Fix PPC optimizeCompareInstr swapped-sub argument handling

When matching a compare with a subtract where the arguments of the compare are
swapped w.r.t. the arguments of the subtract, we need to negate the predicates
(or CR bit indices) of the users. This, however, is not the same as inverting
the predicate (negating LT -> GT, but inverting LT -> GE, for example). The ARM
backend seems to do this correctly, but when I adapted the code for the PPC
backend, I introduced an error in this logic.

Comparison optimization is now enabled again by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179899 91177308-0d34-0410-b5e6-96231b3b80d8
ArrayRefize getMachineNode(). No functionality change.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179901 91177308-0d34-0410-b5e6-96231b3b80d8
Move TryToFoldFastISelLoad to FastISel, where it belongs. In general, I'm
trying to move as much FastISel logic as possible out of the main path in
SelectionDAGISel - intermixing them just adds confusion.




git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179902 91177308-0d34-0410-b5e6-96231b3b80d8
Make variable match any name.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179903 91177308-0d34-0410-b5e6-96231b3b80d8