[llvm][Inline] Remove PriorityInlineOrder in SCC inliner

[taolq]

Summary

Since the size of most of SCC's is 1, the PriorityInlineOrder would not change the inline
order in SCC inliner.

[kazu]

Thank you for cleaning up!

[taolq]

• replace Calls uniptr with instance

[taolq]

• replace Calls uniptr with instance
• Fix missing option in tests

llvm/lib/Transforms/IPO/Inliner.cpp

cl::values(
                    "<Line Number>:<Column Number>"),
         clEnumValN(CallSiteFormat::Format::LineDiscriminator,
                    "LineDiscriminator", "<Line Number>.<Discriminator>"),
         clEnumValN(CallSiteFormat::Format::LineColumnDiscriminator,
                    "LineColumnDiscriminator",
                    "<Line Number>:<Column Number>.<Discriminator> (default)")),
     cl::desc("How cgscc inline replay file is formatted"), cl::Hidden);
 
-static cl::opt<bool> InlineEnablePriorityOrder(
-    "inline-enable-priority-order", cl::Hidden, cl::init(false),
-    cl::desc("Enable the priority inline order for the inliner"));
-
 LegacyInlinerBase::LegacyInlinerBase(char &ID) : CallGraphSCCPass(ID) {}
 
 LegacyInlinerBase::LegacyInlinerBase(char &ID, bool InsertLifetime)
     : CallGraphSCCPass(ID), InsertLifetime(InsertLifetime) {}
 
 /// For this class, we declare that we require and preserve the call graph.
 /// If the derived class implements this method, it should
 /// always explicitly call the implementation here.
PreservedAnalyses InlinerPass::run(LazyCallGraph::SCC &InitialC,
   // don't have a topological ordering to prevent explosions.
   //
   // To compensate for this, we don't process transitive edges made immediate
   // by inlining until we've done one pass of inlining across the entire SCC.
   // Large, highly connected SCCs still lead to some amount of code bloat in
   // this model, but it is uniformly spread across all the functions in the SCC
   // and eventually they all become too large to inline, rather than
   // incrementally maknig a single function grow in a super linear fashion.
-  std::unique_ptr<InlineOrder<std::pair<CallBase *, int>>> Calls;
-  if (InlineEnablePriorityOrder)
-    Calls = std::make_unique<PriorityInlineOrder<InlineSizePriority>>();
-  else
-    Calls = std::make_unique<DefaultInlineOrder<std::pair<CallBase *, int>>>();
-  assert(Calls != nullptr && "Expected an initialized InlineOrder");
+  DefaultInlineOrder<std::pair<CallBase *, int>> Calls;
 
   // Populate the initial list of calls in this SCC.
   for (auto &N : InitialC) {
     auto &ORE =
         FAM.getResult<OptimizationRemarkEmitterAnalysis>(N.getFunction());
     // We want to generally process call sites top-down in order for
     // simplifications stemming from replacing the call with the returned value
     // after inlining to be visible to subsequent inlining decisions.
     // FIXME: Using instructions sequence is a really bad way to do this.
     // Instead we should do an actual RPO walk of the function body.
     for (Instruction &I : instructions(N.getFunction()))
       if (auto *CB = dyn_cast<CallBase>(&I))
         if (Function *Callee = CB->getCalledFunction()) {
           if (!Callee->isDeclaration())
-            Calls->push({CB, -1});
+            Calls.push({CB, -1});
           else if (!isa<IntrinsicInst>(I)) {
             using namespace ore;
             setInlineRemark(*CB, "unavailable definition");
             ORE.emit([&]() {
               return OptimizationRemarkMissed(DEBUG_TYPE, "NoDefinition", &I)
                      << NV("Callee", Callee) << " will not be inlined into "
                      << NV("Caller", CB->getCaller())
                      << " because its definition is unavailable"
                      << setIsVerbose();
             });
           }
         }
   }
-  if (Calls->empty())
+  if (Calls.empty())
     return PreservedAnalyses::all();
 
   // Capture updatable variable for the current SCC.
   auto *C = &InitialC;
 
   // When inlining a callee produces new call sites, we want to keep track of
   // the fact that they were inlined from the callee.  This allows us to avoid
   // infinite inlining in some obscure cases.  To represent this, we use an
PreservedAnalyses InlinerPass::run(LazyCallGraph::SCC &InitialC,
   // defer deleting these to make it easier to handle the call graph updates.
   SmallVector<Function *, 4> DeadFunctions;
 
   // Track potentially dead non-local functions with comdats to see if they can
   // be deleted as a batch after inlining.
   SmallVector<Function *, 4> DeadFunctionsInComdats;
 
   // Loop forward over all of the calls.
-  while (!Calls->empty()) {
+  while (!Calls.empty()) {
     // We expect the calls to typically be batched with sequences of calls that
     // have the same caller, so we first set up some shared infrastructure for
     // this caller. We also do any pruning we can at this layer on the caller
     // alone.
-    Function &F = *Calls->front().first->getCaller();
+    Function &F = *Calls.front().first->getCaller();
     LazyCallGraph::Node &N = *CG.lookup(F);
     if (CG.lookupSCC(N) != C) {
-      Calls->pop();
+      Calls.pop();
       continue;
     }
 
     LLVM_DEBUG(dbgs() << "Inlining calls in: " << F.getName() << "\n"
                       << "    Function size: " << F.getInstructionCount()
                       << "\n");
 
     auto GetAssumptionCache = [&](Function &F) -> AssumptionCache & {
       return FAM.getResult<AssumptionAnalysis>(F);
     };
 
     // Now process as many calls as we have within this caller in the sequence.
     // We bail out as soon as the caller has to change so we can update the
     // call graph and prepare the context of that new caller.
     bool DidInline = false;
-    while (!Calls->empty() && Calls->front().first->getCaller() == &F) {
-      auto P = Calls->pop();
+    while (!Calls.empty() && Calls.front().first->getCaller() == &F) {
+      auto P = Calls.pop();
       CallBase *CB = P.first;
       const int InlineHistoryID = P.second;
       Function &Callee = *CB->getCalledFunction();
 
       if (InlineHistoryID != -1 &&
           inlineHistoryIncludes(&Callee, InlineHistoryID, InlineHistory)) {
         LLVM_DEBUG(dbgs() << "Skipping inlining due to history: "
                           << F.getName() << " -> " << Callee.getName() << "\n");
while (!Calls.empty() && Calls.front().first->getCaller() == &F) {
             // the post-inline cleanup and the next DevirtSCCRepeatedPass
             // iteration because the next iteration may not happen and we may
             // miss inlining it.
             if (tryPromoteCall(*ICB))
               NewCallee = ICB->getCalledFunction();
           }
           if (NewCallee) {
             if (!NewCallee->isDeclaration()) {
-              Calls->push({ICB, NewHistoryID});
+              Calls.push({ICB, NewHistoryID});
               // Continually inlining through an SCC can result in huge compile
               // times and bloated code since we arbitrarily stop at some point
               // when the inliner decides it's not profitable to inline anymore.
               // We attempt to mitigate this by making these calls exponentially
               // more expensive.
               // This doesn't apply to calls in the same SCC since if we do
               // inline through the SCC the function will end up being
               // self-recursive which the inliner bails out on, and inlining
while (!Calls.empty() && Calls.front().first->getCaller() == &F) {
       // whether this makes the callee trivially dead. In that case, we can drop
       // the body of the function eagerly which may reduce the number of callers
       // of other functions to one, changing inline cost thresholds. Non-local
       // discardable functions with comdats are checked later on.
       bool CalleeWasDeleted = false;
       if (Callee.isDiscardableIfUnused() && Callee.hasZeroLiveUses() &&
           !CG.isLibFunction(Callee)) {
         if (Callee.hasLocalLinkage() || !Callee.hasComdat()) {
-          Calls->erase_if([&](const std::pair<CallBase *, int> &Call) {
+          Calls.erase_if([&](const std::pair<CallBase *, int> &Call) {
             return Call.first->getCaller() == &Callee;
           });
           // Clear the body and queue the function itself for deletion when we
           // finish inlining and call graph updates.
           // Note that after this point, it is an error to do anything other
           // than use the callee's address or delete it.
           Callee.dropAllReferences();
           assert(!is_contained(DeadFunctions, &Callee) &&