1 //=== HexagonSplitConst32AndConst64.cpp - split CONST32/Const64 into HI/LO ===//
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 // When the compiler is invoked with no small data, for instance, with the -G0
11 // command line option, then all CONST32_* opcodes should be broken down into
12 // appropriate LO and HI instructions. This splitting is done by this pass.
13 // The only reason this is not done in the DAG lowering itself is that there
14 // is no simple way of getting the register allocator to allot the same hard
15 // register to the result of LO and HI instructions. This pass is always
16 // scheduled after register allocation.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "HexagonMachineFunctionInfo.h"
21 #include "HexagonSubtarget.h"
22 #include "HexagonTargetMachine.h"
23 #include "HexagonTargetObjectFile.h"
24 #include "llvm/ADT/Statistic.h"
25 #include "llvm/CodeGen/LatencyPriorityQueue.h"
26 #include "llvm/CodeGen/MachineDominators.h"
27 #include "llvm/CodeGen/MachineFunctionPass.h"
28 #include "llvm/CodeGen/MachineInstrBuilder.h"
29 #include "llvm/CodeGen/MachineLoopInfo.h"
30 #include "llvm/CodeGen/MachineRegisterInfo.h"
31 #include "llvm/CodeGen/Passes.h"
32 #include "llvm/CodeGen/ScheduleDAGInstrs.h"
33 #include "llvm/CodeGen/ScheduleHazardRecognizer.h"
34 #include "llvm/CodeGen/SchedulerRegistry.h"
35 #include "llvm/Support/CommandLine.h"
36 #include "llvm/Support/Compiler.h"
37 #include "llvm/Support/Debug.h"
38 #include "llvm/Support/MathExtras.h"
39 #include "llvm/Target/TargetInstrInfo.h"
40 #include "llvm/Target/TargetMachine.h"
41 #include "llvm/Target/TargetRegisterInfo.h"
42 #include <map>
43 
44 using namespace llvm;
45 
46 #define DEBUG_TYPE "xfer"
47 
48 namespace {
49 
50 class HexagonSplitConst32AndConst64 : public MachineFunctionPass {
51  public:
52     static char ID;
53     HexagonSplitConst32AndConst64() : MachineFunctionPass(ID) {}
54 
55     const char *getPassName() const override {
56       return "Hexagon Split Const32s and Const64s";
57     }
58     bool runOnMachineFunction(MachineFunction &Fn) override;
59 };
60 
61 
62 char HexagonSplitConst32AndConst64::ID = 0;
63 
64 
65 bool HexagonSplitConst32AndConst64::runOnMachineFunction(MachineFunction &Fn) {
66 
67   const HexagonTargetObjectFile &TLOF =
68       *static_cast<const HexagonTargetObjectFile *>(
69           Fn.getTarget().getObjFileLowering());
70   if (TLOF.IsSmallDataEnabled())
71     return true;
72 
73   const TargetInstrInfo *TII = Fn.getSubtarget().getInstrInfo();
74   const TargetRegisterInfo *TRI = Fn.getSubtarget().getRegisterInfo();
75 
76   // Loop over all of the basic blocks
77   for (MachineFunction::iterator MBBb = Fn.begin(), MBBe = Fn.end();
78        MBBb != MBBe; ++MBBb) {
79     MachineBasicBlock* MBB = MBBb;
80     // Traverse the basic block
81     MachineBasicBlock::iterator MII = MBB->begin();
82     MachineBasicBlock::iterator MIE = MBB->end ();
83     while (MII != MIE) {
84       MachineInstr *MI = MII;
85       int Opc = MI->getOpcode();
86       if (Opc == Hexagon::CONST32_Int_Real &&
87           MI->getOperand(1).isBlockAddress()) {
88         int DestReg = MI->getOperand(0).getReg();
89         MachineOperand &Symbol = MI->getOperand (1);
90 
91         BuildMI (*MBB, MII, MI->getDebugLoc(),
92                  TII->get(Hexagon::LO), DestReg).addOperand(Symbol);
93         BuildMI (*MBB, MII, MI->getDebugLoc(),
94                  TII->get(Hexagon::HI), DestReg).addOperand(Symbol);
95         // MBB->erase returns the iterator to the next instruction, which is the
96         // one we want to process next
97         MII = MBB->erase (MI);
98         continue;
99       }
100 
101       else if (Opc == Hexagon::CONST32_Int_Real ||
102                Opc == Hexagon::CONST32_Float_Real) {
103         int DestReg = MI->getOperand(0).getReg();
104 
105         // We have to convert an FP immediate into its corresponding integer
106         // representation
107         int64_t ImmValue;
108         if (Opc == Hexagon::CONST32_Float_Real) {
109           APFloat Val = MI->getOperand(1).getFPImm()->getValueAPF();
110           ImmValue = *Val.bitcastToAPInt().getRawData();
111         }
112         else
113           ImmValue = MI->getOperand(1).getImm();
114 
115         BuildMI(*MBB, MII, MI->getDebugLoc(),
116                  TII->get(Hexagon::A2_tfrsi), DestReg).addImm(ImmValue);
117         MII = MBB->erase (MI);
118         continue;
119       }
120       else if (Opc == Hexagon::CONST64_Int_Real ||
121                Opc == Hexagon::CONST64_Float_Real) {
122         int DestReg = MI->getOperand(0).getReg();
123 
124         // We have to convert an FP immediate into its corresponding integer
125         // representation
126         int64_t ImmValue;
127         if (Opc == Hexagon::CONST64_Float_Real) {
128           APFloat Val =  MI->getOperand(1).getFPImm()->getValueAPF();
129           ImmValue = *Val.bitcastToAPInt().getRawData();
130         }
131         else
132           ImmValue = MI->getOperand(1).getImm();
133 
134         unsigned DestLo = TRI->getSubReg(DestReg, Hexagon::subreg_loreg);
135         unsigned DestHi = TRI->getSubReg(DestReg, Hexagon::subreg_hireg);
136 
137         int32_t LowWord = (ImmValue & 0xFFFFFFFF);
138         int32_t HighWord = (ImmValue >> 32) & 0xFFFFFFFF;
139 
140         BuildMI(*MBB, MII, MI->getDebugLoc(),
141                  TII->get(Hexagon::A2_tfrsi), DestLo).addImm(LowWord);
142         BuildMI (*MBB, MII, MI->getDebugLoc(),
143                  TII->get(Hexagon::A2_tfrsi), DestHi).addImm(HighWord);
144         MII = MBB->erase (MI);
145         continue;
146       }
147       ++MII;
148     }
149   }
150 
151   return true;
152 }
153 
154 }
155 
156 //===----------------------------------------------------------------------===//
157 //                         Public Constructor Functions
158 //===----------------------------------------------------------------------===//
159 
160 FunctionPass *
161 llvm::createHexagonSplitConst32AndConst64() {
162   return new HexagonSplitConst32AndConst64();
163 }
164