HexagonSplitConst32AndConst64.cpp
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//=== HexagonSplitConst32AndConst64.cpp - split CONST32/Const64 into HI/LO ===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// When the compiler is invoked with no small data, for instance, with the -G0
// command line option, then all CONST* opcodes should be broken down into
// appropriate LO and HI instructions. This splitting is done by this pass.
// The only reason this is not done in the DAG lowering itself is that there
// is no simple way of getting the register allocator to allot the same hard
// register to the result of LO and HI instructions. This pass is always
// scheduled after register allocation.
//
//===----------------------------------------------------------------------===//
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include "HexagonTargetObjectFile.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/Passes.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
using namespace llvm;
#define DEBUG_TYPE "xfer"
namespace llvm {
FunctionPass *createHexagonSplitConst32AndConst64();
void initializeHexagonSplitConst32AndConst64Pass(PassRegistry&);
}
namespace {
class HexagonSplitConst32AndConst64 : public MachineFunctionPass {
public:
static char ID;
HexagonSplitConst32AndConst64() : MachineFunctionPass(ID) {
PassRegistry &R = *PassRegistry::getPassRegistry();
initializeHexagonSplitConst32AndConst64Pass(R);
}
StringRef getPassName() const override {
return "Hexagon Split Const32s and Const64s";
}
bool runOnMachineFunction(MachineFunction &Fn) override;
MachineFunctionProperties getRequiredProperties() const override {
return MachineFunctionProperties().set(
MachineFunctionProperties::Property::NoVRegs);
}
};
}
char HexagonSplitConst32AndConst64::ID = 0;
INITIALIZE_PASS(HexagonSplitConst32AndConst64, "split-const-for-sdata",
"Hexagon Split Const32s and Const64s", false, false)
bool HexagonSplitConst32AndConst64::runOnMachineFunction(MachineFunction &Fn) {
auto &HST = Fn.getSubtarget<HexagonSubtarget>();
auto &HTM = static_cast<const HexagonTargetMachine&>(Fn.getTarget());
auto &TLOF = *HTM.getObjFileLowering();
if (HST.useSmallData() && TLOF.isSmallDataEnabled(HTM))
return false;
const TargetInstrInfo *TII = HST.getInstrInfo();
const TargetRegisterInfo *TRI = HST.getRegisterInfo();
// Loop over all of the basic blocks
for (MachineBasicBlock &B : Fn) {
for (auto I = B.begin(), E = B.end(); I != E; ) {
MachineInstr &MI = *I;
++I;
unsigned Opc = MI.getOpcode();
if (Opc == Hexagon::CONST32) {
Register DestReg = MI.getOperand(0).getReg();
uint64_t ImmValue = MI.getOperand(1).getImm();
const DebugLoc &DL = MI.getDebugLoc();
BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestReg)
.addImm(ImmValue);
B.erase(&MI);
} else if (Opc == Hexagon::CONST64) {
Register DestReg = MI.getOperand(0).getReg();
int64_t ImmValue = MI.getOperand(1).getImm();
const DebugLoc &DL = MI.getDebugLoc();
Register DestLo = TRI->getSubReg(DestReg, Hexagon::isub_lo);
Register DestHi = TRI->getSubReg(DestReg, Hexagon::isub_hi);
int32_t LowWord = (ImmValue & 0xFFFFFFFF);
int32_t HighWord = (ImmValue >> 32) & 0xFFFFFFFF;
BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestLo)
.addImm(LowWord);
BuildMI(B, MI, DL, TII->get(Hexagon::A2_tfrsi), DestHi)
.addImm(HighWord);
B.erase(&MI);
}
}
}
return true;
}
//===----------------------------------------------------------------------===//
// Public Constructor Functions
//===----------------------------------------------------------------------===//
FunctionPass *llvm::createHexagonSplitConst32AndConst64() {
return new HexagonSplitConst32AndConst64();
}