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llvm-mirror/lib/Analysis/Delinearization.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

130 lines
4.5 KiB
C++

//===---- Delinearization.cpp - MultiDimensional Index Delinearization ----===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// 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.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/Passes.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
#include "llvm/IR/Constants.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/Debug.h"
#include "llvm/Support/raw_ostream.h"
using namespace llvm;
#define DL_NAME "delinearize"
#define DEBUG_TYPE DL_NAME
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());
}
bool runOnFunction(Function &F) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
void print(raw_ostream &O, const Module *M = nullptr) const override;
};
} // end anonymous namespace
void Delinearization::getAnalysisUsage(AnalysisUsage &AU) const {
AU.setPreservesAll();
AU.addRequired<LoopInfoWrapperPass>();
AU.addRequired<ScalarEvolutionWrapperPass>();
}
bool Delinearization::runOnFunction(Function &F) {
this->F = &F;
SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
return false;
}
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 != nullptr; L = L->getParentLoop()) {
const SCEV *AccessFn = SE->getSCEVAtScope(getPointerOperand(Inst), L);
const SCEVUnknown *BasePointer =
dyn_cast<SCEVUnknown>(SE->getPointerBase(AccessFn));
// Do not delinearize if we cannot find the base pointer.
if (!BasePointer)
break;
AccessFn = SE->getMinusSCEV(AccessFn, BasePointer);
O << "\n";
O << "Inst:" << *Inst << "\n";
O << "In Loop with Header: " << L->getHeader()->getName() << "\n";
O << "AccessFunction: " << *AccessFn << "\n";
SmallVector<const SCEV *, 3> Subscripts, Sizes;
SE->delinearize(AccessFn, Subscripts, Sizes, SE->getElementSize(Inst));
if (Subscripts.size() == 0 || Sizes.size() == 0 ||
Subscripts.size() != Sizes.size()) {
O << "failed to delinearize\n";
continue;
}
O << "Base offset: " << *BasePointer << "\n";
O << "ArrayDecl[UnknownSize]";
int Size = Subscripts.size();
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(LoopInfoWrapperPass)
INITIALIZE_PASS_END(Delinearization, DL_NAME, delinearization_name, true, true)
FunctionPass *llvm::createDelinearizationPass() { return new Delinearization; }