Revert revision: 171467. This transformation is incorrect and makes some tests fail. Original message:

Simplified TRUNCATE operation that comes after SETCC. It is possible since SETCC result is 0 or -1.
Added a test.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171468 91177308-0d34-0410-b5e6-96231b3b80d8