[ValueTracking] recognize a 'not' of an assumed condition as false

Also, add the corresponding match to the AssumptionCache's 'Affected Values' list.

Differential Revision: https://reviews.llvm.org/D28485



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292239 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed