This patch moves some common utility functions out of IPSCCP and makes them
available globally. The functions determine if interprocedural data-flow
analyses can propagate information through function returns, arguments, and
global variables.
Differential Revision: https://reviews.llvm.org/D37638
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315719 91177308-0d34-0410-b5e6-96231b3b80d8
