Git log can not show history before rename

mkdir tt3
cd tt3
git init-db
touch a.c
git add a.c
git commit -a -m "test1"

git mv a.c b.c
git commit -a -m "rename"

modify b.c
git commit -a -m "test2"

git log -C -M -- b.c
========================================
commit 8d55ed63d2048d41bde8c34dafc52c6a965d61ed
Author: Frank Li [off-list ref]
Date:   Fri Jan 30 19:20:10 2009 +0800
    test2
commit af0214f7d32cf97fda2743e7d906305e6de2e9a2
Author: Frank Li [off-list ref]
Date:   Fri Jan 30 19:19:15 2009 +0800
    rename
=========================================

I can't get history before rename.