[PATCH] Fix for bug in indvars/ SCEV generating infinite loop (pr18886)

[Dinesh Dwivedi]

No problem :) and thanks for explaining, even your comment in commit is very informative. 
I am going thorough Loop Optimization passes to understand how they change IR and there 
I came accross these bugs. 

I will be happy to check in test case, as you suggested. Should I check in pr18886.ll as it 
is or I should put it with your test file.

http://reviews.llvm.org/D3837