[llvm-dev] Problem in adding llvm instructions

[Rasha Omar via llvm-dev]

I have a problem in llvm-pass
I wrote some commands to insert global variables and load and store instructions. Then I wrote dump command to view these values. 
When I run opt command the new results of global variables added and instructions are shown in terminal as I need, but the .ll file is not modified.
What is the cause of this problem?