[all-commits] [llvm/llvm-project] 24ae77: [Attributor] Mark a non-defined `null` pointer as ...

[Johannes Doerfert via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 24ae77eebffbf14ece11061cd4365f056fdaf426
      https://github.com/llvm/llvm-project/commit/24ae77eebffbf14ece11061cd4365f056fdaf426
  Author: Johannes Doerfert <johannes at jdoerfert.de>
  Date:   2020-01-28 (Tue, 28 Jan 2020)

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

  Log Message:
  -----------
  [Attributor] Mark a non-defined `null` pointer as `noalias`

If `null` is not defined we cannot access it, hence the pointer is
`noalias`. While this is not helpful on it's own it simplifies later
deductions that can skip over already known `noalias` pointers in
certain situations.