(spec)[1]) < 0
+    if len(spec) && s:CompareAge(commit, s:DirCommitFile(spec)[1]) < 0
       let mods = s:Mods(mods, 'rightbelow')
     else
       let mods = s:Mods(mods, 'leftabove')