Only print values live at BB or method exit, and insert loads at each

Only print values live at BB or method exit, and insert loads at each
BB exit to read and print values stored in that BB.   Note that only
these stored values are live at method exit!.  Also, print messages at
method entry and exit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@892 91177308-0d34-0410-b5e6-96231b3b80d8