Add a DenseMapInfo specialization for PointerUnion. In tree user to land shortly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206253 91177308-0d34-0410-b5e6-96231b3b80d8
[C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206254 91177308-0d34-0410-b5e6-96231b3b80d8
Break PseudoSourceValue out of the Value hierarchy. It is now the root of its own tree containing FixedStackPseudoSourceValue (which you can use isa/dyn_cast on) and MipsCallEntry (which you can't). Anything that needs to use either a PseudoSourceValue* and Value* is strongly encouraged to use a MachinePointerInfo instead.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@206255 91177308-0d34-0410-b5e6-96231b3b80d8