1 //===- NVPTXSplitBBatBar.cpp - Split BB at Barrier --*- C++ -*--===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // Split basic blocks so that a basic block that contains a barrier instruction 10 // only contains the barrier instruction. 11 // 12 //===----------------------------------------------------------------------===// 13 14 #include "llvm/Function.h" 15 #include "llvm/Instructions.h" 16 #include "llvm/Intrinsics.h" 17 #include "llvm/IntrinsicInst.h" 18 #include "llvm/Support/InstIterator.h" 19 #include "NVPTXUtilities.h" 20 #include "NVPTXSplitBBatBar.h" 21 22 using namespace llvm; 23 24 namespace llvm { 25 FunctionPass *createSplitBBatBarPass(); 26 } 27 28 char NVPTXSplitBBatBar::ID = 0; 29 30 bool NVPTXSplitBBatBar::runOnFunction(Function &F) { 31 32 SmallVector<Instruction *, 4> SplitPoints; 33 bool changed = false; 34 35 // Collect all the split points in SplitPoints 36 for (Function::iterator BI = F.begin(), BE = F.end(); BI != BE; ++BI) { 37 BasicBlock::iterator IB = BI->begin(); 38 BasicBlock::iterator II = IB; 39 BasicBlock::iterator IE = BI->end(); 40 41 // Skit the first intruction. No splitting is needed at this 42 // point even if this is a bar. 43 while (II != IE) { 44 if (IntrinsicInst *inst = dyn_cast<IntrinsicInst>(II)) { 45 Intrinsic::ID id = inst->getIntrinsicID(); 46 // If this is a barrier, split at this instruction 47 // and the next instruction. 48 if (llvm::isBarrierIntrinsic(id)) { 49 if (II != IB) 50 SplitPoints.push_back(II); 51 II++; 52 if ((II != IE) && (!II->isTerminator())) { 53 SplitPoints.push_back(II); 54 II++; 55 } 56 continue; 57 } 58 } 59 II++; 60 } 61 } 62 63 for (unsigned i = 0; i != SplitPoints.size(); i++) { 64 changed = true; 65 Instruction *inst = SplitPoints[i]; 66 inst->getParent()->splitBasicBlock(inst, "bar_split"); 67 } 68 69 return changed; 70 } 71 72 // This interface will most likely not be necessary, because this pass will 73 // not be invoked by the driver, but will be used as a prerequisite to 74 // another pass. 75 FunctionPass *llvm::createSplitBBatBarPass() { 76 return new NVPTXSplitBBatBar(); 77 } 78
