Add documentation for -Oz flag.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@130569 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/tools/clang.pod b/docs/tools/clang.pod
index 50b0199..4f4c7bf 100644
--- a/docs/tools/clang.pod
+++ b/docs/tools/clang.pod
@@ -268,7 +268,8 @@
Specify which optimization level to use. B<-O0> means "no optimization": this
level compiles the fastest and generates the most debuggable code. B<-O2> is a
moderate level of optimization which enables most optimizations. B<-Os> is like
-B<-O2> with extra optimizations to reduce code size. B<-O3> is like B<-O2>,
+B<-O2> with extra optimizations to reduce code size. B<-Oz> is like B<-Os>
+(and thus B<-O2>), but reduces code size further. B<-O3> is like B<-O2>,
except that it enables optimizations that take longer to perform or that may
generate larger code (in an attempt to make the program run faster). On
supported platforms, B<-O4> enables link-time optimization; object files are