1 //===- Inliner.cpp - Code common to all inliners --------------------------===//
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 the mechanics required to implement inlining without
11 // missing any calls and updating the call graph. The decisions of which calls
12 // are profitable to inline are implemented elsewhere.
14 //===----------------------------------------------------------------------===//
16 #define DEBUG_TYPE "inline"
17 #include "llvm/Transforms/IPO/InlinerPass.h"
18 #include "llvm/ADT/SmallPtrSet.h"
19 #include "llvm/ADT/Statistic.h"
20 #include "llvm/Analysis/CallGraph.h"
21 #include "llvm/Analysis/InlineCost.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/Instructions.h"
24 #include "llvm/IR/IntrinsicInst.h"
25 #include "llvm/IR/Module.h"
26 #include "llvm/Support/CallSite.h"
27 #include "llvm/Support/CommandLine.h"
28 #include "llvm/Support/Debug.h"
29 #include "llvm/Support/raw_ostream.h"
30 #include "llvm/Target/TargetLibraryInfo.h"
31 #include "llvm/Transforms/Utils/Cloning.h"
32 #include "llvm/Transforms/Utils/Local.h"
35 STATISTIC(NumInlined, "Number of functions inlined");
36 STATISTIC(NumCallsDeleted, "Number of call sites deleted, not inlined");
37 STATISTIC(NumDeleted, "Number of functions deleted because all callers found");
38 STATISTIC(NumMergedAllocas, "Number of allocas merged together");
40 // This weirdly named statistic tracks the number of times that, when attempting
41 // to inline a function A into B, we analyze the callers of B in order to see
42 // if those would be more profitable and blocked inline steps.
43 STATISTIC(NumCallerCallersAnalyzed, "Number of caller-callers analyzed");
46 InlineLimit("inline-threshold", cl::Hidden, cl::init(225), cl::ZeroOrMore,
47 cl::desc("Control the amount of inlining to perform (default = 225)"));
50 HintThreshold("inlinehint-threshold", cl::Hidden, cl::init(325),
51 cl::desc("Threshold for inlining functions with inline hint"));
53 // Threshold to use when optsize is specified (and there is no -inline-limit).
54 const int OptSizeThreshold = 75;
56 Inliner::Inliner(char &ID)
57 : CallGraphSCCPass(ID), InlineThreshold(InlineLimit), InsertLifetime(true) {}
59 Inliner::Inliner(char &ID, int Threshold, bool InsertLifetime)
60 : CallGraphSCCPass(ID), InlineThreshold(InlineLimit.getNumOccurrences() > 0 ?
61 InlineLimit : Threshold),
62 InsertLifetime(InsertLifetime) {}
64 /// getAnalysisUsage - For this class, we declare that we require and preserve
65 /// the call graph. If the derived class implements this method, it should
66 /// always explicitly call the implementation here.
67 void Inliner::getAnalysisUsage(AnalysisUsage &AU) const {
68 CallGraphSCCPass::getAnalysisUsage(AU);
72 typedef DenseMap<ArrayType*, std::vector<AllocaInst*> >
73 InlinedArrayAllocasTy;
75 /// \brief If the inlined function had a higher stack protection level than the
76 /// calling function, then bump up the caller's stack protection level.
77 static void AdjustCallerSSPLevel(Function *Caller, Function *Callee) {
78 // If upgrading the SSP attribute, clear out the old SSP Attributes first.
79 // Having multiple SSP attributes doesn't actually hurt, but it adds useless
82 B.addAttribute(Attribute::StackProtect)
83 .addAttribute(Attribute::StackProtectStrong);
84 AttributeSet OldSSPAttr = AttributeSet::get(Caller->getContext(),
85 AttributeSet::FunctionIndex,
87 AttributeSet CallerAttr = Caller->getAttributes(),
88 CalleeAttr = Callee->getAttributes();
90 if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
91 Attribute::StackProtectReq)) {
92 Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
93 Caller->addFnAttr(Attribute::StackProtectReq);
94 } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
95 Attribute::StackProtectStrong) &&
96 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
97 Attribute::StackProtectReq)) {
98 Caller->removeAttributes(AttributeSet::FunctionIndex, OldSSPAttr);
99 Caller->addFnAttr(Attribute::StackProtectStrong);
100 } else if (CalleeAttr.hasAttribute(AttributeSet::FunctionIndex,
101 Attribute::StackProtect) &&
102 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
103 Attribute::StackProtectReq) &&
104 !CallerAttr.hasAttribute(AttributeSet::FunctionIndex,
105 Attribute::StackProtectStrong))
106 Caller->addFnAttr(Attribute::StackProtect);
109 /// InlineCallIfPossible - If it is possible to inline the specified call site,
110 /// do so and update the CallGraph for this operation.
112 /// This function also does some basic book-keeping to update the IR. The
113 /// InlinedArrayAllocas map keeps track of any allocas that are already
114 /// available from other functions inlined into the caller. If we are able to
115 /// inline this call site we attempt to reuse already available allocas or add
116 /// any new allocas to the set if not possible.
117 static bool InlineCallIfPossible(CallSite CS, InlineFunctionInfo &IFI,
118 InlinedArrayAllocasTy &InlinedArrayAllocas,
119 int InlineHistory, bool InsertLifetime,
120 const DataLayout *TD) {
121 Function *Callee = CS.getCalledFunction();
122 Function *Caller = CS.getCaller();
124 // Try to inline the function. Get the list of static allocas that were
126 if (!InlineFunction(CS, IFI, InsertLifetime))
129 AdjustCallerSSPLevel(Caller, Callee);
131 // Look at all of the allocas that we inlined through this call site. If we
132 // have already inlined other allocas through other calls into this function,
133 // then we know that they have disjoint lifetimes and that we can merge them.
135 // There are many heuristics possible for merging these allocas, and the
136 // different options have different tradeoffs. One thing that we *really*
137 // don't want to hurt is SRoA: once inlining happens, often allocas are no
138 // longer address taken and so they can be promoted.
140 // Our "solution" for that is to only merge allocas whose outermost type is an
141 // array type. These are usually not promoted because someone is using a
142 // variable index into them. These are also often the most important ones to
145 // A better solution would be to have real memory lifetime markers in the IR
146 // and not have the inliner do any merging of allocas at all. This would
147 // allow the backend to do proper stack slot coloring of all allocas that
148 // *actually make it to the backend*, which is really what we want.
150 // Because we don't have this information, we do this simple and useful hack.
152 SmallPtrSet<AllocaInst*, 16> UsedAllocas;
154 // When processing our SCC, check to see if CS was inlined from some other
155 // call site. For example, if we're processing "A" in this code:
157 // B() { x = alloca ... C() }
158 // C() { y = alloca ... }
159 // Assume that C was not inlined into B initially, and so we're processing A
160 // and decide to inline B into A. Doing this makes an alloca available for
161 // reuse and makes a callsite (C) available for inlining. When we process
162 // the C call site we don't want to do any alloca merging between X and Y
163 // because their scopes are not disjoint. We could make this smarter by
164 // keeping track of the inline history for each alloca in the
165 // InlinedArrayAllocas but this isn't likely to be a significant win.
166 if (InlineHistory != -1) // Only do merging for top-level call sites in SCC.
169 // Loop over all the allocas we have so far and see if they can be merged with
170 // a previously inlined alloca. If not, remember that we had it.
171 for (unsigned AllocaNo = 0, e = IFI.StaticAllocas.size();
172 AllocaNo != e; ++AllocaNo) {
173 AllocaInst *AI = IFI.StaticAllocas[AllocaNo];
175 // Don't bother trying to merge array allocations (they will usually be
176 // canonicalized to be an allocation *of* an array), or allocations whose
177 // type is not itself an array (because we're afraid of pessimizing SRoA).
178 ArrayType *ATy = dyn_cast<ArrayType>(AI->getAllocatedType());
179 if (ATy == 0 || AI->isArrayAllocation())
182 // Get the list of all available allocas for this array type.
183 std::vector<AllocaInst*> &AllocasForType = InlinedArrayAllocas[ATy];
185 // Loop over the allocas in AllocasForType to see if we can reuse one. Note
186 // that we have to be careful not to reuse the same "available" alloca for
187 // multiple different allocas that we just inlined, we use the 'UsedAllocas'
188 // set to keep track of which "available" allocas are being used by this
189 // function. Also, AllocasForType can be empty of course!
190 bool MergedAwayAlloca = false;
191 for (unsigned i = 0, e = AllocasForType.size(); i != e; ++i) {
192 AllocaInst *AvailableAlloca = AllocasForType[i];
194 unsigned Align1 = AI->getAlignment(),
195 Align2 = AvailableAlloca->getAlignment();
196 // If we don't have data layout information, and only one alloca is using
197 // the target default, then we can't safely merge them because we can't
198 // pick the greater alignment.
199 if (!TD && (!Align1 || !Align2) && Align1 != Align2)
202 // The available alloca has to be in the right function, not in some other
203 // function in this SCC.
204 if (AvailableAlloca->getParent() != AI->getParent())
207 // If the inlined function already uses this alloca then we can't reuse
209 if (!UsedAllocas.insert(AvailableAlloca))
212 // Otherwise, we *can* reuse it, RAUW AI into AvailableAlloca and declare
214 DEBUG(dbgs() << " ***MERGED ALLOCA: " << *AI << "\n\t\tINTO: "
215 << *AvailableAlloca << '\n');
217 AI->replaceAllUsesWith(AvailableAlloca);
219 if (Align1 != Align2) {
220 if (!Align1 || !Align2) {
221 assert(TD && "DataLayout required to compare default alignments");
222 unsigned TypeAlign = TD->getABITypeAlignment(AI->getAllocatedType());
224 Align1 = Align1 ? Align1 : TypeAlign;
225 Align2 = Align2 ? Align2 : TypeAlign;
229 AvailableAlloca->setAlignment(AI->getAlignment());
232 AI->eraseFromParent();
233 MergedAwayAlloca = true;
235 IFI.StaticAllocas[AllocaNo] = 0;
239 // If we already nuked the alloca, we're done with it.
240 if (MergedAwayAlloca)
243 // If we were unable to merge away the alloca either because there are no
244 // allocas of the right type available or because we reused them all
245 // already, remember that this alloca came from an inlined function and mark
246 // it used so we don't reuse it for other allocas from this inline
248 AllocasForType.push_back(AI);
249 UsedAllocas.insert(AI);
255 unsigned Inliner::getInlineThreshold(CallSite CS) const {
256 int thres = InlineThreshold; // -inline-threshold or else selected by
259 // If -inline-threshold is not given, listen to the optsize attribute when it
260 // would decrease the threshold.
261 Function *Caller = CS.getCaller();
262 bool OptSize = Caller && !Caller->isDeclaration() &&
263 Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
264 Attribute::OptimizeForSize);
265 if (!(InlineLimit.getNumOccurrences() > 0) && OptSize &&
266 OptSizeThreshold < thres)
267 thres = OptSizeThreshold;
269 // Listen to the inlinehint attribute when it would increase the threshold
270 // and the caller does not need to minimize its size.
271 Function *Callee = CS.getCalledFunction();
272 bool InlineHint = Callee && !Callee->isDeclaration() &&
273 Callee->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
274 Attribute::InlineHint);
275 if (InlineHint && HintThreshold > thres
276 && !Caller->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
278 thres = HintThreshold;
283 /// shouldInline - Return true if the inliner should attempt to inline
284 /// at the given CallSite.
285 bool Inliner::shouldInline(CallSite CS) {
286 InlineCost IC = getInlineCost(CS);
289 DEBUG(dbgs() << " Inlining: cost=always"
290 << ", Call: " << *CS.getInstruction() << "\n");
295 DEBUG(dbgs() << " NOT Inlining: cost=never"
296 << ", Call: " << *CS.getInstruction() << "\n");
300 Function *Caller = CS.getCaller();
302 DEBUG(dbgs() << " NOT Inlining: cost=" << IC.getCost()
303 << ", thres=" << (IC.getCostDelta() + IC.getCost())
304 << ", Call: " << *CS.getInstruction() << "\n");
308 // Try to detect the case where the current inlining candidate caller (call
309 // it B) is a static or linkonce-ODR function and is an inlining candidate
310 // elsewhere, and the current candidate callee (call it C) is large enough
311 // that inlining it into B would make B too big to inline later. In these
312 // circumstances it may be best not to inline C into B, but to inline B into
315 // This only applies to static and linkonce-ODR functions because those are
316 // expected to be available for inlining in the translation units where they
317 // are used. Thus we will always have the opportunity to make local inlining
318 // decisions. Importantly the linkonce-ODR linkage covers inline functions
319 // and templates in C++.
321 // FIXME: All of this logic should be sunk into getInlineCost. It relies on
322 // the internal implementation of the inline cost metrics rather than
323 // treating them as truly abstract units etc.
324 if (Caller->hasLocalLinkage() ||
325 Caller->getLinkage() == GlobalValue::LinkOnceODRLinkage) {
326 int TotalSecondaryCost = 0;
327 // The candidate cost to be imposed upon the current function.
328 int CandidateCost = IC.getCost() - (InlineConstants::CallPenalty + 1);
329 // This bool tracks what happens if we do NOT inline C into B.
330 bool callerWillBeRemoved = Caller->hasLocalLinkage();
331 // This bool tracks what happens if we DO inline C into B.
332 bool inliningPreventsSomeOuterInline = false;
333 for (Value::use_iterator I = Caller->use_begin(), E =Caller->use_end();
337 // If this isn't a call to Caller (it could be some other sort
338 // of reference) skip it. Such references will prevent the caller
339 // from being removed.
340 if (!CS2 || CS2.getCalledFunction() != Caller) {
341 callerWillBeRemoved = false;
345 InlineCost IC2 = getInlineCost(CS2);
346 ++NumCallerCallersAnalyzed;
348 callerWillBeRemoved = false;
354 // See if inlining or original callsite would erase the cost delta of
355 // this callsite. We subtract off the penalty for the call instruction,
356 // which we would be deleting.
357 if (IC2.getCostDelta() <= CandidateCost) {
358 inliningPreventsSomeOuterInline = true;
359 TotalSecondaryCost += IC2.getCost();
362 // If all outer calls to Caller would get inlined, the cost for the last
363 // one is set very low by getInlineCost, in anticipation that Caller will
364 // be removed entirely. We did not account for this above unless there
365 // is only one caller of Caller.
366 if (callerWillBeRemoved && Caller->use_begin() != Caller->use_end())
367 TotalSecondaryCost += InlineConstants::LastCallToStaticBonus;
369 if (inliningPreventsSomeOuterInline && TotalSecondaryCost < IC.getCost()) {
370 DEBUG(dbgs() << " NOT Inlining: " << *CS.getInstruction() <<
371 " Cost = " << IC.getCost() <<
372 ", outer Cost = " << TotalSecondaryCost << '\n');
377 DEBUG(dbgs() << " Inlining: cost=" << IC.getCost()
378 << ", thres=" << (IC.getCostDelta() + IC.getCost())
379 << ", Call: " << *CS.getInstruction() << '\n');
383 /// InlineHistoryIncludes - Return true if the specified inline history ID
384 /// indicates an inline history that includes the specified function.
385 static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
386 const SmallVectorImpl<std::pair<Function*, int> > &InlineHistory) {
387 while (InlineHistoryID != -1) {
388 assert(unsigned(InlineHistoryID) < InlineHistory.size() &&
389 "Invalid inline history ID");
390 if (InlineHistory[InlineHistoryID].first == F)
392 InlineHistoryID = InlineHistory[InlineHistoryID].second;
397 bool Inliner::runOnSCC(CallGraphSCC &SCC) {
398 CallGraph &CG = getAnalysis<CallGraph>();
399 const DataLayout *TD = getAnalysisIfAvailable<DataLayout>();
400 const TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
402 SmallPtrSet<Function*, 8> SCCFunctions;
403 DEBUG(dbgs() << "Inliner visiting SCC:");
404 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
405 Function *F = (*I)->getFunction();
406 if (F) SCCFunctions.insert(F);
407 DEBUG(dbgs() << " " << (F ? F->getName() : "INDIRECTNODE"));
410 // Scan through and identify all call sites ahead of time so that we only
411 // inline call sites in the original functions, not call sites that result
412 // from inlining other functions.
413 SmallVector<std::pair<CallSite, int>, 16> CallSites;
415 // When inlining a callee produces new call sites, we want to keep track of
416 // the fact that they were inlined from the callee. This allows us to avoid
417 // infinite inlining in some obscure cases. To represent this, we use an
418 // index into the InlineHistory vector.
419 SmallVector<std::pair<Function*, int>, 8> InlineHistory;
421 for (CallGraphSCC::iterator I = SCC.begin(), E = SCC.end(); I != E; ++I) {
422 Function *F = (*I)->getFunction();
425 for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
426 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) {
427 CallSite CS(cast<Value>(I));
428 // If this isn't a call, or it is a call to an intrinsic, it can
430 if (!CS || isa<IntrinsicInst>(I))
433 // If this is a direct call to an external function, we can never inline
434 // it. If it is an indirect call, inlining may resolve it to be a
435 // direct call, so we keep it.
436 if (CS.getCalledFunction() && CS.getCalledFunction()->isDeclaration())
439 CallSites.push_back(std::make_pair(CS, -1));
443 DEBUG(dbgs() << ": " << CallSites.size() << " call sites.\n");
445 // If there are no calls in this function, exit early.
446 if (CallSites.empty())
449 // Now that we have all of the call sites, move the ones to functions in the
450 // current SCC to the end of the list.
451 unsigned FirstCallInSCC = CallSites.size();
452 for (unsigned i = 0; i < FirstCallInSCC; ++i)
453 if (Function *F = CallSites[i].first.getCalledFunction())
454 if (SCCFunctions.count(F))
455 std::swap(CallSites[i--], CallSites[--FirstCallInSCC]);
458 InlinedArrayAllocasTy InlinedArrayAllocas;
459 InlineFunctionInfo InlineInfo(&CG, TD);
461 // Now that we have all of the call sites, loop over them and inline them if
462 // it looks profitable to do so.
463 bool Changed = false;
467 // Iterate over the outer loop because inlining functions can cause indirect
468 // calls to become direct calls.
469 for (unsigned CSi = 0; CSi != CallSites.size(); ++CSi) {
470 CallSite CS = CallSites[CSi].first;
472 Function *Caller = CS.getCaller();
473 Function *Callee = CS.getCalledFunction();
475 // If this call site is dead and it is to a readonly function, we should
476 // just delete the call instead of trying to inline it, regardless of
477 // size. This happens because IPSCCP propagates the result out of the
478 // call and then we're left with the dead call.
479 if (isInstructionTriviallyDead(CS.getInstruction(), TLI)) {
480 DEBUG(dbgs() << " -> Deleting dead call: "
481 << *CS.getInstruction() << "\n");
482 // Update the call graph by deleting the edge from Callee to Caller.
483 CG[Caller]->removeCallEdgeFor(CS);
484 CS.getInstruction()->eraseFromParent();
487 // We can only inline direct calls to non-declarations.
488 if (Callee == 0 || Callee->isDeclaration()) continue;
490 // If this call site was obtained by inlining another function, verify
491 // that the include path for the function did not include the callee
492 // itself. If so, we'd be recursively inlining the same function,
493 // which would provide the same callsites, which would cause us to
494 // infinitely inline.
495 int InlineHistoryID = CallSites[CSi].second;
496 if (InlineHistoryID != -1 &&
497 InlineHistoryIncludes(Callee, InlineHistoryID, InlineHistory))
501 // If the policy determines that we should inline this function,
503 if (!shouldInline(CS))
506 // Attempt to inline the function.
507 if (!InlineCallIfPossible(CS, InlineInfo, InlinedArrayAllocas,
508 InlineHistoryID, InsertLifetime, TD))
512 // If inlining this function gave us any new call sites, throw them
513 // onto our worklist to process. They are useful inline candidates.
514 if (!InlineInfo.InlinedCalls.empty()) {
515 // Create a new inline history entry for this, so that we remember
516 // that these new callsites came about due to inlining Callee.
517 int NewHistoryID = InlineHistory.size();
518 InlineHistory.push_back(std::make_pair(Callee, InlineHistoryID));
520 for (unsigned i = 0, e = InlineInfo.InlinedCalls.size();
522 Value *Ptr = InlineInfo.InlinedCalls[i];
523 CallSites.push_back(std::make_pair(CallSite(Ptr), NewHistoryID));
528 // If we inlined or deleted the last possible call site to the function,
529 // delete the function body now.
530 if (Callee && Callee->use_empty() && Callee->hasLocalLinkage() &&
531 // TODO: Can remove if in SCC now.
532 !SCCFunctions.count(Callee) &&
534 // The function may be apparently dead, but if there are indirect
535 // callgraph references to the node, we cannot delete it yet, this
536 // could invalidate the CGSCC iterator.
537 CG[Callee]->getNumReferences() == 0) {
538 DEBUG(dbgs() << " -> Deleting dead function: "
539 << Callee->getName() << "\n");
540 CallGraphNode *CalleeNode = CG[Callee];
542 // Remove any call graph edges from the callee to its callees.
543 CalleeNode->removeAllCalledFunctions();
545 // Removing the node for callee from the call graph and delete it.
546 delete CG.removeFunctionFromModule(CalleeNode);
550 // Remove this call site from the list. If possible, use
551 // swap/pop_back for efficiency, but do not use it if doing so would
552 // move a call site to a function in this SCC before the
553 // 'FirstCallInSCC' barrier.
554 if (SCC.isSingular()) {
555 CallSites[CSi] = CallSites.back();
556 CallSites.pop_back();
558 CallSites.erase(CallSites.begin()+CSi);
565 } while (LocalChange);
570 // doFinalization - Remove now-dead linkonce functions at the end of
571 // processing to avoid breaking the SCC traversal.
572 bool Inliner::doFinalization(CallGraph &CG) {
573 return removeDeadFunctions(CG);
576 /// removeDeadFunctions - Remove dead functions that are not included in
577 /// DNR (Do Not Remove) list.
578 bool Inliner::removeDeadFunctions(CallGraph &CG, bool AlwaysInlineOnly) {
579 SmallVector<CallGraphNode*, 16> FunctionsToRemove;
581 // Scan for all of the functions, looking for ones that should now be removed
582 // from the program. Insert the dead ones in the FunctionsToRemove set.
583 for (CallGraph::iterator I = CG.begin(), E = CG.end(); I != E; ++I) {
584 CallGraphNode *CGN = I->second;
585 Function *F = CGN->getFunction();
586 if (!F || F->isDeclaration())
589 // Handle the case when this function is called and we only want to care
590 // about always-inline functions. This is a bit of a hack to share code
591 // between here and the InlineAlways pass.
592 if (AlwaysInlineOnly &&
593 !F->getAttributes().hasAttribute(AttributeSet::FunctionIndex,
594 Attribute::AlwaysInline))
597 // If the only remaining users of the function are dead constants, remove
599 F->removeDeadConstantUsers();
601 if (!F->isDefTriviallyDead())
604 // Remove any call graph edges from the function to its callees.
605 CGN->removeAllCalledFunctions();
607 // Remove any edges from the external node to the function's call graph
608 // node. These edges might have been made irrelegant due to
609 // optimization of the program.
610 CG.getExternalCallingNode()->removeAnyCallEdgeTo(CGN);
612 // Removing the node for callee from the call graph and delete it.
613 FunctionsToRemove.push_back(CGN);
615 if (FunctionsToRemove.empty())
618 // Now that we know which functions to delete, do so. We didn't want to do
619 // this inline, because that would invalidate our CallGraph::iterator
622 // Note that it doesn't matter that we are iterating over a non-stable order
623 // here to do this, it doesn't matter which order the functions are deleted
625 array_pod_sort(FunctionsToRemove.begin(), FunctionsToRemove.end());
626 FunctionsToRemove.erase(std::unique(FunctionsToRemove.begin(),
627 FunctionsToRemove.end()),
628 FunctionsToRemove.end());
629 for (SmallVectorImpl<CallGraphNode *>::iterator I = FunctionsToRemove.begin(),
630 E = FunctionsToRemove.end();
632 delete CG.removeFunctionFromModule(*I);