[PATCH] D99302: [InlineCost] Make cost-benefit decision explicit

[Wenlei He via Phabricator via llvm-commits]

wenlei updated this revision to Diff 333160.
wenlei added a comment.

Address David's feedback, also make negative decision explicit.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D99302/new/

https://reviews.llvm.org/D99302

Files:
  llvm/lib/Analysis/InlineCost.cpp


Index: llvm/lib/Analysis/InlineCost.cpp
===================================================================
--- llvm/lib/Analysis/InlineCost.cpp
+++ llvm/lib/Analysis/InlineCost.cpp
@@ -489,6 +489,9 @@
   // sense that it's not weighted by profile counts at all.
   int ColdSize = 0;
 
+  // Whether inlining is decided by cost-benefit analysis.
+  bool DecidedByCostBenefit = false;
+
   bool SingleBB = true;
 
   unsigned SROACostSavings = 0;
@@ -825,6 +828,7 @@
       Threshold -= VectorBonus / 2;
 
     if (auto Result = costBenefitAnalysis()) {
+      DecidedByCostBenefit = true;
       if (Result.getValue())
         return InlineResult::success();
       else
@@ -926,6 +930,7 @@
   virtual ~InlineCostCallAnalyzer() {}
   int getThreshold() { return Threshold; }
   int getCost() { return Cost; }
+  bool wasDecidedByCostBenefit() { return DecidedByCostBenefit; }
 };
 } // namespace
 
@@ -2609,6 +2614,16 @@
 
   LLVM_DEBUG(CA.dump());
 
+  // Always make cost benefit based decision explicit.
+  // We use always/never here since threshold is not meaningful,
+  // as it's not what drives cost-benefit analysis.
+  if (CA.wasDecidedByCostBenefit()) {
+    if (ShouldInline.isSuccess())
+      return InlineCost::getAlways("benefit over cost");
+    else
+      return InlineCost::getNever("cost over benefit");
+  }
+
   // Check if there was a reason to force inlining or no inlining.
   if (!ShouldInline.isSuccess() && CA.getCost() < CA.getThreshold())
     return InlineCost::getNever(ShouldInline.getFailureReason());


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