* Be TBAA safe

* Be TBAA safe
* Fix isFPCSafeToPrint to find more constants safe to print, which it was
  failing because ftostr was padding with leading space characters.
* Scan the entire module for global constants instead of each function at a
  time.  This has the advantage of allowing us to emit constants at global
  scope instead of function scope.  This speeds FP programs quite a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@9048 91177308-0d34-0410-b5e6-96231b3b80d8