1 //===- InlineCost.cpp - Cost analysis for inliner -------------------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements inline cost analysis.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/Analysis/InlineCost.h"
15 #include "llvm/Support/CallSite.h"
16 #include "llvm/CallingConv.h"
17 #include "llvm/IntrinsicInst.h"
18 #include "llvm/ADT/SmallPtrSet.h"
22 /// callIsSmall - If a call is likely to lower to a single target instruction,
23 /// or is otherwise deemed small return true.
24 /// TODO: Perhaps calls like memcpy, strcpy, etc?
25 bool llvm::callIsSmall(const Function *F) {
28 if (F->hasLocalLinkage()) return false;
30 if (!F->hasName()) return false;
32 StringRef Name = F->getName();
34 // These will all likely lower to a single selection DAG node.
35 if (Name == "copysign" || Name == "copysignf" || Name == "copysignl" ||
36 Name == "fabs" || Name == "fabsf" || Name == "fabsl" ||
37 Name == "sin" || Name == "sinf" || Name == "sinl" ||
38 Name == "cos" || Name == "cosf" || Name == "cosl" ||
39 Name == "sqrt" || Name == "sqrtf" || Name == "sqrtl" )
42 // These are all likely to be optimized into something smaller.
43 if (Name == "pow" || Name == "powf" || Name == "powl" ||
44 Name == "exp2" || Name == "exp2l" || Name == "exp2f" ||
45 Name == "floor" || Name == "floorf" || Name == "ceil" ||
46 Name == "round" || Name == "ffs" || Name == "ffsl" ||
47 Name == "abs" || Name == "labs" || Name == "llabs")
53 /// analyzeBasicBlock - Fill in the current structure with information gleaned
54 /// from the specified block.
55 void CodeMetrics::analyzeBasicBlock(const BasicBlock *BB) {
57 unsigned NumInstsBeforeThisBB = NumInsts;
58 for (BasicBlock::const_iterator II = BB->begin(), E = BB->end();
60 if (isa<PHINode>(II)) continue; // PHI nodes don't count.
62 // Special handling for calls.
63 if (isa<CallInst>(II) || isa<InvokeInst>(II)) {
64 if (isa<DbgInfoIntrinsic>(II))
65 continue; // Debug intrinsics don't count as size.
67 ImmutableCallSite CS(cast<Instruction>(II));
69 // If this function contains a call to setjmp or _setjmp, never inline
70 // it. This is a hack because we depend on the user marking their local
71 // variables as volatile if they are live across a setjmp call, and they
72 // probably won't do this in callers.
73 if (const Function *F = CS.getCalledFunction()) {
74 // If a function is both internal and has a single use, then it is
75 // extremely likely to get inlined in the future (it was probably
76 // exposed by an interleaved devirtualization pass).
77 if (F->hasInternalLinkage() && F->hasOneUse())
78 ++NumInlineCandidates;
80 if (F->isDeclaration() &&
81 (F->getName() == "setjmp" || F->getName() == "_setjmp"))
84 // If this call is to function itself, then the function is recursive.
85 // Inlining it into other functions is a bad idea, because this is
86 // basically just a form of loop peeling, and our metrics aren't useful
88 if (F == BB->getParent())
92 if (!isa<IntrinsicInst>(II) && !callIsSmall(CS.getCalledFunction())) {
93 // Each argument to a call takes on average one instruction to set up.
94 NumInsts += CS.arg_size();
96 // We don't want inline asm to count as a call - that would prevent loop
97 // unrolling. The argument setup cost is still real, though.
98 if (!isa<InlineAsm>(CS.getCalledValue()))
103 if (const AllocaInst *AI = dyn_cast<AllocaInst>(II)) {
104 if (!AI->isStaticAlloca())
105 this->usesDynamicAlloca = true;
108 if (isa<ExtractElementInst>(II) || II->getType()->isVectorTy())
111 if (const CastInst *CI = dyn_cast<CastInst>(II)) {
112 // Noop casts, including ptr <-> int, don't count.
113 if (CI->isLosslessCast() || isa<IntToPtrInst>(CI) ||
114 isa<PtrToIntInst>(CI))
116 // Result of a cmp instruction is often extended (to be used by other
117 // cmp instructions, logical or return instructions). These are usually
118 // nop on most sane targets.
119 if (isa<CmpInst>(CI->getOperand(0)))
121 } else if (const GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(II)){
122 // If a GEP has all constant indices, it will probably be folded with
124 if (GEPI->hasAllConstantIndices())
131 if (isa<ReturnInst>(BB->getTerminator()))
134 // We never want to inline functions that contain an indirectbr. This is
135 // incorrect because all the blockaddress's (in static global initializers
136 // for example) would be referring to the original function, and this indirect
137 // jump would jump from the inlined copy of the function into the original
138 // function which is extremely undefined behavior.
139 if (isa<IndirectBrInst>(BB->getTerminator()))
140 containsIndirectBr = true;
142 // Remember NumInsts for this BB.
143 NumBBInsts[BB] = NumInsts - NumInstsBeforeThisBB;
146 // CountCodeReductionForConstant - Figure out an approximation for how many
147 // instructions will be constant folded if the specified value is constant.
149 unsigned CodeMetrics::CountCodeReductionForConstant(Value *V) {
150 unsigned Reduction = 0;
151 for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
153 if (isa<BranchInst>(U) || isa<SwitchInst>(U)) {
154 // We will be able to eliminate all but one of the successors.
155 const TerminatorInst &TI = cast<TerminatorInst>(*U);
156 const unsigned NumSucc = TI.getNumSuccessors();
158 for (unsigned I = 0; I != NumSucc; ++I)
159 Instrs += NumBBInsts[TI.getSuccessor(I)];
160 // We don't know which blocks will be eliminated, so use the average size.
161 Reduction += InlineConstants::InstrCost*Instrs*(NumSucc-1)/NumSucc;
163 // Figure out if this instruction will be removed due to simple constant
165 Instruction &Inst = cast<Instruction>(*U);
167 // We can't constant propagate instructions which have effects or
170 // FIXME: It would be nice to capture the fact that a load from a
171 // pointer-to-constant-global is actually a *really* good thing to zap.
172 // Unfortunately, we don't know the pointer that may get propagated here,
173 // so we can't make this decision.
174 if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
175 isa<AllocaInst>(Inst))
178 bool AllOperandsConstant = true;
179 for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
180 if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
181 AllOperandsConstant = false;
185 if (AllOperandsConstant) {
186 // We will get to remove this instruction...
187 Reduction += InlineConstants::InstrCost;
189 // And any other instructions that use it which become constants
191 Reduction += CountCodeReductionForConstant(&Inst);
198 // CountCodeReductionForAlloca - Figure out an approximation of how much smaller
199 // the function will be if it is inlined into a context where an argument
200 // becomes an alloca.
202 unsigned CodeMetrics::CountCodeReductionForAlloca(Value *V) {
203 if (!V->getType()->isPointerTy()) return 0; // Not a pointer
204 unsigned Reduction = 0;
205 for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
206 Instruction *I = cast<Instruction>(*UI);
207 if (isa<LoadInst>(I) || isa<StoreInst>(I))
208 Reduction += InlineConstants::InstrCost;
209 else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(I)) {
210 // If the GEP has variable indices, we won't be able to do much with it.
211 if (GEP->hasAllConstantIndices())
212 Reduction += CountCodeReductionForAlloca(GEP);
213 } else if (BitCastInst *BCI = dyn_cast<BitCastInst>(I)) {
214 // Track pointer through bitcasts.
215 Reduction += CountCodeReductionForAlloca(BCI);
217 // If there is some other strange instruction, we're not going to be able
218 // to do much if we inline this.
226 /// analyzeFunction - Fill in the current structure with information gleaned
227 /// from the specified function.
228 void CodeMetrics::analyzeFunction(Function *F) {
229 // Look at the size of the callee.
230 for (Function::const_iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
231 analyzeBasicBlock(&*BB);
234 /// analyzeFunction - Fill in the current structure with information gleaned
235 /// from the specified function.
236 void InlineCostAnalyzer::FunctionInfo::analyzeFunction(Function *F) {
237 Metrics.analyzeFunction(F);
239 // A function with exactly one return has it removed during the inlining
240 // process (see InlineFunction), so don't count it.
241 // FIXME: This knowledge should really be encoded outside of FunctionInfo.
242 if (Metrics.NumRets==1)
245 // Check out all of the arguments to the function, figuring out how much
246 // code can be eliminated if one of the arguments is a constant.
247 ArgumentWeights.reserve(F->arg_size());
248 for (Function::arg_iterator I = F->arg_begin(), E = F->arg_end(); I != E; ++I)
249 ArgumentWeights.push_back(ArgInfo(Metrics.CountCodeReductionForConstant(I),
250 Metrics.CountCodeReductionForAlloca(I)));
253 /// NeverInline - returns true if the function should never be inlined into
255 bool InlineCostAnalyzer::FunctionInfo::NeverInline() {
256 return (Metrics.callsSetJmp || Metrics.isRecursive ||
257 Metrics.containsIndirectBr);
259 // getSpecializationBonus - The heuristic used to determine the per-call
260 // performance boost for using a specialization of Callee with argument
261 // specializedArgNo replaced by a constant.
262 int InlineCostAnalyzer::getSpecializationBonus(Function *Callee,
263 SmallVectorImpl<unsigned> &SpecializedArgNos)
265 if (Callee->mayBeOverridden())
269 // If this function uses the coldcc calling convention, prefer not to
271 if (Callee->getCallingConv() == CallingConv::Cold)
272 Bonus -= InlineConstants::ColdccPenalty;
274 // Get information about the callee.
275 FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
277 // If we haven't calculated this information yet, do so now.
278 if (CalleeFI->Metrics.NumBlocks == 0)
279 CalleeFI->analyzeFunction(Callee);
283 for (Function::arg_iterator I = Callee->arg_begin(), E = Callee->arg_end();
284 I != E; ++I, ++ArgNo)
285 if (ArgNo == SpecializedArgNos[i]) {
287 Bonus += CountBonusForConstant(I);
290 // Calls usually take a long time, so they make the specialization gain
292 Bonus -= CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty;
297 // ConstantFunctionBonus - Figure out how much of a bonus we can get for
298 // possibly devirtualizing a function. We'll subtract the size of the function
299 // we may wish to inline from the indirect call bonus providing a limit on
300 // growth. Leave an upper limit of 0 for the bonus - we don't want to penalize
301 // inlining because we decide we don't want to give a bonus for
303 int InlineCostAnalyzer::ConstantFunctionBonus(CallSite CS, Constant *C) {
305 // This could just be NULL.
308 Function *F = dyn_cast<Function>(C);
311 int Bonus = InlineConstants::IndirectCallBonus + getInlineSize(CS, F);
312 return (Bonus > 0) ? 0 : Bonus;
315 // CountBonusForConstant - Figure out an approximation for how much per-call
316 // performance boost we can expect if the specified value is constant.
317 int InlineCostAnalyzer::CountBonusForConstant(Value *V, Constant *C) {
319 for (Value::use_iterator UI = V->use_begin(), E = V->use_end(); UI != E;++UI){
321 if (CallInst *CI = dyn_cast<CallInst>(U)) {
322 // Turning an indirect call into a direct call is a BIG win
323 if (CI->getCalledValue() == V)
324 Bonus += ConstantFunctionBonus(CallSite(CI), C);
325 } else if (InvokeInst *II = dyn_cast<InvokeInst>(U)) {
326 // Turning an indirect call into a direct call is a BIG win
327 if (II->getCalledValue() == V)
328 Bonus += ConstantFunctionBonus(CallSite(II), C);
330 // FIXME: Eliminating conditional branches and switches should
331 // also yield a per-call performance boost.
333 // Figure out the bonuses that wll accrue due to simple constant
335 Instruction &Inst = cast<Instruction>(*U);
337 // We can't constant propagate instructions which have effects or
340 // FIXME: It would be nice to capture the fact that a load from a
341 // pointer-to-constant-global is actually a *really* good thing to zap.
342 // Unfortunately, we don't know the pointer that may get propagated here,
343 // so we can't make this decision.
344 if (Inst.mayReadFromMemory() || Inst.mayHaveSideEffects() ||
345 isa<AllocaInst>(Inst))
348 bool AllOperandsConstant = true;
349 for (unsigned i = 0, e = Inst.getNumOperands(); i != e; ++i)
350 if (!isa<Constant>(Inst.getOperand(i)) && Inst.getOperand(i) != V) {
351 AllOperandsConstant = false;
355 if (AllOperandsConstant)
356 Bonus += CountBonusForConstant(&Inst);
363 int InlineCostAnalyzer::getInlineSize(CallSite CS, Function *Callee) {
364 // Get information about the callee.
365 FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
367 // If we haven't calculated this information yet, do so now.
368 if (CalleeFI->Metrics.NumBlocks == 0)
369 CalleeFI->analyzeFunction(Callee);
371 // InlineCost - This value measures how good of an inline candidate this call
372 // site is to inline. A lower inline cost make is more likely for the call to
373 // be inlined. This value may go negative.
377 // Compute any size reductions we can expect due to arguments being passed into
381 CallSite::arg_iterator I = CS.arg_begin();
382 for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
383 FI != FE; ++I, ++FI, ++ArgNo) {
385 // If an alloca is passed in, inlining this function is likely to allow
386 // significant future optimization possibilities (like scalar promotion, and
387 // scalarization), so encourage the inlining of the function.
389 if (isa<AllocaInst>(I))
390 InlineCost -= CalleeFI->ArgumentWeights[ArgNo].AllocaWeight;
392 // If this is a constant being passed into the function, use the argument
393 // weights calculated for the callee to determine how much will be folded
394 // away with this information.
395 else if (isa<Constant>(I))
396 InlineCost -= CalleeFI->ArgumentWeights[ArgNo].ConstantWeight;
399 // Each argument passed in has a cost at both the caller and the callee
400 // sides. Measurements show that each argument costs about the same as an
402 InlineCost -= (CS.arg_size() * InlineConstants::InstrCost);
404 // Now that we have considered all of the factors that make the call site more
405 // likely to be inlined, look at factors that make us not want to inline it.
407 // Calls usually take a long time, so they make the inlining gain smaller.
408 InlineCost += CalleeFI->Metrics.NumCalls * InlineConstants::CallPenalty;
410 // Look at the size of the callee. Each instruction counts as 5.
411 InlineCost += CalleeFI->Metrics.NumInsts*InlineConstants::InstrCost;
416 int InlineCostAnalyzer::getInlineBonuses(CallSite CS, Function *Callee) {
417 // Get information about the callee.
418 FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
420 // If we haven't calculated this information yet, do so now.
421 if (CalleeFI->Metrics.NumBlocks == 0)
422 CalleeFI->analyzeFunction(Callee);
424 bool isDirectCall = CS.getCalledFunction() == Callee;
425 Instruction *TheCall = CS.getInstruction();
428 // If there is only one call of the function, and it has internal linkage,
429 // make it almost guaranteed to be inlined.
431 if (Callee->hasLocalLinkage() && Callee->hasOneUse() && isDirectCall)
432 Bonus += InlineConstants::LastCallToStaticBonus;
434 // If the instruction after the call, or if the normal destination of the
435 // invoke is an unreachable instruction, the function is noreturn. As such,
436 // there is little point in inlining this.
437 if (InvokeInst *II = dyn_cast<InvokeInst>(TheCall)) {
438 if (isa<UnreachableInst>(II->getNormalDest()->begin()))
439 Bonus += InlineConstants::NoreturnPenalty;
440 } else if (isa<UnreachableInst>(++BasicBlock::iterator(TheCall)))
441 Bonus += InlineConstants::NoreturnPenalty;
443 // If this function uses the coldcc calling convention, prefer not to inline
445 if (Callee->getCallingConv() == CallingConv::Cold)
446 Bonus += InlineConstants::ColdccPenalty;
448 // Add to the inline quality for properties that make the call valuable to
449 // inline. This includes factors that indicate that the result of inlining
450 // the function will be optimizable. Currently this just looks at arguments
451 // passed into the function.
453 CallSite::arg_iterator I = CS.arg_begin();
454 for (Function::arg_iterator FI = Callee->arg_begin(), FE = Callee->arg_end();
456 // Compute any constant bonus due to inlining we want to give here.
457 if (isa<Constant>(I))
458 Bonus += CountBonusForConstant(FI, cast<Constant>(I));
463 // getInlineCost - The heuristic used to determine if we should inline the
464 // function call or not.
466 InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
467 SmallPtrSet<const Function*, 16> &NeverInline) {
468 return getInlineCost(CS, CS.getCalledFunction(), NeverInline);
471 InlineCost InlineCostAnalyzer::getInlineCost(CallSite CS,
473 SmallPtrSet<const Function*, 16> &NeverInline) {
474 Instruction *TheCall = CS.getInstruction();
475 Function *Caller = TheCall->getParent()->getParent();
477 // Don't inline functions which can be redefined at link-time to mean
478 // something else. Don't inline functions marked noinline or call sites
480 if (Callee->mayBeOverridden() ||
481 Callee->hasFnAttr(Attribute::NoInline) || NeverInline.count(Callee) ||
483 return llvm::InlineCost::getNever();
485 // Get information about the callee.
486 FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
488 // If we haven't calculated this information yet, do so now.
489 if (CalleeFI->Metrics.NumBlocks == 0)
490 CalleeFI->analyzeFunction(Callee);
492 // If we should never inline this, return a huge cost.
493 if (CalleeFI->NeverInline())
494 return InlineCost::getNever();
496 // FIXME: It would be nice to kill off CalleeFI->NeverInline. Then we
497 // could move this up and avoid computing the FunctionInfo for
498 // things we are going to just return always inline for. This
499 // requires handling setjmp somewhere else, however.
500 if (!Callee->isDeclaration() && Callee->hasFnAttr(Attribute::AlwaysInline))
501 return InlineCost::getAlways();
503 if (CalleeFI->Metrics.usesDynamicAlloca) {
504 // Get infomation about the caller.
505 FunctionInfo &CallerFI = CachedFunctionInfo[Caller];
507 // If we haven't calculated this information yet, do so now.
508 if (CallerFI.Metrics.NumBlocks == 0) {
509 CallerFI.analyzeFunction(Caller);
511 // Recompute the CalleeFI pointer, getting Caller could have invalidated
513 CalleeFI = &CachedFunctionInfo[Callee];
516 // Don't inline a callee with dynamic alloca into a caller without them.
517 // Functions containing dynamic alloca's are inefficient in various ways;
518 // don't create more inefficiency.
519 if (!CallerFI.Metrics.usesDynamicAlloca)
520 return InlineCost::getNever();
523 // InlineCost - This value measures how good of an inline candidate this call
524 // site is to inline. A lower inline cost make is more likely for the call to
525 // be inlined. This value may go negative due to the fact that bonuses
526 // are negative numbers.
528 int InlineCost = getInlineSize(CS, Callee) + getInlineBonuses(CS, Callee);
529 return llvm::InlineCost::get(InlineCost);
532 // getSpecializationCost - The heuristic used to determine the code-size
533 // impact of creating a specialized version of Callee with argument
534 // SpecializedArgNo replaced by a constant.
535 InlineCost InlineCostAnalyzer::getSpecializationCost(Function *Callee,
536 SmallVectorImpl<unsigned> &SpecializedArgNos)
538 // Don't specialize functions which can be redefined at link-time to mean
540 if (Callee->mayBeOverridden())
541 return llvm::InlineCost::getNever();
543 // Get information about the callee.
544 FunctionInfo *CalleeFI = &CachedFunctionInfo[Callee];
546 // If we haven't calculated this information yet, do so now.
547 if (CalleeFI->Metrics.NumBlocks == 0)
548 CalleeFI->analyzeFunction(Callee);
552 // Look at the orginal size of the callee. Each instruction counts as 5.
553 Cost += CalleeFI->Metrics.NumInsts * InlineConstants::InstrCost;
555 // Offset that with the amount of code that can be constant-folded
556 // away with the given arguments replaced by constants.
557 for (SmallVectorImpl<unsigned>::iterator an = SpecializedArgNos.begin(),
558 ae = SpecializedArgNos.end(); an != ae; ++an)
559 Cost -= CalleeFI->ArgumentWeights[*an].ConstantWeight;
561 return llvm::InlineCost::get(Cost);
564 // getInlineFudgeFactor - Return a > 1.0 factor if the inliner should use a
565 // higher threshold to determine if the function call should be inlined.
566 float InlineCostAnalyzer::getInlineFudgeFactor(CallSite CS) {
567 Function *Callee = CS.getCalledFunction();
569 // Get information about the callee.
570 FunctionInfo &CalleeFI = CachedFunctionInfo[Callee];
572 // If we haven't calculated this information yet, do so now.
573 if (CalleeFI.Metrics.NumBlocks == 0)
574 CalleeFI.analyzeFunction(Callee);
577 // Single BB functions are often written to be inlined.
578 if (CalleeFI.Metrics.NumBlocks == 1)
581 // Be more aggressive if the function contains a good chunk (if it mades up
582 // at least 10% of the instructions) of vector instructions.
583 if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/2)
585 else if (CalleeFI.Metrics.NumVectorInsts > CalleeFI.Metrics.NumInsts/10)
590 /// growCachedCostInfo - update the cached cost info for Caller after Callee has
593 InlineCostAnalyzer::growCachedCostInfo(Function *Caller, Function *Callee) {
594 CodeMetrics &CallerMetrics = CachedFunctionInfo[Caller].Metrics;
596 // For small functions we prefer to recalculate the cost for better accuracy.
597 if (CallerMetrics.NumBlocks < 10 || CallerMetrics.NumInsts < 1000) {
598 resetCachedCostInfo(Caller);
602 // For large functions, we can save a lot of computation time by skipping
604 if (CallerMetrics.NumCalls > 0)
605 --CallerMetrics.NumCalls;
607 if (Callee == 0) return;
609 CodeMetrics &CalleeMetrics = CachedFunctionInfo[Callee].Metrics;
611 // If we don't have metrics for the callee, don't recalculate them just to
612 // update an approximation in the caller. Instead, just recalculate the
613 // caller info from scratch.
614 if (CalleeMetrics.NumBlocks == 0) {
615 resetCachedCostInfo(Caller);
619 // Since CalleeMetrics were already calculated, we know that the CallerMetrics
620 // reference isn't invalidated: both were in the DenseMap.
621 CallerMetrics.usesDynamicAlloca |= CalleeMetrics.usesDynamicAlloca;
623 // FIXME: If any of these three are true for the callee, the callee was
624 // not inlined into the caller, so I think they're redundant here.
625 CallerMetrics.callsSetJmp |= CalleeMetrics.callsSetJmp;
626 CallerMetrics.isRecursive |= CalleeMetrics.isRecursive;
627 CallerMetrics.containsIndirectBr |= CalleeMetrics.containsIndirectBr;
629 CallerMetrics.NumInsts += CalleeMetrics.NumInsts;
630 CallerMetrics.NumBlocks += CalleeMetrics.NumBlocks;
631 CallerMetrics.NumCalls += CalleeMetrics.NumCalls;
632 CallerMetrics.NumVectorInsts += CalleeMetrics.NumVectorInsts;
633 CallerMetrics.NumRets += CalleeMetrics.NumRets;
635 // analyzeBasicBlock counts each function argument as an inst.
636 if (CallerMetrics.NumInsts >= Callee->arg_size())
637 CallerMetrics.NumInsts -= Callee->arg_size();
639 CallerMetrics.NumInsts = 0;
641 // We are not updating the argument weights. We have already determined that
642 // Caller is a fairly large function, so we accept the loss of precision.
645 /// clear - empty the cache of inline costs
646 void InlineCostAnalyzer::clear() {
647 CachedFunctionInfo.clear();