diff --git a/Library/Homebrew/extend/ENV/std.rb b/Library/Homebrew/extend/ENV/std.rb
index b6ca357b06..58c021bd65 100644
--- a/Library/Homebrew/extend/ENV/std.rb
+++ b/Library/Homebrew/extend/ENV/std.rb
@@ -133,7 +133,9 @@ module Stdenv
     super
     replace_in_cflags(/-Xarch_#{Hardware::CPU.arch_32_bit} (-march=\S*)/, '\1')
     # Clang mistakenly enables AES-NI on plain Nehalem
-    set_cpu_cflags '-march=native', :nehalem => '-march=native -Xclang -target-feature -Xclang -aes'
+    map = Hardware::CPU.optimization_flags
+    map = map.merge(:nehalem => "-march=native -Xclang -target-feature -Xclang -aes")
+    set_cpu_cflags "-march=native", map
   end
 
   def remove_macosxsdk version=MacOS.version