70 lines · cpp
1//===- ReduceRegisterMasks.cpp - Specialized Delta Pass -------------------===//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-exception6//7//===----------------------------------------------------------------------===//8//9// This file implements a function which calls the Generic Delta pass in order10// to reduce custom register masks from the MachineFunction.11//12//===----------------------------------------------------------------------===//13 14#include "ReduceRegisterMasks.h"15#include "llvm/CodeGen/MachineFunction.h"16#include "llvm/CodeGen/MachineModuleInfo.h"17#include "llvm/CodeGen/MachineRegisterInfo.h"18 19using namespace llvm;20 21static void reduceMasksInFunction(Oracle &O, MachineFunction &MF) {22 DenseSet<const uint32_t *> ConstRegisterMasks;23 const auto *TRI = MF.getSubtarget().getRegisterInfo();24 25 // Track predefined/named regmasks which we ignore.26 const unsigned NumRegs = TRI->getNumRegs();27 ConstRegisterMasks.insert_range(TRI->getRegMasks());28 29 for (MachineBasicBlock &MBB : MF) {30 for (MachineInstr &MI : MBB) {31 for (MachineOperand &MO : MI.operands()) {32 if (!MO.isRegMask())33 continue;34 35 const uint32_t *OldRegMask = MO.getRegMask();36 // We're only reducing custom reg masks.37 if (ConstRegisterMasks.count(OldRegMask))38 continue;39 unsigned RegMaskSize =40 MachineOperand::getRegMaskSize(TRI->getNumRegs());41 std::vector<uint32_t> NewMask(RegMaskSize);42 43 bool MadeChange = false;44 for (unsigned I = 0; I != NumRegs; ++I) {45 if (OldRegMask[I / 32] & (1u << (I % 32))) {46 if (O.shouldKeep())47 NewMask[I / 32] |= 1u << (I % 32);48 } else49 MadeChange = true;50 }51 52 if (MadeChange) {53 uint32_t *UpdatedMask = MF.allocateRegMask();54 std::memcpy(UpdatedMask, NewMask.data(),55 RegMaskSize * sizeof(*OldRegMask));56 MO.setRegMask(UpdatedMask);57 }58 }59 }60 }61}62 63void llvm::reduceRegisterMasksMIRDeltaPass(Oracle &O,64 ReducerWorkItem &WorkItem) {65 for (const Function &F : WorkItem.getModule()) {66 if (auto *MF = WorkItem.MMI->getMachineFunction(F))67 reduceMasksInFunction(O, *MF);68 }69}70