#include "llvm/Transforms/Scalar/BDCE.h"
#include "llvm/ADT/SmallPtrSet.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/DemandedBits.h"
#include "llvm/Analysis/GlobalsModRef.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/InitializePasses.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils/Local.h"

Include dependency graph for BDCE.cpp:

Macros
#define	DEBUG_TYPE "bdce"

Functions
	STATISTIC (NumRemoved, "Number of instructions removed (unused)")

	STATISTIC (NumSimplified, "Number of instructions trivialized (dead bits)")

	STATISTIC (NumSExt2ZExt, "Number of sign extension instructions converted to zero extension")

static void	clearAssumptionsOfUsers (Instruction *I, DemandedBits &DB)
	If an instruction is trivialized (dead), then the chain of users of that instruction may need to be cleared of assumptions that can no longer be guaranteed correct. More...

static bool	bitTrackingDCE (Function &F, DemandedBits &DB)

	INITIALIZE_PASS_BEGIN (BDCELegacyPass, "bdce", "Bit-Tracking Dead Code Elimination", false, false) INITIALIZE_PASS_END(BDCELegacyPass

Variables
	bdce

Bit Tracking Dead Code	Elimination

Bit Tracking Dead Code	false

Macro Definition Documentation

◆ DEBUG_TYPE

#define DEBUG_TYPE "bdce"

Definition at line 34 of file BDCE.cpp.

Function Documentation

◆ bitTrackingDCE()

static bool bitTrackingDCE	(	Function &	F,
		DemandedBits &	DB
	)

static

Definition at line 93 of file BDCE.cpp.

References Builder, clearAssumptionsOfUsers(), llvm::APInt::countLeadingZeros(), llvm::dbgs(), F, llvm::ConstantInt::get(), llvm::DemandedBits::getDemandedBits(), I, llvm::instructions(), llvm::DemandedBits::isInstructionDead(), llvm::APInt::isNullValue(), llvm::DemandedBits::isUseDead(), LLVM_DEBUG, llvm::salvageDebugInfo(), and llvm::wouldInstructionBeTriviallyDead().

Referenced by llvm::BDCEPass::run().

◆ clearAssumptionsOfUsers()

static void clearAssumptionsOfUsers	(	Instruction *	I,
		DemandedBits &	DB
	)

static

If an instruction is trivialized (dead), then the chain of users of that instruction may need to be cleared of assumptions that can no longer be guaranteed correct.

Definition at line 44 of file BDCE.cpp.

References assert(), llvm::Instruction::dropPoisonGeneratingFlags(), llvm::DemandedBits::getDemandedBits(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::APInt::isAllOnesValue(), llvm::SmallVectorImpl< T >::pop_back_val(), and llvm::Value::users().

Referenced by bitTrackingDCE().

◆ INITIALIZE_PASS_BEGIN()

INITIALIZE_PASS_BEGIN	(	BDCELegacyPass	,
		"bdce"	,
		"Bit-Tracking Dead Code Elimination"	,
		false	,
		false
	)

◆ STATISTIC() [1/3]

STATISTIC	(	NumRemoved	,
		"Number of instructions removed (unused)"
	)

◆ STATISTIC() [2/3]

STATISTIC	(	NumSExt2ZExt	,
		"Number of sign extension instructions converted to zero extension"
	)

◆ STATISTIC() [3/3]

STATISTIC	(	NumSimplified	,
		"Number of instructions trivialized (dead bits)"
	)

Variable Documentation

◆ bdce

bdce

Definition at line 202 of file BDCE.cpp.

◆ Elimination

Bit Tracking Dead Code Elimination

Definition at line 203 of file BDCE.cpp.

◆ false

Bit Tracking Dead Code false