[all-commits] [llvm/llvm-project] 83aa93: [VectorUtils] Do not try to add indices matching t...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 83aa93e99542dbbfc5223130482ad6d7744d9a78
      https://github.com/llvm/llvm-project/commit/83aa93e99542dbbfc5223130482ad6d7744d9a78
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2021-01-18 (Mon, 18 Jan 2021)

  Changed paths:
    M llvm/include/llvm/Analysis/VectorUtils.h
    M llvm/test/Transforms/LoopVectorize/X86/interleaved-accesses-large-gap.ll

  Log Message:
  -----------
  [VectorUtils] Do not try to add indices matching tombstone/empty values.

Keys matching the tombstone/empty special values cannot be inserted in a
DenseMap. Under some circumstances, LV tries to add members to an
interleave group that match the special values. Skip adding such
members. This is unlikely to have any impact in practice, because
interleave groups with such indices are very likely to not be
vectorized, due to gaps.

This issue has been surfaced by fuzzing, see
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=11638