* Export method to merge identically named methods

* Export method to merge identically named methods
* Add code to fix PHI nodes that are missing arguments.  These PHI nodes can
  be generated by GCC if there is an uninitialized variable flowing into a merge
  point.  For example:

int foo(int y) {
  int X;
  if (y) X = 1;
  return X;
}

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@1110 91177308-0d34-0410-b5e6-96231b3b80d8