LLVM: lib/CodeGen/DeadMachineInstructionElim.cpp Source File (original) (raw)
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25using namespace llvm;
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27#define DEBUG_TYPE "dead-mi-elimination"
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29STATISTIC(NumDeletes, "Number of dead instructions deleted");
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31namespace {
32class DeadMachineInstructionElimImpl {
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37public:
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40private:
42};
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45public:
46 static char ID;
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48 DeadMachineInstructionElim() : MachineFunctionPass(ID) {
50 }
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52 bool runOnMachineFunction(MachineFunction &MF) override {
54 return false;
55 return DeadMachineInstructionElimImpl().runImpl(MF);
56 }
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58 void getAnalysisUsage(AnalysisUsage &AU) const override {
61 }
62};
63}
64
68 if (!DeadMachineInstructionElimImpl().runImpl(MF))
72 return PA;
73}
74
75char DeadMachineInstructionElim::ID = 0;
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79 "Remove dead machine instructions", false, false)
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82 MRI = &MF.getRegInfo();
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85 TII = ST.getInstrInfo();
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88 bool AnyChanges = eliminateDeadMI(MF);
89 while (AnyChanges && eliminateDeadMI(MF))
90 ;
91 return AnyChanges;
92}
93
94bool DeadMachineInstructionElimImpl::eliminateDeadMI(MachineFunction &MF) {
95 bool AnyChanges = false;
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108 LLVM_DEBUG(dbgs() << "DeadMachineInstructionElim: DELETING: " << MI);
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112 MI.eraseFromParent();
113 AnyChanges = true;
114 ++NumDeletes;
115 continue;
116 }
118 }
119 }
121 return AnyChanges;
122}
unsigned const MachineRegisterInfo * MRI
const TargetInstrInfo & TII
static bool runImpl(Function &F, const TargetLowering &TLI, const LibcallLoweringInfo &Libcalls, AssumptionCache *AC)
#define INITIALIZE_PASS(passName, arg, name, cfg, analysis)
This file builds on the ADT/GraphTraits.h file to build a generic graph post order iterator.
This file defines the 'Statistic' class, which is designed to be an easy way to expose various metric...
#define STATISTIC(VARNAME, DESC)
LLVM_ABI void setPreservesCFG()
This function should be called by the pass, iff they do not:
Represents analyses that only rely on functions' control flow.
PreservedAnalyses run(MachineFunction &MF, MachineFunctionAnalysisManager &MFAM)
Definition DeadMachineInstructionElim.cpp:66
A set of physical registers with utility functions to track liveness when walking backward/forward th...
void clear()
Clears the set.
void stepBackward(const MachineInstr &MI)
Simulates liveness when stepping backwards over an instruction(bundle).
void init(const TargetRegisterInfo &TRI)
(re-)initializes and clears the set.
void addLiveOuts(const MachineBasicBlock &MBB)
Adds all live-out registers of basic block MBB.
A set of register units used to track register liveness.
MachineFunctionPass - This class adapts the FunctionPass interface to allow convenient creation of pa...
void getAnalysisUsage(AnalysisUsage &AU) const override
getAnalysisUsage - Subclasses that override getAnalysisUsage must call this.
Function & getFunction()
Return the LLVM function that this machine code represents.
Representation of each machine instruction.
MachineRegisterInfo - Keep track of information for virtual and physical registers,...
static LLVM_ABI PassRegistry * getPassRegistry()
getPassRegistry - Access the global registry object, which is automatically initialized at applicatio...
A set of analyses that are preserved following a run of a transformation pass.
static PreservedAnalyses all()
Construct a special preserved set that preserves all passes.
PreservedAnalyses & preserveSet()
Mark an analysis set as preserved.
TargetInstrInfo - Interface to description of machine instruction set.
TargetSubtargetInfo - Generic base class for all target subtargets.
This is an optimization pass for GlobalISel generic memory operations.
iterator_range< early_inc_iterator_impl< detail::IterOfRange< RangeT > > > make_early_inc_range(RangeT &&Range)
Make a range that does early increment to allow mutation of the underlying range without disrupting i...
iterator_range< po_iterator< T > > post_order(const T &G)
AnalysisManager< MachineFunction > MachineFunctionAnalysisManager
LLVM_ABI PreservedAnalyses getMachineFunctionPassPreservedAnalyses()
Returns the minimum set of Analyses that all machine function passes must preserve.
auto reverse(ContainerTy &&C)
LLVM_ABI raw_ostream & dbgs()
dbgs() - This returns a reference to a raw_ostream for debugging messages.
LLVM_ABI void initializeDeadMachineInstructionElimPass(PassRegistry &)
LLVM_ABI char & DeadMachineInstructionElimID
DeadMachineInstructionElim - This pass removes dead machine instructions.
Definition DeadMachineInstructionElim.cpp:76