Can we map a instruction in IR back to source code?

Hi all,
Can we map an IR instruction to the correlated source code?

Or, if I want to recognize an assignment statement in the source code, can we quickly find all the related IR instructions according to a ‘store’?
E.g., i = j +k + m[5] in IR will have some loads and some getelementptrs. Can we define which IRs are related to this assignment?

Thanks.

Regards,
–Wenbin

Does this help?

http://llvm.org/docs/SourceLevelDebugging.html