llvm-svn: 75262

merge the new functionality and unittests into ConstantRange. Thanks to
Nick Lewycky for pointing out that it isn't necessary to have two separate
classes here.

llvm-svn: 75191

what ConstantRange does for unsigned integers. Factor out a
common base class for common functionality.

Add some new functions for performing arithmetic on constant
ranges. Some of these are currently just stubbed out with
conservative implementations.

Add unittests for ConstantRange and ConstantSignedRange.

llvm-svn: 75177

llvm-svn: 71993

to make the copy constructor and destructor protected, and corresponding
adjustments to the unittests.

llvm-svn: 70644

the comparison operators were not only unnecessary in the presence of the
implicit conversion; they caused ambiguous overload errors. So I deleted them.

llvm-svn: 70243

Patch by Jeffrey Yasskin!

llvm-svn: 70084

llvm-svn: 68258

llvm-svn: 68249

llvm-svn: 67326

llvm-svn: 67083