[all-commits] [llvm/llvm-project] 7e496c: [tests] Stablize tests for possible change in dere...

[Philip Reames via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 7e496c29e2bc85e5b769e0175ca9637dbff5615a
      https://github.com/llvm/llvm-project/commit/7e496c29e2bc85e5b769e0175ca9637dbff5615a
  Author: Philip Reames <listmail at philipreames.com>
  Date:   2021-07-14 (Wed, 14 Jul 2021)

  Changed paths:
    M llvm/test/Analysis/BasicAA/dereferenceable.ll

  Log Message:
  -----------
  [tests] Stablize tests for possible change in deref semantics

This is conceptually part of e75a2dfe.  This file contains both tests whose results don't change (with the right attributes added), and tests which fundementally regress with the current proposal.  Doing the update took some care, thus the seperate change.

Here's the e75a2dfe context repeated:

There's a potential change in dereferenceability attribute semantics in the nearish future.  See llvm-dev thread "RFC: Decomposing deref(N) into deref(N) + nofree" and D99100 for context.

This change simply adds appropriate attributes to tests to keep transform logic exercised under both old and new/proposed semantics.  Note that for many of these cases, O3 would infer exactly these attributes on the test IR.

This change handles the idiomatic pattern of a dereferenceable object being passed to a call which can not free that memory.  There's a couple other tests which need more one-off attention, they'll be handled in another change.