1 //===- ARMMacroFusion.cpp - ARM Macro Fusion ----------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 /// \file This file contains the ARM implementation of the DAG scheduling
11 /// mutation to pair instructions back to back.
12 //
13 //===----------------------------------------------------------------------===//
14
15 #include "ARMMacroFusion.h"
16 #include "ARMSubtarget.h"
17 #include "llvm/CodeGen/MacroFusion.h"
18 #include "llvm/CodeGen/TargetInstrInfo.h"
19
20 namespace llvm {
21
22 // Fuse AES crypto encoding or decoding.
isAESPair(const MachineInstr * FirstMI,const MachineInstr & SecondMI)23 static bool isAESPair(const MachineInstr *FirstMI,
24 const MachineInstr &SecondMI) {
25 // Assume the 1st instr to be a wildcard if it is unspecified.
26 unsigned FirstOpcode =
27 FirstMI ? FirstMI->getOpcode()
28 : static_cast<unsigned>(ARM::INSTRUCTION_LIST_END);
29 unsigned SecondOpcode = SecondMI.getOpcode();
30
31 switch(SecondOpcode) {
32 // AES encode.
33 case ARM::AESMC :
34 return FirstOpcode == ARM::AESE ||
35 FirstOpcode == ARM::INSTRUCTION_LIST_END;
36 // AES decode.
37 case ARM::AESIMC:
38 return FirstOpcode == ARM::AESD ||
39 FirstOpcode == ARM::INSTRUCTION_LIST_END;
40 }
41
42 return false;
43 }
44
45 // Fuse literal generation.
isLiteralsPair(const MachineInstr * FirstMI,const MachineInstr & SecondMI)46 static bool isLiteralsPair(const MachineInstr *FirstMI,
47 const MachineInstr &SecondMI) {
48 // Assume the 1st instr to be a wildcard if it is unspecified.
49 unsigned FirstOpcode =
50 FirstMI ? FirstMI->getOpcode()
51 : static_cast<unsigned>(ARM::INSTRUCTION_LIST_END);
52 unsigned SecondOpcode = SecondMI.getOpcode();
53
54 // 32 bit immediate.
55 if ((FirstOpcode == ARM::INSTRUCTION_LIST_END ||
56 FirstOpcode == ARM::MOVi16) &&
57 SecondOpcode == ARM::MOVTi16)
58 return true;
59
60 return false;
61 }
62
63 /// Check if the instr pair, FirstMI and SecondMI, should be fused
64 /// together. Given SecondMI, when FirstMI is unspecified, then check if
65 /// SecondMI may be part of a fused pair at all.
shouldScheduleAdjacent(const TargetInstrInfo & TII,const TargetSubtargetInfo & TSI,const MachineInstr * FirstMI,const MachineInstr & SecondMI)66 static bool shouldScheduleAdjacent(const TargetInstrInfo &TII,
67 const TargetSubtargetInfo &TSI,
68 const MachineInstr *FirstMI,
69 const MachineInstr &SecondMI) {
70 const ARMSubtarget &ST = static_cast<const ARMSubtarget&>(TSI);
71
72 if (ST.hasFuseAES() && isAESPair(FirstMI, SecondMI))
73 return true;
74 if (ST.hasFuseLiterals() && isLiteralsPair(FirstMI, SecondMI))
75 return true;
76
77 return false;
78 }
79
createARMMacroFusionDAGMutation()80 std::unique_ptr<ScheduleDAGMutation> createARMMacroFusionDAGMutation () {
81 return createMacroFusionDAGMutation(shouldScheduleAdjacent);
82 }
83
84 } // end namespace llvm
85