[all-commits] [llvm/llvm-project] 1dea8e: [BasicAA] Remove unnecessary known size requirement

[Nikita Popov via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 1dea8ed8b7dd2ff5ea89dd6dcaf0b682a81e9815
      https://github.com/llvm/llvm-project/commit/1dea8ed8b7dd2ff5ea89dd6dcaf0b682a81e9815
  Author: Nikita Popov <nikita.ppv at gmail.com>
  Date:   2020-11-28 (Sat, 28 Nov 2020)

  Changed paths:
    M llvm/lib/Analysis/BasicAliasAnalysis.cpp
    M llvm/test/Analysis/BasicAA/negoffset.ll

  Log Message:
  -----------
  [BasicAA] Remove unnecessary known size requirement

The size requirement on V2 was present because it was not clear
whether an unknown size would allow an access before the start of
V2, which could then overlap. This is clarified since D91649: In
this part of BasicAA, all accesses can occur only after the base
pointer, even if they have unknown size.

This makes the positive and negative offset cases symmetric.

Differential Revision: https://reviews.llvm.org/D91482