How to identify the end of a branch in the symbolic execution in clang?

I am writing a taint tracking checker with clang static analyzer, and currently I want to do something when a branch is finished being analyzed. So I need to know when the symbolic execution reaches the end of a branch, which means how can I notice that the symbolic execution reaches the end of an If code block or Else code block? I have tried the CompoundStmt, but it didn’t work in the callback function CheckPostStmt, and neither did the BlockExpr work. Are there any possible ways to achieve this goal?

Thank you!