[all-commits] [llvm/llvm-project] 7ad17e: [Attributor] Avoid REQUIRED dependences in favor o...

[Johannes Doerfert via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 7ad17e008b0abec9b791f17de2f75f9112510d9d
      https://github.com/llvm/llvm-project/commit/7ad17e008b0abec9b791f17de2f75f9112510d9d
  Author: Johannes Doerfert <johannes at jdoerfert.de>
  Date:   2020-01-23 (Thu, 23 Jan 2020)

  Changed paths:
    M llvm/lib/Transforms/IPO/Attributor.cpp
    M llvm/test/Transforms/Attributor/nocapture-2.ll

  Log Message:
  -----------
  [Attributor] Avoid REQUIRED dependences in favor of OPTIONAL ones

When we use information only to short-cut deduction or improve it, we
can use OPTIONAL dependences instead of REQUIRED ones to avoid cascading
pessimistic fixpoints.

We also need to track dependences only when we use assumed information,
e.g., we act on assumed liveness information.