void RegionGenerator::copyStmt(ScopStmt &Stmt, ValueMapT &GlobalMap, LoopToScevMapT <S) { assert(Stmt.isRegionStmt() && "Only region statements can be copied by the block generator"); // Forget all old mappings. BlockMap.clear(); RegionMaps.clear(); IncompletePHINodeMap.clear(); // The region represented by the statement. Region *R = Stmt.getRegion(); // Create a dedicated entry for the region where we can reload all demoted // inputs. BasicBlock *EntryBB = R->getEntry(); BasicBlock *EntryBBCopy = SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); EntryBBCopy->setName("polly.stmt." + EntryBB->getName() + ".entry"); Builder.SetInsertPoint(EntryBBCopy->begin()); for (auto PI = pred_begin(EntryBB), PE = pred_end(EntryBB); PI != PE; ++PI) if (!R->contains(*PI)) BlockMap[*PI] = EntryBBCopy; // Iterate over all blocks in the region in a breadth-first search. std::deque<BasicBlock *> Blocks; SmallPtrSet<BasicBlock *, 8> SeenBlocks; Blocks.push_back(EntryBB); SeenBlocks.insert(EntryBB); while (!Blocks.empty()) { BasicBlock *BB = Blocks.front(); Blocks.pop_front(); // First split the block and update dominance information. BasicBlock *BBCopy = splitBB(BB); BasicBlock *BBCopyIDom = repairDominance(BB, BBCopy); // In order to remap PHI nodes we store also basic block mappings. BlockMap[BB] = BBCopy; // Get the mapping for this block and initialize it with the mapping // available at its immediate dominator (in the new region). ValueMapT &RegionMap = RegionMaps[BBCopy]; RegionMap = RegionMaps[BBCopyIDom]; // Copy the block with the BlockGenerator. copyBB(Stmt, BB, BBCopy, RegionMap, GlobalMap, LTS); // In order to remap PHI nodes we store also basic block mappings. BlockMap[BB] = BBCopy; // Add values to incomplete PHI nodes waiting for this block to be copied. for (const PHINodePairTy &PHINodePair : IncompletePHINodeMap[BB]) addOperandToPHI(Stmt, PHINodePair.first, PHINodePair.second, BB, GlobalMap, LTS); IncompletePHINodeMap[BB].clear(); // And continue with new successors inside the region. for (auto SI = succ_begin(BB), SE = succ_end(BB); SI != SE; SI++) if (R->contains(*SI) && SeenBlocks.insert(*SI).second) Blocks.push_back(*SI); } // Now create a new dedicated region exit block and add it to the region map. BasicBlock *ExitBBCopy = SplitBlock(Builder.GetInsertBlock(), Builder.GetInsertPoint(), &DT, &LI); ExitBBCopy->setName("polly.stmt." + R->getExit()->getName() + ".exit"); BlockMap[R->getExit()] = ExitBBCopy; repairDominance(R->getExit(), ExitBBCopy); // As the block generator doesn't handle control flow we need to add the // region control flow by hand after all blocks have been copied. for (BasicBlock *BB : SeenBlocks) { BranchInst *BI = cast<BranchInst>(BB->getTerminator()); BasicBlock *BBCopy = BlockMap[BB]; Instruction *BICopy = BBCopy->getTerminator(); ValueMapT &RegionMap = RegionMaps[BBCopy]; RegionMap.insert(BlockMap.begin(), BlockMap.end()); Builder.SetInsertPoint(BBCopy); copyInstScalar(Stmt, BI, RegionMap, GlobalMap, LTS); BICopy->eraseFromParent(); } // Add counting PHI nodes to all loops in the region that can be used as // replacement for SCEVs refering to the old loop. for (BasicBlock *BB : SeenBlocks) { Loop *L = LI.getLoopFor(BB); if (L == nullptr || L->getHeader() != BB) continue; BasicBlock *BBCopy = BlockMap[BB]; Value *NullVal = Builder.getInt32(0); PHINode *LoopPHI = PHINode::Create(Builder.getInt32Ty(), 2, "polly.subregion.iv"); Instruction *LoopPHIInc = BinaryOperator::CreateAdd( LoopPHI, Builder.getInt32(1), "polly.subregion.iv.inc"); LoopPHI->insertBefore(BBCopy->begin()); LoopPHIInc->insertBefore(BBCopy->getTerminator()); for (auto *PredBB : make_range(pred_begin(BB), pred_end(BB))) { if (!R->contains(PredBB)) continue; if (L->contains(PredBB)) LoopPHI->addIncoming(LoopPHIInc, BlockMap[PredBB]); else LoopPHI->addIncoming(NullVal, BlockMap[PredBB]); } for (auto *PredBBCopy : make_range(pred_begin(BBCopy), pred_end(BBCopy))) if (LoopPHI->getBasicBlockIndex(PredBBCopy) < 0) LoopPHI->addIncoming(NullVal, PredBBCopy); LTS[L] = SE.getUnknown(LoopPHI); } // Add all mappings from the region to the global map so outside uses will use // the copied instructions. for (auto &BBMap : RegionMaps) GlobalMap.insert(BBMap.second.begin(), BBMap.second.end()); // Reset the old insert point for the build. Builder.SetInsertPoint(ExitBBCopy->begin()); }