llvm-6502/lib/Analysis/Delinearization.cpp
Chandler Carruth 876ac60880 [Modules] Move InstIterator out of the Support library, where it had no
business.

This header includes Function and BasicBlock and directly uses the
interfaces of both classes. It has to do with the IR, it even has that
in the name. =] Put it in the library it belongs to.

This is one step toward making LLVM's Support library survive a C++
modules bootstrap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202814 91177308-0d34-0410-b5e6-96231b3b80d8
2014-03-04 10:30:26 +00:00

134 lines
4.4 KiB
C++

//===---- Delinearization.cpp - MultiDimensional Index Delinearization ----===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This implements an analysis pass that tries to delinearize all GEP
// instructions in all loops using the SCEV analysis functionality. This pass is
// only used for testing purposes: if your pass needs delinearization, please
// use the on-demand SCEVAddRecExpr::delinearize() function.
//
//===----------------------------------------------------------------------===//
#define DL_NAME "delinearize"
#define DEBUG_TYPE DL_NAME
#include "llvm/IR/Constants.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Type.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
namespace {
class Delinearization : public FunctionPass {
Delinearization(const Delinearization &); // do not implement
protected:
Function *F;
LoopInfo *LI;
ScalarEvolution *SE;
public:
static char ID; // Pass identification, replacement for typeid
Delinearization() : FunctionPass(ID) {
initializeDelinearizationPass(*PassRegistry::getPassRegistry());
}
virtual bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const;
virtual void print(raw_ostream &O, const Module *M = 0) const;
};
} // end anonymous namespace
void Delinearization::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<LoopInfo>();
AU.addRequired<ScalarEvolution>();
}
bool Delinearization::runOnFunction(Function &F) {
this->F = &F;
SE = &getAnalysis<ScalarEvolution>();
LI = &getAnalysis<LoopInfo>();
return false;
}
static Value *getPointerOperand(Instruction &Inst) {
if (LoadInst *Load = dyn_cast<LoadInst>(&Inst))
return Load->getPointerOperand();
else if (StoreInst *Store = dyn_cast<StoreInst>(&Inst))
return Store->getPointerOperand();
else if (GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(&Inst))
return Gep->getPointerOperand();
return NULL;
}
void Delinearization::print(raw_ostream &O, const Module *) const {
O << "Delinearization on function " << F->getName() << ":\n";
for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
Instruction *Inst = &(*I);
// Only analyze loads and stores.
if (!isa<StoreInst>(Inst) && !isa<LoadInst>(Inst) &&
!isa<GetElementPtrInst>(Inst))
continue;
const BasicBlock *BB = Inst->getParent();
// Delinearize the memory access as analyzed in all the surrounding loops.
// Do not analyze memory accesses outside loops.
for (Loop *L = LI->getLoopFor(BB); L != NULL; L = L->getParentLoop()) {
const SCEV *AccessFn = SE->getSCEVAtScope(getPointerOperand(*Inst), L);
const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(AccessFn);
// Do not try to delinearize memory accesses that are not AddRecs.
if (!AR)
break;
O << "AddRec: " << *AR << "\n";
SmallVector<const SCEV *, 3> Subscripts, Sizes;
const SCEV *Res = AR->delinearize(*SE, Subscripts, Sizes);
int Size = Subscripts.size();
if (Res == AR || Size == 0) {
O << "failed to delinearize\n";
continue;
}
O << "Base offset: " << *Res << "\n";
O << "ArrayDecl[UnknownSize]";
for (int i = 0; i < Size - 1; i++)
O << "[" << *Sizes[i] << "]";
O << " with elements of " << *Sizes[Size - 1] << " bytes.\n";
O << "ArrayRef";
for (int i = 0; i < Size; i++)
O << "[" << *Subscripts[i] << "]";
O << "\n";
}
}
}
char Delinearization::ID = 0;
static const char delinearization_name[] = "Delinearization";
INITIALIZE_PASS_BEGIN(Delinearization, DL_NAME, delinearization_name, true,
true)
INITIALIZE_PASS_DEPENDENCY(LoopInfo)
INITIALIZE_PASS_END(Delinearization, DL_NAME, delinearization_name, true, true)
FunctionPass *llvm::createDelinearizationPass() { return new Delinearization; }