diff --git a/Library/Homebrew/extend/ENV/std.rb b/Library/Homebrew/extend/ENV/std.rb
index 3815497448..b6ca357b06 100644
--- a/Library/Homebrew/extend/ENV/std.rb
+++ b/Library/Homebrew/extend/ENV/std.rb
@@ -301,17 +301,19 @@ module Stdenv
     remove flags, %r{-mssse3}
     remove flags, %r{-msse4(\.\d)?}
     append flags, xarch unless xarch.empty?
+    append flags, map.fetch(effective_arch, default)
+  end
 
+  def effective_arch
     if ARGV.build_bottle?
-      arch = ARGV.bottle_arch || Hardware.oldest_cpu
-      append flags, Hardware::CPU.optimization_flags.fetch(arch)
+      ARGV.bottle_arch || Hardware.oldest_cpu
     elsif Hardware::CPU.intel? && !Hardware::CPU.sse4?
       # If the CPU doesn't support SSE4, we cannot trust -march=native or
       # -march=<cpu family> to do the right thing because we might be running
       # in a VM or on a Hackintosh.
-      append flags, Hardware::CPU.optimization_flags.fetch(Hardware.oldest_cpu)
+      Hardware.oldest_cpu
     else
-      append flags, map.fetch(Hardware::CPU.family, default)
+      Hardware::CPU.family
     end
   end