[Hexagon] Adding unsigned halfword load.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224772 91177308-0d34-0410-b5e6-96231b3b80d8
Fix a leak found by asan.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224773 91177308-0d34-0410-b5e6-96231b3b80d8
[Hexagon] Adding signed halfword loads.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224774 91177308-0d34-0410-b5e6-96231b3b80d8