diff --git a/autoload/fugitive.vim b/autoload/fugitive.vim
index d077c9c..807d72d 100644
--- a/autoload/fugitive.vim
+++ b/autoload/fugitive.vim
@@ -4095,7 +4095,6 @@ function! s:GrepSubcommand(line1, line2, range, bang, mods, args) abort
   endif
   let tree = s:Tree(dir)
   let args = a:args
-  let prefix = FugitiveVimPath(s:HasOpt(args, '--cached') || empty(tree) ? 'fugitive://' . dir . '//0/' : tree . '/')
   let name_only = s:HasOpt(args, '-l', '--files-with-matches', '--name-only', '-L', '--files-without-match')
   let title = [listnr < 0 ? ':Ggrep' : ':Glgrep'] + args
   if listnr > 0
@@ -4108,6 +4107,9 @@ function! s:GrepSubcommand(line1, line2, range, bang, mods, args) abort
   let tempfile = tempname()
   let event = listnr < 0 ? 'grep-fugitive' : 'lgrep-fugitive'
   silent exe s:DoAutocmd('QuickFixCmdPre ' . event)
+  let prefix = FugitiveVimPath(s:HasOpt(args, '--cached') || empty(tree) ?
+        \ 'fugitive://' . dir . '//0/' :
+        \ s:cpath(getcwd(), tree) ? '' : tree . '/')
   exe '!' . escape(s:UserCommand(dir, cmd + args), '%#!')
         \ printf(&shellpipe . (&shellpipe =~# '%s' ? '' : ' %s'), s:shellesc(tempfile))
   let list = map(readfile(tempfile), 's:GrepParseLine(prefix, name_only, dir, v:val)')