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https://github.com/c64scene-ar/llvm-6502.git
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running tail duplication when doing branch folding for if-conversion, and we also want to be able to run tail duplication earlier to fix some reg alloc problems. Move the CanFallThrough function from BranchFolding to MachineBasicBlock so that it can be shared by TailDuplication. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89904 91177308-0d34-0410-b5e6-96231b3b80d8
445 lines
18 KiB
C++
445 lines
18 KiB
C++
//===-- llvm/CodeGen/MachineBasicBlock.h ------------------------*- C++ -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// Collect the sequence of machine instructions for a basic block.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_CODEGEN_MACHINEBASICBLOCK_H
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#define LLVM_CODEGEN_MACHINEBASICBLOCK_H
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#include "llvm/CodeGen/MachineInstr.h"
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#include "llvm/ADT/GraphTraits.h"
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namespace llvm {
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class BasicBlock;
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class MachineFunction;
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class raw_ostream;
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template <>
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struct ilist_traits<MachineInstr> : public ilist_default_traits<MachineInstr> {
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private:
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mutable ilist_half_node<MachineInstr> Sentinel;
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// this is only set by the MachineBasicBlock owning the LiveList
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friend class MachineBasicBlock;
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MachineBasicBlock* Parent;
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public:
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MachineInstr *createSentinel() const {
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return static_cast<MachineInstr*>(&Sentinel);
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}
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void destroySentinel(MachineInstr *) const {}
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MachineInstr *provideInitialHead() const { return createSentinel(); }
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MachineInstr *ensureHead(MachineInstr*) const { return createSentinel(); }
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static void noteHead(MachineInstr*, MachineInstr*) {}
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void addNodeToList(MachineInstr* N);
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void removeNodeFromList(MachineInstr* N);
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void transferNodesFromList(ilist_traits &SrcTraits,
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ilist_iterator<MachineInstr> first,
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ilist_iterator<MachineInstr> last);
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void deleteNode(MachineInstr *N);
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private:
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void createNode(const MachineInstr &);
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};
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class MachineBasicBlock : public ilist_node<MachineBasicBlock> {
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typedef ilist<MachineInstr> Instructions;
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Instructions Insts;
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const BasicBlock *BB;
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int Number;
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MachineFunction *xParent;
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/// Predecessors/Successors - Keep track of the predecessor / successor
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/// basicblocks.
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std::vector<MachineBasicBlock *> Predecessors;
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std::vector<MachineBasicBlock *> Successors;
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/// LiveIns - Keep track of the physical registers that are livein of
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/// the basicblock.
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std::vector<unsigned> LiveIns;
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/// Alignment - Alignment of the basic block. Zero if the basic block does
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/// not need to be aligned.
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unsigned Alignment;
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/// IsLandingPad - Indicate that this basic block is entered via an
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/// exception handler.
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bool IsLandingPad;
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/// AddressTaken - Indicate that this basic block is potentially the
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/// target of an indirect branch.
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bool AddressTaken;
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// Intrusive list support
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MachineBasicBlock() {}
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explicit MachineBasicBlock(MachineFunction &mf, const BasicBlock *bb);
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~MachineBasicBlock();
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// MachineBasicBlocks are allocated and owned by MachineFunction.
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friend class MachineFunction;
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public:
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/// getBasicBlock - Return the LLVM basic block that this instance
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/// corresponded to originally. Note that this may be NULL if this instance
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/// does not correspond directly to an LLVM basic block.
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///
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const BasicBlock *getBasicBlock() const { return BB; }
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/// getName - Return the name of the corresponding LLVM basic block, or
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/// "(null)".
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StringRef getName() const;
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/// hasAddressTaken - Test whether this block is potentially the target
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/// of an indirect branch.
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bool hasAddressTaken() const { return AddressTaken; }
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/// setHasAddressTaken - Set this block to reflect that it potentially
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/// is the target of an indirect branch.
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void setHasAddressTaken() { AddressTaken = true; }
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/// getParent - Return the MachineFunction containing this basic block.
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///
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const MachineFunction *getParent() const { return xParent; }
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MachineFunction *getParent() { return xParent; }
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typedef Instructions::iterator iterator;
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typedef Instructions::const_iterator const_iterator;
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typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
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typedef std::reverse_iterator<iterator> reverse_iterator;
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unsigned size() const { return (unsigned)Insts.size(); }
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bool empty() const { return Insts.empty(); }
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MachineInstr& front() { return Insts.front(); }
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MachineInstr& back() { return Insts.back(); }
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const MachineInstr& front() const { return Insts.front(); }
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const MachineInstr& back() const { return Insts.back(); }
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iterator begin() { return Insts.begin(); }
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const_iterator begin() const { return Insts.begin(); }
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iterator end() { return Insts.end(); }
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const_iterator end() const { return Insts.end(); }
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reverse_iterator rbegin() { return Insts.rbegin(); }
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const_reverse_iterator rbegin() const { return Insts.rbegin(); }
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reverse_iterator rend () { return Insts.rend(); }
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const_reverse_iterator rend () const { return Insts.rend(); }
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// Machine-CFG iterators
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typedef std::vector<MachineBasicBlock *>::iterator pred_iterator;
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typedef std::vector<MachineBasicBlock *>::const_iterator const_pred_iterator;
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typedef std::vector<MachineBasicBlock *>::iterator succ_iterator;
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typedef std::vector<MachineBasicBlock *>::const_iterator const_succ_iterator;
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typedef std::vector<MachineBasicBlock *>::reverse_iterator
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pred_reverse_iterator;
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typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
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const_pred_reverse_iterator;
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typedef std::vector<MachineBasicBlock *>::reverse_iterator
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succ_reverse_iterator;
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typedef std::vector<MachineBasicBlock *>::const_reverse_iterator
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const_succ_reverse_iterator;
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pred_iterator pred_begin() { return Predecessors.begin(); }
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const_pred_iterator pred_begin() const { return Predecessors.begin(); }
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pred_iterator pred_end() { return Predecessors.end(); }
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const_pred_iterator pred_end() const { return Predecessors.end(); }
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pred_reverse_iterator pred_rbegin()
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{ return Predecessors.rbegin();}
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const_pred_reverse_iterator pred_rbegin() const
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{ return Predecessors.rbegin();}
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pred_reverse_iterator pred_rend()
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{ return Predecessors.rend(); }
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const_pred_reverse_iterator pred_rend() const
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{ return Predecessors.rend(); }
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unsigned pred_size() const {
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return (unsigned)Predecessors.size();
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}
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bool pred_empty() const { return Predecessors.empty(); }
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succ_iterator succ_begin() { return Successors.begin(); }
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const_succ_iterator succ_begin() const { return Successors.begin(); }
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succ_iterator succ_end() { return Successors.end(); }
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const_succ_iterator succ_end() const { return Successors.end(); }
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succ_reverse_iterator succ_rbegin()
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{ return Successors.rbegin(); }
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const_succ_reverse_iterator succ_rbegin() const
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{ return Successors.rbegin(); }
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succ_reverse_iterator succ_rend()
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{ return Successors.rend(); }
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const_succ_reverse_iterator succ_rend() const
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{ return Successors.rend(); }
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unsigned succ_size() const {
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return (unsigned)Successors.size();
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}
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bool succ_empty() const { return Successors.empty(); }
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// LiveIn management methods.
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/// addLiveIn - Add the specified register as a live in. Note that it
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/// is an error to add the same register to the same set more than once.
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void addLiveIn(unsigned Reg) { LiveIns.push_back(Reg); }
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/// removeLiveIn - Remove the specified register from the live in set.
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///
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void removeLiveIn(unsigned Reg);
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/// isLiveIn - Return true if the specified register is in the live in set.
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///
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bool isLiveIn(unsigned Reg) const;
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// Iteration support for live in sets. These sets are kept in sorted
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// order by their register number.
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typedef std::vector<unsigned>::iterator livein_iterator;
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typedef std::vector<unsigned>::const_iterator const_livein_iterator;
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livein_iterator livein_begin() { return LiveIns.begin(); }
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const_livein_iterator livein_begin() const { return LiveIns.begin(); }
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livein_iterator livein_end() { return LiveIns.end(); }
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const_livein_iterator livein_end() const { return LiveIns.end(); }
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bool livein_empty() const { return LiveIns.empty(); }
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/// getAlignment - Return alignment of the basic block.
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///
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unsigned getAlignment() const { return Alignment; }
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/// setAlignment - Set alignment of the basic block.
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///
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void setAlignment(unsigned Align) { Alignment = Align; }
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/// isLandingPad - Returns true if the block is a landing pad. That is
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/// this basic block is entered via an exception handler.
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bool isLandingPad() const { return IsLandingPad; }
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/// setIsLandingPad - Indicates the block is a landing pad. That is
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/// this basic block is entered via an exception handler.
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void setIsLandingPad() { IsLandingPad = true; }
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// Code Layout methods.
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/// moveBefore/moveAfter - move 'this' block before or after the specified
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/// block. This only moves the block, it does not modify the CFG or adjust
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/// potential fall-throughs at the end of the block.
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void moveBefore(MachineBasicBlock *NewAfter);
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void moveAfter(MachineBasicBlock *NewBefore);
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/// updateTerminator - Update the terminator instructions in block to account
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/// for changes to the layout. If the block previously used a fallthrough,
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/// it may now need a branch, and if it previously used branching it may now
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/// be able to use a fallthrough.
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void updateTerminator();
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// Machine-CFG mutators
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/// addSuccessor - Add succ as a successor of this MachineBasicBlock.
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/// The Predecessors list of succ is automatically updated.
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///
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void addSuccessor(MachineBasicBlock *succ);
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/// removeSuccessor - Remove successor from the successors list of this
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/// MachineBasicBlock. The Predecessors list of succ is automatically updated.
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///
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void removeSuccessor(MachineBasicBlock *succ);
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/// removeSuccessor - Remove specified successor from the successors list of
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/// this MachineBasicBlock. The Predecessors list of succ is automatically
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/// updated. Return the iterator to the element after the one removed.
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///
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succ_iterator removeSuccessor(succ_iterator I);
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/// transferSuccessors - Transfers all the successors from MBB to this
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/// machine basic block (i.e., copies all the successors fromMBB and
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/// remove all the successors from fromMBB).
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void transferSuccessors(MachineBasicBlock *fromMBB);
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/// isSuccessor - Return true if the specified MBB is a successor of this
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/// block.
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bool isSuccessor(const MachineBasicBlock *MBB) const;
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/// isLayoutSuccessor - Return true if the specified MBB will be emitted
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/// immediately after this block, such that if this block exits by
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/// falling through, control will transfer to the specified MBB. Note
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/// that MBB need not be a successor at all, for example if this block
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/// ends with an unconditional branch to some other block.
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bool isLayoutSuccessor(const MachineBasicBlock *MBB) const;
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/// canFallThrough - Return true if the block can implicitly transfer
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/// control to the block after it by falling off the end of it. This should
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/// return false if it can reach the block after it, but it uses an explicit
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/// branch to do so (e.g., a table jump). True is a conservative answer.
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bool canFallThrough();
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/// getFirstTerminator - returns an iterator to the first terminator
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/// instruction of this basic block. If a terminator does not exist,
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/// it returns end()
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iterator getFirstTerminator();
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/// isOnlyReachableViaFallthough - Return true if this basic block has
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/// exactly one predecessor and the control transfer mechanism between
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/// the predecessor and this block is a fall-through.
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bool isOnlyReachableByFallthrough() const;
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void pop_front() { Insts.pop_front(); }
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void pop_back() { Insts.pop_back(); }
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void push_back(MachineInstr *MI) { Insts.push_back(MI); }
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template<typename IT>
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void insert(iterator I, IT S, IT E) { Insts.insert(I, S, E); }
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iterator insert(iterator I, MachineInstr *M) { return Insts.insert(I, M); }
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// erase - Remove the specified element or range from the instruction list.
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// These functions delete any instructions removed.
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//
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iterator erase(iterator I) { return Insts.erase(I); }
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iterator erase(iterator I, iterator E) { return Insts.erase(I, E); }
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MachineInstr *remove(MachineInstr *I) { return Insts.remove(I); }
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void clear() { Insts.clear(); }
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/// splice - Take an instruction from MBB 'Other' at the position From,
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/// and insert it into this MBB right before 'where'.
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void splice(iterator where, MachineBasicBlock *Other, iterator From) {
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Insts.splice(where, Other->Insts, From);
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}
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/// splice - Take a block of instructions from MBB 'Other' in the range [From,
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/// To), and insert them into this MBB right before 'where'.
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void splice(iterator where, MachineBasicBlock *Other, iterator From,
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iterator To) {
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Insts.splice(where, Other->Insts, From, To);
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}
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/// removeFromParent - This method unlinks 'this' from the containing
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/// function, and returns it, but does not delete it.
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MachineBasicBlock *removeFromParent();
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/// eraseFromParent - This method unlinks 'this' from the containing
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/// function and deletes it.
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void eraseFromParent();
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/// ReplaceUsesOfBlockWith - Given a machine basic block that branched to
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/// 'Old', change the code and CFG so that it branches to 'New' instead.
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void ReplaceUsesOfBlockWith(MachineBasicBlock *Old, MachineBasicBlock *New);
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/// CorrectExtraCFGEdges - Various pieces of code can cause excess edges in
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/// the CFG to be inserted. If we have proven that MBB can only branch to
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/// DestA and DestB, remove any other MBB successors from the CFG. DestA and
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/// DestB can be null. Besides DestA and DestB, retain other edges leading
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/// to LandingPads (currently there can be only one; we don't check or require
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/// that here). Note it is possible that DestA and/or DestB are LandingPads.
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bool CorrectExtraCFGEdges(MachineBasicBlock *DestA,
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MachineBasicBlock *DestB,
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bool isCond);
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// Debugging methods.
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void dump() const;
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void print(raw_ostream &OS) const;
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/// getNumber - MachineBasicBlocks are uniquely numbered at the function
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/// level, unless they're not in a MachineFunction yet, in which case this
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/// will return -1.
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///
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int getNumber() const { return Number; }
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void setNumber(int N) { Number = N; }
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private: // Methods used to maintain doubly linked list of blocks...
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friend struct ilist_traits<MachineBasicBlock>;
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// Machine-CFG mutators
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/// addPredecessor - Remove pred as a predecessor of this MachineBasicBlock.
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/// Don't do this unless you know what you're doing, because it doesn't
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/// update pred's successors list. Use pred->addSuccessor instead.
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///
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void addPredecessor(MachineBasicBlock *pred);
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/// removePredecessor - Remove pred as a predecessor of this
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/// MachineBasicBlock. Don't do this unless you know what you're
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/// doing, because it doesn't update pred's successors list. Use
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/// pred->removeSuccessor instead.
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///
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void removePredecessor(MachineBasicBlock *pred);
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};
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raw_ostream& operator<<(raw_ostream &OS, const MachineBasicBlock &MBB);
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void WriteAsOperand(raw_ostream &, const MachineBasicBlock*, bool t);
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//===--------------------------------------------------------------------===//
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// GraphTraits specializations for machine basic block graphs (machine-CFGs)
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//===--------------------------------------------------------------------===//
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// Provide specializations of GraphTraits to be able to treat a
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// MachineFunction as a graph of MachineBasicBlocks...
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//
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template <> struct GraphTraits<MachineBasicBlock *> {
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typedef MachineBasicBlock NodeType;
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typedef MachineBasicBlock::succ_iterator ChildIteratorType;
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static NodeType *getEntryNode(MachineBasicBlock *BB) { return BB; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->succ_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->succ_end();
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}
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};
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template <> struct GraphTraits<const MachineBasicBlock *> {
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typedef const MachineBasicBlock NodeType;
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typedef MachineBasicBlock::const_succ_iterator ChildIteratorType;
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static NodeType *getEntryNode(const MachineBasicBlock *BB) { return BB; }
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->succ_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->succ_end();
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}
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};
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// Provide specializations of GraphTraits to be able to treat a
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// MachineFunction as a graph of MachineBasicBlocks... and to walk it
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// in inverse order. Inverse order for a function is considered
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// to be when traversing the predecessor edges of a MBB
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// instead of the successor edges.
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//
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template <> struct GraphTraits<Inverse<MachineBasicBlock*> > {
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typedef MachineBasicBlock NodeType;
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typedef MachineBasicBlock::pred_iterator ChildIteratorType;
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static NodeType *getEntryNode(Inverse<MachineBasicBlock *> G) {
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return G.Graph;
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}
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->pred_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->pred_end();
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}
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};
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template <> struct GraphTraits<Inverse<const MachineBasicBlock*> > {
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typedef const MachineBasicBlock NodeType;
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typedef MachineBasicBlock::const_pred_iterator ChildIteratorType;
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static NodeType *getEntryNode(Inverse<const MachineBasicBlock*> G) {
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return G.Graph;
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}
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static inline ChildIteratorType child_begin(NodeType *N) {
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return N->pred_begin();
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}
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static inline ChildIteratorType child_end(NodeType *N) {
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return N->pred_end();
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}
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};
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} // End llvm namespace
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#endif
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