include/llvm/Transforms/Scalar/MergedLoadStoreMotion.h

   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
  29 namespace llvm {
  30 struct 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
  41 class MergedLoadStoreMotionPass
  42     : public PassInfoMixin<MergedLoadStoreMotionPass> {
  43   MergedLoadStoreMotionOptions Options;
  44
  45 public:
  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