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

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//===------ CodeGeneration.cpp - Code generate the Scops. -----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// The CodeGeneration pass takes a Scop created by ScopInfo and translates it
// back to LLVM-IR using Cloog.
//
// The Scop describes the high level memory behaviour of a control flow region.
// Transformation passes can update the schedule (execution order) of statements
// in the Scop. Cloog is used to generate an abstract syntax tree (clast) that
// reflects the updated execution order. This clast is used to create new
// LLVM-IR that is computational equivalent to the original control flow region,
// but executes its code in the new execution order defined by the changed
// scattering.
//
//===----------------------------------------------------------------------===//
#include "polly/CodeGen/Cloog.h"
#ifdef CLOOG_FOUND
#define DEBUG_TYPE "polly-codegen"
#include "polly/Dependences.h"
#include "polly/LinkAllPasses.h"
#include "polly/Options.h"
#include "polly/ScopInfo.h"
#include "polly/TempScopInfo.h"
#include "polly/CodeGen/CodeGeneration.h"
#include "polly/CodeGen/BlockGenerators.h"
#include "polly/CodeGen/LoopGenerators.h"
#include "polly/CodeGen/PTXGenerator.h"
#include "polly/CodeGen/Utils.h"
#include "polly/Support/GICHelper.h"
#include "polly/Support/ScopHelper.h"
#include "llvm/IR/Module.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Support/Debug.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#define CLOOG_INT_GMP 1
#include "cloog/cloog.h"
#include "cloog/isl/cloog.h"
#include "isl/aff.h"
#include <vector>
#include <utility>
using namespace polly;
using namespace llvm;
struct isl_set;
namespace polly {
static cl::opt<bool>
OpenMP("enable-polly-openmp", cl::desc("Generate OpenMP parallel code"),
cl::value_desc("OpenMP code generation enabled if true"),
cl::init(false), cl::ZeroOrMore, cl::cat(PollyCategory));
#ifdef GPU_CODEGEN
static cl::opt<bool>
GPGPU("enable-polly-gpgpu", cl::desc("Generate GPU parallel code"), cl::Hidden,
cl::value_desc("GPGPU code generation enabled if true"), cl::init(false),
cl::ZeroOrMore, cl::cat(PollyCategory));
static cl::opt<std::string>
GPUTriple("polly-gpgpu-triple",
cl::desc("Target triple for GPU code generation"), cl::Hidden,
cl::init(""), cl::cat(PollyCategory));
#endif /* GPU_CODEGEN */
typedef DenseMap<const char *, Value *> CharMapT;
/// Class to generate LLVM-IR that calculates the value of a clast_expr.
class ClastExpCodeGen {
IRBuilder<> &Builder;
const CharMapT &IVS;
Value *codegen(const clast_name *e, Type *Ty);
Value *codegen(const clast_term *e, Type *Ty);
Value *codegen(const clast_binary *e, Type *Ty);
Value *codegen(const clast_reduction *r, Type *Ty);
public:
// A generator for clast expressions.
//
// @param B The IRBuilder that defines where the code to calculate the
// clast expressions should be inserted.
// @param IVMAP A Map that translates strings describing the induction
// variables to the Values* that represent these variables
// on the LLVM side.
ClastExpCodeGen(IRBuilder<> &B, CharMapT &IVMap);
// Generates code to calculate a given clast expression.
//
// @param e The expression to calculate.
// @return The Value that holds the result.
Value *codegen(const clast_expr *e, Type *Ty);
};
Value *ClastExpCodeGen::codegen(const clast_name *e, Type *Ty) {
CharMapT::const_iterator I = IVS.find(e->name);
assert(I != IVS.end() && "Clast name not found");
return Builder.CreateSExtOrBitCast(I->second, Ty);
}
Value *ClastExpCodeGen::codegen(const clast_term *e, Type *Ty) {
APInt a = APInt_from_MPZ(e->val);
Value *ConstOne = ConstantInt::get(Builder.getContext(), a);
ConstOne = Builder.CreateSExtOrBitCast(ConstOne, Ty);
if (!e->var)
return ConstOne;
Value *var = codegen(e->var, Ty);
return Builder.CreateMul(ConstOne, var);
}
Value *ClastExpCodeGen::codegen(const clast_binary *e, Type *Ty) {
Value *LHS = codegen(e->LHS, Ty);
APInt RHS_AP = APInt_from_MPZ(e->RHS);
Value *RHS = ConstantInt::get(Builder.getContext(), RHS_AP);
RHS = Builder.CreateSExtOrBitCast(RHS, Ty);
switch (e->type) {
case clast_bin_mod:
return Builder.CreateSRem(LHS, RHS);
case clast_bin_fdiv: {
// floord(n,d) ((n < 0) ? (n - d + 1) : n) / d
Value *One = ConstantInt::get(Ty, 1);
Value *Zero = ConstantInt::get(Ty, 0);
Value *Sum1 = Builder.CreateSub(LHS, RHS);
Value *Sum2 = Builder.CreateAdd(Sum1, One);
Value *isNegative = Builder.CreateICmpSLT(LHS, Zero);
Value *Dividend = Builder.CreateSelect(isNegative, Sum2, LHS);
return Builder.CreateSDiv(Dividend, RHS);
}
case clast_bin_cdiv: {
// ceild(n,d) ((n < 0) ? n : (n + d - 1)) / d
Value *One = ConstantInt::get(Ty, 1);
Value *Zero = ConstantInt::get(Ty, 0);
Value *Sum1 = Builder.CreateAdd(LHS, RHS);
Value *Sum2 = Builder.CreateSub(Sum1, One);
Value *isNegative = Builder.CreateICmpSLT(LHS, Zero);
Value *Dividend = Builder.CreateSelect(isNegative, LHS, Sum2);
return Builder.CreateSDiv(Dividend, RHS);
}
case clast_bin_div:
return Builder.CreateSDiv(LHS, RHS);
}
llvm_unreachable("Unknown clast binary expression type");
}
Value *ClastExpCodeGen::codegen(const clast_reduction *r, Type *Ty) {
assert((r->type == clast_red_min || r->type == clast_red_max ||
r->type == clast_red_sum) &&
"Clast reduction type not supported");
Value *old = codegen(r->elts[0], Ty);
for (int i = 1; i < r->n; ++i) {
Value *exprValue = codegen(r->elts[i], Ty);
switch (r->type) {
case clast_red_min: {
Value *cmp = Builder.CreateICmpSLT(old, exprValue);
old = Builder.CreateSelect(cmp, old, exprValue);
break;
}
case clast_red_max: {
Value *cmp = Builder.CreateICmpSGT(old, exprValue);
old = Builder.CreateSelect(cmp, old, exprValue);
break;
}
case clast_red_sum:
old = Builder.CreateAdd(old, exprValue);
break;
}
}
return old;
}
ClastExpCodeGen::ClastExpCodeGen(IRBuilder<> &B, CharMapT &IVMap)
: Builder(B), IVS(IVMap) {}
Value *ClastExpCodeGen::codegen(const clast_expr *e, Type *Ty) {
switch (e->type) {
case clast_expr_name:
return codegen((const clast_name *)e, Ty);
case clast_expr_term:
return codegen((const clast_term *)e, Ty);
case clast_expr_bin:
return codegen((const clast_binary *)e, Ty);
case clast_expr_red:
return codegen((const clast_reduction *)e, Ty);
}
llvm_unreachable("Unknown clast expression!");
}
class ClastStmtCodeGen {
public:
const std::vector<std::string> &getParallelLoops();
private:
// The Scop we code generate.
Scop *S;
Pass *P;
// The Builder specifies the current location to code generate at.
IRBuilder<> &Builder;
// Map the Values from the old code to their counterparts in the new code.
ValueMapT ValueMap;
// Map the loops from the old code to expressions function of the induction
// variables in the new code. For example, when the code generator produces
// this AST:
//
// for (int c1 = 0; c1 <= 1023; c1 += 1)
// for (int c2 = 0; c2 <= 1023; c2 += 1)
// Stmt(c2 + 3, c1);
//
// LoopToScev is a map associating:
// "outer loop in the old loop nest" -> SCEV("c2 + 3"),
// "inner loop in the old loop nest" -> SCEV("c1").
LoopToScevMapT LoopToScev;
// clastVars maps from the textual representation of a clast variable to its
// current *Value. clast variables are scheduling variables, original
// induction variables or parameters. They are used either in loop bounds or
// to define the statement instance that is executed.
//
// for (s = 0; s < n + 3; ++i)
// for (t = s; t < m; ++j)
// Stmt(i = s + 3 * m, j = t);
//
// {s,t,i,j,n,m} is the set of clast variables in this clast.
CharMapT ClastVars;
// Codegenerator for clast expressions.
ClastExpCodeGen ExpGen;
// Do we currently generate parallel code?
bool parallelCodeGeneration;
std::vector<std::string> parallelLoops;
void codegen(const clast_assignment *a);
void codegen(const clast_assignment *a, ScopStmt *Statement,
unsigned Dimension, int vectorDim,
std::vector<ValueMapT> *VectorVMap = 0,
std::vector<LoopToScevMapT> *VLTS = 0);
void codegenSubstitutions(const clast_stmt *Assignment, ScopStmt *Statement,
int vectorDim = 0,
std::vector<ValueMapT> *VectorVMap = 0,
std::vector<LoopToScevMapT> *VLTS = 0);
void codegen(const clast_user_stmt *u, std::vector<Value *> *IVS = NULL,
const char *iterator = NULL,
__isl_take isl_set *scatteringDomain = 0);
void codegen(const clast_block *b);
/// @brief Create a classical sequential loop.
void codegenForSequential(const clast_for *f);
/// @brief Create OpenMP structure values.
///
/// Create a list of values that has to be stored into the OpenMP subfuncition
/// structure.
SetVector<Value *> getOMPValues(const clast_stmt *Body);
/// @brief Update ClastVars and ValueMap according to a value map.
///
/// @param VMap A map from old to new values.
void updateWithValueMap(OMPGenerator::ValueToValueMapTy &VMap);
/// @brief Create an OpenMP parallel for loop.
///
/// This loop reflects a loop as if it would have been created by an OpenMP
/// statement.
void codegenForOpenMP(const clast_for *f);
#ifdef GPU_CODEGEN
/// @brief Create GPGPU device memory access values.
///
/// Create a list of values that will be set to be parameters of the GPGPU
/// subfunction. These parameters represent device memory base addresses
/// and the size in bytes.
SetVector<Value *> getGPUValues(unsigned &OutputBytes);
/// @brief Create a GPU parallel for loop.
///
/// This loop reflects a loop as if it would have been created by a GPU
/// statement.
void codegenForGPGPU(const clast_for *F);
/// @brief Get innermost for loop.
const clast_stmt *getScheduleInfo(const clast_for *F,
std::vector<int> &NumIters,
unsigned &LoopDepth,
unsigned &NonPLoopDepth);
#endif /* GPU_CODEGEN */
/// @brief Check if a loop is parallel
///
/// Detect if a clast_for loop can be executed in parallel.
///
/// @param For The clast for loop to check.
///
/// @return bool Returns true if the incoming clast_for statement can
/// execute in parallel.
bool isParallelFor(const clast_for *For);
bool isInnermostLoop(const clast_for *f);
/// @brief Get the number of loop iterations for this loop.
/// @param f The clast for loop to check.
int getNumberOfIterations(const clast_for *f);
/// @brief Create vector instructions for this loop.
void codegenForVector(const clast_for *f);
void codegen(const clast_for *f);
Value *codegen(const clast_equation *eq);
void codegen(const clast_guard *g);
void codegen(const clast_stmt *stmt);
void addParameters(const CloogNames *names);
IntegerType *getIntPtrTy();
public:
void codegen(const clast_root *r);
ClastStmtCodeGen(Scop *scop, IRBuilder<> &B, Pass *P);
};
}
IntegerType *ClastStmtCodeGen::getIntPtrTy() {
return P->getAnalysis<DataLayout>().getIntPtrType(Builder.getContext());
}
const std::vector<std::string> &ClastStmtCodeGen::getParallelLoops() {
return parallelLoops;
}
void ClastStmtCodeGen::codegen(const clast_assignment *a) {
Value *V = ExpGen.codegen(a->RHS, getIntPtrTy());
ClastVars[a->LHS] = V;
}
void ClastStmtCodeGen::codegen(const clast_assignment *A, ScopStmt *Stmt,
unsigned Dim, int VectorDim,
std::vector<ValueMapT> *VectorVMap,
std::vector<LoopToScevMapT> *VLTS) {
Value *RHS;
assert(!A->LHS && "Statement assignments do not have left hand side");
RHS = ExpGen.codegen(A->RHS, Builder.getInt64Ty());
const llvm::SCEV *URHS = S->getSE()->getUnknown(RHS);
if (VLTS)
(*VLTS)[VectorDim][Stmt->getLoopForDimension(Dim)] = URHS;
LoopToScev[Stmt->getLoopForDimension(Dim)] = URHS;
const PHINode *PN = Stmt->getInductionVariableForDimension(Dim);
if (PN) {
RHS = Builder.CreateTruncOrBitCast(RHS, PN->getType());
if (VectorVMap)
(*VectorVMap)[VectorDim][PN] = RHS;
ValueMap[PN] = RHS;
}
}
void ClastStmtCodeGen::codegenSubstitutions(const clast_stmt *Assignment,
ScopStmt *Statement, int vectorDim,
std::vector<ValueMapT> *VectorVMap,
std::vector<LoopToScevMapT> *VLTS) {
int Dimension = 0;
while (Assignment) {
assert(CLAST_STMT_IS_A(Assignment, stmt_ass) &&
"Substitions are expected to be assignments");
codegen((const clast_assignment *)Assignment, Statement, Dimension,
vectorDim, VectorVMap, VLTS);
Assignment = Assignment->next;
Dimension++;
}
}
// Takes the cloog specific domain and translates it into a map Statement ->
// PartialSchedule, where the PartialSchedule contains all the dimensions that
// have been code generated up to this point.
static __isl_give isl_map *extractPartialSchedule(ScopStmt *Statement,
__isl_take isl_set *Domain) {
isl_map *Schedule = Statement->getScattering();
int ScheduledDimensions = isl_set_dim(Domain, isl_dim_set);
int UnscheduledDimensions =
isl_map_dim(Schedule, isl_dim_out) - ScheduledDimensions;
isl_set_free(Domain);
return isl_map_project_out(Schedule, isl_dim_out, ScheduledDimensions,
UnscheduledDimensions);
}
void ClastStmtCodeGen::codegen(const clast_user_stmt *u,
std::vector<Value *> *IVS, const char *iterator,
__isl_take isl_set *Domain) {
ScopStmt *Statement = (ScopStmt *)u->statement->usr;
if (u->substitutions)
codegenSubstitutions(u->substitutions, Statement);
int VectorDimensions = IVS ? IVS->size() : 1;
if (VectorDimensions == 1) {
BlockGenerator::generate(Builder, *Statement, ValueMap, LoopToScev, P);
return;
}
VectorValueMapT VectorMap(VectorDimensions);
std::vector<LoopToScevMapT> VLTS(VectorDimensions);
if (IVS) {
assert(u->substitutions && "Substitutions expected!");
int i = 0;
for (std::vector<Value *>::iterator II = IVS->begin(), IE = IVS->end();
II != IE; ++II) {
ClastVars[iterator] = *II;
codegenSubstitutions(u->substitutions, Statement, i, &VectorMap, &VLTS);
i++;
}
}
isl_map *Schedule = extractPartialSchedule(Statement, Domain);
VectorBlockGenerator::generate(Builder, *Statement, VectorMap, VLTS, Schedule,
P);
isl_map_free(Schedule);
}
void ClastStmtCodeGen::codegen(const clast_block *b) {
if (b->body)
codegen(b->body);
}
void ClastStmtCodeGen::codegenForSequential(const clast_for *f) {
Value *LowerBound, *UpperBound, *IV, *Stride;
BasicBlock *ExitBlock;
Type *IntPtrTy = getIntPtrTy();
LowerBound = ExpGen.codegen(f->LB, IntPtrTy);
UpperBound = ExpGen.codegen(f->UB, IntPtrTy);
Stride = Builder.getInt(APInt_from_MPZ(f->stride));
IV = createLoop(LowerBound, UpperBound, Stride, Builder, P, ExitBlock,
CmpInst::ICMP_SLE);
// Add loop iv to symbols.
ClastVars[f->iterator] = IV;
if (f->body)
codegen(f->body);
// Loop is finished, so remove its iv from the live symbols.
ClastVars.erase(f->iterator);
Builder.SetInsertPoint(ExitBlock->begin());
}
// Helper class to determine all scalar parameters used in the basic blocks of a
// clast. Scalar parameters are scalar variables defined outside of the SCoP.
class ParameterVisitor : public ClastVisitor {
std::set<Value *> Values;
public:
ParameterVisitor() : ClastVisitor(), Values() {}
void visitUser(const clast_user_stmt *Stmt) {
const ScopStmt *S = static_cast<const ScopStmt *>(Stmt->statement->usr);
const BasicBlock *BB = S->getBasicBlock();
// Check all the operands of instructions in the basic block.
for (BasicBlock::const_iterator BI = BB->begin(), BE = BB->end(); BI != BE;
++BI) {
const Instruction &Inst = *BI;
for (Instruction::const_op_iterator II = Inst.op_begin(),
IE = Inst.op_end();
II != IE; ++II) {
Value *SrcVal = *II;
if (Instruction *OpInst = dyn_cast<Instruction>(SrcVal))
if (S->getParent()->getRegion().contains(OpInst))
continue;
if (isa<Instruction>(SrcVal) || isa<Argument>(SrcVal))
Values.insert(SrcVal);
}
}
}
// Iterator to iterate over the values found.
typedef std::set<Value *>::const_iterator const_iterator;
inline const_iterator begin() const { return Values.begin(); }
inline const_iterator end() const { return Values.end(); }
};
SetVector<Value *> ClastStmtCodeGen::getOMPValues(const clast_stmt *Body) {
SetVector<Value *> Values;
// The clast variables
for (CharMapT::iterator I = ClastVars.begin(), E = ClastVars.end(); I != E;
I++)
Values.insert(I->second);
// Find the temporaries that are referenced in the clast statements'
// basic blocks but are not defined by these blocks (e.g., references
// to function arguments or temporaries defined before the start of
// the SCoP).
ParameterVisitor Params;
Params.visit(Body);
for (ParameterVisitor::const_iterator PI = Params.begin(), PE = Params.end();
PI != PE; ++PI) {
Value *V = *PI;
Values.insert(V);
DEBUG(dbgs() << "Adding temporary for OMP copy-in: " << *V << "\n");
}
return Values;
}
void
ClastStmtCodeGen::updateWithValueMap(OMPGenerator::ValueToValueMapTy &VMap) {
std::set<Value *> Inserted;
for (CharMapT::iterator I = ClastVars.begin(), E = ClastVars.end(); I != E;
I++) {
ClastVars[I->first] = VMap[I->second];
Inserted.insert(I->second);
}
for (OMPGenerator::ValueToValueMapTy::iterator I = VMap.begin(),
E = VMap.end();
I != E; ++I) {
if (Inserted.count(I->first))
continue;
ValueMap[I->first] = I->second;
}
}
static void clearDomtree(Function *F, DominatorTree &DT) {
DomTreeNode *N = DT.getNode(&F->getEntryBlock());
std::vector<BasicBlock *> Nodes;
for (po_iterator<DomTreeNode *> I = po_begin(N), E = po_end(N); I != E; ++I)
Nodes.push_back(I->getBlock());
for (std::vector<BasicBlock *>::iterator I = Nodes.begin(), E = Nodes.end();
I != E; ++I)
DT.eraseNode(*I);
}
void ClastStmtCodeGen::codegenForOpenMP(const clast_for *For) {
Value *Stride, *LB, *UB, *IV;
BasicBlock::iterator LoopBody;
IntegerType *IntPtrTy = getIntPtrTy();
SetVector<Value *> Values;
OMPGenerator::ValueToValueMapTy VMap;
OMPGenerator OMPGen(Builder, P);
Stride = Builder.getInt(APInt_from_MPZ(For->stride));
Stride = Builder.CreateSExtOrBitCast(Stride, IntPtrTy);
LB = ExpGen.codegen(For->LB, IntPtrTy);
UB = ExpGen.codegen(For->UB, IntPtrTy);
Values = getOMPValues(For->body);
IV = OMPGen.createParallelLoop(LB, UB, Stride, Values, VMap, &LoopBody);
BasicBlock::iterator AfterLoop = Builder.GetInsertPoint();
Builder.SetInsertPoint(LoopBody);
// Save the current values.
const ValueMapT ValueMapCopy = ValueMap;
const CharMapT ClastVarsCopy = ClastVars;
updateWithValueMap(VMap);
ClastVars[For->iterator] = IV;
if (For->body)
codegen(For->body);
// Restore the original values.
ValueMap = ValueMapCopy;
ClastVars = ClastVarsCopy;
clearDomtree((*LoopBody).getParent()->getParent(),
P->getAnalysis<DominatorTree>());
Builder.SetInsertPoint(AfterLoop);
}
#ifdef GPU_CODEGEN
static unsigned getArraySizeInBytes(const ArrayType *AT) {
unsigned Bytes = AT->getNumElements();
if (const ArrayType *T = dyn_cast<ArrayType>(AT->getElementType()))
Bytes *= getArraySizeInBytes(T);
else
Bytes *= AT->getElementType()->getPrimitiveSizeInBits() / 8;
return Bytes;
}
SetVector<Value *> ClastStmtCodeGen::getGPUValues(unsigned &OutputBytes) {
SetVector<Value *> Values;
OutputBytes = 0;
// Record the memory reference base addresses.
for (Scop::iterator SI = S->begin(), SE = S->end(); SI != SE; ++SI) {
ScopStmt *Stmt = *SI;
for (SmallVector<MemoryAccess *, 8>::iterator I = Stmt->memacc_begin(),
E = Stmt->memacc_end();
I != E; ++I) {
Value *BaseAddr = const_cast<Value *>((*I)->getBaseAddr());
Values.insert((BaseAddr));
// FIXME: we assume that there is one and only one array to be written
// in a SCoP.
int NumWrites = 0;
if ((*I)->isWrite()) {
++NumWrites;
assert(NumWrites <= 1 &&
"We support at most one array to be written in a SCoP.");
if (const PointerType *PT =
dyn_cast<PointerType>(BaseAddr->getType())) {
Type *T = PT->getArrayElementType();
const ArrayType *ATy = dyn_cast<ArrayType>(T);
OutputBytes = getArraySizeInBytes(ATy);
}
}
}
}
return Values;
}
const clast_stmt *ClastStmtCodeGen::getScheduleInfo(const clast_for *F,
std::vector<int> &NumIters,
unsigned &LoopDepth,
unsigned &NonPLoopDepth) {
clast_stmt *Stmt = (clast_stmt *)F;
const clast_for *Result;
bool NonParaFlag = false;
LoopDepth = 0;
NonPLoopDepth = 0;
while (Stmt) {
if (CLAST_STMT_IS_A(Stmt, stmt_for)) {
const clast_for *T = (clast_for *)Stmt;
if (isParallelFor(T)) {
if (!NonParaFlag) {
NumIters.push_back(getNumberOfIterations(T));
Result = T;
}
} else
NonParaFlag = true;
Stmt = T->body;
LoopDepth++;
continue;
}
Stmt = Stmt->next;
}
assert(NumIters.size() == 4 &&
"The loops should be tiled into 4-depth parallel loops and an "
"innermost non-parallel one (if exist).");
NonPLoopDepth = LoopDepth - NumIters.size();
assert(NonPLoopDepth <= 1 &&
"We support only one innermost non-parallel loop currently.");
return (const clast_stmt *)Result->body;
}
void ClastStmtCodeGen::codegenForGPGPU(const clast_for *F) {
BasicBlock::iterator LoopBody;
SetVector<Value *> Values;
SetVector<Value *> IVS;
std::vector<int> NumIterations;
PTXGenerator::ValueToValueMapTy VMap;
assert(!GPUTriple.empty() &&
"Target triple should be set properly for GPGPU code generation.");
PTXGenerator PTXGen(Builder, P, GPUTriple);
// Get original IVS and ScopStmt
unsigned TiledLoopDepth, NonPLoopDepth;
const clast_stmt *InnerStmt =
getScheduleInfo(F, NumIterations, TiledLoopDepth, NonPLoopDepth);
const clast_stmt *TmpStmt;
const clast_user_stmt *U;
const clast_for *InnerFor;
if (CLAST_STMT_IS_A(InnerStmt, stmt_for)) {
InnerFor = (const clast_for *)InnerStmt;
TmpStmt = InnerFor->body;
} else
TmpStmt = InnerStmt;
U = (const clast_user_stmt *)TmpStmt;
ScopStmt *Statement = (ScopStmt *)U->statement->usr;
for (unsigned i = 0; i < Statement->getNumIterators() - NonPLoopDepth; i++) {
const Value *IV = Statement->getInductionVariableForDimension(i);
IVS.insert(const_cast<Value *>(IV));
}
unsigned OutBytes;
Values = getGPUValues(OutBytes);
PTXGen.setOutputBytes(OutBytes);
PTXGen.startGeneration(Values, IVS, VMap, &LoopBody);
BasicBlock::iterator AfterLoop = Builder.GetInsertPoint();
Builder.SetInsertPoint(LoopBody);
BasicBlock *AfterBB = 0;
if (NonPLoopDepth) {
Value *LowerBound, *UpperBound, *IV, *Stride;
Type *IntPtrTy = getIntPtrTy();
LowerBound = ExpGen.codegen(InnerFor->LB, IntPtrTy);
UpperBound = ExpGen.codegen(InnerFor->UB, IntPtrTy);
Stride = Builder.getInt(APInt_from_MPZ(InnerFor->stride));
IV = createLoop(LowerBound, UpperBound, Stride, Builder, P, AfterBB,
CmpInst::ICMP_SLE);
const Value *OldIV_ = Statement->getInductionVariableForDimension(2);
Value *OldIV = const_cast<Value *>(OldIV_);
VMap.insert(std::make_pair<Value *, Value *>(OldIV, IV));
}
updateWithValueMap(VMap);
BlockGenerator::generate(Builder, *Statement, ValueMap, P);
if (AfterBB)
Builder.SetInsertPoint(AfterBB->begin());
// FIXME: The replacement of the host base address with the parameter of ptx
// subfunction should have been done by updateWithValueMap. We use the
// following codes to avoid affecting other parts of Polly. This should be
// fixed later.
Function *FN = Builder.GetInsertBlock()->getParent();
for (unsigned j = 0; j < Values.size(); j++) {
Value *baseAddr = Values[j];
for (Function::iterator B = FN->begin(); B != FN->end(); ++B) {
for (BasicBlock::iterator I = B->begin(); I != B->end(); ++I)
I->replaceUsesOfWith(baseAddr, ValueMap[baseAddr]);
}
}
Builder.SetInsertPoint(AfterLoop);
PTXGen.setLaunchingParameters(NumIterations[0], NumIterations[1],
NumIterations[2], NumIterations[3]);
PTXGen.finishGeneration(FN);
}
#endif
bool ClastStmtCodeGen::isInnermostLoop(const clast_for *f) {
const clast_stmt *stmt = f->body;
while (stmt) {
if (!CLAST_STMT_IS_A(stmt, stmt_user))
return false;
stmt = stmt->next;
}
return true;
}
int ClastStmtCodeGen::getNumberOfIterations(const clast_for *For) {
isl_set *LoopDomain = isl_set_copy(isl_set_from_cloog_domain(For->domain));
int NumberOfIterations = polly::getNumberOfIterations(LoopDomain);
if (NumberOfIterations == -1)
return -1;
return NumberOfIterations / isl_int_get_si(For->stride) + 1;
}
void ClastStmtCodeGen::codegenForVector(const clast_for *F) {
DEBUG(dbgs() << "Vectorizing loop '" << F->iterator << "'\n";);
int VectorWidth = getNumberOfIterations(F);
Value *LB = ExpGen.codegen(F->LB, getIntPtrTy());
APInt Stride = APInt_from_MPZ(F->stride);
IntegerType *LoopIVType = dyn_cast<IntegerType>(LB->getType());
Stride = Stride.zext(LoopIVType->getBitWidth());
Value *StrideValue = ConstantInt::get(LoopIVType, Stride);
std::vector<Value *> IVS(VectorWidth);
IVS[0] = LB;
for (int i = 1; i < VectorWidth; i++)
IVS[i] = Builder.CreateAdd(IVS[i - 1], StrideValue, "p_vector_iv");
isl_set *Domain = isl_set_copy(isl_set_from_cloog_domain(F->domain));
// Add loop iv to symbols.
ClastVars[F->iterator] = LB;
const clast_stmt *Stmt = F->body;
while (Stmt) {
codegen((const clast_user_stmt *)Stmt, &IVS, F->iterator,
isl_set_copy(Domain));
Stmt = Stmt->next;
}
// Loop is finished, so remove its iv from the live symbols.
isl_set_free(Domain);
ClastVars.erase(F->iterator);
}
bool ClastStmtCodeGen::isParallelFor(const clast_for *f) {
isl_set *Domain = isl_set_copy(isl_set_from_cloog_domain(f->domain));
assert(Domain && "Cannot access domain of loop");
Dependences &D = P->getAnalysis<Dependences>();
return D.isParallelDimension(Domain, isl_set_n_dim(Domain));
}
void ClastStmtCodeGen::codegen(const clast_for *f) {
bool Vector = PollyVectorizerChoice != VECTORIZER_NONE;
if ((Vector || OpenMP) && isParallelFor(f)) {
if (Vector && isInnermostLoop(f) && (-1 != getNumberOfIterations(f)) &&
(getNumberOfIterations(f) <= 16)) {
codegenForVector(f);
return;
}
if (OpenMP && !parallelCodeGeneration) {
parallelCodeGeneration = true;
parallelLoops.push_back(f->iterator);
codegenForOpenMP(f);
parallelCodeGeneration = false;
return;
}
}
#ifdef GPU_CODEGEN
if (GPGPU && isParallelFor(f)) {
if (!parallelCodeGeneration) {
parallelCodeGeneration = true;
parallelLoops.push_back(f->iterator);
codegenForGPGPU(f);
parallelCodeGeneration = false;
return;
}
}
#endif
codegenForSequential(f);
}
Value *ClastStmtCodeGen::codegen(const clast_equation *eq) {
Value *LHS = ExpGen.codegen(eq->LHS, getIntPtrTy());
Value *RHS = ExpGen.codegen(eq->RHS, getIntPtrTy());
CmpInst::Predicate P;
if (eq->sign == 0)
P = ICmpInst::ICMP_EQ;
else if (eq->sign > 0)
P = ICmpInst::ICMP_SGE;
else
P = ICmpInst::ICMP_SLE;
return Builder.CreateICmp(P, LHS, RHS);
}
void ClastStmtCodeGen::codegen(const clast_guard *g) {
Function *F = Builder.GetInsertBlock()->getParent();
LLVMContext &Context = F->getContext();
BasicBlock *CondBB =
SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), P);
CondBB->setName("polly.cond");
BasicBlock *MergeBB = SplitBlock(CondBB, CondBB->begin(), P);
MergeBB->setName("polly.merge");
BasicBlock *ThenBB = BasicBlock::Create(Context, "polly.then", F);
DominatorTree &DT = P->getAnalysis<DominatorTree>();
DT.addNewBlock(ThenBB, CondBB);
DT.changeImmediateDominator(MergeBB, CondBB);
CondBB->getTerminator()->eraseFromParent();
Builder.SetInsertPoint(CondBB);
Value *Predicate = codegen(&(g->eq[0]));
for (int i = 1; i < g->n; ++i) {
Value *TmpPredicate = codegen(&(g->eq[i]));
Predicate = Builder.CreateAnd(Predicate, TmpPredicate);
}
Builder.CreateCondBr(Predicate, ThenBB, MergeBB);
Builder.SetInsertPoint(ThenBB);
Builder.CreateBr(MergeBB);
Builder.SetInsertPoint(ThenBB->begin());
LoopInfo &LI = P->getAnalysis<LoopInfo>();
Loop *L = LI.getLoopFor(CondBB);
if (L)
L->addBasicBlockToLoop(ThenBB, LI.getBase());
codegen(g->then);
Builder.SetInsertPoint(MergeBB->begin());
}
void ClastStmtCodeGen::codegen(const clast_stmt *stmt) {
if (CLAST_STMT_IS_A(stmt, stmt_root))
assert(false && "No second root statement expected");
else if (CLAST_STMT_IS_A(stmt, stmt_ass))
codegen((const clast_assignment *)stmt);
else if (CLAST_STMT_IS_A(stmt, stmt_user))
codegen((const clast_user_stmt *)stmt);
else if (CLAST_STMT_IS_A(stmt, stmt_block))
codegen((const clast_block *)stmt);
else if (CLAST_STMT_IS_A(stmt, stmt_for))
codegen((const clast_for *)stmt);
else if (CLAST_STMT_IS_A(stmt, stmt_guard))
codegen((const clast_guard *)stmt);
if (stmt->next)
codegen(stmt->next);
}
void ClastStmtCodeGen::addParameters(const CloogNames *names) {
SCEVExpander Rewriter(P->getAnalysis<ScalarEvolution>(), "polly");
int i = 0;
for (Scop::param_iterator PI = S->param_begin(), PE = S->param_end();
PI != PE; ++PI) {
assert(i < names->nb_parameters && "Not enough parameter names");
const SCEV *Param = *PI;
Type *Ty = Param->getType();
Instruction *insertLocation = --(Builder.GetInsertBlock()->end());
Value *V = Rewriter.expandCodeFor(Param, Ty, insertLocation);
ClastVars[names->parameters[i]] = V;
++i;
}
}
void ClastStmtCodeGen::codegen(const clast_root *r) {
addParameters(r->names);
parallelCodeGeneration = false;
const clast_stmt *stmt = (const clast_stmt *)r;
if (stmt->next)
codegen(stmt->next);
}
ClastStmtCodeGen::ClastStmtCodeGen(Scop *scop, IRBuilder<> &B, Pass *P)
: S(scop), P(P), Builder(B), ExpGen(Builder, ClastVars) {}
namespace {
class CodeGeneration : public ScopPass {
std::vector<std::string> ParallelLoops;
public:
static char ID;
CodeGeneration() : ScopPass(ID) {}
bool runOnScop(Scop &S) {
ParallelLoops.clear();
assert(!S.getRegion().isTopLevelRegion() &&
"Top level regions are not supported");
simplifyRegion(&S, this);
BasicBlock *StartBlock = executeScopConditionally(S, this);
IRBuilder<> Builder(StartBlock->begin());
ClastStmtCodeGen CodeGen(&S, Builder, this);
CloogInfo &C = getAnalysis<CloogInfo>();
CodeGen.codegen(C.getClast());
ParallelLoops.insert(ParallelLoops.begin(),
CodeGen.getParallelLoops().begin(),
CodeGen.getParallelLoops().end());
return true;
}
virtual void printScop(raw_ostream &OS) const {
for (std::vector<std::string>::const_iterator PI = ParallelLoops.begin(),
PE = ParallelLoops.end();
PI != PE; ++PI)
OS << "Parallel loop with iterator '" << *PI << "' generated\n";
}
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<CloogInfo>();
AU.addRequired<Dependences>();
AU.addRequired<DominatorTree>();
AU.addRequired<RegionInfo>();
AU.addRequired<ScalarEvolution>();
AU.addRequired<ScopDetection>();
AU.addRequired<ScopInfo>();
AU.addRequired<DataLayout>();
AU.addRequired<LoopInfo>();
AU.addPreserved<CloogInfo>();
AU.addPreserved<Dependences>();
AU.addPreserved<LoopInfo>();
AU.addPreserved<DominatorTree>();
AU.addPreserved<ScopDetection>();
AU.addPreserved<ScalarEvolution>();
// FIXME: We do not yet add regions for the newly generated code to the
// region tree.
AU.addPreserved<RegionInfo>();
AU.addPreserved<TempScopInfo>();
AU.addPreserved<ScopInfo>();
AU.addPreservedID(IndependentBlocksID);
}
};
}
char CodeGeneration::ID = 1;
Pass *polly::createCodeGenerationPass() { return new CodeGeneration(); }
INITIALIZE_PASS_BEGIN(CodeGeneration, "polly-codegen",
"Polly - Create LLVM-IR from SCoPs", false, false);
INITIALIZE_PASS_DEPENDENCY(CloogInfo);
INITIALIZE_PASS_DEPENDENCY(Dependences);
INITIALIZE_PASS_DEPENDENCY(DominatorTree);
INITIALIZE_PASS_DEPENDENCY(RegionInfo);
INITIALIZE_PASS_DEPENDENCY(ScalarEvolution);
INITIALIZE_PASS_DEPENDENCY(ScopDetection);
INITIALIZE_PASS_DEPENDENCY(DataLayout);
INITIALIZE_PASS_END(CodeGeneration, "polly-codegen",
"Polly - Create LLVM-IR from SCoPs", false, false)
#endif // CLOOG_FOUND
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