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

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//===-- FPMover.cpp - Sparc double-precision floating point move fixer ----===//
//
// The LLVM Compiler Infrastructure
//
// This file 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.
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "fpmover"
#include "Sparc.h"
#include "SparcSubtarget.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Target/TargetInstrInfo.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
using namespace llvm;
STATISTIC(NumFpDs , "Number of instructions translated");
STATISTIC(NoopFpDs, "Number of noop instructions removed");
namespace {
struct FPMover : public MachineFunctionPass {
/// Target machine description which we query for reg. names, data
/// layout, etc.
///
TargetMachine &TM;
static char ID;
explicit FPMover(TargetMachine &tm)
: MachineFunctionPass(&ID), TM(tm) { }
virtual const char *getPassName() const {
return "Sparc Double-FP Move Fixer";
}
bool runOnMachineBasicBlock(MachineBasicBlock &MBB);
bool runOnMachineFunction(MachineFunction &F);
};
char FPMover::ID = 0;
} // end of anonymous namespace
/// createSparcFPMoverPass - Returns a pass that turns FpMOVD
/// instructions into FMOVS instructions
///
FunctionPass *llvm::createSparcFPMoverPass(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[] = {
SP::F0, SP::F2, SP::F4, SP::F6, SP::F8, SP::F10, SP::F12, SP::F14,
SP::F16, SP::F18, SP::F20, SP::F22, SP::F24, SP::F26, SP::F28, SP::F30
};
static const unsigned OddHalvesOfPairs[] = {
SP::F1, SP::F3, SP::F5, SP::F7, SP::F9, SP::F11, SP::F13, SP::F15,
SP::F17, SP::F19, SP::F21, SP::F23, SP::F25, SP::F27, SP::F29, SP::F31
};
static const unsigned DoubleRegsInOrder[] = {
SP::D0, SP::D1, SP::D2, SP::D3, SP::D4, SP::D5, SP::D6, SP::D7, SP::D8,
SP::D9, SP::D10, SP::D11, SP::D12, SP::D13, SP::D14, SP::D15
};
for (unsigned i = 0; i < sizeof(DoubleRegsInOrder)/sizeof(unsigned); ++i)
if (DoubleRegsInOrder[i] == DoubleReg) {
EvenReg = EvenHalvesOfPairs[i];
OddReg = OddHalvesOfPairs[i];
return;
}
llvm_unreachable("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++;
DebugLoc dl = MI->getDebugLoc();
if (MI->getOpcode() == SP::FpMOVD || MI->getOpcode() == SP::FpABSD ||
MI->getOpcode() == SP::FpNEGD) {
Changed = true;
unsigned DestDReg = MI->getOperand(0).getReg();
unsigned SrcDReg = MI->getOperand(1).getReg();
if (DestDReg == SrcDReg && MI->getOpcode() == SP::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);
const TargetInstrInfo *TII = TM.getInstrInfo();
if (MI->getOpcode() == SP::FpMOVD)
MI->setDesc(TII->get(SP::FMOVS));
else if (MI->getOpcode() == SP::FpNEGD)
MI->setDesc(TII->get(SP::FNEGS));
else if (MI->getOpcode() == SP::FpABSD)
MI->setDesc(TII->get(SP::FABSS));
else
llvm_unreachable("Unknown opcode!");
MI->getOperand(0).setReg(EvenDestReg);
MI->getOperand(1).setReg(EvenSrcReg);
DOUT << "FPMover: the modified instr is: " << *MI;
// Insert copy for the other half of the double.
if (DestDReg != SrcDReg) {
MI = BuildMI(MBB, I, dl, TM.getInstrInfo()->get(SP::FMOVS), OddDestReg)
.addReg(OddSrcReg);
DOUT << "FPMover: the inserted instr is: " << *MI;
}
++NumFpDs;
}
}
return Changed;
}
bool FPMover::runOnMachineFunction(MachineFunction &F) {
// If the target has V9 instructions, the fp-mover pseudos will never be
// emitted. Avoid a scan of the instructions to improve compile time.
if (TM.getSubtarget<SparcSubtarget>().isV9())
return false;
bool Changed = false;
for (MachineFunction::iterator FI = F.begin(), FE = F.end();
FI != FE; ++FI)
Changed |= runOnMachineBasicBlock(*FI);
return Changed;
}