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-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file implements a function which calls the Generic Delta pass in order
10 // 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
19 using namespace llvm;
20
reduceMasksInFunction(Oracle & O,MachineFunction & MF)21 static 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 for (const uint32_t *Mask : TRI->getRegMasks())
28 ConstRegisterMasks.insert(Mask);
29
30 for (MachineBasicBlock &MBB : MF) {
31 for (MachineInstr &MI : MBB) {
32 for (MachineOperand &MO : MI.operands()) {
33 if (!MO.isRegMask())
34 continue;
35
36 const uint32_t *OldRegMask = MO.getRegMask();
37 // We're only reducing custom reg masks.
38 if (ConstRegisterMasks.count(OldRegMask))
39 continue;
40 unsigned RegMaskSize =
41 MachineOperand::getRegMaskSize(TRI->getNumRegs());
42 std::vector<uint32_t> NewMask(RegMaskSize);
43
44 bool MadeChange = false;
45 for (unsigned I = 0; I != NumRegs; ++I) {
46 if (OldRegMask[I / 32] & (1u << (I % 32))) {
47 if (O.shouldKeep())
48 NewMask[I / 32] |= 1u << (I % 32);
49 } else
50 MadeChange = true;
51 }
52
53 if (MadeChange) {
54 uint32_t *UpdatedMask = MF.allocateRegMask();
55 std::memcpy(UpdatedMask, NewMask.data(),
56 RegMaskSize * sizeof(*OldRegMask));
57 MO.setRegMask(UpdatedMask);
58 }
59 }
60 }
61 }
62 }
63
reduceMasksInModule(Oracle & O,ReducerWorkItem & WorkItem)64 static void reduceMasksInModule(Oracle &O, ReducerWorkItem &WorkItem) {
65 for (const Function &F : WorkItem.getModule()) {
66 if (auto *MF = WorkItem.MMI->getMachineFunction(F))
67 reduceMasksInFunction(O, *MF);
68 }
69 }
70
reduceRegisterMasksMIRDeltaPass(TestRunner & Test)71 void llvm::reduceRegisterMasksMIRDeltaPass(TestRunner &Test) {
72 runDeltaPass(Test, reduceMasksInModule, "Reducing register masks");
73 }
74