Question about range comparison

Hi internals,

I want to compare the range between two commits of the PHP GitHub.

I did the git checkout like this one [1]

The problem is that I cannot compare, because in the timeline of commits, it only appears the commits sent by the users, and not the commits that were merged in the branch master.

In other words, the timeline only shows the commits sent without rebase, so, if I try the comparison, I will compare two forks of the PHP, and not the PHP branch master with the commits applied.

I wonder how I could I do this?

Thanks.

[1] http://stackoverflow.com/questions/7832770/get-certain-commit-from-github-project