[all-commits] [llvm/llvm-project] 9a99a1: [InstCombine] Add one-use limitation to box multip...

[shaojingzhi via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 9a99a1a39e1d067abb9a6cc0d53e7708d6c49995
      https://github.com/llvm/llvm-project/commit/9a99a1a39e1d067abb9a6cc0d53e7708d6c49995
  Author: shaojingzhi <shaojingzhi98 at gmail.com>
  Date:   2023-12-04 (Mon, 04 Dec 2023)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    M llvm/test/Transforms/InstCombine/mul_fold.ll
    M llvm/test/Transforms/InstCombine/mul_full_64.ll

  Log Message:
  -----------
  [InstCombine] Add one-use limitation to box multiply fold (#72876)

Check the operands of I are used in no more than one place, which can
not be deleted, cause a mul instruction has far more weight than add and
shl instruction in IR, thus this method cannot achieve the goal of
simplifying instructions, just return null.