1 //===- CGSCCPassManager.cpp - Managing & running CGSCC passes -------------===//
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 #include "llvm/Analysis/CGSCCPassManager.h"
11 #include "llvm/IR/CallSite.h"
12 #include "llvm/IR/InstIterator.h"
16 // Explicit template instantiations and specialization defininitions for core
20 // Explicit instantiations for the core proxy templates.
21 template class AllAnalysesOn<LazyCallGraph::SCC>;
22 template class AnalysisManager<LazyCallGraph::SCC, LazyCallGraph &>;
23 template class PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager,
24 LazyCallGraph &, CGSCCUpdateResult &>;
25 template class InnerAnalysisManagerProxy<CGSCCAnalysisManager, Module>;
26 template class OuterAnalysisManagerProxy<ModuleAnalysisManager,
27 LazyCallGraph::SCC, LazyCallGraph &>;
28 template class OuterAnalysisManagerProxy<CGSCCAnalysisManager, Function>;
30 /// Explicitly specialize the pass manager run method to handle call graph
34 PassManager<LazyCallGraph::SCC, CGSCCAnalysisManager, LazyCallGraph &,
35 CGSCCUpdateResult &>::run(LazyCallGraph::SCC &InitialC,
36 CGSCCAnalysisManager &AM,
37 LazyCallGraph &G, CGSCCUpdateResult &UR) {
38 PreservedAnalyses PA = PreservedAnalyses::all();
41 dbgs() << "Starting CGSCC pass manager run.\n";
43 // The SCC may be refined while we are running passes over it, so set up
44 // a pointer that we can update.
45 LazyCallGraph::SCC *C = &InitialC;
47 for (auto &Pass : Passes) {
49 dbgs() << "Running pass: " << Pass->name() << " on " << *C << "\n";
51 PreservedAnalyses PassPA = Pass->run(*C, AM, G, UR);
53 // Update the SCC if necessary.
54 C = UR.UpdatedC ? UR.UpdatedC : C;
56 // Check that we didn't miss any update scenario.
57 assert(!UR.InvalidatedSCCs.count(C) && "Processing an invalid SCC!");
58 assert(C->begin() != C->end() && "Cannot have an empty SCC!");
60 // Update the analysis manager as each pass runs and potentially
61 // invalidates analyses.
62 AM.invalidate(*C, PassPA);
64 // Finally, we intersect the final preserved analyses to compute the
65 // aggregate preserved set for this pass manager.
66 PA.intersect(std::move(PassPA));
68 // FIXME: Historically, the pass managers all called the LLVM context's
69 // yield function here. We don't have a generic way to acquire the
70 // context and it isn't yet clear what the right pattern is for yielding
71 // in the new pass manager so it is currently omitted.
72 // ...getContext().yield();
75 // Invaliadtion was handled after each pass in the above loop for the current
76 // SCC. Therefore, the remaining analysis results in the AnalysisManager are
77 // preserved. We mark this with a set so that we don't need to inspect each
79 PA.preserveSet<AllAnalysesOn<LazyCallGraph::SCC>>();
82 dbgs() << "Finished CGSCC pass manager run.\n";
87 bool CGSCCAnalysisManagerModuleProxy::Result::invalidate(
88 Module &M, const PreservedAnalyses &PA,
89 ModuleAnalysisManager::Invalidator &Inv) {
90 // If literally everything is preserved, we're done.
91 if (PA.areAllPreserved())
92 return false; // This is still a valid proxy.
94 // If this proxy or the call graph is going to be invalidated, we also need
95 // to clear all the keys coming from that analysis.
97 // We also directly invalidate the FAM's module proxy if necessary, and if
98 // that proxy isn't preserved we can't preserve this proxy either. We rely on
99 // it to handle module -> function analysis invalidation in the face of
100 // structural changes and so if it's unavailable we conservatively clear the
101 // entire SCC layer as well rather than trying to do invalidation ourselves.
102 auto PAC = PA.getChecker<CGSCCAnalysisManagerModuleProxy>();
103 if (!(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Module>>()) ||
104 Inv.invalidate<LazyCallGraphAnalysis>(M, PA) ||
105 Inv.invalidate<FunctionAnalysisManagerModuleProxy>(M, PA)) {
108 // And the proxy itself should be marked as invalid so that we can observe
109 // the new call graph. This isn't strictly necessary because we cheat
110 // above, but is still useful.
114 // Directly check if the relevant set is preserved so we can short circuit
115 // invalidating SCCs below.
116 bool AreSCCAnalysesPreserved =
117 PA.allAnalysesInSetPreserved<AllAnalysesOn<LazyCallGraph::SCC>>();
119 // Ok, we have a graph, so we can propagate the invalidation down into it.
121 for (auto &RC : G->postorder_ref_sccs())
123 Optional<PreservedAnalyses> InnerPA;
125 // Check to see whether the preserved set needs to be adjusted based on
126 // module-level analysis invalidation triggering deferred invalidation
128 if (auto *OuterProxy =
129 InnerAM->getCachedResult<ModuleAnalysisManagerCGSCCProxy>(C))
130 for (const auto &OuterInvalidationPair :
131 OuterProxy->getOuterInvalidations()) {
132 AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
133 const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
134 if (Inv.invalidate(OuterAnalysisID, M, PA)) {
137 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
138 InnerPA->abandon(InnerAnalysisID);
142 // Check if we needed a custom PA set. If so we'll need to run the inner
145 InnerAM->invalidate(C, *InnerPA);
149 // Otherwise we only need to do invalidation if the original PA set didn't
150 // preserve all SCC analyses.
151 if (!AreSCCAnalysesPreserved)
152 InnerAM->invalidate(C, PA);
155 // Return false to indicate that this result is still a valid proxy.
160 CGSCCAnalysisManagerModuleProxy::Result
161 CGSCCAnalysisManagerModuleProxy::run(Module &M, ModuleAnalysisManager &AM) {
162 // Force the Function analysis manager to also be available so that it can
163 // be accessed in an SCC analysis and proxied onward to function passes.
164 // FIXME: It is pretty awkward to just drop the result here and assert that
165 // we can find it again later.
166 (void)AM.getResult<FunctionAnalysisManagerModuleProxy>(M);
168 return Result(*InnerAM, AM.getResult<LazyCallGraphAnalysis>(M));
171 AnalysisKey FunctionAnalysisManagerCGSCCProxy::Key;
173 FunctionAnalysisManagerCGSCCProxy::Result
174 FunctionAnalysisManagerCGSCCProxy::run(LazyCallGraph::SCC &C,
175 CGSCCAnalysisManager &AM,
177 // Collect the FunctionAnalysisManager from the Module layer and use that to
178 // build the proxy result.
180 // This allows us to rely on the FunctionAnalysisMangaerModuleProxy to
181 // invalidate the function analyses.
182 auto &MAM = AM.getResult<ModuleAnalysisManagerCGSCCProxy>(C, CG).getManager();
183 Module &M = *C.begin()->getFunction().getParent();
184 auto *FAMProxy = MAM.getCachedResult<FunctionAnalysisManagerModuleProxy>(M);
185 assert(FAMProxy && "The CGSCC pass manager requires that the FAM module "
186 "proxy is run on the module prior to entering the CGSCC "
189 // Note that we special-case invalidation handling of this proxy in the CGSCC
190 // analysis manager's Module proxy. This avoids the need to do anything
191 // special here to recompute all of this if ever the FAM's module proxy goes
193 return Result(FAMProxy->getManager());
196 bool FunctionAnalysisManagerCGSCCProxy::Result::invalidate(
197 LazyCallGraph::SCC &C, const PreservedAnalyses &PA,
198 CGSCCAnalysisManager::Invalidator &Inv) {
199 // If literally everything is preserved, we're done.
200 if (PA.areAllPreserved())
201 return false; // This is still a valid proxy.
203 // If this proxy isn't marked as preserved, then even if the result remains
204 // valid, the key itself may no longer be valid, so we clear everything.
206 // Note that in order to preserve this proxy, a module pass must ensure that
207 // the FAM has been completely updated to handle the deletion of functions.
208 // Specifically, any FAM-cached results for those functions need to have been
209 // forcibly cleared. When preserved, this proxy will only invalidate results
210 // cached on functions *still in the module* at the end of the module pass.
211 auto PAC = PA.getChecker<FunctionAnalysisManagerCGSCCProxy>();
212 if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<LazyCallGraph::SCC>>()) {
213 for (LazyCallGraph::Node &N : C)
214 FAM->clear(N.getFunction());
219 // Directly check if the relevant set is preserved.
220 bool AreFunctionAnalysesPreserved =
221 PA.allAnalysesInSetPreserved<AllAnalysesOn<Function>>();
223 // Now walk all the functions to see if any inner analysis invalidation is
225 for (LazyCallGraph::Node &N : C) {
226 Function &F = N.getFunction();
227 Optional<PreservedAnalyses> FunctionPA;
229 // Check to see whether the preserved set needs to be pruned based on
230 // SCC-level analysis invalidation that triggers deferred invalidation
231 // registered with the outer analysis manager proxy for this function.
232 if (auto *OuterProxy =
233 FAM->getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F))
234 for (const auto &OuterInvalidationPair :
235 OuterProxy->getOuterInvalidations()) {
236 AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
237 const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
238 if (Inv.invalidate(OuterAnalysisID, C, PA)) {
241 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
242 FunctionPA->abandon(InnerAnalysisID);
246 // Check if we needed a custom PA set, and if so we'll need to run the
247 // inner invalidation.
249 FAM->invalidate(F, *FunctionPA);
253 // Otherwise we only need to do invalidation if the original PA set didn't
254 // preserve all function analyses.
255 if (!AreFunctionAnalysesPreserved)
256 FAM->invalidate(F, PA);
259 // Return false to indicate that this result is still a valid proxy.
263 } // End llvm namespace
265 /// When a new SCC is created for the graph and there might be function
266 /// analysis results cached for the functions now in that SCC two forms of
267 /// updates are required.
269 /// First, a proxy from the SCC to the FunctionAnalysisManager needs to be
270 /// created so that any subsequent invalidation events to the SCC are
271 /// propagated to the function analysis results cached for functions within it.
273 /// Second, if any of the functions within the SCC have analysis results with
274 /// outer analysis dependencies, then those dependencies would point to the
275 /// *wrong* SCC's analysis result. We forcibly invalidate the necessary
276 /// function analyses so that they don't retain stale handles.
277 static void updateNewSCCFunctionAnalyses(LazyCallGraph::SCC &C,
279 CGSCCAnalysisManager &AM) {
280 // Get the relevant function analysis manager.
282 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(C, G).getManager();
284 // Now walk the functions in this SCC and invalidate any function analysis
285 // results that might have outer dependencies on an SCC analysis.
286 for (LazyCallGraph::Node &N : C) {
287 Function &F = N.getFunction();
290 FAM.getCachedResult<CGSCCAnalysisManagerFunctionProxy>(F);
292 // No outer analyses were queried, nothing to do.
295 // Forcibly abandon all the inner analyses with dependencies, but
296 // invalidate nothing else.
297 auto PA = PreservedAnalyses::all();
298 for (const auto &OuterInvalidationPair :
299 OuterProxy->getOuterInvalidations()) {
300 const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
301 for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
302 PA.abandon(InnerAnalysisID);
305 // Now invalidate anything we found.
306 FAM.invalidate(F, PA);
311 /// Helper function to update both the \c CGSCCAnalysisManager \p AM and the \c
312 /// CGSCCPassManager's \c CGSCCUpdateResult \p UR based on a range of newly
315 /// The range of new SCCs must be in postorder already. The SCC they were split
316 /// out of must be provided as \p C. The current node being mutated and
317 /// triggering updates must be passed as \p N.
319 /// This function returns the SCC containing \p N. This will be either \p C if
320 /// no new SCCs have been split out, or it will be the new SCC containing \p N.
321 template <typename SCCRangeT>
323 incorporateNewSCCRange(const SCCRangeT &NewSCCRange, LazyCallGraph &G,
324 LazyCallGraph::Node &N, LazyCallGraph::SCC *C,
325 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR,
326 bool DebugLogging = false) {
327 typedef LazyCallGraph::SCC SCC;
329 if (NewSCCRange.begin() == NewSCCRange.end())
332 // Add the current SCC to the worklist as its shape has changed.
333 UR.CWorklist.insert(C);
335 dbgs() << "Enqueuing the existing SCC in the worklist:" << *C << "\n";
339 // Update the current SCC. Note that if we have new SCCs, this must actually
341 assert(C != &*NewSCCRange.begin() &&
342 "Cannot insert new SCCs without changing current SCC!");
343 C = &*NewSCCRange.begin();
344 assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
346 // If we had a cached FAM proxy originally, we will want to create more of
347 // them for each SCC that was split off.
349 AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(*OldC) != nullptr;
351 // We need to propagate an invalidation call to all but the newly current SCC
352 // because the outer pass manager won't do that for us after splitting them.
353 // FIXME: We should accept a PreservedAnalysis from the CG updater so that if
354 // there are preserved ananalyses we can avoid invalidating them here for
356 // We know however that this will preserve any FAM proxy so go ahead and mark
358 PreservedAnalyses PA;
359 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
360 AM.invalidate(*OldC, PA);
362 // Ensure the now-current SCC's function analyses are updated.
364 updateNewSCCFunctionAnalyses(*C, G, AM);
367 reverse(make_range(std::next(NewSCCRange.begin()), NewSCCRange.end()))) {
368 assert(C != &NewC && "No need to re-visit the current SCC!");
369 assert(OldC != &NewC && "Already handled the original SCC!");
370 UR.CWorklist.insert(&NewC);
372 dbgs() << "Enqueuing a newly formed SCC:" << NewC << "\n";
374 // Ensure new SCCs' function analyses are updated.
376 updateNewSCCFunctionAnalyses(NewC, G, AM);
378 // Also propagate a normal invalidation to the new SCC as only the current
379 // will get one from the pass manager infrastructure.
380 AM.invalidate(NewC, PA);
386 LazyCallGraph::SCC &llvm::updateCGAndAnalysisManagerForFunctionPass(
387 LazyCallGraph &G, LazyCallGraph::SCC &InitialC, LazyCallGraph::Node &N,
388 CGSCCAnalysisManager &AM, CGSCCUpdateResult &UR, bool DebugLogging) {
389 typedef LazyCallGraph::Node Node;
390 typedef LazyCallGraph::Edge Edge;
391 typedef LazyCallGraph::SCC SCC;
392 typedef LazyCallGraph::RefSCC RefSCC;
394 RefSCC &InitialRC = InitialC.getOuterRefSCC();
396 RefSCC *RC = &InitialRC;
397 Function &F = N.getFunction();
399 // Walk the function body and build up the set of retained, promoted, and
401 SmallVector<Constant *, 16> Worklist;
402 SmallPtrSet<Constant *, 16> Visited;
403 SmallPtrSet<Node *, 16> RetainedEdges;
404 SmallSetVector<Node *, 4> PromotedRefTargets;
405 SmallSetVector<Node *, 4> DemotedCallTargets;
407 // First walk the function and handle all called functions. We do this first
408 // because if there is a single call edge, whether there are ref edges is
410 for (Instruction &I : instructions(F))
411 if (auto CS = CallSite(&I))
412 if (Function *Callee = CS.getCalledFunction())
413 if (Visited.insert(Callee).second && !Callee->isDeclaration()) {
414 Node &CalleeN = *G.lookup(*Callee);
415 Edge *E = N->lookup(CalleeN);
416 // FIXME: We should really handle adding new calls. While it will
417 // make downstream usage more complex, there is no fundamental
418 // limitation and it will allow passes within the CGSCC to be a bit
419 // more flexible in what transforms they can do. Until then, we
420 // verify that new calls haven't been introduced.
421 assert(E && "No function transformations should introduce *new* "
422 "call edges! Any new calls should be modeled as "
423 "promoted existing ref edges!");
424 RetainedEdges.insert(&CalleeN);
426 PromotedRefTargets.insert(&CalleeN);
429 // Now walk all references.
430 for (Instruction &I : instructions(F))
431 for (Value *Op : I.operand_values())
432 if (Constant *C = dyn_cast<Constant>(Op))
433 if (Visited.insert(C).second)
434 Worklist.push_back(C);
436 auto VisitRef = [&](Function &Referee) {
437 Node &RefereeN = *G.lookup(Referee);
438 Edge *E = N->lookup(RefereeN);
439 // FIXME: Similarly to new calls, we also currently preclude
440 // introducing new references. See above for details.
441 assert(E && "No function transformations should introduce *new* ref "
442 "edges! Any new ref edges would require IPO which "
443 "function passes aren't allowed to do!");
444 RetainedEdges.insert(&RefereeN);
446 DemotedCallTargets.insert(&RefereeN);
448 LazyCallGraph::visitReferences(Worklist, Visited, VisitRef);
450 // Include synthetic reference edges to known, defined lib functions.
451 for (auto *F : G.getLibFunctions())
454 // First remove all of the edges that are no longer present in this function.
455 // We have to build a list of dead targets first and then remove them as the
456 // data structures will all be invalidated by removing them.
457 SmallVector<PointerIntPair<Node *, 1, Edge::Kind>, 4> DeadTargets;
459 if (!RetainedEdges.count(&E.getNode()))
460 DeadTargets.push_back({&E.getNode(), E.getKind()});
461 for (auto DeadTarget : DeadTargets) {
462 Node &TargetN = *DeadTarget.getPointer();
463 bool IsCall = DeadTarget.getInt() == Edge::Call;
464 SCC &TargetC = *G.lookupSCC(TargetN);
465 RefSCC &TargetRC = TargetC.getOuterRefSCC();
467 if (&TargetRC != RC) {
468 RC->removeOutgoingEdge(N, TargetN);
470 dbgs() << "Deleting outgoing edge from '" << N << "' to '" << TargetN
475 dbgs() << "Deleting internal " << (IsCall ? "call" : "ref")
476 << " edge from '" << N << "' to '" << TargetN << "'\n";
480 // For separate SCCs this is trivial.
481 RC->switchTrivialInternalEdgeToRef(N, TargetN);
483 // Now update the call graph.
484 C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, TargetN), G,
485 N, C, AM, UR, DebugLogging);
489 auto NewRefSCCs = RC->removeInternalRefEdge(N, TargetN);
490 if (!NewRefSCCs.empty()) {
491 // Note that we don't bother to invalidate analyses as ref-edge
492 // connectivity is not really observable in any way and is intended
493 // exclusively to be used for ordering of transforms rather than for
494 // analysis conclusions.
496 // The RC worklist is in reverse postorder, so we first enqueue the
497 // current RefSCC as it will remain the parent of all split RefSCCs, then
498 // we enqueue the new ones in RPO except for the one which contains the
499 // source node as that is the "bottom" we will continue processing in the
501 UR.RCWorklist.insert(RC);
503 dbgs() << "Enqueuing the existing RefSCC in the update worklist: "
505 // Update the RC to the "bottom".
506 assert(G.lookupSCC(N) == C && "Changed the SCC when splitting RefSCCs!");
507 RC = &C->getOuterRefSCC();
508 assert(G.lookupRefSCC(N) == RC && "Failed to update current RefSCC!");
509 assert(NewRefSCCs.front() == RC &&
510 "New current RefSCC not first in the returned list!");
511 for (RefSCC *NewRC : reverse(
512 make_range(std::next(NewRefSCCs.begin()), NewRefSCCs.end()))) {
513 assert(NewRC != RC && "Should not encounter the current RefSCC further "
514 "in the postorder list of new RefSCCs.");
515 UR.RCWorklist.insert(NewRC);
517 dbgs() << "Enqueuing a new RefSCC in the update worklist: " << *NewRC
523 // Next demote all the call edges that are now ref edges. This helps make
524 // the SCCs small which should minimize the work below as we don't want to
525 // form cycles that this would break.
526 for (Node *RefTarget : DemotedCallTargets) {
527 SCC &TargetC = *G.lookupSCC(*RefTarget);
528 RefSCC &TargetRC = TargetC.getOuterRefSCC();
530 // The easy case is when the target RefSCC is not this RefSCC. This is
531 // only supported when the target RefSCC is a child of this RefSCC.
532 if (&TargetRC != RC) {
533 assert(RC->isAncestorOf(TargetRC) &&
534 "Cannot potentially form RefSCC cycles here!");
535 RC->switchOutgoingEdgeToRef(N, *RefTarget);
537 dbgs() << "Switch outgoing call edge to a ref edge from '" << N
538 << "' to '" << *RefTarget << "'\n";
542 // We are switching an internal call edge to a ref edge. This may split up
545 // For separate SCCs this is trivial.
546 RC->switchTrivialInternalEdgeToRef(N, *RefTarget);
550 // Now update the call graph.
551 C = incorporateNewSCCRange(RC->switchInternalEdgeToRef(N, *RefTarget), G, N,
552 C, AM, UR, DebugLogging);
555 // Now promote ref edges into call edges.
556 for (Node *CallTarget : PromotedRefTargets) {
557 SCC &TargetC = *G.lookupSCC(*CallTarget);
558 RefSCC &TargetRC = TargetC.getOuterRefSCC();
560 // The easy case is when the target RefSCC is not this RefSCC. This is
561 // only supported when the target RefSCC is a child of this RefSCC.
562 if (&TargetRC != RC) {
563 assert(RC->isAncestorOf(TargetRC) &&
564 "Cannot potentially form RefSCC cycles here!");
565 RC->switchOutgoingEdgeToCall(N, *CallTarget);
567 dbgs() << "Switch outgoing ref edge to a call edge from '" << N
568 << "' to '" << *CallTarget << "'\n";
572 dbgs() << "Switch an internal ref edge to a call edge from '" << N
573 << "' to '" << *CallTarget << "'\n";
575 // Otherwise we are switching an internal ref edge to a call edge. This
576 // may merge away some SCCs, and we add those to the UpdateResult. We also
577 // need to make sure to update the worklist in the event SCCs have moved
578 // before the current one in the post-order sequence
579 bool HasFunctionAnalysisProxy = false;
580 auto InitialSCCIndex = RC->find(*C) - RC->begin();
581 bool FormedCycle = RC->switchInternalEdgeToCall(
582 N, *CallTarget, [&](ArrayRef<SCC *> MergedSCCs) {
583 for (SCC *MergedC : MergedSCCs) {
584 assert(MergedC != &TargetC && "Cannot merge away the target SCC!");
586 HasFunctionAnalysisProxy |=
587 AM.getCachedResult<FunctionAnalysisManagerCGSCCProxy>(
588 *MergedC) != nullptr;
590 // Mark that this SCC will no longer be valid.
591 UR.InvalidatedSCCs.insert(MergedC);
593 // FIXME: We should really do a 'clear' here to forcibly release
594 // memory, but we don't have a good way of doing that and
595 // preserving the function analyses.
596 auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>();
597 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
598 AM.invalidate(*MergedC, PA);
602 // If we formed a cycle by creating this call, we need to update more data
606 assert(G.lookupSCC(N) == C && "Failed to update current SCC!");
608 // If one of the invalidated SCCs had a cached proxy to a function
609 // analysis manager, we need to create a proxy in the new current SCC as
610 // the invaliadted SCCs had their functions moved.
611 if (HasFunctionAnalysisProxy)
612 AM.getResult<FunctionAnalysisManagerCGSCCProxy>(*C, G);
614 // Any analyses cached for this SCC are no longer precise as the shape
615 // has changed by introducing this cycle. However, we have taken care to
616 // update the proxies so it remains valide.
617 auto PA = PreservedAnalyses::allInSet<AllAnalysesOn<Function>>();
618 PA.preserve<FunctionAnalysisManagerCGSCCProxy>();
619 AM.invalidate(*C, PA);
621 auto NewSCCIndex = RC->find(*C) - RC->begin();
622 if (InitialSCCIndex < NewSCCIndex) {
623 // Put our current SCC back onto the worklist as we'll visit other SCCs
624 // that are now definitively ordered prior to the current one in the
625 // post-order sequence, and may end up observing more precise context to
626 // optimize the current SCC.
627 UR.CWorklist.insert(C);
629 dbgs() << "Enqueuing the existing SCC in the worklist: " << *C << "\n";
630 // Enqueue in reverse order as we pop off the back of the worklist.
631 for (SCC &MovedC : reverse(make_range(RC->begin() + InitialSCCIndex,
632 RC->begin() + NewSCCIndex))) {
633 UR.CWorklist.insert(&MovedC);
635 dbgs() << "Enqueuing a newly earlier in post-order SCC: " << MovedC
641 assert(!UR.InvalidatedSCCs.count(C) && "Invalidated the current SCC!");
642 assert(!UR.InvalidatedRefSCCs.count(RC) && "Invalidated the current RefSCC!");
643 assert(&C->getOuterRefSCC() == RC && "Current SCC not in current RefSCC!");
645 // Record the current RefSCC and SCC for higher layers of the CGSCC pass
646 // manager now that all the updates have been applied.
647 if (RC != &InitialRC)