* Fix a problem setting a name on a constant value that died because no symbol table was passed in
* Add some comments describing the passes
* Implement a new peephole:
// Peephole optimize the following instructions:
// %t = cast <T1>* %P to <T2> * ;; If T1 is losslessly convertable to T2
// store <T2> %V, <T2>* %t
//
// Into:
// %t = cast <T2> %V to <T1>
// store <T1> %t2, <T1>* %P
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1080 91177308-0d34-0410-b5e6-96231b3b80d8