[all-commits] [llvm/llvm-project] b45a73: [InstCombine] Fold binop of shifts with related am...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b45a73f4d07424b37395f543974ef1ef6dec6332
      https://github.com/llvm/llvm-project/commit/b45a73f4d07424b37395f543974ef1ef6dec6332
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2023-06-28 (Wed, 28 Jun 2023)

  Changed paths:
    M llvm/lib/Transforms/InstCombine/InstCombineAddSub.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
    M llvm/lib/Transforms/InstCombine/InstCombineInternal.h
    M llvm/test/Transforms/InstCombine/binop-of-displaced-shifts.ll

  Log Message:
  -----------
  [InstCombine] Fold binop of shifts with related amounts

Fold

  binop(shift(ShiftedC1, ShAmt), shift(ShiftedC2, add(ShAmt, AddC)))
    ->
  shift(binop(ShiftedC1, shift(ShiftedC2, AddC)), ShAmt)

where both shifts are the same and AddC is a valid shift amount.

Proofs: https://alive2.llvm.org/ce/z/PhVVeg

Differential Revision: https://reviews.llvm.org/D152927