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 CONST* 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 "HexagonSubtarget.h"
21 #include "HexagonTargetMachine.h"
22 #include "HexagonTargetObjectFile.h"
23 #include "llvm/CodeGen/MachineFunctionPass.h"
24 #include "llvm/CodeGen/MachineInstrBuilder.h"
25 #include "llvm/CodeGen/Passes.h"
26 #include "llvm/CodeGen/TargetInstrInfo.h"
27 #include "llvm/CodeGen/TargetRegisterInfo.h"
28
29 using namespace llvm;
30
31 #define DEBUG_TYPE "xfer"
32
33 namespace llvm {
34 FunctionPass *createHexagonSplitConst32AndConst64();
35 void initializeHexagonSplitConst32AndConst64Pass(PassRegistry&);
36 }
37
38 namespace {
39 class HexagonSplitConst32AndConst64 : public MachineFunctionPass {
40 public:
41 static char ID;
HexagonSplitConst32AndConst64()42 HexagonSplitConst32AndConst64() : MachineFunctionPass(ID) {
43 PassRegistry &R = *PassRegistry::getPassRegistry();
44 initializeHexagonSplitConst32AndConst64Pass(R);
45 }
getPassName() const46 StringRef getPassName() const override {
47 return "Hexagon Split Const32s and Const64s";
48 }
49 bool runOnMachineFunction(MachineFunction &Fn) override;
getRequiredProperties() const50 MachineFunctionProperties getRequiredProperties() const override {
51 return MachineFunctionProperties().set(
52 MachineFunctionProperties::Property::NoVRegs);
53 }
54 };
55 }
56
57 char HexagonSplitConst32AndConst64::ID = 0;
58
59 INITIALIZE_PASS(HexagonSplitConst32AndConst64, "split-const-for-sdata",
60 "Hexagon Split Const32s and Const64s", false, false)
61
runOnMachineFunction(MachineFunction & Fn)62 bool HexagonSplitConst32AndConst64::runOnMachineFunction(MachineFunction &Fn) {
63 auto &HST = Fn.getSubtarget<HexagonSubtarget>();
64 auto &HTM = static_cast<const HexagonTargetMachine&>(Fn.getTarget());
65 auto &TLOF = *HTM.getObjFileLowering();
66 if (HST.useSmallData() && TLOF.isSmallDataEnabled())
67 return false;
68
69 const TargetInstrInfo *TII = HST.getInstrInfo();
70 const TargetRegisterInfo *TRI = HST.getRegisterInfo();
71
72 // Loop over all of the basic blocks
73 for (MachineBasicBlock &B : Fn) {
74 for (auto I = B.begin(), E = B.end(); I != E; ) {
75 MachineInstr &MI = *I;
76 ++I;
77 unsigned Opc = MI.getOpcode();
78
79 if (Opc == Hexagon::CONST32) {
80 unsigned DestReg = MI.getOperand(0).getReg();
81 uint64_t ImmValue = MI.getOperand(1).getImm();
82 const DebugLoc &DL = MI.getDebugLoc();
83 BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestReg)
84 .addImm(ImmValue);
85 B.erase(&MI);
86 } else if (Opc == Hexagon::CONST64) {
87 unsigned DestReg = MI.getOperand(0).getReg();
88 int64_t ImmValue = MI.getOperand(1).getImm();
89 const DebugLoc &DL = MI.getDebugLoc();
90 unsigned DestLo = TRI->getSubReg(DestReg, Hexagon::isub_lo);
91 unsigned DestHi = TRI->getSubReg(DestReg, Hexagon::isub_hi);
92
93 int32_t LowWord = (ImmValue & 0xFFFFFFFF);
94 int32_t HighWord = (ImmValue >> 32) & 0xFFFFFFFF;
95
96 BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestLo)
97 .addImm(LowWord);
98 BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestHi)
99 .addImm(HighWord);
100 B.erase(&MI);
101 }
102 }
103 }
104
105 return true;
106 }
107
108
109 //===----------------------------------------------------------------------===//
110 // Public Constructor Functions
111 //===----------------------------------------------------------------------===//
createHexagonSplitConst32AndConst64()112 FunctionPass *llvm::createHexagonSplitConst32AndConst64() {
113 return new HexagonSplitConst32AndConst64();
114 }
115