[all-commits] [llvm/llvm-project] bebe6a: [GlobalISel] Combine (logic_op (op x...), (op y......

[Jessica Paquette via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: bebe6a6449811e877f7eba3f1798ddd1fa83e440
      https://github.com/llvm/llvm-project/commit/bebe6a6449811e877f7eba3f1798ddd1fa83e440
  Author: Jessica Paquette <jpaquette at apple.com>
  Date:   2020-08-11 (Tue, 11 Aug 2020)

  Changed paths:
    M llvm/include/llvm/CodeGen/GlobalISel/CombinerHelper.h
    M llvm/include/llvm/Target/GlobalISel/Combine.td
    M llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
    M llvm/lib/Target/AArch64/AArch64Combine.td
    A llvm/test/CodeGen/AArch64/GlobalISel/postlegalizercombiner-hoist-same-hands.mir
    A llvm/test/CodeGen/AArch64/GlobalISel/prelegalizercombiner-hoist-same-hands.mir

  Log Message:
  -----------
  [GlobalISel] Combine (logic_op (op x...), (op y...)) -> (op (logic_op x, y))

This implements

```
(logic_op (op x...), (op y...)) -> (op (logic_op x, y))
```

when `op` is an extend, a shift, or an and.

This is similar to `DAGCombiner::hoistLogicOpWithSameOpcodeHands`
(with a bunch of missing cases, e.g. G_TRUNC, G_BITCAST, etc.)

This is implemented so it works both pre and post-legalization.

This also adds a general way to add a series of instructions in a combine.
(`applyBuildInstructionSteps`).

Differential Revision: https://reviews.llvm.org/D85050