diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt
index 50d87bc173a..0e90b12f033 100644
--- a/lib/Target/X86/README.txt
+++ b/lib/Target/X86/README.txt
@@ -443,3 +443,8 @@ It might be better to generate
 	movw al, 8(%edx)
 	
 when we can spare a register. It reduces code size.
+
+//===---------------------------------------------------------------------===//
+
+Use .zerofill on x86/darwin when appropriate.
+