LLVM 19.0.0git
ARMMacroFusion.cpp
Go to the documentation of this file.
1//===- ARMMacroFusion.cpp - ARM Macro Fusion ----------------------===//
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/// \file This file contains the ARM implementation of the DAG scheduling
10/// mutation to pair instructions back to back.
11//
12//===----------------------------------------------------------------------===//
13
14#include "ARMMacroFusion.h"
15#include "ARMSubtarget.h"
18
19namespace llvm {
20
21// Fuse AES crypto encoding or decoding.
22static bool isAESPair(const MachineInstr *FirstMI,
23 const MachineInstr &SecondMI) {
24 // Assume the 1st instr to be a wildcard if it is unspecified.
25 switch(SecondMI.getOpcode()) {
26 // AES encode.
27 case ARM::AESMC :
28 return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESE;
29 // AES decode.
30 case ARM::AESIMC:
31 return FirstMI == nullptr || FirstMI->getOpcode() == ARM::AESD;
32 }
33
34 return false;
35}
36
37// Fuse literal generation.
38static bool isLiteralsPair(const MachineInstr *FirstMI,
39 const MachineInstr &SecondMI) {
40 // Assume the 1st instr to be a wildcard if it is unspecified.
41 if ((FirstMI == nullptr || FirstMI->getOpcode() == ARM::MOVi16) &&
42 SecondMI.getOpcode() == ARM::MOVTi16)
43 return true;
44
45 return false;
46}
47
48/// Check if the instr pair, FirstMI and SecondMI, should be fused
49/// together. Given SecondMI, when FirstMI is unspecified, then check if
50/// SecondMI may be part of a fused pair at all.
52 const TargetSubtargetInfo &TSI,
53 const MachineInstr *FirstMI,
54 const MachineInstr &SecondMI) {
55 const ARMSubtarget &ST = static_cast<const ARMSubtarget&>(TSI);
56
57 if (ST.hasFuseAES() && isAESPair(FirstMI, SecondMI))
58 return true;
59 if (ST.hasFuseLiterals() && isLiteralsPair(FirstMI, SecondMI))
60 return true;
61
62 return false;
63}
64
65std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation() {
67}
68
69} // end namespace llvm
const HexagonInstrInfo * TII
Representation of each machine instruction.
Definition: MachineInstr.h:69
unsigned getOpcode() const
Returns the opcode of this MachineInstr.
Definition: MachineInstr.h:566
TargetInstrInfo - Interface to description of machine instruction set.
TargetSubtargetInfo - Generic base class for all target subtargets.
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
static bool isAESPair(const MachineInstr *FirstMI, const MachineInstr &SecondMI)
std::unique_ptr< ScheduleDAGMutation > createMacroFusionDAGMutation(ArrayRef< MacroFusionPredTy > Predicates, bool BranchOnly=false)
Create a DAG scheduling mutation to pair instructions back to back for instructions that benefit acco...
std::unique_ptr< ScheduleDAGMutation > createARMMacroFusionDAGMutation()
Note that you have to add: DAG.addMutation(createARMMacroFusionDAGMutation()); to ARMPassConfig::crea...
static bool isLiteralsPair(const MachineInstr *FirstMI, const MachineInstr &SecondMI)
static bool shouldScheduleAdjacent(const TargetInstrInfo &TII, const TargetSubtargetInfo &TSI, const MachineInstr *FirstMI, const MachineInstr &SecondMI)
Check if the instr pair, FirstMI and SecondMI, should be fused together.