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llvm-project/polly/lib/CodeGen/PTXGenerator.cpp

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//===------ PTXGenerator.cpp - IR helper to create loops -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file contains functions to create GPU parallel codes as LLVM-IR.
//
//===----------------------------------------------------------------------===//
#include "polly/CodeGen/PTXGenerator.h"
#ifdef GPU_CODEGEN
#include "polly/ScopDetection.h"
#include "polly/ScopInfo.h"
#include "llvm/PassManager.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/TargetRegistry.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/Module.h"
#include "llvm/Target/TargetMachine.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Transforms/Utils/Cloning.h"
using namespace llvm;
using namespace polly;
PTXGenerator::PTXGenerator(IRBuilder<> &Builder, Pass *P,
const std::string &Triple)
: Builder(Builder), P(P), GPUTriple(Triple), GridWidth(1), GridHeight(1),
BlockWidth(1), BlockHeight(1), OutputBytes(0) {
InitializeGPUDataTypes();
}
Module *PTXGenerator::getModule() {
return Builder.GetInsertBlock()->getParent()->getParent();
}
Function *PTXGenerator::createSubfunctionDefinition(int NumArgs) {
assert(NumArgs == 1 && "we support only one array access now.");
Module *M = getModule();
Function *F = Builder.GetInsertBlock()->getParent();
std::vector<Type *> Arguments;
for (int i = 0; i < NumArgs; i++)
Arguments.push_back(Builder.getInt8PtrTy());
FunctionType *FT = FunctionType::get(Builder.getVoidTy(), Arguments, false);
Function *FN = Function::Create(FT, Function::InternalLinkage,
F->getName() + "_ptx_subfn", M);
FN->setCallingConv(CallingConv::PTX_Kernel);
// Do not run any optimization pass on the new function.
P->getAnalysis<polly::ScopDetection>().markFunctionAsInvalid(FN);
for (Function::arg_iterator AI = FN->arg_begin(); AI != FN->arg_end(); ++AI)
AI->setName("ptx.Array");
return FN;
}
void PTXGenerator::createSubfunction(SetVector<Value *> &UsedValues,
SetVector<Value *> &OriginalIVS,
PTXGenerator::ValueToValueMapTy &VMap,
Function **SubFunction) {
Function *FN = createSubfunctionDefinition(UsedValues.size());
Module *M = getModule();
LLVMContext &Context = FN->getContext();
IntegerType *Ty = Builder.getInt64Ty();
// Store the previous basic block.
BasicBlock *PrevBB = Builder.GetInsertBlock();
// Create basic blocks.
BasicBlock *HeaderBB = BasicBlock::Create(Context, "ptx.setup", FN);
BasicBlock *ExitBB = BasicBlock::Create(Context, "ptx.exit", FN);
BasicBlock *BodyBB = BasicBlock::Create(Context, "ptx.loop_body", FN);
DominatorTree &DT = P->getAnalysis<DominatorTree>();
DT.addNewBlock(HeaderBB, PrevBB);
DT.addNewBlock(ExitBB, HeaderBB);
DT.addNewBlock(BodyBB, HeaderBB);
Builder.SetInsertPoint(HeaderBB);
// Insert VMap items with maps of array base address on the host to base
// address on the device.
Function::arg_iterator AI = FN->arg_begin();
for (unsigned j = 0; j < UsedValues.size(); j++) {
Value *BaseAddr = UsedValues[j];
Type *ArrayTy = BaseAddr->getType();
Value *Param = Builder.CreateBitCast(AI, ArrayTy);
VMap.insert(std::make_pair<Value *, Value *>(BaseAddr, Param));
AI++;
}
// FIXME: These intrinsics should be inserted on-demand. However, we insert
// them all currently for simplicity.
Function *GetNctaidX =
Intrinsic::getDeclaration(M, Intrinsic::ptx_read_nctaid_x);
Function *GetNctaidY =
Intrinsic::getDeclaration(M, Intrinsic::ptx_read_nctaid_y);
Function *GetCtaidX =
Intrinsic::getDeclaration(M, Intrinsic::ptx_read_ctaid_x);
Function *GetCtaidY =
Intrinsic::getDeclaration(M, Intrinsic::ptx_read_ctaid_y);
Function *GetNtidX = Intrinsic::getDeclaration(M, Intrinsic::ptx_read_ntid_x);
Function *GetNtidY = Intrinsic::getDeclaration(M, Intrinsic::ptx_read_ntid_y);
Function *GetTidX = Intrinsic::getDeclaration(M, Intrinsic::ptx_read_tid_x);
Function *GetTidY = Intrinsic::getDeclaration(M, Intrinsic::ptx_read_tid_y);
Value *GridWidth = Builder.CreateCall(GetNctaidX);
GridWidth = Builder.CreateIntCast(GridWidth, Ty, false);
Value *GridHeight = Builder.CreateCall(GetNctaidY);
GridHeight = Builder.CreateIntCast(GridHeight, Ty, false);
Value *BlockWidth = Builder.CreateCall(GetNtidX);
BlockWidth = Builder.CreateIntCast(BlockWidth, Ty, false);
Value *BlockHeight = Builder.CreateCall(GetNtidY);
BlockHeight = Builder.CreateIntCast(BlockHeight, Ty, false);
Value *BIDx = Builder.CreateCall(GetCtaidX);
BIDx = Builder.CreateIntCast(BIDx, Ty, false);
Value *BIDy = Builder.CreateCall(GetCtaidY);
BIDy = Builder.CreateIntCast(BIDy, Ty, false);
Value *TIDx = Builder.CreateCall(GetTidX);
TIDx = Builder.CreateIntCast(TIDx, Ty, false);
Value *TIDy = Builder.CreateCall(GetTidY);
TIDy = Builder.CreateIntCast(TIDy, Ty, false);
Builder.CreateBr(BodyBB);
Builder.SetInsertPoint(BodyBB);
unsigned NumDims = OriginalIVS.size();
std::vector<Value *> Substitutions;
Value *BlockID, *ThreadID;
switch (NumDims) {
case 1: {
Value *BlockSize =
Builder.CreateMul(BlockWidth, BlockHeight, "p_gpu_blocksize");
BlockID = Builder.CreateMul(BIDy, GridWidth, "p_gpu_index_i");
BlockID = Builder.CreateAdd(BlockID, BIDx);
BlockID = Builder.CreateMul(BlockID, BlockSize);
ThreadID = Builder.CreateMul(TIDy, BlockWidth, "p_gpu_index_j");
ThreadID = Builder.CreateAdd(ThreadID, TIDx);
ThreadID = Builder.CreateAdd(ThreadID, BlockID);
Substitutions.push_back(ThreadID);
break;
}
case 2: {
BlockID = Builder.CreateMul(BIDy, GridWidth, "p_gpu_index_i");
BlockID = Builder.CreateAdd(BlockID, BIDx);
Substitutions.push_back(BlockID);
ThreadID = Builder.CreateMul(TIDy, BlockWidth, "p_gpu_index_j");
ThreadID = Builder.CreateAdd(ThreadID, TIDx);
Substitutions.push_back(ThreadID);
break;
}
case 3: {
BlockID = Builder.CreateMul(BIDy, GridWidth, "p_gpu_index_i");
BlockID = Builder.CreateAdd(BlockID, BIDx);
Substitutions.push_back(BlockID);
Substitutions.push_back(TIDy);
Substitutions.push_back(TIDx);
break;
}
case 4: {
Substitutions.push_back(BIDy);
Substitutions.push_back(BIDx);
Substitutions.push_back(TIDy);
Substitutions.push_back(TIDx);
break;
}
default:
assert(true &&
"We cannot transform parallel loops whose depth is larger than 4.");
return;
}
assert(OriginalIVS.size() == Substitutions.size() &&
"The size of IVS should be equal to the size of substitutions.");
for (unsigned i = 0; i < OriginalIVS.size(); ++i) {
VMap.insert(
std::make_pair<Value *, Value *>(OriginalIVS[i], Substitutions[i]));
}
Builder.CreateBr(ExitBB);
Builder.SetInsertPoint(--Builder.GetInsertPoint());
BasicBlock::iterator LoopBody = Builder.GetInsertPoint();
// Add the termination of the ptx-device subfunction.
Builder.SetInsertPoint(ExitBB);
Builder.CreateRetVoid();
Builder.SetInsertPoint(LoopBody);
*SubFunction = FN;
}
void PTXGenerator::startGeneration(SetVector<Value *> &UsedValues,
SetVector<Value *> &OriginalIVS,
ValueToValueMapTy &VMap,
BasicBlock::iterator *LoopBody) {
Function *SubFunction;
BasicBlock::iterator PrevInsertPoint = Builder.GetInsertPoint();
createSubfunction(UsedValues, OriginalIVS, VMap, &SubFunction);
*LoopBody = Builder.GetInsertPoint();
Builder.SetInsertPoint(PrevInsertPoint);
}
IntegerType *PTXGenerator::getInt64Type() { return Builder.getInt64Ty(); }
PointerType *PTXGenerator::getI8PtrType() {
return PointerType::getUnqual(Builder.getInt8Ty());
}
PointerType *PTXGenerator::getPtrI8PtrType() {
return PointerType::getUnqual(getI8PtrType());
}
PointerType *PTXGenerator::getFloatPtrType() {
return llvm::Type::getFloatPtrTy(getModule()->getContext());
}
PointerType *PTXGenerator::getGPUContextPtrType() {
return PointerType::getUnqual(ContextTy);
}
PointerType *PTXGenerator::getGPUModulePtrType() {
return PointerType::getUnqual(ModuleTy);
}
PointerType *PTXGenerator::getGPUDevicePtrType() {
return PointerType::getUnqual(DeviceTy);
}
PointerType *PTXGenerator::getPtrGPUDevicePtrType() {
return PointerType::getUnqual(DevDataTy);
}
PointerType *PTXGenerator::getGPUFunctionPtrType() {
return PointerType::getUnqual(KernelTy);
}
PointerType *PTXGenerator::getGPUEventPtrType() {
return PointerType::getUnqual(EventTy);
}
void PTXGenerator::InitializeGPUDataTypes() {
LLVMContext &Context = getModule()->getContext();
ContextTy = StructType::create(Context, "struct.PollyGPUContextT");
ModuleTy = StructType::create(Context, "struct.PollyGPUModuleT");
KernelTy = StructType::create(Context, "struct.PollyGPUFunctionT");
DeviceTy = StructType::create(Context, "struct.PollyGPUDeviceT");
DevDataTy = StructType::create(Context, "struct.PollyGPUDevicePtrT");
EventTy = StructType::create(Context, "struct.PollyGPUEventT");
}
void PTXGenerator::createCallInitDevice(Value *Context, Value *Device) {
const char *Name = "polly_initDevice";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(PointerType::getUnqual(getGPUContextPtrType()));
Args.push_back(PointerType::getUnqual(getGPUDevicePtrType()));
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall2(F, Context, Device);
}
void PTXGenerator::createCallGetPTXModule(Value *Buffer, Value *Module) {
const char *Name = "polly_getPTXModule";
llvm::Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getI8PtrType());
Args.push_back(PointerType::getUnqual(getGPUModulePtrType()));
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall2(F, Buffer, Module);
}
void PTXGenerator::createCallGetPTXKernelEntry(Value *Entry, Value *Module,
Value *Kernel) {
const char *Name = "polly_getPTXKernelEntry";
llvm::Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getI8PtrType());
Args.push_back(getGPUModulePtrType());
Args.push_back(PointerType::getUnqual(getGPUFunctionPtrType()));
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, Entry, Module, Kernel);
}
void PTXGenerator::createCallAllocateMemoryForHostAndDevice(Value *HostData,
Value *DeviceData,
Value *Size) {
const char *Name = "polly_allocateMemoryForHostAndDevice";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getPtrI8PtrType());
Args.push_back(PointerType::getUnqual(getPtrGPUDevicePtrType()));
Args.push_back(getInt64Type());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, HostData, DeviceData, Size);
}
void PTXGenerator::createCallCopyFromHostToDevice(Value *DeviceData,
Value *HostData,
Value *Size) {
const char *Name = "polly_copyFromHostToDevice";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getPtrGPUDevicePtrType());
Args.push_back(getI8PtrType());
Args.push_back(getInt64Type());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, DeviceData, HostData, Size);
}
void PTXGenerator::createCallCopyFromDeviceToHost(Value *HostData,
Value *DeviceData,
Value *Size) {
const char *Name = "polly_copyFromDeviceToHost";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getI8PtrType());
Args.push_back(getPtrGPUDevicePtrType());
Args.push_back(getInt64Type());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, HostData, DeviceData, Size);
}
void PTXGenerator::createCallSetKernelParameters(Value *Kernel,
Value *BlockWidth,
Value *BlockHeight,
Value *DeviceData) {
const char *Name = "polly_setKernelParameters";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getGPUFunctionPtrType());
Args.push_back(getInt64Type());
Args.push_back(getInt64Type());
Args.push_back(getPtrGPUDevicePtrType());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall4(F, Kernel, BlockWidth, BlockHeight, DeviceData);
}
void PTXGenerator::createCallLaunchKernel(Value *Kernel, Value *GridWidth,
Value *GridHeight) {
const char *Name = "polly_launchKernel";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getGPUFunctionPtrType());
Args.push_back(getInt64Type());
Args.push_back(getInt64Type());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, Kernel, GridWidth, GridHeight);
}
void PTXGenerator::createCallStartTimerByCudaEvent(Value *StartEvent,
Value *StopEvent) {
const char *Name = "polly_startTimerByCudaEvent";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(PointerType::getUnqual(getGPUEventPtrType()));
Args.push_back(PointerType::getUnqual(getGPUEventPtrType()));
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall2(F, StartEvent, StopEvent);
}
void PTXGenerator::createCallStopTimerByCudaEvent(Value *StartEvent,
Value *StopEvent,
Value *Timer) {
const char *Name = "polly_stopTimerByCudaEvent";
Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getGPUEventPtrType());
Args.push_back(getGPUEventPtrType());
Args.push_back(getFloatPtrType());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall3(F, StartEvent, StopEvent, Timer);
}
void PTXGenerator::createCallCleanupGPGPUResources(Value *HostData,
Value *DeviceData,
Value *Module,
Value *Context,
Value *Kernel) {
const char *Name = "polly_cleanupGPGPUResources";
llvm::Module *M = getModule();
Function *F = M->getFunction(Name);
// If F is not available, declare it.
if (!F) {
GlobalValue::LinkageTypes Linkage = Function::ExternalLinkage;
std::vector<Type *> Args;
Args.push_back(getI8PtrType());
Args.push_back(getPtrGPUDevicePtrType());
Args.push_back(getGPUModulePtrType());
Args.push_back(getGPUContextPtrType());
Args.push_back(getGPUFunctionPtrType());
FunctionType *Ty = FunctionType::get(Builder.getVoidTy(), Args, false);
F = Function::Create(Ty, Linkage, Name, M);
}
Builder.CreateCall5(F, HostData, DeviceData, Module, Context, Kernel);
}
Value *PTXGenerator::getCUDAGridWidth() {
return ConstantInt::get(getInt64Type(), GridWidth);
}
Value *PTXGenerator::getCUDAGridHeight() {
return ConstantInt::get(getInt64Type(), GridHeight);
}
Value *PTXGenerator::getCUDABlockWidth() {
return ConstantInt::get(getInt64Type(), BlockWidth);
}
Value *PTXGenerator::getCUDABlockHeight() {
return ConstantInt::get(getInt64Type(), BlockHeight);
}
Value *PTXGenerator::getOutputArraySizeInBytes() {
return ConstantInt::get(getInt64Type(), OutputBytes);
}
Value *PTXGenerator::createPTXKernelFunction(Function *SubFunction) {
Module *M = getModule();
std::string LLVMKernelStr;
raw_string_ostream NameROS(LLVMKernelStr);
formatted_raw_ostream FOS(NameROS);
FOS << "target triple = \"" << GPUTriple << "\"\n";
SubFunction->print(FOS);
// Insert ptx intrinsics into the kernel string.
for (Module::iterator I = M->begin(), E = M->end(); I != E;) {
Function *F = I++;
// Function must be a prototype and unused.
if (F->isDeclaration() && F->isIntrinsic()) {
switch (F->getIntrinsicID()) {
case Intrinsic::ptx_read_nctaid_x:
case Intrinsic::ptx_read_nctaid_y:
case Intrinsic::ptx_read_ctaid_x:
case Intrinsic::ptx_read_ctaid_y:
case Intrinsic::ptx_read_ntid_x:
case Intrinsic::ptx_read_ntid_y:
case Intrinsic::ptx_read_tid_x:
case Intrinsic::ptx_read_tid_y:
F->print(FOS);
break;
default:
break;
}
}
}
Value *LLVMKernel =
Builder.CreateGlobalStringPtr(LLVMKernelStr, "llvm_kernel");
Value *MCPU = Builder.CreateGlobalStringPtr("sm_10", "mcpu");
Value *Features = Builder.CreateGlobalStringPtr("", "cpu_features");
Function *GetDeviceKernel = Intrinsic::getDeclaration(M, Intrinsic::codegen);
return Builder.CreateCall3(GetDeviceKernel, LLVMKernel, MCPU, Features);
}
Value *PTXGenerator::getPTXKernelEntryName(Function *SubFunction) {
StringRef Entry = SubFunction->getName();
return Builder.CreateGlobalStringPtr(Entry, "ptx_entry");
}
void PTXGenerator::eraseUnusedFunctions(Function *SubFunction) {
Module *M = getModule();
SubFunction->eraseFromParent();
if (Function *FuncPTXReadNCtaidX = M->getFunction("llvm.ptx.read.nctaid.x")) {
FuncPTXReadNCtaidX->eraseFromParent();
}
if (Function *FuncPTXReadNCtaidY = M->getFunction("llvm.ptx.read.nctaid.y")) {
FuncPTXReadNCtaidY->eraseFromParent();
}
if (Function *FuncPTXReadCtaidX = M->getFunction("llvm.ptx.read.ctaid.x")) {
FuncPTXReadCtaidX->eraseFromParent();
}
if (Function *FuncPTXReadCtaidY = M->getFunction("llvm.ptx.read.ctaid.y")) {
FuncPTXReadCtaidY->eraseFromParent();
}
if (Function *FuncPTXReadNTidX = M->getFunction("llvm.ptx.read.ntid.x")) {
FuncPTXReadNTidX->eraseFromParent();
}
if (Function *FuncPTXReadNTidY = M->getFunction("llvm.ptx.read.ntid.y")) {
FuncPTXReadNTidY->eraseFromParent();
}
if (Function *FuncPTXReadTidX = M->getFunction("llvm.ptx.read.tid.x")) {
FuncPTXReadTidX->eraseFromParent();
}
if (Function *FuncPTXReadTidY = M->getFunction("llvm.ptx.read.tid.y")) {
FuncPTXReadTidY->eraseFromParent();
}
}
void PTXGenerator::finishGeneration(Function *F) {
// Define data used by the GPURuntime library.
AllocaInst *PtrCUContext =
Builder.CreateAlloca(getGPUContextPtrType(), 0, "phcontext");
AllocaInst *PtrCUDevice =
Builder.CreateAlloca(getGPUDevicePtrType(), 0, "phdevice");
AllocaInst *PtrCUModule =
Builder.CreateAlloca(getGPUModulePtrType(), 0, "phmodule");
AllocaInst *PtrCUKernel =
Builder.CreateAlloca(getGPUFunctionPtrType(), 0, "phkernel");
AllocaInst *PtrCUStartEvent =
Builder.CreateAlloca(getGPUEventPtrType(), 0, "pstart_timer");
AllocaInst *PtrCUStopEvent =
Builder.CreateAlloca(getGPUEventPtrType(), 0, "pstop_timer");
AllocaInst *PtrDevData =
Builder.CreateAlloca(getPtrGPUDevicePtrType(), 0, "pdevice_data");
AllocaInst *PtrHostData =
Builder.CreateAlloca(getI8PtrType(), 0, "phost_data");
Type *FloatTy = llvm::Type::getFloatTy(getModule()->getContext());
AllocaInst *PtrElapsedTimes = Builder.CreateAlloca(FloatTy, 0, "ptimer");
// Initialize the GPU device.
createCallInitDevice(PtrCUContext, PtrCUDevice);
// Create the GPU kernel module and entry function.
Value *PTXString = createPTXKernelFunction(F);
Value *PTXEntry = getPTXKernelEntryName(F);
createCallGetPTXModule(PTXString, PtrCUModule);
LoadInst *CUModule = Builder.CreateLoad(PtrCUModule, "cumodule");
createCallGetPTXKernelEntry(PTXEntry, CUModule, PtrCUKernel);
// Allocate device memory and its corresponding host memory.
createCallAllocateMemoryForHostAndDevice(PtrHostData, PtrDevData,
getOutputArraySizeInBytes());
// Get the pointer to the device memory and set the GPU execution parameters.
LoadInst *DData = Builder.CreateLoad(PtrDevData, "device_data");
LoadInst *CUKernel = Builder.CreateLoad(PtrCUKernel, "cukernel");
createCallSetKernelParameters(CUKernel, getCUDABlockWidth(),
getCUDABlockHeight(), DData);
// Create the start and end timer and record the start time.
createCallStartTimerByCudaEvent(PtrCUStartEvent, PtrCUStopEvent);
// Launch the GPU kernel.
createCallLaunchKernel(CUKernel, getCUDAGridWidth(), getCUDAGridHeight());
// Copy the results back from the GPU to the host.
LoadInst *HData = Builder.CreateLoad(PtrHostData, "host_data");
createCallCopyFromDeviceToHost(HData, DData, getOutputArraySizeInBytes());
// Record the end time.
LoadInst *CUStartEvent = Builder.CreateLoad(PtrCUStartEvent, "start_timer");
LoadInst *CUStopEvent = Builder.CreateLoad(PtrCUStopEvent, "stop_timer");
createCallStopTimerByCudaEvent(CUStartEvent, CUStopEvent, PtrElapsedTimes);
// Cleanup all the resources used.
LoadInst *CUContext = Builder.CreateLoad(PtrCUContext, "cucontext");
createCallCleanupGPGPUResources(HData, DData, CUModule, CUContext, CUKernel);
// Erase the ptx kernel and device subfunctions and ptx intrinsics from
// current module.
eraseUnusedFunctions(F);
}
#endif /* GPU_CODEGEN */
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