llvm-6502/lib/Target/SparcV8/FPMover.cpp

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//===-- FPMover.cpp - SparcV8 double-precision floating point move fixer --===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Expand FpMOVD/FpABSD/FpNEGD instructions into their single-precision pieces.
//
//===----------------------------------------------------------------------===//
#include "SparcV8.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
using namespace llvm;
namespace {
Statistic<> NumFpDs("fpmover", "Number of instructions translated");
Statistic<> NoopFpDs("fpmover", "Number of noop instructions removed");
struct FPMover : public MachineFunctionPass {
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
FPMover(TargetMachine &tm) : TM(tm) { }
virtual const char *getPassName() const {
return "SparcV8 Double-FP Move Fixer";
}
bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
bool runOnMachineFunction(MachineFunction &F) {
bool Changed = false;
for (MachineFunction::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI)
Changed |= runOnMachineBasicBlock(*FI);
return Changed;
}
};
} // end of anonymous namespace
/// createSparcV8FPMoverPass - Returns a pass that turns FpMOVD
/// instructions into FMOVS instructions
///
FunctionPass *llvm::createSparcV8FPMoverPass(TargetMachine &tm) {
return new FPMover(tm);
}
/// getDoubleRegPair - Given a DFP register, return the even and odd FP
/// registers that correspond to it.
static void getDoubleRegPair(unsigned DoubleReg, unsigned &EvenReg,
unsigned &OddReg) {
static const unsigned EvenHalvesOfPairs[] = {
V8::F0, V8::F2, V8::F4, V8::F6, V8::F8, V8::F10, V8::F12, V8::F14,
V8::F16, V8::F18, V8::F20, V8::F22, V8::F24, V8::F26, V8::F28, V8::F30
};
static const unsigned OddHalvesOfPairs[] = {
V8::F1, V8::F3, V8::F5, V8::F7, V8::F9, V8::F11, V8::F13, V8::F15,
V8::F17, V8::F19, V8::F21, V8::F23, V8::F25, V8::F27, V8::F29, V8::F31
};
static const unsigned DoubleRegsInOrder[] = {
V8::D0, V8::D1, V8::D2, V8::D3, V8::D4, V8::D5, V8::D6, V8::D7, V8::D8,
V8::D9, V8::D10, V8::D11, V8::D12, V8::D13, V8::D14, V8::D15
};
for (unsigned i = 0; i < sizeof(DoubleRegsInOrder)/sizeof(unsigned); ++i)
if (DoubleRegsInOrder[i] == DoubleReg) {
EvenReg = EvenHalvesOfPairs[i];
OddReg = OddHalvesOfPairs[i];
return;
}
assert(0 && "Can't find reg");
}
/// runOnMachineBasicBlock - Fixup FpMOVD instructions in this MBB.
///
bool FPMover::runOnMachineBasicBlock(MachineBasicBlock &MBB) {
bool Changed = false;
for (MachineBasicBlock::iterator I = MBB.begin(); I != MBB.end(); ) {
MachineInstr *MI = I++;
if (MI->getOpcode() == V8::FpMOVD || MI->getOpcode() == V8::FpABSD ||
MI->getOpcode() == V8::FpNEGD) {
Changed = true;
unsigned DestDReg = MI->getOperand(0).getReg();
unsigned SrcDReg = MI->getOperand(1).getReg();
if (DestDReg == SrcDReg && MI->getOpcode() == V8::FpMOVD) {
MBB.erase(MI); // Eliminate the noop copy.
++NoopFpDs;
continue;
}
unsigned EvenSrcReg = 0, OddSrcReg = 0, EvenDestReg = 0, OddDestReg = 0;
getDoubleRegPair(DestDReg, EvenDestReg, OddDestReg);
getDoubleRegPair(SrcDReg, EvenSrcReg, OddSrcReg);
if (MI->getOpcode() == V8::FpMOVD)
MI->setOpcode(V8::FMOVS);
else if (MI->getOpcode() == V8::FpNEGD)
MI->setOpcode(V8::FNEGS);
else if (MI->getOpcode() == V8::FpABSD)
MI->setOpcode(V8::FABSS);
else
assert(0 && "Unknown opcode!");
MI->SetMachineOperandReg(0, EvenDestReg);
MI->SetMachineOperandReg(1, EvenSrcReg);
DEBUG(std::cerr << "FPMover: the modified instr is: " << *MI);
// Insert copy for the other half of the double.
if (DestDReg != SrcDReg) {
MI = BuildMI(MBB, I, V8::FMOVS, 1, OddDestReg).addReg(OddSrcReg);
DEBUG(std::cerr << "FPMover: the inserted instr is: " << *MI);
}
++NumFpDs;
}
}
return Changed;
}