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|
//===- InlineCost.cpp - Cost analysis for inliner -------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements inline cost analysis.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Support/CallSite.h"
#include "llvm/CallingConv.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForConstant(
const CodeMetrics &Metrics, Value *V) {
unsigned Reduction = 0;
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
// We will be able to eliminate all but one of the successors.
const TerminatorInst &TI = cast<TerminatorInst>(*U);
const unsigned NumSucc = TI.getNumSuccessors();
unsigned Instrs = 0;
for (unsigned I = 0; I != NumSucc; ++I)
Instrs += Metrics.NumBBInsts.lookup(TI.getSuccessor(I));
// We don't know which blocks will be eliminated, so use the average size.
Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
continue;
}
// Figure out if this instruction will be removed due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
//
// FIXME: It would be nice to capture the fact that a load from a
// pointer-to-constant-global is actually a *really* good thing to zap.
// Unfortunately, we don't know the pointer that may get propagated here,
// so we can't make this decision.
if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
isa<AllocaInst>(Inst))
continue;
bool AllOperandsConstant = true;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
AllOperandsConstant = false;
break;
}
if (!AllOperandsConstant)
continue;
// We will get to remove this instruction...
Reduction += InlineConstants::InstrCost;
// And any other instructions that use it which become constants
// themselves.
Worklist.push_back(&Inst);
}
} while (!Worklist.empty());
return Reduction;
}
static unsigned countCodeReductionForAllocaICmp(const CodeMetrics &Metrics,
ICmpInst *ICI) {
unsigned Reduction = 0;
// Bail if this is comparing against a non-constant; there is nothing we can
// do there.
if (!isa<Constant>(ICI->getOperand(1)))
return Reduction;
// An icmp pred (alloca, C) becomes true if the predicate is true when
// equal and false otherwise.
bool Result = ICI->isTrueWhenEqual();
SmallVector<Instruction *, 4> Worklist;
Worklist.push_back(ICI);
do {
Instruction *U = Worklist.pop_back_val();
Reduction += InlineConstants::InstrCost;
for (Value::use_iterator UI = U->use_begin(), UE = U->use_end();
UI != UE; ++UI) {
Instruction *I = dyn_cast<Instruction>(*UI);
if (!I || I->mayHaveSideEffects()) continue;
if (I->getNumOperands() == 1)
Worklist.push_back(I);
if (BinaryOperator *BO = dyn_cast<BinaryOperator>(I)) {
// If BO produces the same value as U, then the other operand is
// irrelevant and we can put it into the Worklist to continue
// deleting dead instructions. If BO produces the same value as the
// other operand, we can delete BO but that's it.
if (Result == true) {
if (BO->getOpcode() == Instruction::Or)
Worklist.push_back(I);
if (BO->getOpcode() == Instruction::And)
Reduction += InlineConstants::InstrCost;
} else {
if (BO->getOpcode() == Instruction::Or ||
BO->getOpcode() == Instruction::Xor)
Reduction += InlineConstants::InstrCost;
if (BO->getOpcode() == Instruction::And)
Worklist.push_back(I);
}
}
if (BranchInst *BI = dyn_cast<BranchInst>(I)) {
BasicBlock *BB = BI->getSuccessor(Result ? 0 : 1);
if (BB->getSinglePredecessor())
Reduction
+= InlineConstants::InstrCost * Metrics.NumBBInsts.lookup(BB);
}
}
} while (!Worklist.empty());
return Reduction;
}
/// \brief Compute the reduction possible for a given instruction if we are able
/// to SROA an alloca.
///
/// The reduction for this instruction is added to the SROAReduction output
/// parameter. Returns false if this instruction is expected to defeat SROA in
/// general.
static bool countCodeReductionForSROAInst(Instruction *I,
SmallVectorImpl<Value *> &Worklist,
unsigned &SROAReduction) {
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (!LI->isSimple())
return false;
SROAReduction += InlineConstants::InstrCost;
return true;
}
if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
if (!SI->isSimple())
return false;
SROAReduction += InlineConstants::InstrCost;
return true;
}
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has variable indices, we won't be able to do much with it.
if (!GEP->hasAllConstantIndices())
return false;
// A non-zero GEP will likely become a mask operation after SROA.
if (GEP->hasAllZeroIndices())
SROAReduction += InlineConstants::InstrCost;
Worklist.push_back(GEP);
return true;
}
if (BitCastInst *BCI = dyn_cast<BitCastInst>(I)) {
// Track pointer through bitcasts.
Worklist.push_back(BCI);
SROAReduction += InlineConstants::InstrCost;
return true;
}
// We just look for non-constant operands to ICmp instructions as those will
// defeat SROA. The actual reduction for these happens even without SROA.
if (ICmpInst *ICI = dyn_cast<ICmpInst>(I))
return isa<Constant>(ICI->getOperand(1));
if (SelectInst *SI = dyn_cast<SelectInst>(I)) {
// SROA can handle a select of alloca iff all uses of the alloca are
// loads, and dereferenceable. We assume it's dereferenceable since
// we're told the input is an alloca.
for (Value::use_iterator UI = SI->use_begin(), UE = SI->use_end();
UI != UE; ++UI) {
LoadInst *LI = dyn_cast<LoadInst>(*UI);
if (LI == 0 || !LI->isSimple())
return false;
}
// We don't know whether we'll be deleting the rest of the chain of
// instructions from the SelectInst on, because we don't know whether
// the other side of the select is also an alloca or not.
return true;
}
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(I)) {
switch (II->getIntrinsicID()) {
default:
return false;
case Intrinsic::memset:
case Intrinsic::memcpy:
case Intrinsic::memmove:
case Intrinsic::lifetime_start:
case Intrinsic::lifetime_end:
// SROA can usually chew through these intrinsics.
SROAReduction += InlineConstants::InstrCost;
return true;
}
}
// If there is some other strange instruction, we're not going to be
// able to do much if we inline this.
return false;
}
unsigned InlineCostAnalyzer::FunctionInfo::countCodeReductionForAlloca(
const CodeMetrics &Metrics, Value *V) {
if (!V->getType()->isPointerTy()) return 0; // Not a pointer
unsigned Reduction = 0;
unsigned SROAReduction = 0;
bool CanSROAAlloca = true;
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI){
Instruction *I = cast<Instruction>(*UI);
if (ICmpInst *ICI = dyn_cast<ICmpInst>(I))
Reduction += countCodeReductionForAllocaICmp(Metrics, ICI);
if (CanSROAAlloca)
CanSROAAlloca = countCodeReductionForSROAInst(I, Worklist,
SROAReduction);
}
} while (!Worklist.empty());
return Reduction + (CanSROAAlloca ? SROAReduction : 0);
}
void InlineCostAnalyzer::FunctionInfo::countCodeReductionForPointerPair(
const CodeMetrics &Metrics, DenseMap<Value *, unsigned> &PointerArgs,
Value *V, unsigned ArgIdx) {
SmallVector<Value *, 4> Worklist;
Worklist.push_back(V);
do {
Value *V = Worklist.pop_back_val();
for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
UI != E; ++UI){
Instruction *I = cast<Instruction>(*UI);
if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
// If the GEP has variable indices, we won't be able to do much with it.
if (!GEP->hasAllConstantIndices())
continue;
// Unless the GEP is in-bounds, some comparisons will be non-constant.
// Fortunately, the real-world cases where this occurs uses in-bounds
// GEPs, and so we restrict the optimization to them here.
if (!GEP->isInBounds())
continue;
// Constant indices just change the constant offset. Add the resulting
// value both to our worklist for this argument, and to the set of
// viable paired values with future arguments.
PointerArgs[GEP] = ArgIdx;
Worklist.push_back(GEP);
continue;
}
// Track pointer through casts. Even when the result is not a pointer, it
// remains a constant relative to constants derived from other constant
// pointers.
if (CastInst *CI = dyn_cast<CastInst>(I)) {
PointerArgs[CI] = ArgIdx;
Worklist.push_back(CI);
continue;
}
// There are two instructions which produce a strict constant value when
// applied to two related pointer values. Ignore everything else.
if (!isa<ICmpInst>(I) && I->getOpcode() != Instruction::Sub)
continue;
assert(I->getNumOperands() == 2);
// Ensure that the two operands are in our set of potentially paired
// pointers (or are derived from them).
Value *OtherArg = I->getOperand(0);
if (OtherArg == V)
OtherArg = I->getOperand(1);
DenseMap<Value *, unsigned>::const_iterator ArgIt
= PointerArgs.find(OtherArg);
if (ArgIt == PointerArgs.end())
continue;
std::pair<unsigned, unsigned> ArgPair(ArgIt->second, ArgIdx);
if (ArgPair.first > ArgPair.second)
std::swap(ArgPair.first, ArgPair.second);
PointerArgPairWeights[ArgPair]
+= countCodeReductionForConstant(Metrics, I);
}
} while (!Worklist.empty());
}
/// analyzeFunction - Fill in the current structure with information gleaned
/// from the specified function.
void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F,
const TargetData *TD) {
Metrics.analyzeFunction(F, TD);
// A function with exactly one return has it removed during the inlining
// process (see InlineFunction), so don't count it.
// FIXME: This knowledge should really be encoded outside of FunctionInfo.
if (Metrics.NumRets==1)
--Metrics.NumInsts;
ArgumentWeights.reserve(F->arg_size());
DenseMap<Value *, unsigned> PointerArgs;
unsigned ArgIdx = 0;
for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E;
++I, ++ArgIdx) {
// Count how much code can be eliminated if one of the arguments is
// a constant or an alloca.
ArgumentWeights.push_back(ArgInfo(countCodeReductionForConstant(Metrics, I),
countCodeReductionForAlloca(Metrics, I)));
// If the argument is a pointer, also check for pairs of pointers where
// knowing a fixed offset between them allows simplification. This pattern
// arises mostly due to STL algorithm patterns where pointers are used as
// random access iterators.
if (!I->getType()->isPointerTy())
continue;
PointerArgs[I] = ArgIdx;
countCodeReductionForPointerPair(Metrics, PointerArgs, I, ArgIdx);
}
}
/// NeverInline - returns true if the function should never be inlined into
/// any caller
bool InlineCostAnalyzer::FunctionInfo::NeverInline() {
return (Metrics.exposesReturnsTwice || Metrics.isRecursive ||
Metrics.containsIndirectBr);
}
// ConstantFunctionBonus - Figure out how much of a bonus we can get for
// possibly devirtualizing a function. We'll subtract the size of the function
// we may wish to inline from the indirect call bonus providing a limit on
// growth. Leave an upper limit of 0 for the bonus - we don't want to penalize
// inlining because we decide we don't want to give a bonus for
// devirtualizing.
int InlineCostAnalyzer::ConstantFunctionBonus(CallSite CS, Constant *C) {
// This could just be NULL.
if (!C) return 0;
Function *F = dyn_cast<Function>(C);
if (!F) return 0;
int Bonus = InlineConstants::IndirectCallBonus + getInlineSize(CS, F);
return (Bonus > 0) ? 0 : Bonus;
}
// CountBonusForConstant - Figure out an approximation for how much per-call
// performance boost we can expect if the specified value is constant.
int InlineCostAnalyzer::CountBonusForConstant(Value *V, Constant *C) {
unsigned Bonus = 0;
for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
User *U = *UI;
if (CallInst *CI = dyn_cast<CallInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (CI->getCalledValue() == V)
Bonus += ConstantFunctionBonus(CallSite(CI), C);
} else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
// Turning an indirect call into a direct call is a BIG win
if (II->getCalledValue() == V)
Bonus += ConstantFunctionBonus(CallSite(II), C);
}
// FIXME: Eliminating conditional branches and switches should
// also yield a per-call performance boost.
else {
// Figure out the bonuses that wll accrue due to simple constant
// propagation.
Instruction &Inst = cast<Instruction>(*U);
// We can't constant propagate instructions which have effects or
// read memory.
//
// FIXME: It would be nice to capture the fact that a load from a
// pointer-to-constant-global is actually a *really* good thing to zap.
// Unfortunately, we don't know the pointer that may get propagated here,
// so we can't make this decision.
if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
isa<AllocaInst>(Inst))
continue;
bool AllOperandsConstant = true;
for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
AllOperandsConstant = false;
break;
}
if (AllOperandsConstant)
Bonus += CountBonusForConstant(&Inst);
}
}
return Bonus;
}
int InlineCostAnalyzer::getInlineSize(CallSite CS, Function *Callee) {
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee, TD);
// InlineCost - This value measures how good of an inline candidate this call
// site is to inline. A lower inline cost make is more likely for the call to
// be inlined. This value may go negative.
//
int InlineCost = 0;
// Compute any size reductions we can expect due to arguments being passed into
// the function.
//
unsigned ArgNo = 0;
CallSite::arg_iterator I = CS.arg_begin();
for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
FI != FE; ++I, ++FI, ++ArgNo) {
// If an alloca is passed in, inlining this function is likely to allow
// significant future optimization possibilities (like scalar promotion, and
// scalarization), so encourage the inlining of the function.
//
if (isa<AllocaInst>(I))
InlineCost -= CalleeFI->ArgumentWeights[ArgNo].AllocaWeight;
// If this is a constant being passed into the function, use the argument
// weights calculated for the callee to determine how much will be folded
// away with this information.
else if (isa<Constant>(I))
InlineCost -= CalleeFI->ArgumentWeights[ArgNo].ConstantWeight;
}
const DenseMap<std::pair<unsigned, unsigned>, unsigned> &ArgPairWeights
= CalleeFI->PointerArgPairWeights;
for (DenseMap<std::pair<unsigned, unsigned>, unsigned>::const_iterator I
= ArgPairWeights.begin(), E = ArgPairWeights.end();
I != E; ++I)
if (CS.getArgument(I->first.first)->stripInBoundsConstantOffsets() ==
CS.getArgument(I->first.second)->stripInBoundsConstantOffsets())
InlineCost -= I->second;
// Each argument passed in has a cost at both the caller and the callee
// sides. Measurements show that each argument costs about the same as an
// instruction.
InlineCost -= (CS.arg_size() * InlineConstants::InstrCost);
// Now that we have considered all of the factors that make the call site more
// likely to be inlined, look at factors that make us not want to inline it.
// Calls usually take a long time, so they make the inlining gain smaller.
InlineCost += CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty;
// Look at the size of the callee. Each instruction counts as 5.
InlineCost += CalleeFI->Metrics.NumInsts * InlineConstants::InstrCost;
return InlineCost;
}
int InlineCostAnalyzer::getInlineBonuses(CallSite CS, Function *Callee) {
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee, TD);
bool isDirectCall = CS.getCalledFunction() == Callee;
Instruction *TheCall = CS.getInstruction();
int Bonus = 0;
// If there is only one call of the function, and it has internal linkage,
// make it almost guaranteed to be inlined.
//
if (Callee->hasLocalLinkage() && Callee->hasOneUse() && isDirectCall)
Bonus += InlineConstants::LastCallToStaticBonus;
// If the instruction after the call, or if the normal destination of the
// invoke is an unreachable instruction, the function is noreturn. As such,
// there is little point in inlining this.
if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
if (isa<UnreachableInst>(II->getNormalDest()->begin()))
Bonus += InlineConstants::NoreturnPenalty;
} else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
Bonus += InlineConstants::NoreturnPenalty;
// If this function uses the coldcc calling convention, prefer not to inline
// it.
if (Callee->getCallingConv() == CallingConv::Cold)
Bonus += InlineConstants::ColdccPenalty;
// Add to the inline quality for properties that make the call valuable to
// inline. This includes factors that indicate that the result of inlining
// the function will be optimizable. Currently this just looks at arguments
// passed into the function.
//
CallSite::arg_iterator I = CS.arg_begin();
for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
FI != FE; ++I, ++FI)
// Compute any constant bonus due to inlining we want to give here.
if (isa<Constant>(I))
Bonus += CountBonusForConstant(FI, cast<Constant>(I));
return Bonus;
}
// getInlineCost - The heuristic used to determine if we should inline the
// function call or not.
//
InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS) {
return getInlineCost(CS, CS.getCalledFunction());
}
InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS, Function *Callee) {
Instruction *TheCall = CS.getInstruction();
Function *Caller = TheCall->getParent()->getParent();
// Don't inline functions which can be redefined at link-time to mean
// something else. Don't inline functions marked noinline or call sites
// marked noinline.
if (Callee->mayBeOverridden() || Callee->hasFnAttr(Attribute::NoInline) ||
CS.isNoInline())
return llvm::InlineCost::getNever();
// Get information about the callee.
FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI->Metrics.NumBlocks == 0)
CalleeFI->analyzeFunction(Callee, TD);
// If we should never inline this, return a huge cost.
if (CalleeFI->NeverInline())
return InlineCost::getNever();
// FIXME: It would be nice to kill off CalleeFI->NeverInline. Then we
// could move this up and avoid computing the FunctionInfo for
// things we are going to just return always inline for. This
// requires handling setjmp somewhere else, however.
if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline))
return InlineCost::getAlways();
if (CalleeFI->Metrics.usesDynamicAlloca) {
// Get information about the caller.
FunctionInfo &CallerFI = CachedFunctionInfo[Caller];
// If we haven't calculated this information yet, do so now.
if (CallerFI.Metrics.NumBlocks == 0) {
CallerFI.analyzeFunction(Caller, TD);
// Recompute the CalleeFI pointer, getting Caller could have invalidated
// it.
CalleeFI = &CachedFunctionInfo[Callee];
}
// Don't inline a callee with dynamic alloca into a caller without them.
// Functions containing dynamic alloca's are inefficient in various ways;
// don't create more inefficiency.
if (!CallerFI.Metrics.usesDynamicAlloca)
return InlineCost::getNever();
}
// InlineCost - This value measures how good of an inline candidate this call
// site is to inline. A lower inline cost make is more likely for the call to
// be inlined. This value may go negative due to the fact that bonuses
// are negative numbers.
//
int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee);
return llvm::InlineCost::get(InlineCost);
}
// getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a
// higher threshold to determine if the function call should be inlined.
float InlineCostAnalyzer::getInlineFudgeFactor(CallSite CS) {
Function *Callee = CS.getCalledFunction();
// Get information about the callee.
FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
// If we haven't calculated this information yet, do so now.
if (CalleeFI.Metrics.NumBlocks == 0)
CalleeFI.analyzeFunction(Callee, TD);
float Factor = 1.0f;
// Single BB functions are often written to be inlined.
if (CalleeFI.Metrics.NumBlocks == 1)
Factor += 0.5f;
// Be more aggressive if the function contains a good chunk (if it mades up
// at least 10% of the instructions) of vector instructions.
if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/2)
Factor += 2.0f;
else if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/10)
Factor += 1.5f;
return Factor;
}
/// growCachedCostInfo - update the cached cost info for Caller after Callee has
/// been inlined.
void
InlineCostAnalyzer::growCachedCostInfo(Function *Caller, Function *Callee) {
CodeMetrics &CallerMetrics = CachedFunctionInfo[Caller].Metrics;
// For small functions we prefer to recalculate the cost for better accuracy.
if (CallerMetrics.NumBlocks < 10 && CallerMetrics.NumInsts < 1000) {
resetCachedCostInfo(Caller);
return;
}
// For large functions, we can save a lot of computation time by skipping
// recalculations.
if (CallerMetrics.NumCalls > 0)
--CallerMetrics.NumCalls;
if (Callee == 0) return;
CodeMetrics &CalleeMetrics = CachedFunctionInfo[Callee].Metrics;
// If we don't have metrics for the callee, don't recalculate them just to
// update an approximation in the caller. Instead, just recalculate the
// caller info from scratch.
if (CalleeMetrics.NumBlocks == 0) {
resetCachedCostInfo(Caller);
return;
}
// Since CalleeMetrics were already calculated, we know that the CallerMetrics
// reference isn't invalidated: both were in the DenseMap.
CallerMetrics.usesDynamicAlloca |= CalleeMetrics.usesDynamicAlloca;
// FIXME: If any of these three are true for the callee, the callee was
// not inlined into the caller, so I think they're redundant here.
CallerMetrics.exposesReturnsTwice |= CalleeMetrics.exposesReturnsTwice;
CallerMetrics.isRecursive |= CalleeMetrics.isRecursive;
CallerMetrics.containsIndirectBr |= CalleeMetrics.containsIndirectBr;
CallerMetrics.NumInsts += CalleeMetrics.NumInsts;
CallerMetrics.NumBlocks += CalleeMetrics.NumBlocks;
CallerMetrics.NumCalls += CalleeMetrics.NumCalls;
CallerMetrics.NumVectorInsts += CalleeMetrics.NumVectorInsts;
CallerMetrics.NumRets += CalleeMetrics.NumRets;
// analyzeBasicBlock counts each function argument as an inst.
if (CallerMetrics.NumInsts >= Callee->arg_size())
CallerMetrics.NumInsts -= Callee->arg_size();
else
CallerMetrics.NumInsts = 0;
// We are not updating the argument weights. We have already determined that
// Caller is a fairly large function, so we accept the loss of precision.
}
/// clear - empty the cache of inline costs
void InlineCostAnalyzer::clear() {
CachedFunctionInfo.clear();
}
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