[RTC] Split alias groups according to read only base addresses

  If there are multiple read only base addresses in an alias group
  we can split it into multiple alias groups each with only one
  read only access. This way we might reduce the number of
  comparisons significantly as it grows linear in the number of
  alias groups but exponential in their size.

Differential Revision: http://reviews.llvm.org/D5435



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@218757 91177308-0d34-0410-b5e6-96231b3b80d8
[RTC] Use the domain to split alias groups.

  We use a parametric abstraction of the domain to split alias groups
  if accesses cannot be executed under the same parameter evaluation.

  The two test cases check that we can remove alias groups if the
  pointers which might alias are never accessed under the same parameter
  evaluation and that the minimal/maximal accesses are not global but
  with regards to the parameter evaluation.

Differential Revision: http://reviews.llvm.org/D5436



git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@218758 91177308-0d34-0410-b5e6-96231b3b80d8