[all-commits] [llvm/llvm-project] 6c25ec: [Attributor] Add flag for undef value to the state...

[Shinji Okumura via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 6c25eca6142cec0695016b6fd012df56b50ee01b
      https://github.com/llvm/llvm-project/commit/6c25eca6142cec0695016b6fd012df56b50ee01b
  Author: Shinji Okumura <okuraofvegetable at gmail.com>
  Date:   2020-08-27 (Thu, 27 Aug 2020)

  Changed paths:
    M llvm/include/llvm/Transforms/IPO/Attributor.h
    M llvm/lib/Transforms/IPO/Attributor.cpp
    M llvm/lib/Transforms/IPO/AttributorAttributes.cpp
    M llvm/test/Transforms/Attributor/potential.ll
    M llvm/test/Transforms/Attributor/value-simplify.ll

  Log Message:
  -----------
  [Attributor] Add flag for undef value to the state of AAPotentialValues

Currently, an undef value is reduced to 0 when it is added to a set of potential values.
This patch introduces a flag for under values. By this, for example, we can merge two states `{undef}`, `{1}` to `{1}` (because we can reduce the undef to 1).

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D85592