llvm/lib/Target/R600/R600ExpandSpecialInstrs.cpp
Eric Christopher 6035518e3b Have MachineFunction cache a pointer to the subtarget to make lookups
shorter/easier and have the DAG use that to do the same lookup. This
can be used in the future for TargetMachine based caching lookups from
the MachineFunction easily.

Update the MIPS subtarget switching machinery to update this pointer
at the same time it runs.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214838 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-05 02:39:49 +00:00

350 lines
12 KiB
C++

//===-- R600ExpandSpecialInstrs.cpp - Expand special instructions ---------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
/// \file
/// Vector, Reduction, and Cube instructions need to fill the entire instruction
/// group to work correctly. This pass expands these individual instructions
/// into several instructions that will completely fill the instruction group.
//
//===----------------------------------------------------------------------===//
#include "AMDGPU.h"
#include "R600Defines.h"
#include "R600InstrInfo.h"
#include "R600MachineFunctionInfo.h"
#include "R600RegisterInfo.h"
#include "AMDGPUSubtarget.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
using namespace llvm;
namespace {
class R600ExpandSpecialInstrsPass : public MachineFunctionPass {
private:
static char ID;
const R600InstrInfo *TII;
void SetFlagInNewMI(MachineInstr *NewMI, const MachineInstr *OldMI,
unsigned Op);
public:
R600ExpandSpecialInstrsPass(TargetMachine &tm) : MachineFunctionPass(ID),
TII(nullptr) { }
bool runOnMachineFunction(MachineFunction &MF) override;
const char *getPassName() const override {
return "R600 Expand special instructions pass";
}
};
} // End anonymous namespace
char R600ExpandSpecialInstrsPass::ID = 0;
FunctionPass *llvm::createR600ExpandSpecialInstrsPass(TargetMachine &TM) {
return new R600ExpandSpecialInstrsPass(TM);
}
void R600ExpandSpecialInstrsPass::SetFlagInNewMI(MachineInstr *NewMI,
const MachineInstr *OldMI, unsigned Op) {
int OpIdx = TII->getOperandIdx(*OldMI, Op);
if (OpIdx > -1) {
uint64_t Val = OldMI->getOperand(OpIdx).getImm();
TII->setImmOperand(NewMI, Op, Val);
}
}
bool R600ExpandSpecialInstrsPass::runOnMachineFunction(MachineFunction &MF) {
TII = static_cast<const R600InstrInfo *>(MF.getSubtarget().getInstrInfo());
const R600RegisterInfo &TRI = TII->getRegisterInfo();
for (MachineFunction::iterator BB = MF.begin(), BB_E = MF.end();
BB != BB_E; ++BB) {
MachineBasicBlock &MBB = *BB;
MachineBasicBlock::iterator I = MBB.begin();
while (I != MBB.end()) {
MachineInstr &MI = *I;
I = std::next(I);
// Expand LDS_*_RET instructions
if (TII->isLDSRetInstr(MI.getOpcode())) {
int DstIdx = TII->getOperandIdx(MI.getOpcode(), AMDGPU::OpName::dst);
assert(DstIdx != -1);
MachineOperand &DstOp = MI.getOperand(DstIdx);
MachineInstr *Mov = TII->buildMovInstr(&MBB, I,
DstOp.getReg(), AMDGPU::OQAP);
DstOp.setReg(AMDGPU::OQAP);
int LDSPredSelIdx = TII->getOperandIdx(MI.getOpcode(),
AMDGPU::OpName::pred_sel);
int MovPredSelIdx = TII->getOperandIdx(Mov->getOpcode(),
AMDGPU::OpName::pred_sel);
// Copy the pred_sel bit
Mov->getOperand(MovPredSelIdx).setReg(
MI.getOperand(LDSPredSelIdx).getReg());
}
switch (MI.getOpcode()) {
default: break;
// Expand PRED_X to one of the PRED_SET instructions.
case AMDGPU::PRED_X: {
uint64_t Flags = MI.getOperand(3).getImm();
// The native opcode used by PRED_X is stored as an immediate in the
// third operand.
MachineInstr *PredSet = TII->buildDefaultInstruction(MBB, I,
MI.getOperand(2).getImm(), // opcode
MI.getOperand(0).getReg(), // dst
MI.getOperand(1).getReg(), // src0
AMDGPU::ZERO); // src1
TII->addFlag(PredSet, 0, MO_FLAG_MASK);
if (Flags & MO_FLAG_PUSH) {
TII->setImmOperand(PredSet, AMDGPU::OpName::update_exec_mask, 1);
} else {
TII->setImmOperand(PredSet, AMDGPU::OpName::update_pred, 1);
}
MI.eraseFromParent();
continue;
}
case AMDGPU::INTERP_PAIR_XY: {
MachineInstr *BMI;
unsigned PReg = AMDGPU::R600_ArrayBaseRegClass.getRegister(
MI.getOperand(2).getImm());
for (unsigned Chan = 0; Chan < 4; ++Chan) {
unsigned DstReg;
if (Chan < 2)
DstReg = MI.getOperand(Chan).getReg();
else
DstReg = Chan == 2 ? AMDGPU::T0_Z : AMDGPU::T0_W;
BMI = TII->buildDefaultInstruction(MBB, I, AMDGPU::INTERP_XY,
DstReg, MI.getOperand(3 + (Chan % 2)).getReg(), PReg);
if (Chan > 0) {
BMI->bundleWithPred();
}
if (Chan >= 2)
TII->addFlag(BMI, 0, MO_FLAG_MASK);
if (Chan != 3)
TII->addFlag(BMI, 0, MO_FLAG_NOT_LAST);
}
MI.eraseFromParent();
continue;
}
case AMDGPU::INTERP_PAIR_ZW: {
MachineInstr *BMI;
unsigned PReg = AMDGPU::R600_ArrayBaseRegClass.getRegister(
MI.getOperand(2).getImm());
for (unsigned Chan = 0; Chan < 4; ++Chan) {
unsigned DstReg;
if (Chan < 2)
DstReg = Chan == 0 ? AMDGPU::T0_X : AMDGPU::T0_Y;
else
DstReg = MI.getOperand(Chan-2).getReg();
BMI = TII->buildDefaultInstruction(MBB, I, AMDGPU::INTERP_ZW,
DstReg, MI.getOperand(3 + (Chan % 2)).getReg(), PReg);
if (Chan > 0) {
BMI->bundleWithPred();
}
if (Chan < 2)
TII->addFlag(BMI, 0, MO_FLAG_MASK);
if (Chan != 3)
TII->addFlag(BMI, 0, MO_FLAG_NOT_LAST);
}
MI.eraseFromParent();
continue;
}
case AMDGPU::INTERP_VEC_LOAD: {
const R600RegisterInfo &TRI = TII->getRegisterInfo();
MachineInstr *BMI;
unsigned PReg = AMDGPU::R600_ArrayBaseRegClass.getRegister(
MI.getOperand(1).getImm());
unsigned DstReg = MI.getOperand(0).getReg();
for (unsigned Chan = 0; Chan < 4; ++Chan) {
BMI = TII->buildDefaultInstruction(MBB, I, AMDGPU::INTERP_LOAD_P0,
TRI.getSubReg(DstReg, TRI.getSubRegFromChannel(Chan)), PReg);
if (Chan > 0) {
BMI->bundleWithPred();
}
if (Chan != 3)
TII->addFlag(BMI, 0, MO_FLAG_NOT_LAST);
}
MI.eraseFromParent();
continue;
}
case AMDGPU::DOT_4: {
const R600RegisterInfo &TRI = TII->getRegisterInfo();
unsigned DstReg = MI.getOperand(0).getReg();
unsigned DstBase = TRI.getEncodingValue(DstReg) & HW_REG_MASK;
for (unsigned Chan = 0; Chan < 4; ++Chan) {
bool Mask = (Chan != TRI.getHWRegChan(DstReg));
unsigned SubDstReg =
AMDGPU::R600_TReg32RegClass.getRegister((DstBase * 4) + Chan);
MachineInstr *BMI =
TII->buildSlotOfVectorInstruction(MBB, &MI, Chan, SubDstReg);
if (Chan > 0) {
BMI->bundleWithPred();
}
if (Mask) {
TII->addFlag(BMI, 0, MO_FLAG_MASK);
}
if (Chan != 3)
TII->addFlag(BMI, 0, MO_FLAG_NOT_LAST);
unsigned Opcode = BMI->getOpcode();
// While not strictly necessary from hw point of view, we force
// all src operands of a dot4 inst to belong to the same slot.
unsigned Src0 = BMI->getOperand(
TII->getOperandIdx(Opcode, AMDGPU::OpName::src0))
.getReg();
unsigned Src1 = BMI->getOperand(
TII->getOperandIdx(Opcode, AMDGPU::OpName::src1))
.getReg();
(void) Src0;
(void) Src1;
if ((TRI.getEncodingValue(Src0) & 0xff) < 127 &&
(TRI.getEncodingValue(Src1) & 0xff) < 127)
assert(TRI.getHWRegChan(Src0) == TRI.getHWRegChan(Src1));
}
MI.eraseFromParent();
continue;
}
}
bool IsReduction = TII->isReductionOp(MI.getOpcode());
bool IsVector = TII->isVector(MI);
bool IsCube = TII->isCubeOp(MI.getOpcode());
if (!IsReduction && !IsVector && !IsCube) {
continue;
}
// Expand the instruction
//
// Reduction instructions:
// T0_X = DP4 T1_XYZW, T2_XYZW
// becomes:
// TO_X = DP4 T1_X, T2_X
// TO_Y (write masked) = DP4 T1_Y, T2_Y
// TO_Z (write masked) = DP4 T1_Z, T2_Z
// TO_W (write masked) = DP4 T1_W, T2_W
//
// Vector instructions:
// T0_X = MULLO_INT T1_X, T2_X
// becomes:
// T0_X = MULLO_INT T1_X, T2_X
// T0_Y (write masked) = MULLO_INT T1_X, T2_X
// T0_Z (write masked) = MULLO_INT T1_X, T2_X
// T0_W (write masked) = MULLO_INT T1_X, T2_X
//
// Cube instructions:
// T0_XYZW = CUBE T1_XYZW
// becomes:
// TO_X = CUBE T1_Z, T1_Y
// T0_Y = CUBE T1_Z, T1_X
// T0_Z = CUBE T1_X, T1_Z
// T0_W = CUBE T1_Y, T1_Z
for (unsigned Chan = 0; Chan < 4; Chan++) {
unsigned DstReg = MI.getOperand(
TII->getOperandIdx(MI, AMDGPU::OpName::dst)).getReg();
unsigned Src0 = MI.getOperand(
TII->getOperandIdx(MI, AMDGPU::OpName::src0)).getReg();
unsigned Src1 = 0;
// Determine the correct source registers
if (!IsCube) {
int Src1Idx = TII->getOperandIdx(MI, AMDGPU::OpName::src1);
if (Src1Idx != -1) {
Src1 = MI.getOperand(Src1Idx).getReg();
}
}
if (IsReduction) {
unsigned SubRegIndex = TRI.getSubRegFromChannel(Chan);
Src0 = TRI.getSubReg(Src0, SubRegIndex);
Src1 = TRI.getSubReg(Src1, SubRegIndex);
} else if (IsCube) {
static const int CubeSrcSwz[] = {2, 2, 0, 1};
unsigned SubRegIndex0 = TRI.getSubRegFromChannel(CubeSrcSwz[Chan]);
unsigned SubRegIndex1 = TRI.getSubRegFromChannel(CubeSrcSwz[3 - Chan]);
Src1 = TRI.getSubReg(Src0, SubRegIndex1);
Src0 = TRI.getSubReg(Src0, SubRegIndex0);
}
// Determine the correct destination registers;
bool Mask = false;
bool NotLast = true;
if (IsCube) {
unsigned SubRegIndex = TRI.getSubRegFromChannel(Chan);
DstReg = TRI.getSubReg(DstReg, SubRegIndex);
} else {
// Mask the write if the original instruction does not write to
// the current Channel.
Mask = (Chan != TRI.getHWRegChan(DstReg));
unsigned DstBase = TRI.getEncodingValue(DstReg) & HW_REG_MASK;
DstReg = AMDGPU::R600_TReg32RegClass.getRegister((DstBase * 4) + Chan);
}
// Set the IsLast bit
NotLast = (Chan != 3 );
// Add the new instruction
unsigned Opcode = MI.getOpcode();
switch (Opcode) {
case AMDGPU::CUBE_r600_pseudo:
Opcode = AMDGPU::CUBE_r600_real;
break;
case AMDGPU::CUBE_eg_pseudo:
Opcode = AMDGPU::CUBE_eg_real;
break;
default:
break;
}
MachineInstr *NewMI =
TII->buildDefaultInstruction(MBB, I, Opcode, DstReg, Src0, Src1);
if (Chan != 0)
NewMI->bundleWithPred();
if (Mask) {
TII->addFlag(NewMI, 0, MO_FLAG_MASK);
}
if (NotLast) {
TII->addFlag(NewMI, 0, MO_FLAG_NOT_LAST);
}
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::clamp);
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::literal);
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::src0_abs);
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::src1_abs);
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::src0_neg);
SetFlagInNewMI(NewMI, &MI, AMDGPU::OpName::src1_neg);
}
MI.eraseFromParent();
}
}
return false;
}