[LLVMdev] Request for review: Loss of Sign Checker

[Soumitra Chatterjee]

Hi,
	I just submitted a patch (Phabricator diff #28096) for a new 'Loss of 
Sign' checker, that would help diagnose the case when a negative value 
is assigned to an unsigned variable. The test case is included.

Unfortunately, there are no existing diagnostics for such assignments 
that lose the sign, which can cause nasty silent runtime failures.

Can someone please review the above changes? Since I do not have commit 
privilege, I would need someone to please help me with committing the 
changes once the review is over.

Please do let me know in case I missed anything.

Thanks,
Soumitra