1) With X86 lowering change, the following can no longer happen since

1) With X86 lowering change, the following can no longer happen since
   the branch's chain is also produced by cmp.
          [ch, r : ld]
             ^ ^
             | |
      [XX]--/   \- [flag : cmp]
       ^             ^
       |             |
       \---[br flag]-

Remove an isel check which prevents loads from being folded into cmp / test
instructions.

2) Whenever possible, delete a selected node to allow more load folding
opportunities. Note not all nodes can be deleted after it has been
selected. Some may have simply morphed; some have not changed at all (e.g.
EntryToken).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30242 91177308-0d34-0410-b5e6-96231b3b80d8