AlwaysInliner: Factor out some code in preparation for a future change.

llvm/lib/Transforms/IPO/AlwaysInliner.cpp

@@ -30,6 +30,47 @@ using namespace llvm;
 
 namespace {
 
+/// Sanity check for a call site's inlinability based on inline attributes.
+static bool canInlineCallBase(CallBase *CB) {
+  return CB->hasFnAttr(Attribute::AlwaysInline) &&
+         !CB->getAttributes().hasFnAttr(Attribute::NoInline);
+}
+
+/// Attempt to inline a call site \p CB into its caller.
+/// Returns true if the inlining was successful, false otherwise.
+static bool attemptInlineFunction(
+    Function &F, CallBase *CB, bool InsertLifetime,
+    function_ref<AAResults &(Function &)> &GetAAR,
+    function_ref<AssumptionCache &(Function &)> &GetAssumptionCache,
+    ProfileSummaryInfo &PSI) {
+  Function *Caller = CB->getCaller();
+  OptimizationRemarkEmitter ORE(Caller);
+  DebugLoc DLoc = CB->getDebugLoc();
+  BasicBlock *Block = CB->getParent();
+
+  InlineFunctionInfo IFI(GetAssumptionCache, &PSI, nullptr, nullptr);
+  InlineResult Res = InlineFunction(*CB, IFI, /*MergeAttributes=*/true,
+                                    &GetAAR(F), InsertLifetime);
+  if (!Res.isSuccess()) {
+    ORE.emit([&]() {
+      return OptimizationRemarkMissed(DEBUG_TYPE, "NotInlined", DLoc, Block)
+             << "'" << ore::NV("Callee", &F) << "' is not inlined into '"
+             << ore::NV("Caller", Caller)
+             << "': " << ore::NV("Reason", Res.getFailureReason());
+    });
+    return false;
+  }
+
+  emitInlinedIntoBasedOnCost(ORE, DLoc, Block, F, *Caller,
+                             InlineCost::getAlways("always inline attribute"),
+                             /*ForProfileContext=*/false, DEBUG_TYPE);
+
+  return true;
+}
+
+/// This function inlines all functions that are marked with the always_inline
+/// attribute. It also removes the inlined functions if they are dead after the
+/// inlining process.
 bool AlwaysInlineImpl(
     Module &M, bool InsertLifetime, ProfileSummaryInfo &PSI,
     FunctionAnalysisManager *FAM,
@@ -50,36 +91,13 @@ bool AlwaysInlineImpl(
 
     for (User *U : F.users())
       if (auto *CB = dyn_cast<CallBase>(U))
-        if (CB->getCalledFunction() == &F &&
-            CB->hasFnAttr(Attribute::AlwaysInline) &&
-            !CB->getAttributes().hasFnAttr(Attribute::NoInline))
+        if (CB->getCalledFunction() == &F && canInlineCallBase(CB))
           Calls.insert(CB);
 
     for (CallBase *CB : Calls) {
       Function *Caller = CB->getCaller();
-      OptimizationRemarkEmitter ORE(Caller);
-      DebugLoc DLoc = CB->getDebugLoc();
-      BasicBlock *Block = CB->getParent();
-
-      InlineFunctionInfo IFI(GetAssumptionCache, &PSI, nullptr, nullptr);
-      InlineResult Res = InlineFunction(*CB, IFI, /*MergeAttributes=*/true,
-                                        &GetAAR(F), InsertLifetime);
-      if (!Res.isSuccess()) {
-        ORE.emit([&]() {
-          return OptimizationRemarkMissed(DEBUG_TYPE, "NotInlined", DLoc, Block)
-                 << "'" << ore::NV("Callee", &F) << "' is not inlined into '"
-                 << ore::NV("Caller", Caller)
-                 << "': " << ore::NV("Reason", Res.getFailureReason());
-        });
-        continue;
-      }
-
-      emitInlinedIntoBasedOnCost(
-          ORE, DLoc, Block, F, *Caller,
-          InlineCost::getAlways("always inline attribute"),
-          /*ForProfileContext=*/false, DEBUG_TYPE);
-
-      Changed = true;
+      Changed |= attemptInlineFunction(F, CB, InsertLifetime, GetAAR,
+                                       GetAssumptionCache, PSI);
       if (FAM)
         FAM->invalidate(*Caller, PreservedAnalyses::none());
     }