MemCpyOptimizer.cpp File Reference

#include "llvm/Transforms/Scalar/MemCpyOptimizer.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/ScopeExit.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CFG.h"
#include "llvm/Analysis/CaptureTracking.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/Loads.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Analysis/MemorySSA.h"
#include "llvm/Analysis/MemorySSAUpdater.h"
#include "llvm/Analysis/PostDominators.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstrTypes.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/PassManager.h"
#include "llvm/IR/Type.h"
#include "llvm/IR/User.h"
#include "llvm/IR/Value.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Utils/Local.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
#include <optional>

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "memcpyopt"

Functions
	STATISTIC (NumMemCpyInstr, "Number of memcpy instructions deleted")
	STATISTIC (NumMemMoveInstr, "Number of memmove instructions deleted")
	STATISTIC (NumMemSetInfer, "Number of memsets inferred")
	STATISTIC (NumMoveToCpy, "Number of memmoves converted to memcpy")
	STATISTIC (NumCpyToSet, "Number of memcpys converted to memset")
	STATISTIC (NumCallSlot, "Number of call slot optimizations performed")
	STATISTIC (NumStackMove, "Number of stack-move optimizations performed")
static bool	overreadUndefContents (MemorySSA *MSSA, MemCpyInst *MemCpy, MemIntrinsic *MemSrc, BatchAAResults &BAA)
static bool	mayBeVisibleThroughUnwinding (Value *V, Instruction *Start, Instruction *End)
static bool	accessedBetween (BatchAAResults &AA, MemoryLocation Loc, const MemoryUseOrDef *Start, const MemoryUseOrDef *End, Instruction **SkippedLifetimeStart=nullptr)
static bool	writtenBetween (MemorySSA *MSSA, BatchAAResults &AA, MemoryLocation Loc, const MemoryUseOrDef *Start, const MemoryUseOrDef *End)
static bool	hasUndefContents (MemorySSA *MSSA, BatchAAResults &AA, Value *V, MemoryDef *Def)
	Determine whether the pointer V had only undefined content (due to Def), either because it was freshly alloca'd or started its lifetime.
static bool	isZeroSize (Value *Size)

Variables
static cl::opt< bool >	EnableMemCpyOptWithoutLibcalls ("enable-memcpyopt-without-libcalls", cl::Hidden, cl::desc("Enable memcpyopt even when libcalls are disabled"))

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "memcpyopt"

Definition at line 64 of file MemCpyOptimizer.cpp.

Function Documentation

accessedBetween()

static bool accessedBetween ( BatchAAResults &  AA, MemoryLocation  Loc, const MemoryUseOrDef *  Start, const MemoryUseOrDef *  End, Instruction **  SkippedLifetimeStart = nullptr  )

static

Definition at line 298 of file MemCpyOptimizer.cpp.

References assert(), End, llvm::BatchAAResults::getModRefInfo(), I, II, llvm::isModOrRefSet(), and llvm::make_range().

hasUndefContents()

static bool hasUndefContents ( MemorySSA *  MSSA, BatchAAResults &  AA, Value *  V, MemoryDef *  Def  )

static

Determine whether the pointer V had only undefined content (due to Def), either because it was freshly alloca'd or started its lifetime.

Definition at line 1388 of file MemCpyOptimizer.cpp.

References llvm::getUnderlyingObject(), II, and llvm::MemorySSA::isLiveOnEntryDef().

Referenced by overreadUndefContents().

isZeroSize()

static bool isZeroSize ( Value *  Size )

static

Definition at line 1700 of file MemCpyOptimizer.cpp.

References llvm::CallingConv::C, I, llvm::simplifyInstruction(), and Size.

mayBeVisibleThroughUnwinding()

static bool mayBeVisibleThroughUnwinding ( Value *  V, Instruction *  Start, Instruction *  End  )

static

Definition at line 268 of file MemCpyOptimizer.cpp.

References llvm::any_of(), assert(), End, llvm::getUnderlyingObject(), I, llvm::isNotVisibleOnUnwind(), and llvm::make_range().

overreadUndefContents()

static bool overreadUndefContents ( MemorySSA *  MSSA, MemCpyInst *  MemCpy, MemIntrinsic *  MemSrc, BatchAAResults &  BAA  )

static

Definition at line 1406 of file MemCpyOptimizer.cpp.

References llvm::MemorySSAWalker::getClobberingMemoryAccess(), llvm::MemoryUseOrDef::getDefiningAccess(), llvm::MemoryLocation::getForSource(), llvm::MemorySSA::getMemoryAccess(), llvm::MemTransferBase< BaseCL >::getSource(), llvm::MemorySSA::getWalker(), and hasUndefContents().

STATISTIC() [1/7]

STATISTIC	(	NumCallSlot	,
		"Number of call slot optimizations performed"
	)

STATISTIC() [2/7]

STATISTIC	(	NumCpyToSet	,
		"Number of memcpys converted to memset"
	)

STATISTIC() [3/7]

STATISTIC	(	NumMemCpyInstr	,
		"Number of memcpy instructions deleted"
	)

STATISTIC() [4/7]

STATISTIC	(	NumMemMoveInstr	,
		"Number of memmove instructions deleted"
	)

STATISTIC() [5/7]

STATISTIC	(	NumMemSetInfer	,
		"Number of memsets inferred"
	)

STATISTIC() [6/7]

STATISTIC	(	NumMoveToCpy	,
		"Number of memmoves converted to memcpy"
	)

STATISTIC() [7/7]

STATISTIC	(	NumStackMove	,
		"Number of stack-move optimizations performed"
	)

References End.

writtenBetween()

static bool writtenBetween ( MemorySSA *  MSSA, BatchAAResults &  AA, MemoryLocation  Loc, const MemoryUseOrDef *  Start, const MemoryUseOrDef *  End  )

static

Definition at line 322 of file MemCpyOptimizer.cpp.

References llvm::any_of(), llvm::MemorySSA::dominates(), End, llvm::MemorySSAWalker::getClobberingMemoryAccess(), llvm::MemorySSA::getWalker(), and llvm::make_range().

Variable Documentation

EnableMemCpyOptWithoutLibcalls

cl::opt< bool > EnableMemCpyOptWithoutLibcalls("enable-memcpyopt-without-libcalls", cl::Hidden, cl::desc("Enable memcpyopt even when libcalls are disabled")) ( "enable-memcpyopt-without-libcalls"  , cl::Hidden  , cl::desc("Enable memcpyopt even when libcalls are disabled")    )

static