revert r310985 which breaks for the following case:

struct string {
  ~string();
};
void f2();
void f1(int) { f2(); }
void run(int c) {
  string body;
  while (true) {
    if (c)
      f1(c);
    else
      f1(c);
  }
}

Will recommit once the issue is fixed.

llvm-svn: 311864