1 //===- TailDuplication.cpp - Duplicate blocks into predecessors' tails ----===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass duplicates basic blocks ending in unconditional branches into
11 // the tails of their predecessors, using the TailDuplicator utility class.
13 //===----------------------------------------------------------------------===//
15 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
16 #include "llvm/CodeGen/MachineFunction.h"
17 #include "llvm/CodeGen/MachineFunctionPass.h"
18 #include "llvm/CodeGen/TailDuplicator.h"
19 #include "llvm/Pass.h"
23 #define DEBUG_TYPE "tailduplication"
27 /// Perform tail duplication. Delegates to TailDuplicator
28 class TailDuplicatePass : public MachineFunctionPass {
29 TailDuplicator Duplicator;
34 explicit TailDuplicatePass() : MachineFunctionPass(ID) {}
36 bool runOnMachineFunction(MachineFunction &MF) override;
38 void getAnalysisUsage(AnalysisUsage &AU) const override;
41 } // end anonymous namespace
43 char TailDuplicatePass::ID = 0;
45 char &llvm::TailDuplicateID = TailDuplicatePass::ID;
47 INITIALIZE_PASS(TailDuplicatePass, DEBUG_TYPE, "Tail Duplication", false, false)
49 bool TailDuplicatePass::runOnMachineFunction(MachineFunction &MF) {
50 if (skipFunction(*MF.getFunction()))
53 auto MBPI = &getAnalysis<MachineBranchProbabilityInfo>();
55 Duplicator.initMF(MF, MBPI, /* LayoutMode */ false);
57 bool MadeChange = false;
58 while (Duplicator.tailDuplicateBlocks())
64 void TailDuplicatePass::getAnalysisUsage(AnalysisUsage &AU) const {
65 AU.addRequired<MachineBranchProbabilityInfo>();
66 MachineFunctionPass::getAnalysisUsage(AU);