llvm/llvm/lib/Target/AMDGPU/SIInsertHardClauses.cpp

//===- SIInsertHardClauses.cpp - Insert Hard Clauses ----------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Insert s_clause instructions to form hard clauses.
///
/// Clausing load instructions can give cache coherency benefits. Before gfx10,
/// the hardware automatically detected "soft clauses", which were sequences of
/// memory instructions of the same type. In gfx10 this detection was removed,
/// and the s_clause instruction was introduced to explicitly mark "hard
/// clauses".
///
/// It's the scheduler's job to form the clauses by putting similar memory
/// instructions next to each other. Our job is just to insert an s_clause
/// instruction to mark the start of each clause.
///
/// Note that hard clauses are very similar to, but logically distinct from, the
/// groups of instructions that have to be restartable when XNACK is enabled.
/// The rules are slightly different in each case. For example an s_nop
/// instruction breaks a restartable group, but can appear in the middle of a
/// hard clause. (Before gfx10 there wasn't a distinction, and both were called
/// "soft clauses" or just "clauses".)
///
/// The SIFormMemoryClauses pass and GCNHazardRecognizer deal with restartable
/// groups, not hard clauses.
//
//===----------------------------------------------------------------------===//

#include "AMDGPU.h"
#include "GCNSubtarget.h"
#include "MCTargetDesc/AMDGPUMCTargetDesc.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/MachineFunctionPass.h"

usingnamespacellvm;

#define DEBUG_TYPE …

namespace {

enum HardClauseType { … };

class SIInsertHardClauses : public MachineFunctionPass { … };

} // namespace

char SIInsertHardClauses::ID = …;

char &llvm::SIInsertHardClausesID = …;

INITIALIZE_PASS(…)