#include "llvm/Analysis/MemorySSA.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/DenseMapInfo.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/ADT/DepthFirstIterator.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/None.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/iterator.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/IteratedDominanceFrontier.h"
#include "llvm/Analysis/MemoryLocation.h"
#include "llvm/Config/llvm-config.h"
#include "llvm/IR/AssemblyAnnotationWriter.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.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/PassManager.h"
#include "llvm/IR/Use.h"
#include "llvm/Pass.h"
#include "llvm/Support/AtomicOrdering.h"
#include "llvm/Support/Casting.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Support/FormattedStream.h"
#include "llvm/Support/raw_ostream.h"
#include <algorithm>
#include <cassert>
#include <iterator>
#include <memory>
#include <utility>

Include dependency graph for MemorySSA.cpp:

Classes
class	llvm::MemorySSAAnnotatedWriter
	An assembly annotator class to print Memory SSA information in comments. More...

struct	llvm::DenseMapInfo< MemoryLocOrCall >

class	llvm::MemorySSA::ClobberWalkerBase

class	llvm::MemorySSA::CachingWalker
	A MemorySSAWalker that does AA walks to disambiguate accesses. More...

class	llvm::MemorySSA::SkipSelfWalker

class	llvm::MemorySSA::OptimizeUses
	This class is a batch walker of all MemoryUse's in the program, and points their defining access at the thing that actually clobbers them. More...

Namespaces
	llvm
	This class represents lattice values for constants.

Macros
#define	DEBUG_TYPE "memoryssa"

Functions
	INITIALIZE_PASS_BEGIN (MemorySSAWrapperPass, "memoryssa", "Memory SSA", false, true) INITIALIZE_PASS_END(MemorySSAWrapperPass

Memory true	INITIALIZE_PASS_BEGIN (MemorySSAPrinterLegacyPass, "print-memoryssa", "Memory SSA Printer", false, false) INITIALIZE_PASS_END(MemorySSAPrinterLegacyPass

Memory true print Memory SSA static false cl::opt< unsigned >	MaxCheckLimit ("memssa-check-limit", cl::Hidden, cl::init(100), cl::desc("The maximum number of stores/phis MemorySSA" "will consider trying to walk past (default = 100)"))

static bool	areLoadsReorderable (const LoadInst Use, const LoadInst MayClobber)
	This does one-way checks to see if Use could theoretically be hoisted above MayClobber. More...

static ClobberAlias	instructionClobbersQuery (const MemoryDef MD, const MemoryLocation &UseLoc, const Instruction UseInst, AliasAnalysis &AA)

static ClobberAlias	instructionClobbersQuery (MemoryDef MD, const MemoryUseOrDef MU, const MemoryLocOrCall &UseMLOC, AliasAnalysis &AA)

static bool	lifetimeEndsAt (MemoryDef *MD, const MemoryLocation &Loc, AliasAnalysis &AA)

static bool	isUseTriviallyOptimizableToLiveOnEntry (AliasAnalysis &AA, const Instruction *I)

static void	checkClobberSanity (const MemoryAccess Start, MemoryAccess ClobberAt, const MemoryLocation &StartLoc, const MemorySSA &MSSA, const UpwardsMemoryQuery &Query, AliasAnalysis &AA, bool AllowImpreciseClobber=false)
	Verifies that `Start` is clobbered by `ClobberAt`, and that nothing inbetween `Start` and `ClobberAt` can clobbers `Start`. More...

static bool	isOrdered (const Instruction *I)

Variables
	memoryssa

Memory	SSA

Memory	false

Memory true print Memory SSA	Printer

static cl::opt< bool, true >	VerifyMemorySSAX ("verify-memoryssa", cl::location(VerifyMemorySSA), cl::Hidden, cl::desc("Enable verification of MemorySSA."))

static const char	LiveOnEntryStr [] = "liveOnEntry"

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE "memoryssa"

Definition at line 59 of file MemorySSA.cpp.

Function Documentation

◆ areLoadsReorderable()

static bool areLoadsReorderable	(	const LoadInst *	Use,
		const LoadInst *	MayClobber
	)

static

This does one-way checks to see if Use could theoretically be hoisted above MayClobber.

This will not check the other way around.

This assumes that, for the purposes of MemorySSA, Use comes directly after MayClobber, with no potentially clobbering operations in between them. (Where potentially clobbering ops are memory barriers, aliased stores, etc.)

Definition at line 220 of file MemorySSA.cpp.

References llvm::Acquire, llvm::LoadInst::getOrdering(), llvm::isAtLeastOrStrongerThan(), llvm::LoadInst::isVolatile(), and llvm::SequentiallyConsistent.

Referenced by instructionClobbersQuery().

◆ checkClobberSanity()

static void checkClobberSanity	(	const MemoryAccess *	Start,
		MemoryAccess *	ClobberAt,
		const MemoryLocation &	StartLoc,
		const MemorySSA &	MSSA,
		const UpwardsMemoryQuery &	Query,
		AliasAnalysis &	AA,
		bool	AllowImpreciseClobber = `false`
	)

static

Verifies that Start is clobbered by ClobberAt, and that nothing inbetween Start and ClobberAt can clobbers Start.

This is meant to be as simple and self-contained as possible. Because it uses no cache, etc., it can be relatively expensive.

Parameters

Start	The MemoryAccess that we want to walk from.
ClobberAt	A clobber for Start.
StartLoc	The MemoryLocation for Start.
MSSA	The MemorySSA instance that Start and ClobberAt belong to.
Query	The UpwardsMemoryQuery we used for our search.
AA	The AliasAnalysis we used for our search.
AllowImpreciseClobber	Always false, unless we do relaxed verify.

Definition at line 385 of file MemorySSA.cpp.

Referenced by llvm::MemorySSA::checkClobberSanityAccess().

◆ INITIALIZE_PASS_BEGIN() [1/2]

INITIALIZE_PASS_BEGIN	(	MemorySSAWrapperPass	,
		"memoryssa"	,
		"Memory SSA"	,
		false	,
		true
	)

◆ INITIALIZE_PASS_BEGIN() [2/2]

Memory true INITIALIZE_PASS_BEGIN	(	MemorySSAPrinterLegacyPass	,
		"print-memoryssa"	,
		"Memory SSA Printer"	,
		false	,
		false
	)

◆ instructionClobbersQuery() [1/2]

static ClobberAlias instructionClobbersQuery	(	const MemoryDef *	MD,
		const MemoryLocation &	UseLoc,
		const Instruction *	UseInst,
		AliasAnalysis &	AA
	)

static

◆ instructionClobbersQuery() [2/2]

static ClobberAlias instructionClobbersQuery	(	MemoryDef *	MD,
		const MemoryUseOrDef *	MU,
		const MemoryLocOrCall &	UseMLOC,
		AliasAnalysis &	AA
	)

static

Definition at line 303 of file MemorySSA.cpp.

References llvm::MemoryUseOrDef::getMemoryInst(), and instructionClobbersQuery().

◆ isOrdered()

static bool isOrdered ( const Instruction * I )

inlinestatic

Definition at line 1633 of file MemorySSA.cpp.

References Arg, assert(), llvm::Intrinsic::assume, llvm::tgtok::Def, llvm::MemoryAccess::getBlock(), llvm::Value::getContext(), llvm::Instruction::getParent(), I, llvm::isModSet(), llvm::isRefSet(), llvm::ModRef, llvm::None, and SI.

Referenced by llvm::MemoryDependenceResults::getNonLocalPointerDependency(), and llvm::CmpInst::isFalseWhenEqual().

◆ isUseTriviallyOptimizableToLiveOnEntry()

static bool isUseTriviallyOptimizableToLiveOnEntry	(	AliasAnalysis &	AA,
		const Instruction *	I
	)

static

Definition at line 362 of file MemorySSA.cpp.

References llvm::Instruction::getMetadata(), llvm::getPointerOperand(), I, llvm::LLVMContext::MD_invariant_load, and llvm::AAResults::pointsToConstantMemory().

Referenced by llvm::MemorySSA::ClobberWalkerBase::getClobberingMemoryAccessBase(), and llvm::MemorySSA::OptimizeUses::OptimizeUses().

◆ lifetimeEndsAt()

static bool lifetimeEndsAt	(	MemoryDef *	MD,
		const MemoryLocation &	Loc,
		AliasAnalysis &	AA
	)

static

Definition at line 348 of file MemorySSA.cpp.

References llvm::MemoryUseOrDef::getMemoryInst(), llvm::AAResults::isMustAlias(), and llvm::Intrinsic::lifetime_end.

Referenced by llvm::MemorySSA::OptimizeUses::OptimizeUses().

◆ MaxCheckLimit()

Memory true print Memory SSA static false cl::opt<unsigned> MaxCheckLimit	(	"memssa-check-limit"	,
		cl::Hidden	,
		cl::init(100)	,
		cl::desc("The maximum number of stores/phis MemorySSA" "will consider trying to walk past (default = 100)")
	)