LowerExpectIntrinsic.cpp File Reference

#include "llvm/Transforms/Scalar/LowerExpectIntrinsic.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/ADT/iterator_range.h"
#include "llvm/IR/BasicBlock.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/MDBuilder.h"
#include "llvm/IR/Metadata.h"
#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Debug.h"
#include "llvm/Transforms/Scalar.h"

Include dependency graph for LowerExpectIntrinsic.cpp:

Go to the source code of this file.

Macros
#define	DEBUG_TYPE   "lower-expect-intrinsic"

Functions
	STATISTIC (ExpectIntrinsicsHandled, "Number of 'expect' intrinsic instructions handled")
static bool	handleSwitchExpect (SwitchInst &SI)
static void	handlePhiDef (CallInst *Expect)
	Handler for PHINodes that define the value argument to an .expect call. More...
template<class BrSelInst >
static bool	handleBrSelExpect (BrSelInst &BSI)
static bool	handleBranchExpect (BranchInst &BI)
static bool	lowerExpectIntrinsic (Function &F)
	INITIALIZE_PASS (LowerExpectIntrinsic, "lower-expect", "Lower 'expect' Intrinsics", false, false) FunctionPass *llvm

Variables
static cl::opt< uint32_t >	LikelyBranchWeight ("likely-branch-weight", cl::Hidden, cl::init(2000), cl::desc("Weight of the branch likely to be taken (default = 2000)"))
static cl::opt< uint32_t >	UnlikelyBranchWeight ("unlikely-branch-weight", cl::Hidden, cl::init(1), cl::desc("Weight of the branch unlikely to be taken (default = 1)"))

Macro Definition Documentation

DEBUG_TYPE

#define DEBUG_TYPE   "lower-expect-intrinsic"

Definition at line 33 of file LowerExpectIntrinsic.cpp.

Function Documentation

handleBranchExpect()

static bool handleBranchExpect ( BranchInst &  BI )

static

Definition at line 300 of file LowerExpectIntrinsic.cpp.

References llvm::BranchInst::isUnconditional().

Referenced by lowerExpectIntrinsic().

handleBrSelExpect()

template<class BrSelInst >

static bool handleBrSelExpect ( BrSelInst &  BSI )

static

Definition at line 233 of file LowerExpectIntrinsic.cpp.

References llvm::dyn_cast(), llvm::Intrinsic::expect, llvm::CallBase::getArgOperand(), llvm::ConstantInt::getBitWidth(), llvm::CallBase::getCalledFunction(), llvm::Value::getContext(), llvm::Function::getIntrinsicID(), llvm::User::getOperand(), llvm::CmpInst::getPredicate(), llvm::ConstantInt::getZExtValue(), llvm::CmpInst::ICMP_EQ, and llvm::CmpInst::ICMP_NE.

Referenced by lowerExpectIntrinsic().

handlePhiDef()

static void handlePhiDef ( CallInst *  Expect )

static

Handler for PHINodes that define the value argument to an .expect call.

If the operand of the phi has a constant value and it 'contradicts' with the expected value of phi def, then the corresponding incoming edge of the phi is unlikely to be taken. Using that information, the branch probability info for the originating branch can be inferred.

Definition at line 94 of file LowerExpectIntrinsic.cpp.

References Arg, llvm::dyn_cast(), llvm::CallBase::getArgOperand(), llvm::BinaryOperator::getOpcode(), llvm::User::getOperand(), llvm::Instruction::getParent(), llvm::BasicBlock::getParent(), llvm::BasicBlock::getSinglePredecessor(), llvm::BranchInst::getSuccessor(), llvm::BasicBlock::getTerminator(), llvm::ConstantInt::getValue(), llvm::BranchInst::isConditional(), llvm::BranchInst::isUnconditional(), LikelyBranchWeight, llvm_unreachable, llvm::LLVMContext::MD_prof, llvm::SmallVectorTemplateBase< T >::push_back(), llvm::reverse(), llvm::Instruction::setMetadata(), llvm::APInt::sext(), UnlikelyBranchWeight, and llvm::APInt::zext().

Referenced by lowerExpectIntrinsic().

handleSwitchExpect()

static bool handleSwitchExpect ( SwitchInst &  SI )

static

Definition at line 57 of file LowerExpectIntrinsic.cpp.

References llvm::SwitchInst::case_default(), llvm::dyn_cast(), llvm::Intrinsic::expect, llvm::SwitchInst::findCaseValue(), llvm::CallBase::getArgOperand(), llvm::CallBase::getCalledFunction(), llvm::SwitchInst::CaseHandleImpl< SwitchInstT, ConstantIntT, BasicBlockT >::getCaseIndex(), llvm::SwitchInst::getCondition(), llvm::Value::getContext(), llvm::Function::getIntrinsicID(), llvm::SwitchInst::getNumCases(), LikelyBranchWeight, llvm::LLVMContext::MD_prof, llvm::SwitchInst::setCondition(), llvm::Instruction::setMetadata(), and UnlikelyBranchWeight.

Referenced by lowerExpectIntrinsic().

INITIALIZE_PASS()

INITIALIZE_PASS	(	LowerExpectIntrinsic	,
		"lower-expect"	,
		"Lower 'expect' Intrinsics"	,
		false	,
		false
	)

Definition at line 378 of file LowerExpectIntrinsic.cpp.

lowerExpectIntrinsic()

static bool lowerExpectIntrinsic ( Function &  F )

static

Definition at line 307 of file LowerExpectIntrinsic.cpp.

References llvm::dyn_cast(), llvm::Instruction::eraseFromParent(), llvm::Intrinsic::expect, llvm::CallBase::getArgOperand(), llvm::CallBase::getCalledFunction(), llvm::Function::getIntrinsicID(), handleBranchExpect(), handleBrSelExpect(), handlePhiDef(), handleSwitchExpect(), llvm::Value::replaceAllUsesWith(), and SI.

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

STATISTIC()

STATISTIC	(	ExpectIntrinsicsHandled	,
		"Number of 'expect' intrinsic instructions handled"
	)

Variable Documentation

LikelyBranchWeight

cl::opt<uint32_t> LikelyBranchWeight("likely-branch-weight", cl::Hidden, cl::init(2000), cl::desc("Weight of the branch likely to be taken (default = 2000)"))

static

Referenced by handlePhiDef(), and handleSwitchExpect().

UnlikelyBranchWeight

cl::opt<uint32_t> UnlikelyBranchWeight("unlikely-branch-weight", cl::Hidden, cl::init(1), cl::desc("Weight of the branch unlikely to be taken (default = 1)"))

static

Referenced by handlePhiDef(), and handleSwitchExpect().