1 files changed, 125 insertions, 0 deletions
diff --git a/lib/Analysis/Delinearization.cpp b/lib/Analysis/Delinearization.cpp
new file mode 100644
index 0000000000..98a1ad3e63
--- /dev/null
+++ b/lib/Analysis/Delinearization.cpp
@@ -0,0 +1,125 @@
+//===---- 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/IR/DerivedTypes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/LLVMContext.h"
+#include "llvm/Pass.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/Passes.h"
+#include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/Analysis/ScalarEvolutionExpressions.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/InstIterator.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace llvm;
+
+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;
+};
+
+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);
+    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);
+      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; }