[InlineCost] Set LastCallToStaticBonus in ML inlining models.

[junparser]

Summary

This patch set LastCallToStaticBonus based on check, it has
no noticeable size reduction on an internal workload and linux kernel
with Os/Oz.

[mtrofin]

lgtm, thanks!

llvm/lib/Analysis/InlineCost.cpp

 //===- InlineCost.cpp - Cost analysis for inliner -------------------------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
private:
 
   InlineResult onAnalysisStart() override {
     increment(InlineCostFeatureIndex::CallSiteCost,
               -1 * getCallsiteCost(this->CandidateCall, DL));
 
     set(InlineCostFeatureIndex::ColdCcPenalty,
         (F.getCallingConv() == CallingConv::Cold));
 
+    set(InlineCostFeatureIndex::LastCallToStaticBonus,
+        (F.hasLocalLinkage() && F.hasOneLiveUse() &&
+         &F == CandidateCall.getCalledFunction()));
+
     // FIXME: we shouldn't repeat this logic in both the Features and Cost
     // analyzer - instead, we should abstract it to a common method in the
     // CallAnalyzer
     int SingleBBBonusPercent = 50;
     int VectorBonusPercent = TTI.getInlinerVectorBonusPercent();
     Threshold += TTI.adjustInliningThreshold(&CandidateCall);
     Threshold *= TTI.getInliningThresholdMultiplier();
     SingleBBBonus = Threshold * SingleBBBonusPercent / 100;