[PATCH] D153797: [CSSPGO][Preinliner] Bump up the threshold to favor previous compiler inline decision.

[Hongtao Yu via Phabricator via llvm-commits]

hoy updated this revision to Diff 534791.
hoy added a comment.

Updating D153797 <https://reviews.llvm.org/D153797>: [CSSPGO][Preinliner] Bump up the threshold to favor previous compiler inline decision.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D153797/new/

https://reviews.llvm.org/D153797

Files:
  llvm/tools/llvm-profgen/CSPreInliner.cpp


Index: llvm/tools/llvm-profgen/CSPreInliner.cpp
===================================================================
--- llvm/tools/llvm-profgen/CSPreInliner.cpp
+++ llvm/tools/llvm-profgen/CSPreInliner.cpp
@@ -57,6 +57,12 @@
     cl::desc(
         "Replay previous inlining and adjust context profile accordingly"));
 
+static cl::opt<int> CSPreinlMultiplierForPrevInl(
+    "csspgo-preinliner-multiplier-for-previous-inlining", cl::Hidden,
+    cl::init(100),
+    cl::desc(
+        "Multiplier to bump up callsite threshold for previous inlining."));
+
 CSPreInliner::CSPreInliner(SampleContextTracker &Tracker,
                            ProfiledBinary &Binary, ProfileSummary *Summary)
     : UseContextCost(UseContextCostForPreInliner),
@@ -153,11 +159,12 @@
 }
 
 bool CSPreInliner::shouldInline(ProfiledInlineCandidate &Candidate) {
+  bool WasInlined =
+      Candidate.CalleeSamples->getContext().hasAttribute(ContextWasInlined);
   // If replay inline is requested, simply follow the inline decision of the
   // profiled binary.
   if (SamplePreInlineReplay)
-    return Candidate.CalleeSamples->getContext().hasAttribute(
-        ContextWasInlined);
+    return WasInlined;
 
   unsigned int SampleThreshold = SampleColdCallSiteThreshold;
   uint64_t ColdCountThreshold = ProfileSummaryBuilder::getColdCountThreshold(
@@ -184,6 +191,12 @@
     // want any inlining for cold callsites.
     SampleThreshold = SampleHotCallSiteThreshold * NormalizedHotness * 100 +
                       SampleColdCallSiteThreshold + 1;
+    // Bump up the threshold to favor previous compiler inline decision. The
+    // compiler has more insight and knowledge about functions based on their IR
+    // and attribures and should be able to make a more reasonable inline
+    // decision.
+    if (WasInlined)
+      SampleThreshold *= CSPreinlMultiplierForPrevInl;
   }
 
   return (Candidate.SizeCost < SampleThreshold);


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