diff --git a/llvm/docs/CommandGuide/llc.pod b/llvm/docs/CommandGuide/llc.pod
index f5fd34f..eba7859 100644
--- a/llvm/docs/CommandGuide/llc.pod
+++ b/llvm/docs/CommandGuide/llc.pod
@@ -41,6 +41,12 @@
 
 Print a summary of command line options.
 
+=item B<-O>=I<uint>
+
+Generate code at different optimization levels. These correspond to the I<-O0>,
+I<-O1>, I<-O2>, I<-O3>, and I<-O4> optimization levels used by B<llvm-gcc> and
+B<clang>.
+
 =item B<-f>
 
 Overwrite output files. By default, B<llc> will refuse to overwrite