1239310Sdim//===- NVPTXLowerAggrCopies.cpp - ------------------------------*- C++ -*--===// 2239310Sdim// 3239310Sdim// The LLVM Compiler Infrastructure 4239310Sdim// 5239310Sdim// This file is distributed under the University of Illinois Open Source 6239310Sdim// License. See LICENSE.TXT for details. 7239310Sdim// 8239310Sdim//===----------------------------------------------------------------------===// 9239310Sdim// Lower aggregate copies, memset, memcpy, memmov intrinsics into loops when 10239310Sdim// the size is large or is not a compile-time constant. 11239310Sdim// 12239310Sdim//===----------------------------------------------------------------------===// 13239310Sdim 14239310Sdim#include "NVPTXLowerAggrCopies.h" 15249423Sdim#include "llvm/IR/Constants.h" 16249423Sdim#include "llvm/IR/DataLayout.h" 17249423Sdim#include "llvm/IR/Function.h" 18249423Sdim#include "llvm/IR/IRBuilder.h" 19249423Sdim#include "llvm/IR/Instructions.h" 20249423Sdim#include "llvm/IR/IntrinsicInst.h" 21249423Sdim#include "llvm/IR/Intrinsics.h" 22249423Sdim#include "llvm/IR/LLVMContext.h" 23249423Sdim#include "llvm/IR/Module.h" 24239310Sdim#include "llvm/Support/InstIterator.h" 25239310Sdim 26239310Sdimusing namespace llvm; 27239310Sdim 28249423Sdimnamespace llvm { FunctionPass *createLowerAggrCopies(); } 29239310Sdim 30239310Sdimchar NVPTXLowerAggrCopies::ID = 0; 31239310Sdim 32239310Sdim// Lower MemTransferInst or load-store pair to loop 33249423Sdimstatic void convertTransferToLoop( 34249423Sdim Instruction *splitAt, Value *srcAddr, Value *dstAddr, Value *len, 35249423Sdim //unsigned numLoads, 36249423Sdim bool srcVolatile, bool dstVolatile, LLVMContext &Context, Function &F) { 37239310Sdim Type *indType = len->getType(); 38239310Sdim 39239310Sdim BasicBlock *origBB = splitAt->getParent(); 40239310Sdim BasicBlock *newBB = splitAt->getParent()->splitBasicBlock(splitAt, "split"); 41239310Sdim BasicBlock *loopBB = BasicBlock::Create(Context, "loadstoreloop", &F, newBB); 42239310Sdim 43239310Sdim origBB->getTerminator()->setSuccessor(0, loopBB); 44239310Sdim IRBuilder<> builder(origBB, origBB->getTerminator()); 45239310Sdim 46239310Sdim // srcAddr and dstAddr are expected to be pointer types, 47239310Sdim // so no check is made here. 48249423Sdim unsigned srcAS = dyn_cast<PointerType>(srcAddr->getType())->getAddressSpace(); 49249423Sdim unsigned dstAS = dyn_cast<PointerType>(dstAddr->getType())->getAddressSpace(); 50239310Sdim 51239310Sdim // Cast pointers to (char *) 52239310Sdim srcAddr = builder.CreateBitCast(srcAddr, Type::getInt8PtrTy(Context, srcAS)); 53239310Sdim dstAddr = builder.CreateBitCast(dstAddr, Type::getInt8PtrTy(Context, dstAS)); 54239310Sdim 55239310Sdim IRBuilder<> loop(loopBB); 56239310Sdim // The loop index (ind) is a phi node. 57239310Sdim PHINode *ind = loop.CreatePHI(indType, 0); 58239310Sdim // Incoming value for ind is 0 59239310Sdim ind->addIncoming(ConstantInt::get(indType, 0), origBB); 60239310Sdim 61239310Sdim // load from srcAddr+ind 62239310Sdim Value *val = loop.CreateLoad(loop.CreateGEP(srcAddr, ind), srcVolatile); 63239310Sdim // store at dstAddr+ind 64239310Sdim loop.CreateStore(val, loop.CreateGEP(dstAddr, ind), dstVolatile); 65239310Sdim 66239310Sdim // The value for ind coming from backedge is (ind + 1) 67239310Sdim Value *newind = loop.CreateAdd(ind, ConstantInt::get(indType, 1)); 68239310Sdim ind->addIncoming(newind, loopBB); 69239310Sdim 70239310Sdim loop.CreateCondBr(loop.CreateICmpULT(newind, len), loopBB, newBB); 71239310Sdim} 72239310Sdim 73239310Sdim// Lower MemSetInst to loop 74239310Sdimstatic void convertMemSetToLoop(Instruction *splitAt, Value *dstAddr, 75239310Sdim Value *len, Value *val, LLVMContext &Context, 76239310Sdim Function &F) { 77239310Sdim BasicBlock *origBB = splitAt->getParent(); 78239310Sdim BasicBlock *newBB = splitAt->getParent()->splitBasicBlock(splitAt, "split"); 79239310Sdim BasicBlock *loopBB = BasicBlock::Create(Context, "loadstoreloop", &F, newBB); 80239310Sdim 81239310Sdim origBB->getTerminator()->setSuccessor(0, loopBB); 82239310Sdim IRBuilder<> builder(origBB, origBB->getTerminator()); 83239310Sdim 84249423Sdim unsigned dstAS = dyn_cast<PointerType>(dstAddr->getType())->getAddressSpace(); 85239310Sdim 86239310Sdim // Cast pointer to the type of value getting stored 87249423Sdim dstAddr = 88249423Sdim builder.CreateBitCast(dstAddr, PointerType::get(val->getType(), dstAS)); 89239310Sdim 90239310Sdim IRBuilder<> loop(loopBB); 91239310Sdim PHINode *ind = loop.CreatePHI(len->getType(), 0); 92239310Sdim ind->addIncoming(ConstantInt::get(len->getType(), 0), origBB); 93239310Sdim 94239310Sdim loop.CreateStore(val, loop.CreateGEP(dstAddr, ind), false); 95239310Sdim 96239310Sdim Value *newind = loop.CreateAdd(ind, ConstantInt::get(len->getType(), 1)); 97239310Sdim ind->addIncoming(newind, loopBB); 98239310Sdim 99239310Sdim loop.CreateCondBr(loop.CreateICmpULT(newind, len), loopBB, newBB); 100239310Sdim} 101239310Sdim 102239310Sdimbool NVPTXLowerAggrCopies::runOnFunction(Function &F) { 103239310Sdim SmallVector<LoadInst *, 4> aggrLoads; 104239310Sdim SmallVector<MemTransferInst *, 4> aggrMemcpys; 105239310Sdim SmallVector<MemSetInst *, 4> aggrMemsets; 106239310Sdim 107243830Sdim DataLayout *TD = &getAnalysis<DataLayout>(); 108239310Sdim LLVMContext &Context = F.getParent()->getContext(); 109239310Sdim 110239310Sdim // 111239310Sdim // Collect all the aggrLoads, aggrMemcpys and addrMemsets. 112239310Sdim // 113239310Sdim //const BasicBlock *firstBB = &F.front(); // first BB in F 114239310Sdim for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) { 115239310Sdim //BasicBlock *bb = BI; 116239310Sdim for (BasicBlock::iterator II = BI->begin(), IE = BI->end(); II != IE; 117249423Sdim ++II) { 118249423Sdim if (LoadInst *load = dyn_cast<LoadInst>(II)) { 119239310Sdim 120249423Sdim if (load->hasOneUse() == false) 121249423Sdim continue; 122239310Sdim 123249423Sdim if (TD->getTypeStoreSize(load->getType()) < MaxAggrCopySize) 124249423Sdim continue; 125239310Sdim 126239310Sdim User *use = *(load->use_begin()); 127249423Sdim if (StoreInst *store = dyn_cast<StoreInst>(use)) { 128239310Sdim if (store->getOperand(0) != load) //getValueOperand 129249423Sdim continue; 130239310Sdim aggrLoads.push_back(load); 131239310Sdim } 132249423Sdim } else if (MemTransferInst *intr = dyn_cast<MemTransferInst>(II)) { 133239310Sdim Value *len = intr->getLength(); 134239310Sdim // If the number of elements being copied is greater 135239310Sdim // than MaxAggrCopySize, lower it to a loop 136249423Sdim if (ConstantInt *len_int = dyn_cast<ConstantInt>(len)) { 137239310Sdim if (len_int->getZExtValue() >= MaxAggrCopySize) { 138239310Sdim aggrMemcpys.push_back(intr); 139239310Sdim } 140239310Sdim } else { 141239310Sdim // turn variable length memcpy/memmov into loop 142239310Sdim aggrMemcpys.push_back(intr); 143239310Sdim } 144249423Sdim } else if (MemSetInst *memsetintr = dyn_cast<MemSetInst>(II)) { 145239310Sdim Value *len = memsetintr->getLength(); 146249423Sdim if (ConstantInt *len_int = dyn_cast<ConstantInt>(len)) { 147239310Sdim if (len_int->getZExtValue() >= MaxAggrCopySize) { 148239310Sdim aggrMemsets.push_back(memsetintr); 149239310Sdim } 150239310Sdim } else { 151239310Sdim // turn variable length memset into loop 152239310Sdim aggrMemsets.push_back(memsetintr); 153239310Sdim } 154239310Sdim } 155239310Sdim } 156239310Sdim } 157249423Sdim if ((aggrLoads.size() == 0) && (aggrMemcpys.size() == 0) && 158249423Sdim (aggrMemsets.size() == 0)) 159249423Sdim return false; 160239310Sdim 161239310Sdim // 162239310Sdim // Do the transformation of an aggr load/copy/set to a loop 163239310Sdim // 164239310Sdim for (unsigned i = 0, e = aggrLoads.size(); i != e; ++i) { 165239310Sdim LoadInst *load = aggrLoads[i]; 166239310Sdim StoreInst *store = dyn_cast<StoreInst>(*load->use_begin()); 167239310Sdim Value *srcAddr = load->getOperand(0); 168239310Sdim Value *dstAddr = store->getOperand(1); 169239310Sdim unsigned numLoads = TD->getTypeStoreSize(load->getType()); 170239310Sdim Value *len = ConstantInt::get(Type::getInt32Ty(Context), numLoads); 171239310Sdim 172239310Sdim convertTransferToLoop(store, srcAddr, dstAddr, len, load->isVolatile(), 173239310Sdim store->isVolatile(), Context, F); 174239310Sdim 175239310Sdim store->eraseFromParent(); 176239310Sdim load->eraseFromParent(); 177239310Sdim } 178239310Sdim 179239310Sdim for (unsigned i = 0, e = aggrMemcpys.size(); i != e; ++i) { 180239310Sdim MemTransferInst *cpy = aggrMemcpys[i]; 181239310Sdim Value *len = cpy->getLength(); 182239310Sdim // llvm 2.7 version of memcpy does not have volatile 183239310Sdim // operand yet. So always making it non-volatile 184239310Sdim // optimistically, so that we don't see unnecessary 185239310Sdim // st.volatile in ptx 186239310Sdim convertTransferToLoop(cpy, cpy->getSource(), cpy->getDest(), len, false, 187239310Sdim false, Context, F); 188239310Sdim cpy->eraseFromParent(); 189239310Sdim } 190239310Sdim 191239310Sdim for (unsigned i = 0, e = aggrMemsets.size(); i != e; ++i) { 192239310Sdim MemSetInst *memsetinst = aggrMemsets[i]; 193239310Sdim Value *len = memsetinst->getLength(); 194239310Sdim Value *val = memsetinst->getValue(); 195239310Sdim convertMemSetToLoop(memsetinst, memsetinst->getDest(), len, val, Context, 196239310Sdim F); 197239310Sdim memsetinst->eraseFromParent(); 198239310Sdim } 199239310Sdim 200239310Sdim return true; 201239310Sdim} 202239310Sdim 203239310SdimFunctionPass *llvm::createLowerAggrCopies() { 204239310Sdim return new NVPTXLowerAggrCopies(); 205239310Sdim} 206