Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//===- LoopSink.h - Loop Sink Pass ------------------------------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

//

// This file provides the interface for the Loop Sink pass.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_TRANSFORMS_SCALAR_LOOPSINK_H

#define LLVM_TRANSFORMS_SCALAR_LOOPSINK_H

#include "llvm/IR/PassManager.h"

namespace llvm {

class Function;

/// A pass that does profile-guided sinking of instructions into loops.

///

/// This is a function pass as it shouldn't be composed into any kind of

/// unified loop pass pipeline. The goal of it is to sink code into loops that

/// is loop invariant but only required within the loop body when doing so

/// reduces the global expected dynamic frequency with which it executes.

/// A classic example is an extremely cold branch within a loop body.

///

/// We do this as a separate pass so that during normal optimization all

/// invariant operations can be held outside the loop body to simplify

/// fundamental analyses and transforms of the loop.

class LoopSinkPass : public PassInfoMixin<LoopSinkPass> {

public:

  PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);

};

}

#endif // LLVM_TRANSFORMS_SCALAR_LOOPSINK_H