[all-commits] [llvm/llvm-project] 337215: [DAG] ABD is not reassociative

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 337215ddf93f074575e530d796589b67044d0406
      https://github.com/llvm/llvm-project/commit/337215ddf93f074575e530d796589b67044d0406
  Author: David Green <david.green at arm.com>
  Date:   2023-03-01 (Wed, 01 Mar 2023)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
    M llvm/test/CodeGen/AArch64/abd-combine.ll

  Log Message:
  -----------
  [DAG] ABD is not reassociative

I'm not sure how I missed this in the testing, but as far as I understand
whilst ABDS and ABDU are commutive they are not associative. This patch
disables reassociateOps from visitABD, fixing the problems found in #61069.
ABDU: https://alive2.llvm.org/ce/z/eiT5QG
ABDS: https://alive2.llvm.org/ce/z/HzE29l

Differential Revision: https://reviews.llvm.org/D145064