llvm/llvm/lib/Target/RISCV/RISCVPushPopOptimizer.cpp

//===------- RISCVPushPopOptimizer.cpp - RISC-V Push/Pop opt. pass --------===//
//
// 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 contains a pass that replaces Zcmp POP instructions with
// POPRET[Z] where possible.
//
//===----------------------------------------------------------------------===//

#include "RISCVInstrInfo.h"
#include "RISCVMachineFunctionInfo.h"

usingnamespacellvm;

#define RISCV_PUSH_POP_OPT_NAME …

namespace {
struct RISCVPushPopOpt : public MachineFunctionPass { … };

char RISCVPushPopOpt::ID = …;

} // end of anonymous namespace

INITIALIZE_PASS(…)

// Check if POP instruction was inserted into the MBB and return iterator to it.
static MachineBasicBlock::iterator containsPop(MachineBasicBlock &MBB) { … }

bool RISCVPushPopOpt::usePopRet(MachineBasicBlock::iterator &MBBI,
                                MachineBasicBlock::iterator &NextI,
                                bool IsReturnZero) { … }

// Search for last assignment to a0 and if possible use ret_val slot of POP to
// store return value.
bool RISCVPushPopOpt::adjustRetVal(MachineBasicBlock::iterator &MBBI) { … }

bool RISCVPushPopOpt::runOnMachineFunction(MachineFunction &Fn) { … }

/// createRISCVPushPopOptimizationPass - returns an instance of the
/// Push/Pop optimization pass.
FunctionPass *llvm::createRISCVPushPopOptimizationPass() { … }