BDCE.cpp File Reference

#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/Transforms/Utils/Local.h"
#include "llvm/IR/InstIterator.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.h"

Include dependency graph for BDCE.cpp:

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "bdce"

Functions
	STATISTIC (NumRemoved, "Number of instructions removed (unused)")
	STATISTIC (NumSimplified, "Number of instructions trivialized (dead bits)")
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 32 of file BDCE.cpp.

Function Documentation

bitTrackingDCE()

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

static

Definition at line 89 of file BDCE.cpp.

References clearAssumptionsOfUsers(), llvm::dbgs(), llvm::ConstantInt::get(), llvm::DemandedBits::getDemandedBits(), I, llvm::instructions(), llvm::DemandedBits::isInstructionDead(), llvm::APInt::isNullValue(), llvm::DemandedBits::isUseDead(), LLVM_DEBUG, llvm::SmallVectorTemplateBase< T >::push_back(), 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 40 of file BDCE.cpp.

References assert(), llvm::SmallPtrSetImpl< PtrType >::count(), llvm::Instruction::dropPoisonGeneratingFlags(), llvm::dyn_cast(), llvm::DemandedBits::getDemandedBits(), llvm::Value::getType(), llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::APInt::isAllOnesValue(), llvm::Type::isIntOrIntVectorTy(), and llvm::Value::users().

Referenced by bitTrackingDCE().

INITIALIZE_PASS_BEGIN()

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

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

STATISTIC() [1/2]

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

STATISTIC() [2/2]

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

Variable Documentation

bdce

bdce

Definition at line 181 of file BDCE.cpp.

Elimination

Bit Tracking Dead Code Elimination

Definition at line 181 of file BDCE.cpp.

false

Bit Tracking Dead Code false

Definition at line 181 of file BDCE.cpp.