Debugging a issue in MachineFrameInfo?

Hi all:
I wrote some IR transform passes that works perfectly fine at IR level and running through opt -verify on the yielded IR results in no error.
However when I try to compile the transformed IR into object code using llc Output.ll -filetype=obj , it asserts out with Assertion failed: (unsigned(ObjectIdx+NumFixedObjects) < Objects.size() && “Invalid Object Idx!”), function getObjectAlignment, file include/llvm/CodeGen/MachineFrameInfo.h, line 424.

I’m currently using LLVM 6.0 release version and it would be great if someone could point out the correct way to fix this issue

Zhang