LLVM  14.0.0git
Macros | Typedefs | Functions | Variables
PeepholeOptimizer.cpp File Reference
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/CodeGen/MachineBasicBlock.h"
#include "llvm/CodeGen/MachineDominators.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/MachineFunctionPass.h"
#include "llvm/CodeGen/MachineInstr.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineLoopInfo.h"
#include "llvm/CodeGen/MachineOperand.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/CodeGen/TargetInstrInfo.h"
#include "llvm/CodeGen/TargetOpcodes.h"
#include "llvm/CodeGen/TargetRegisterInfo.h"
#include "llvm/CodeGen/TargetSubtargetInfo.h"
#include "llvm/InitializePasses.h"
#include "llvm/MC/LaneBitmask.h"
#include "llvm/MC/MCInstrDesc.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/raw_ostream.h"
#include <cassert>
#include <cstdint>
#include <memory>
#include <utility>
Include dependency graph for PeepholeOptimizer.cpp:

Go to the source code of this file.

Macros

#define DEBUG_TYPE   "peephole-opt"
 

Typedefs

using RegSubRegPair = TargetInstrInfo::RegSubRegPair
 
using RegSubRegPairAndIdx = TargetInstrInfo::RegSubRegPairAndIdx
 

Functions

 STATISTIC (NumReuse, "Number of extension results reused")
 
 STATISTIC (NumCmps, "Number of compares eliminated")
 
 STATISTIC (NumImmFold, "Number of move immediate folded")
 
 STATISTIC (NumLoadFold, "Number of loads folded")
 
 STATISTIC (NumSelects, "Number of selects optimized")
 
 STATISTIC (NumUncoalescableCopies, "Number of uncoalescable copies optimized")
 
 STATISTIC (NumRewrittenCopies, "Number of copies rewritten")
 
 STATISTIC (NumNAPhysCopies, "Number of non-allocatable physical copies removed")
 
 INITIALIZE_PASS_BEGIN (PeepholeOptimizer, DEBUG_TYPE, "Peephole Optimizations", false, false) INITIALIZE_PASS_END(PeepholeOptimizer
 
static MachineInstrinsertPHI (MachineRegisterInfo &MRI, const TargetInstrInfo &TII, const SmallVectorImpl< RegSubRegPair > &SrcRegs, MachineInstr &OrigPHI)
 Insert a PHI instruction with incoming edges SrcRegs that are guaranteed to have the same register class. More...
 
static RewritergetCopyRewriter (MachineInstr &MI, const TargetInstrInfo &TII)
 Get the appropriated Rewriter for MI. More...
 
static RegSubRegPair getNewSource (MachineRegisterInfo *MRI, const TargetInstrInfo *TII, RegSubRegPair Def, const PeepholeOptimizer::RewriteMapTy &RewriteMap, bool HandleMultipleSources=true)
 Given a Def.Reg and Def.SubReg pair, use RewriteMap to find the new source to use for rewrite. More...
 
static bool isVirtualRegisterOperand (MachineOperand &MO)
 \bried Returns true if MO is a virtual register operand. More...
 

Variables

static cl::opt< bool > Aggressive ("aggressive-ext-opt", cl::Hidden, cl::desc("Aggressive extension optimization"))
 
static cl::opt< bool > DisablePeephole ("disable-peephole", cl::Hidden, cl::init(false), cl::desc("Disable the peephole optimizer"))
 
static cl::opt< bool > DisableAdvCopyOpt ("disable-adv-copy-opt", cl::Hidden, cl::init(false), cl::desc("Disable advanced copy optimization"))
 Specifiy whether or not the value tracking looks through complex instructions. More...
 
static cl::opt< bool > DisableNAPhysCopyOpt ("disable-non-allocatable-phys-copy-opt", cl::Hidden, cl::init(false), cl::desc("Disable non-allocatable physical register copy optimization"))
 
static cl::opt< unsigned > RewritePHILimit ("rewrite-phi-limit", cl::Hidden, cl::init(10), cl::desc("Limit the length of PHI chains to lookup"))
 
static cl::opt< unsigned > MaxRecurrenceChain ("recurrence-chain-limit", cl::Hidden, cl::init(3), cl::desc("Maximum length of recurrence chain when evaluating the benefit " "of commuting operands"))
 
 DEBUG_TYPE
 
Peephole Optimizations
 
Peephole false
 

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE   "peephole-opt"

Definition at line 104 of file PeepholeOptimizer.cpp.

Typedef Documentation

◆ RegSubRegPair

Definition at line 101 of file PeepholeOptimizer.cpp.

◆ RegSubRegPairAndIdx

Definition at line 102 of file PeepholeOptimizer.cpp.

Function Documentation

◆ getCopyRewriter()

static Rewriter* getCopyRewriter ( MachineInstr MI,
const TargetInstrInfo TII 
)
static

Get the appropriated Rewriter for MI.

Returns
A pointer to a dynamically allocated Rewriter or nullptr if no rewriter works for MI.

Definition at line 1105 of file PeepholeOptimizer.cpp.

References MI, and TII.

◆ getNewSource()

static RegSubRegPair getNewSource ( MachineRegisterInfo MRI,
const TargetInstrInfo TII,
RegSubRegPair  Def,
const PeepholeOptimizer::RewriteMapTy RewriteMap,
bool  HandleMultipleSources = true 
)
static

Given a Def.Reg and Def.SubReg pair, use RewriteMap to find the new source to use for rewrite.

If HandleMultipleSources is true and multiple sources for a given Def are found along the way, we found a PHI instructions that needs to be rewritten. TODO: HandleMultipleSources should be removed once we test PHI handling with coalescable copies.

Definition at line 1132 of file PeepholeOptimizer.cpp.

References llvm::dbgs(), llvm::tgtok::Def, llvm::MachineInstr::getOperand(), llvm::MachineOperand::getReg(), llvm::MachineOperand::getSubReg(), i, insertPHI(), LLVM_DEBUG, llvm::DenseMapBase< DerivedT, KeyT, ValueT, KeyInfoT, BucketT >::lookup(), MRI, llvm::TargetInstrInfo::RegSubRegPair::Reg, llvm::TargetInstrInfo::RegSubRegPair::SubReg, and TII.

◆ INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN ( PeepholeOptimizer  ,
DEBUG_TYPE  ,
"Peephole Optimizations ,
false  ,
false   
)

◆ insertPHI()

static MachineInstr& insertPHI ( MachineRegisterInfo MRI,
const TargetInstrInfo TII,
const SmallVectorImpl< RegSubRegPair > &  SrcRegs,
MachineInstr OrigPHI 
)
static

Insert a PHI instruction with incoming edges SrcRegs that are guaranteed to have the same register class.

This is necessary whenever we successfully traverse a PHI instruction and find suitable sources coming from its edges. By inserting a new PHI, we provide a rewritten PHI def suitable to be used in a new COPY instruction.

Definition at line 776 of file PeepholeOptimizer.cpp.

References llvm::MachineInstrBuilder::addMBB(), llvm::MachineInstrBuilder::addReg(), assert(), llvm::BuildMI(), llvm::MachineRegisterInfo::clearKillFlags(), llvm::MachineRegisterInfo::createVirtualRegister(), llvm::MachineInstr::getDebugLoc(), llvm::MachineOperand::getMBB(), llvm::MachineInstr::getOperand(), llvm::MachineInstr::getParent(), llvm::MachineRegisterInfo::getRegClass(), MBB, MRI, Reg, SubReg, and TII.

Referenced by getNewSource().

◆ isVirtualRegisterOperand()

static bool isVirtualRegisterOperand ( MachineOperand MO)
static

\bried Returns true if MO is a virtual register operand.

Definition at line 1503 of file PeepholeOptimizer.cpp.

References llvm::MachineOperand::getReg(), llvm::MachineOperand::isReg(), and llvm::Register::isVirtual().

◆ STATISTIC() [1/8]

STATISTIC ( NumCmps  ,
"Number of compares eliminated"   
)

◆ STATISTIC() [2/8]

STATISTIC ( NumImmFold  ,
"Number of move immediate folded"   
)

◆ STATISTIC() [3/8]

STATISTIC ( NumLoadFold  ,
"Number of loads folded"   
)

◆ STATISTIC() [4/8]

STATISTIC ( NumNAPhysCopies  ,
"Number of non-allocatable physical copies removed  
)

◆ STATISTIC() [5/8]

STATISTIC ( NumReuse  ,
"Number of extension results reused"   
)

◆ STATISTIC() [6/8]

STATISTIC ( NumRewrittenCopies  ,
"Number of copies rewritten  
)

◆ STATISTIC() [7/8]

STATISTIC ( NumSelects  ,
"Number of selects optimized"   
)

◆ STATISTIC() [8/8]

STATISTIC ( NumUncoalescableCopies  ,
"Number of uncoalescable copies optimized"   
)

Variable Documentation

◆ Aggressive

cl::opt<bool> Aggressive("aggressive-ext-opt", cl::Hidden, cl::desc("Aggressive extension optimization"))
static

◆ DEBUG_TYPE

DEBUG_TYPE

Definition at line 449 of file PeepholeOptimizer.cpp.

◆ DisableAdvCopyOpt

cl::opt<bool> DisableAdvCopyOpt("disable-adv-copy-opt", cl::Hidden, cl::init(false), cl::desc("Disable advanced copy optimization"))
static

Specifiy whether or not the value tracking looks through complex instructions.

When this is true, the value tracker bails on everything that is not a copy or a bitcast.

◆ DisableNAPhysCopyOpt

cl::opt<bool> DisableNAPhysCopyOpt("disable-non-allocatable-phys-copy-opt", cl::Hidden, cl::init(false), cl::desc("Disable non-allocatable physical register copy optimization"))
static

◆ DisablePeephole

cl::opt<bool> DisablePeephole("disable-peephole", cl::Hidden, cl::init(false), cl::desc("Disable the peephole optimizer"))
static

◆ false

Peephole false

Definition at line 450 of file PeepholeOptimizer.cpp.

◆ MaxRecurrenceChain

cl::opt<unsigned> MaxRecurrenceChain("recurrence-chain-limit", cl::Hidden, cl::init(3), cl::desc("Maximum length of recurrence chain when evaluating the benefit " "of commuting operands"))
static

◆ Optimizations

Peephole Optimizations

Definition at line 450 of file PeepholeOptimizer.cpp.

◆ RewritePHILimit

cl::opt<unsigned> RewritePHILimit("rewrite-phi-limit", cl::Hidden, cl::init(10), cl::desc("Limit the length of PHI chains to lookup"))
static