1//===- MergedLoadStoreMotion.h - merge and hoist/sink load/stores ---------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9//! \file
10//! This pass performs merges of loads and stores on both sides of a
11//  diamond (hammock). It hoists the loads and sinks the stores.
12//
13// The algorithm iteratively hoists two loads to the same address out of a
14// diamond (hammock) and merges them into a single load in the header. Similar
15// it sinks and merges two stores to the tail block (footer). The algorithm
16// iterates over the instructions of one side of the diamond and attempts to
17// find a matching load/store on the other side. It hoists / sinks when it
18// thinks it safe to do so.  This optimization helps with eg. hiding load
19// latencies, triggering if-conversion, and reducing static code size.
20//
21//===----------------------------------------------------------------------===//
22
23#ifndef LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
24#define LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
25
26#include "llvm/IR/Module.h"
27#include "llvm/IR/PassManager.h"
28
29namespace llvm {
30struct MergedLoadStoreMotionOptions {
31  bool SplitFooterBB;
32  MergedLoadStoreMotionOptions(bool SplitFooterBB = false)
33      : SplitFooterBB(SplitFooterBB) {}
34
35  MergedLoadStoreMotionOptions &splitFooterBB(bool SFBB) {
36    SplitFooterBB = SFBB;
37    return *this;
38  }
39};
40
41class MergedLoadStoreMotionPass
42    : public PassInfoMixin<MergedLoadStoreMotionPass> {
43  MergedLoadStoreMotionOptions Options;
44
45public:
46  MergedLoadStoreMotionPass()
47      : MergedLoadStoreMotionPass(MergedLoadStoreMotionOptions()) {}
48  MergedLoadStoreMotionPass(const MergedLoadStoreMotionOptions &PassOptions)
49      : Options(PassOptions) {}
50  PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
51};
52}
53
54#endif // LLVM_TRANSFORMS_SCALAR_MERGEDLOADSTOREMOTION_H
55