1 //===-- TailDuplication.cpp - Duplicate blocks into predecessors' tails ---===// 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 // 10 // This pass duplicates basic blocks ending in unconditional branches into 11 // the tails of their predecessors, using the TailDuplicator utility class. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "llvm/CodeGen/MachineFunctionPass.h" 16 #include "llvm/CodeGen/Passes.h" 17 #include "llvm/CodeGen/TailDuplicator.h" 18 #include "llvm/IR/Function.h" 19 #include "llvm/Support/Debug.h" 20 using namespace llvm; 21 22 #define DEBUG_TYPE "tailduplication" 23 24 namespace { 25 /// Perform tail duplication. Delegates to TailDuplicator 26 class TailDuplicatePass : public MachineFunctionPass { 27 TailDuplicator Duplicator; 28 29 public: 30 static char ID; 31 explicit TailDuplicatePass() : MachineFunctionPass(ID) {} 32 33 bool runOnMachineFunction(MachineFunction &MF) override; 34 35 void getAnalysisUsage(AnalysisUsage &AU) const override; 36 }; 37 38 char TailDuplicatePass::ID = 0; 39 } 40 41 char &llvm::TailDuplicateID = TailDuplicatePass::ID; 42 43 INITIALIZE_PASS(TailDuplicatePass, "tailduplication", "Tail Duplication", false, 44 false) 45 46 bool TailDuplicatePass::runOnMachineFunction(MachineFunction &MF) { 47 if (skipFunction(*MF.getFunction())) 48 return false; 49 50 auto MMI = getAnalysisIfAvailable<MachineModuleInfo>(); 51 auto MBPI = &getAnalysis<MachineBranchProbabilityInfo>(); 52 53 Duplicator.initMF(MF, MMI, MBPI); 54 55 bool MadeChange = false; 56 while (Duplicator.tailDuplicateBlocks(MF)) 57 MadeChange = true; 58 59 return MadeChange; 60 } 61 62 void TailDuplicatePass::getAnalysisUsage(AnalysisUsage &AU) const { 63 AU.addRequired<MachineBranchProbabilityInfo>(); 64 MachineFunctionPass::getAnalysisUsage(AU); 65 } 66
