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

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

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 96 of file BDCE.cpp.

References clearAssumptionsOfUsers(), llvm::APInt::countl_zero(), llvm::IRBuilderBase::CreateZExt(), llvm::dbgs(), F, I, instructions, llvm::APInt::intersects(), llvm::APInt::isAllOnes(), llvm::APInt::isSubsetOf(), LLVM_DEBUG, llvm::PatternMatch::m_APInt(), llvm::PatternMatch::match(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), llvm::reverse(), 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::dropPoisonGeneratingAnnotations(), llvm::SmallVectorBase< Size_T >::empty(), I, llvm::SmallPtrSetImpl< PtrType >::insert(), llvm::SmallVectorImpl< T >::pop_back_val(), llvm::SmallVectorTemplateBase< T, bool >::push_back(), and llvm::Value::users().

Referenced by bitTrackingDCE().

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)"
	)