llvm/llvm/include/llvm/CodeGen/ExecutionDomainFix.h

//==-- llvm/CodeGen/ExecutionDomainFix.h - Execution Domain Fix -*- 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
//
//===----------------------------------------------------------------------===//
//
/// \file Execution Domain Fix pass.
///
/// Some X86 SSE instructions like mov, and, or, xor are available in different
/// variants for different operand types. These variant instructions are
/// equivalent, but on Nehalem and newer cpus there is extra latency
/// transferring data between integer and floating point domains.  ARM cores
/// have similar issues when they are configured with both VFP and NEON
/// pipelines.
///
/// This pass changes the variant instructions to minimize domain crossings.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_CODEGEN_EXECUTIONDOMAINFIX_H
#define LLVM_CODEGEN_EXECUTIONDOMAINFIX_H

#include "llvm/ADT/SmallVector.h"
#include "llvm/CodeGen/LoopTraversal.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/ReachingDefAnalysis.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"

namespace llvm {

class MachineInstr;
class TargetInstrInfo;

/// A DomainValue is a bit like LiveIntervals' ValNo, but it also keeps track
/// of execution domains.
///
/// An open DomainValue represents a set of instructions that can still switch
/// execution domain. Multiple registers may refer to the same open
/// DomainValue - they will eventually be collapsed to the same execution
/// domain.
///
/// A collapsed DomainValue represents a single register that has been forced
/// into one of more execution domains. There is a separate collapsed
/// DomainValue for each register, but it may contain multiple execution
/// domains. A register value is initially created in a single execution
/// domain, but if we were forced to pay the penalty of a domain crossing, we
/// keep track of the fact that the register is now available in multiple
/// domains.
struct DomainValue { … };

class ExecutionDomainFix : public MachineFunctionPass { … };

} // namespace llvm

#endif // LLVM_CODEGEN_EXECUTIONDOMAINFIX_H