* Adjust to changes in TargetLowering interfaces.

* Adjust to changes in TargetLowering interfaces.
* Remove custom promotion for bool and byte select ops.  Legalize now
  promotes them for us.
* Allow folding ConstantPoolIndexes into EXTLOAD's, useful for float immediates.
* Declare which operations are not supported better.
* Add some hacky code for TRUNCSTORE to pretend that we have truncstore
  for i16 types.  This is useful for testing promotion code because I can
  just remove 16-bit registers all together and verify that programs work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19614 91177308-0d34-0410-b5e6-96231b3b80d8