1 //===---- Delinearization.cpp - MultiDimensional Index Delinearization ----===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This implements an analysis pass that tries to delinearize all GEP
11 // instructions in all loops using the SCEV analysis functionality. This pass is
12 // only used for testing purposes: if your pass needs delinearization, please
13 // use the on-demand SCEVAddRecExpr::delinearize() function.
15 //===----------------------------------------------------------------------===//
17 #define DL_NAME "delinearize"
18 #define DEBUG_TYPE DL_NAME
19 #include "llvm/IR/Constants.h"
20 #include "llvm/IR/DerivedTypes.h"
21 #include "llvm/IR/Function.h"
22 #include "llvm/IR/Instructions.h"
23 #include "llvm/IR/LLVMContext.h"
24 #include "llvm/Pass.h"
25 #include "llvm/IR/Type.h"
26 #include "llvm/Analysis/LoopInfo.h"
27 #include "llvm/Analysis/Passes.h"
28 #include "llvm/Analysis/ScalarEvolution.h"
29 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
30 #include "llvm/Support/CommandLine.h"
31 #include "llvm/Support/Debug.h"
32 #include "llvm/Support/InstIterator.h"
33 #include "llvm/Support/raw_ostream.h"
39 class Delinearization : public FunctionPass {
40 Delinearization(const Delinearization &); // do not implement
47 static char ID; // Pass identification, replacement for typeid
49 Delinearization() : FunctionPass(ID) {
50 initializeDelinearizationPass(*PassRegistry::getPassRegistry());
52 virtual bool runOnFunction(Function &F);
53 virtual void getAnalysisUsage(AnalysisUsage &AU) const;
54 virtual void print(raw_ostream &O, const Module *M = 0) const;
57 } // end anonymous namespace
59 void Delinearization::getAnalysisUsage(AnalysisUsage &AU) const {
61 AU.addRequired<LoopInfo>();
62 AU.addRequired<ScalarEvolution>();
65 bool Delinearization::runOnFunction(Function &F) {
67 SE = &getAnalysis<ScalarEvolution>();
68 LI = &getAnalysis<LoopInfo>();
72 static Value *getPointerOperand(Instruction &Inst) {
73 if (LoadInst *Load = dyn_cast<LoadInst>(&Inst))
74 return Load->getPointerOperand();
75 else if (StoreInst *Store = dyn_cast<StoreInst>(&Inst))
76 return Store->getPointerOperand();
77 else if (GetElementPtrInst *Gep = dyn_cast<GetElementPtrInst>(&Inst))
78 return Gep->getPointerOperand();
82 void Delinearization::print(raw_ostream &O, const Module *) const {
83 O << "Delinearization on function " << F->getName() << ":\n";
84 for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I) {
85 Instruction *Inst = &(*I);
86 if (!isa<StoreInst>(Inst) && !isa<LoadInst>(Inst) &&
87 !isa<GetElementPtrInst>(Inst))
90 const BasicBlock *BB = Inst->getParent();
91 // Delinearize the memory access as analyzed in all the surrounding loops.
92 // Do not analyze memory accesses outside loops.
93 for (Loop *L = LI->getLoopFor(BB); L != NULL; L = L->getParentLoop()) {
94 const SCEV *AccessFn = SE->getSCEVAtScope(getPointerOperand(*Inst), L);
95 const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(AccessFn);
99 O << "AddRec: " << *AR << "\n";
101 SmallVector<const SCEV *, 3> Subscripts, Sizes;
102 const SCEV *Res = AR->delinearize(*SE, Subscripts, Sizes);
103 int Size = Subscripts.size();
104 if (Res == AR || Size == 0) {
105 O << "failed to delinearize\n";
108 O << "Base offset: " << *Res << "\n";
109 O << "ArrayDecl[UnknownSize]";
110 for (int i = 0; i < Size - 1; i++)
111 O << "[" << *Sizes[i] << "]";
112 O << " with elements of " << *Sizes[Size - 1] << " bytes.\n";
115 for (int i = 0; i < Size; i++)
116 O << "[" << *Subscripts[i] << "]";
122 char Delinearization::ID = 0;
123 static const char delinearization_name[] = "Delinearization";
124 INITIALIZE_PASS_BEGIN(Delinearization, DL_NAME, delinearization_name, true,
126 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
127 INITIALIZE_PASS_END(Delinearization, DL_NAME, delinearization_name, true, true)
129 FunctionPass *llvm::createDelinearizationPass() { return new Delinearization; }