LoopSplitter - fix issues

src/BatchMaker.cpp

@@ -45,6 +45,7 @@ void BatchMaker::createBatchedFormFnPrototype(vector<TASArgAttr> & BatchFuncArgL
   }
 
   // Batch size parameter
+  BatchSizeArgPos = i;
   BatchFuncArgList.emplace_back(
       TASArgAttr { false, i++, Type::getInt32Ty(Ctx), nullptr, BatchSizeVarName});
 
@@ -85,6 +86,10 @@ void BatchMaker::replaceOldArgUsesWithBatchArgs(vector<TASArgAttr> & BatchFuncAr
       [&] (TASArgAttr & Attr) {
       if (Attr.IsBatch) BatchArgs.push_back(Attr.Val); });
 
+  Builder.SetInsertPoint(&EntryBB->front());
+  BatchSizeAlloca = Builder.CreateAlloca(BatchFuncArgList[BatchSizeArgPos].Ty);
+  Builder.CreateStore(BatchFuncArgList[BatchSizeArgPos].Val, BatchSizeAlloca);
+
   for (auto & BatchArg : BatchArgs) {
     Builder.SetInsertPoint(&EntryBB->front());
     auto BatchArgAlloca = Builder.CreateAlloca(BatchArg->getType());
@@ -179,10 +184,8 @@ void BatchMaker::addBatchLoop(BasicBlock * RetBlock, AllocaInst * IdxPtr) {
              [&] (BasicBlock * BB) { setSuccessor(BB, UniqueExitingBlock); });
   }
 
-  auto BatchSizeVal = BatchFunc->getValueSymbolTable()->lookup(BatchSizeVarName);
-
   auto TL0 = TASForLoop(BatchFunc->getContext(), ParentBB, RetBlock,
-                        std::string("loop0"), BatchFunc, BatchSizeVal, IdxPtr);
+                        std::string("loop0"), BatchFunc, BatchSizeAlloca, IdxPtr);
 
   TL0.setLoopBody(BatchBB, UniqueExitingBlock);
 }

src/BatchMaker.h

@@ -40,6 +40,8 @@ class BatchMaker {
   bool IsRetTyVoid = false;
   std::string BatchSizeVarName = std::string("TAS_BatchSize");
   std::string ReturnVarName = std::string("TAS_ReturnVar");
+  unsigned BatchSizeArgPos;
+  llvm::AllocaInst * BatchSizeAlloca;
 
   void createBatchedFormFnPrototype(std::vector<TASArgAttr> & BatchFuncArgList);
   void addBatchLoop(llvm::BasicBlock * RetBlock, llvm::AllocaInst * IdxPtr);

src/ForLoop.cpp

@@ -10,7 +10,7 @@ namespace tas {
 
 TASForLoop::TASForLoop(LLVMContext & Ctx, BasicBlock * Prev,
     BasicBlock * Next, const std::string & Name, Function * F,
-    llvm::Value * TC, AllocaInst * IP)
+    llvm::AllocaInst * TC, AllocaInst * IP)
   : F(F), Name (std::move(Name)), TripCount(TC), IdxVarPtr(IP)
 {
   addEmptyLoop(Ctx, Prev, Next);
@@ -32,8 +32,9 @@ void TASForLoop::addEmptyLoop(LLVMContext & Ctx, BasicBlock * Prev,
   addIncrementIndexOp(IdxVarPtr, BI);
 
   Builder.SetInsertPoint(Header);
+  auto TCVal = Builder.CreateLoad(TripCount);
   IndexVar = Builder.CreateLoad(IdxVarPtr);
-  auto * icmp = Builder.CreateICmpSLT(IndexVar, TripCount, "loop-predicate");
+  auto * icmp = Builder.CreateICmpSLT(IndexVar, TCVal, "loop-predicate");
 
   // Stitch entry point in control flow.
   if (Prev) {

src/ForLoop.h

@@ -29,7 +29,7 @@ public:
   explicit TASForLoop(llvm::LLVMContext & Ctx,
       llvm::BasicBlock * Prev, llvm::BasicBlock * Next,
       const std::string & Name, llvm::Function * F = nullptr,
-      llvm::Value * TC = nullptr, llvm::AllocaInst * IP = nullptr);
+      llvm::AllocaInst * TC = nullptr, llvm::AllocaInst * IP = nullptr);
 
   void addEmptyLoop(llvm::LLVMContext & Ctx, llvm::BasicBlock * Prev, llvm::BasicBlock * Next);
   void setLoopBody(llvm::BasicBlock * BodyBB);

src/ForLoopV2.cpp

@@ -23,7 +23,7 @@ void IRLoop::analyze(Loop * L) {
   }
 }
 
-void IRLoop::constructEmptyLoop(Value * TripCount, BasicBlock * ExitBlock) {
+void IRLoop::constructEmptyLoop(AllocaInst * TripCount, BasicBlock * ExitBlock) {
   auto & Ctx = ExitBlock->getContext();
   const auto & F = ExitBlock->getParent();
 
@@ -54,25 +54,37 @@ void IRLoop::constructEmptyLoop(Value * TripCount, BasicBlock * ExitBlock) {
   // Populate header block
   Builder.SetInsertPoint(Header);
   auto IdxVal = Builder.CreateLoad(IdxAlloca);
-  auto * Icmp = Builder.CreateICmpSLT(IdxVal, TripCount, "loop-predicate");
+  auto TC = Builder.CreateLoad(TripCount);
+  auto * Icmp = Builder.CreateICmpSLT(IdxVal, TC, "loop-predicate");
   Builder.CreateCondBr(Icmp, EmptyBody, ExitBlock);
 }
 
-void IRLoop::setLoopBlocks(SmallVectorImpl<BasicBlock *> & Blocks) {
-  for_each(Blocks, [&] (auto & BB) { Blocks.push_back(BB); });
+void IRLoop::setLoopBlocks(std::vector<BasicBlock *> & BlockList) {
+  for_each(BlockList, [&] (auto & BB) { Blocks.push_back(BB); });
   assert (!Blocks.empty() && "Blocks can't be empty");
   setSuccessor(Header, Blocks.front()); // True Path
   assert (Latch && "Latch is NULL");
   setSuccessor(Blocks.back(), Latch);
 }
 
-void LoopBodyTraverser::traverse(SmallVectorImpl<BasicBlock *> & Blocks,
+void LoopBodyTraverser::traverse(std::vector<BasicBlock *> & Blocks,
                                  BasicBlock * Start, BasicBlock * End) {
+  if (std::find(Blocks.begin(), Blocks.end(), Start) != Blocks.end()) return;
   if (Start == End) return;
   Blocks.push_back(Start);
   for (auto * BB : successors(Start)){
     // Don't travel out of loop
-    //if (std::find(ExitBlocks.begin(), ExitBlocks.end(), BB) != Blocks.end()) continue;
+    if (std::find(ExitBlocks.begin(), ExitBlocks.end(), BB) != ExitBlocks.end()) continue;
+    traverse(Blocks, BB, End);
+  }
+}
+
+void LoopBodyTraverser::traverseReverse(std::vector<BasicBlock *> & Blocks,
+                                 BasicBlock * Start, BasicBlock * End) {
+  if (std::find(Blocks.begin(), Blocks.end(), Start) != Blocks.end()) return;
+  if (Start == End) return;
+  Blocks.push_back(Start);
+  for (auto * BB : predecessors(Start)){
     traverse(Blocks, BB, End);
   }
 }

src/ForLoopV2.h

@@ -23,10 +23,10 @@ public:
   IRLoop() = default;
 
   void analyze(llvm::Loop * L);
-  void constructEmptyLoop(llvm::Value * TripCount,
+  void constructEmptyLoop(llvm::AllocaInst * TripCount,
                           llvm::BasicBlock * InsertAfter);
   void extractLoopSkeleton(llvm::Loop * L);
-  void setLoopBlocks(llvm::SmallVectorImpl<llvm::BasicBlock *> & Blocks);
+  void setLoopBlocks(std::vector<llvm::BasicBlock *> & Blocks);
 
   llvm::BasicBlock * getPreHeader() {
     return PreHeader;
@@ -35,6 +35,16 @@ public:
   llvm::BasicBlock * getHeader() {
     return Header;
   }
+
+  void printLooopInfo() {
+    llvm::errs() << "LoopInfo:";
+    Header->printAsOperand(llvm::errs());
+    llvm::errs() << "  ";
+    Latch->printAsOperand(llvm::errs());
+    llvm::errs() << "  ";
+    llvm::errs() << *IdxAlloca << "\n";
+    llvm::errs() << " No of Blocks = " << Blocks.size() << "\n";
+  }
 };
 
 class LoopBodyTraverser {
@@ -45,7 +55,10 @@ public:
     L->getExitBlocks(ExitBlocks);
   }
 
-  void traverse(llvm::SmallVectorImpl<llvm::BasicBlock *> & Blocks,
+  void traverse(std::vector<llvm::BasicBlock *> & Blocks,
+                llvm::BasicBlock * Start, llvm::BasicBlock * End);
+
+  void traverseReverse(std::vector<llvm::BasicBlock *> & Blocks,
                 llvm::BasicBlock * Start, llvm::BasicBlock * End);
 
   void printExitBlocks() {

src/LoopSplitter.cpp

@@ -10,8 +10,10 @@
 #include <llvm/IR/IRBuilder.h>
 
 #include <iostream>
+#include <vector>
 #include <string>
 
+using namespace std;
 using namespace llvm;
 
 #define DEBUG_TYPE "tas-batch-process"
@@ -30,8 +32,6 @@ void LoopSplitter::addAdapterBasicBlocks(Loop * L, Instruction * SP, Value * Idx
   setSuccessor(CollectBB, DistBB);
   LoopSplitEdgeBlocks.push_back(CollectBB);
 
-  // General case: Find all edges from basic blocks above tophalf
-  // and connect it to CollectBB, use switch Inst
   IRBuilder<> Builder(&F->getEntryBlock().front());
   auto BrTgtArray = createArray(F, Builder.getInt32Ty(), 32 /*XXX Max Batch size*/);
 
@@ -42,23 +42,12 @@ void LoopSplitter::addAdapterBasicBlocks(Loop * L, Instruction * SP, Value * Idx
   auto BrVal = Builder.CreateLoad(BrValPtr);
   SwitchI = Builder.CreateSwitch(BrVal, BottomHalf);
 
-  // Handle diverge blocks
-  auto OldHeader = L->getHeader();
-  auto OldEntry = cast<BranchInst>(OldHeader->getTerminator())->getSuccessor(0);
-
-  SmallVector<BasicBlock *, 4> TopBlocks;
-  SmallVector<BasicBlock *, 4> BottomBlocks;
-  LoopBodyTraverser LBT (L);
-  LBT.traverse(TopBlocks, OldEntry, DistBB);
-  LBT.traverse(BottomBlocks, DistBB, L->getLoopLatch());
+  writeToAsmFile(*F->getParent());
 
   SmallVector<BasicBlock *, 4> DivergeBlocks;
-  for (auto & BB : TopBlocks) {
-    for (auto * Succ : successors(BB)) {
-      Succ->printAsOperand(errs());
-      if (std::find(BottomBlocks.begin(), BottomBlocks.end(), Succ) != BottomBlocks.end())
-        DivergeBlocks.push_back(BB);
-    }
+  auto DivergeBlock = TopHalf->getUniquePredecessor();
+  if (DivergeBlock != L->getHeader()) {
+    DivergeBlocks.push_back(DivergeBlock);
   }
 
   for (auto & DivergeBB : DivergeBlocks) {
@@ -115,24 +104,27 @@ void LoopSplitter::doLoopSplit(Function * F, Loop * L0, BasicBlock * SplitBlock)
   auto LBT = LoopBodyTraverser(L0);
 
   // Collect Blocks in range [OldEntry, MidBlock)
-  SmallVector<BasicBlock *, 4> TopLoopBlocks;
+  vector<BasicBlock *> TopLoopBlocks;
   LBT.traverse(TopLoopBlocks, OldEntry, MidBlock);
 
   // Collect Blocks in range [MidBlock, Latch)
-  SmallVector<BasicBlock *, 4> BottomLoopBlocks;
+  vector<BasicBlock *> BottomLoopBlocks;
   LBT.traverse(BottomLoopBlocks, MidBlock, L0->getLoopLatch());
 
   auto BottomLoop = IRLoop();
   BottomLoop.extractLoopSkeleton(L0);
 
   auto TopLoop = IRLoop();
-  TopLoop.constructEmptyLoop(getLoopTripCount(L0), BottomLoop.getHeader());
+  TopLoop.constructEmptyLoop(getLoopTripCount(L0), PreLoopBB ? PreLoopBB : BottomLoop.getHeader());
 
   TopLoop.setLoopBlocks(TopLoopBlocks);
   BottomLoop.setLoopBlocks(BottomLoopBlocks);
 
   setSuccessor(PreLoopBB, TopLoop.getPreHeader());
-  setSuccessor(TopLoop.getHeader(), BottomLoop.getHeader(), 1); 
+  // TODO Setting index value to 0 when entering new loop.
+  BasicBlock * BLoopEntry = BottomLoop.getPreHeader() == &F->getEntryBlock() ?
+                            BottomLoop.getHeader() : BottomLoop.getPreHeader();
+  setSuccessor(TopLoop.getHeader(), BLoopEntry, 1); 
   setSuccessor(BottomLoop.getHeader(), PostLoopBB, 1);
 
   /*
@@ -197,8 +189,6 @@ bool LoopSplitter::run() {
   bool changed = prepareForLoopSplit(F, L0, stat);
   if (!changed) return false;
 
-//  F->print(errs());
-
   DominatorTree DT (*F);
   LoopInfo NewLI (DT);
   L0 = *NewLI.begin();
@@ -207,7 +197,10 @@ bool LoopSplitter::run() {
     return false;
   }
   auto & SplitBB = LoopSplitEdgeBlocks.front();
-//  doLoopSplit(F, L0, SplitBB);
+
+  doLoopSplit(F, L0, SplitBB);
+
+  assert(stat.AnnotatedVarsSize == 1 && "Atleast one annotation must be there!");
 
   return true;
 }

src/Util.cpp

@@ -115,7 +115,6 @@ SmallVector<LoadInst *, 4> detectExpPtrUses(SmallVectorImpl<Value *> & Annotated
   for_each(AnnotatedVars, [&]
       (const auto & Var) { 
         auto FU = findEarliestPointerDerefInstruction(Var);
-        errs() << *FU << "\n";
         if (!FU) return;
         VarUsePoints.push_back(const_cast<LoadInst *>(FU));
       });
@@ -480,10 +479,11 @@ void visitSuccessor(SmallVectorImpl<BasicBlock *> & Blocks, BasicBlock * StartBl
   }
 }
 
-Value * getLoopTripCount(Loop * L0) {
+AllocaInst * getLoopTripCount(Loop * L0) {
   auto Header = L0->getHeader();
   auto Cond = cast<BranchInst>(Header->getTerminator())->getCondition();
-  return cast<ICmpInst>(Cond)->getOperand(1);
+  auto TCVal = cast<ICmpInst>(Cond)->getOperand(1);
+  return cast<AllocaInst>(cast<LoadInst>(TCVal)->getOperand(0));
 }
 
 BasicBlock * getPreLoopBlock(Loop * L) {

src/Util.h

@@ -112,7 +112,7 @@ void visitSuccessor(llvm::SmallVectorImpl<llvm::BasicBlock *> & Blocks,
                     llvm::BasicBlock * CurBlock,
                     llvm::BasicBlock * EndBlock);
 
-llvm::Value * getLoopTripCount(llvm::Loop * L0);
+llvm::AllocaInst * getLoopTripCount(llvm::Loop * L0);
 
 llvm::BasicBlock * getPreLoopBlock(llvm::Loop * L);
 

test/unittests/blockPredication_test.cpp

@@ -167,7 +167,6 @@ TEST_CASE("fast_flows_packet") {
   REQUIRE(M != nullptr);
   auto F = M->getFunction("fast_flows_packet");
 
-  errs() << "Running block predication\n";
   BlockPredication BP(F);
   BP.run();
 

test/unittests/loopSplitter_test.cpp

@@ -61,9 +61,8 @@ TEST_CASE("fn with single loop") {
   LoopSplitter LS(F, &LI);
   LS.run();
 
-  auto Stats = LS.getStats();
-  REQUIRE(Stats.AnnotatedVarsSize == 1);
-  REQUIRE(Stats.VarUsePointsSize == 1);
+  REQUIRE(LS.getStats().AnnotatedVarsSize == 1);
+  REQUIRE(LS.getStats().VarUsePointsSize == 1);
 
   //F->print(errs());
   auto asmFile = writeToAsmFile(*M);
@@ -76,3 +75,24 @@ TEST_CASE("fn with single loop") {
   auto ret = system(binary.c_str());
   REQUIRE(ret == 0);
 }
+
+TEST_CASE("fast_flows_packet loop split") {
+  std::string filePrefix = "fast_flows";
+  auto M = parseIR(generateIR(filePrefix + string(".c"), input_dir, true), input_dir);
+  REQUIRE(M != nullptr);
+  M->setSourceFileName(filePrefix + string("_batch.ll"));
+  {
+    std::string functionName = "fast_flows_packet";
+
+    auto F = M->getFunction(functionName);
+    DominatorTree DT(*F);
+    LoopInfo LI(DT);
+
+    LoopSplitter LS(F, &LI);
+    LS.run();
+
+    //F->print(errs());
+    auto asmFile = writeToAsmFile(*M);
+    auto TestObject = generateObject(asmFile);
+  }
+}

tools/tasopt.cpp

@@ -77,7 +77,6 @@ int main(int argc, char * argv[]) {
   for (auto & FnStr : FnLists) {
     if (FnStr.second.compare("tas_block_predicate") != 0) continue;
     // Block Predication
-    errs() << "Running block predication on " << FnStr.second << "\n";
     tas::BlockPredication BP(FnStr.first);
     auto res = BP.run();
     if (!res) {
@@ -90,6 +89,7 @@ int main(int argc, char * argv[]) {
     tas::BatchMaker BM(FnStr.first);
     auto BatchFunc = BM.run();
 
+    writeToAsmFile(*M);
     // Loop Splitting
     DominatorTree DT(*BatchFunc);
     LoopInfo LI(DT);