llvm-svn: 56334

  if we know that 'len != 0' and know that 'i == 0' then we know that
  'i < len' must evaluate to true and cannot evaluate to false

llvm-svn: 56260

llvm-svn: 55559

llvm-svn: 55537

llvm-svn: 55536

llvm-svn: 55412