1 //===-- HexagonExpandPredSpillCode.cpp - Expand Predicate Spill Code ------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
9 // The Hexagon processor has no instructions that load or store predicate
10 // registers directly. So, when these registers must be spilled a general
11 // purpose register must be found and the value copied to/from it from/to
12 // the predicate register. This code currently does not use the register
13 // scavenger mechanism available in the allocator. There are two registers
14 // reserved to allow spilling/restoring predicate registers. One is used to
15 // hold the predicate value. The other is used when stack frame offsets are
18 //===----------------------------------------------------------------------===//
20 #include "HexagonTargetMachine.h"
21 #include "HexagonSubtarget.h"
22 #include "HexagonMachineFunctionInfo.h"
23 #include "llvm/ADT/Statistic.h"
24 #include "llvm/CodeGen/LatencyPriorityQueue.h"
25 #include "llvm/CodeGen/MachineDominators.h"
26 #include "llvm/CodeGen/MachineFunctionPass.h"
27 #include "llvm/CodeGen/MachineInstrBuilder.h"
28 #include "llvm/CodeGen/MachineLoopInfo.h"
29 #include "llvm/CodeGen/MachineRegisterInfo.h"
30 #include "llvm/CodeGen/Passes.h"
31 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
32 #include "llvm/CodeGen/SchedulerRegistry.h"
33 #include "llvm/Target/TargetMachine.h"
34 #include "llvm/Target/TargetInstrInfo.h"
35 #include "llvm/Target/TargetRegisterInfo.h"
36 #include "llvm/Support/Compiler.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/MathExtras.h"
45 class HexagonExpandPredSpillCode : public MachineFunctionPass {
46 HexagonTargetMachine& QTM;
47 const HexagonSubtarget &QST;
51 HexagonExpandPredSpillCode(HexagonTargetMachine& TM) :
52 MachineFunctionPass(ID), QTM(TM), QST(*TM.getSubtargetImpl()) {}
54 const char *getPassName() const {
55 return "Hexagon Expand Predicate Spill Code";
57 bool runOnMachineFunction(MachineFunction &Fn);
61 char HexagonExpandPredSpillCode::ID = 0;
64 bool HexagonExpandPredSpillCode::runOnMachineFunction(MachineFunction &Fn) {
66 const HexagonInstrInfo *TII = QTM.getInstrInfo();
68 // Loop over all of the basic blocks.
69 for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
70 MBBb != MBBe; ++MBBb) {
71 MachineBasicBlock* MBB = MBBb;
72 // Traverse the basic block.
73 for (MachineBasicBlock::iterator MII = MBB->begin(); MII != MBB->end();
75 MachineInstr *MI = MII;
76 int Opc = MI->getOpcode();
77 if (Opc == Hexagon::STriw_pred) {
78 // STriw_pred [R30], ofst, SrcReg;
79 unsigned FP = MI->getOperand(0).getReg();
80 assert(FP == QTM.getRegisterInfo()->getFrameRegister() &&
81 "Not a Frame Pointer, Nor a Spill Slot");
82 assert(MI->getOperand(1).isImm() && "Not an offset");
83 int Offset = MI->getOperand(1).getImm();
84 int SrcReg = MI->getOperand(2).getReg();
85 assert(Hexagon::PredRegsRegClass.contains(SrcReg) &&
86 "Not a predicate register");
87 if (!TII->isValidOffset(Hexagon::STriw, Offset)) {
88 if (!TII->isValidOffset(Hexagon::ADD_ri, Offset)) {
89 BuildMI(*MBB, MII, MI->getDebugLoc(),
90 TII->get(Hexagon::CONST32_Int_Real),
91 HEXAGON_RESERVED_REG_1).addImm(Offset);
92 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::ADD_rr),
93 HEXAGON_RESERVED_REG_1)
94 .addReg(FP).addReg(HEXAGON_RESERVED_REG_1);
95 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_RsPd),
96 HEXAGON_RESERVED_REG_2).addReg(SrcReg);
97 BuildMI(*MBB, MII, MI->getDebugLoc(),
98 TII->get(Hexagon::STriw))
99 .addReg(HEXAGON_RESERVED_REG_1)
100 .addImm(0).addReg(HEXAGON_RESERVED_REG_2);
102 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::ADD_ri),
103 HEXAGON_RESERVED_REG_1).addReg(FP).addImm(Offset);
104 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_RsPd),
105 HEXAGON_RESERVED_REG_2).addReg(SrcReg);
106 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::STriw))
107 .addReg(HEXAGON_RESERVED_REG_1)
109 .addReg(HEXAGON_RESERVED_REG_2);
112 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_RsPd),
113 HEXAGON_RESERVED_REG_2).addReg(SrcReg);
114 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::STriw)).
115 addReg(FP).addImm(Offset).addReg(HEXAGON_RESERVED_REG_2);
117 MII = MBB->erase(MI);
119 } else if (Opc == Hexagon::LDriw_pred) {
120 // DstReg = LDriw_pred [R30], ofst.
121 int DstReg = MI->getOperand(0).getReg();
122 assert(Hexagon::PredRegsRegClass.contains(DstReg) &&
123 "Not a predicate register");
124 unsigned FP = MI->getOperand(1).getReg();
125 assert(FP == QTM.getRegisterInfo()->getFrameRegister() &&
126 "Not a Frame Pointer, Nor a Spill Slot");
127 assert(MI->getOperand(2).isImm() && "Not an offset");
128 int Offset = MI->getOperand(2).getImm();
129 if (!TII->isValidOffset(Hexagon::LDriw, Offset)) {
130 if (!TII->isValidOffset(Hexagon::ADD_ri, Offset)) {
131 BuildMI(*MBB, MII, MI->getDebugLoc(),
132 TII->get(Hexagon::CONST32_Int_Real),
133 HEXAGON_RESERVED_REG_1).addImm(Offset);
134 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::ADD_rr),
135 HEXAGON_RESERVED_REG_1)
137 .addReg(HEXAGON_RESERVED_REG_1);
138 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::LDriw),
139 HEXAGON_RESERVED_REG_2)
140 .addReg(HEXAGON_RESERVED_REG_1)
142 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_PdRs),
143 DstReg).addReg(HEXAGON_RESERVED_REG_2);
145 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::ADD_ri),
146 HEXAGON_RESERVED_REG_1).addReg(FP).addImm(Offset);
147 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::LDriw),
148 HEXAGON_RESERVED_REG_2)
149 .addReg(HEXAGON_RESERVED_REG_1)
151 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_PdRs),
152 DstReg).addReg(HEXAGON_RESERVED_REG_2);
155 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::LDriw),
156 HEXAGON_RESERVED_REG_2).addReg(FP).addImm(Offset);
157 BuildMI(*MBB, MII, MI->getDebugLoc(), TII->get(Hexagon::TFR_PdRs),
158 DstReg).addReg(HEXAGON_RESERVED_REG_2);
160 MII = MBB->erase(MI);
171 //===----------------------------------------------------------------------===//
172 // Public Constructor Functions
173 //===----------------------------------------------------------------------===//
175 FunctionPass *llvm::createHexagonExpandPredSpillCode(HexagonTargetMachine &TM) {
176 return new HexagonExpandPredSpillCode(TM);