diff --git a/Library/Homebrew/keg_fix_install_names.rb b/Library/Homebrew/keg_fix_install_names.rb
index e60ba72f1a..2d79e91807 100644
--- a/Library/Homebrew/keg_fix_install_names.rb
+++ b/Library/Homebrew/keg_fix_install_names.rb
@@ -64,6 +64,7 @@ class Keg
   #   some_variable="/opt/homebrew/Cellar/foo/1.0/lib"
   # and add quotes to protect against paths containing spaces.
   def replace_pkgconfig_file_path(s, old, new)
+    return if old == new
     s.gsub!(%r[([\S]+)="?#{Regexp.escape(old)}(.*?)"?$], "\\1=\"#{new}\\2\"")
   end