Fix dereferencing end iterator in SimplifyCFG. Patch by Ye Mei.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187646 91177308-0d34-0410-b5e6-96231b3b80d8
Pacify GCC, which worries about falling off the end of the switch.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187649 91177308-0d34-0410-b5e6-96231b3b80d8
Fix handling of CHECK-DAG combined with CHECK-NOT

Patch by Daniel Sanders.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187651 91177308-0d34-0410-b5e6-96231b3b80d8