[llvm] 347a599 - [Inlining] Introduce -enable-npm-pgo-inline-deferral

[Kazu Hirata via llvm-commits]

Author: Kazu Hirata
Date: 2020-06-04T00:40:58-07:00
New Revision: 347a599e5f03ab708943559d0a131127b206b576

URL: https://github.com/llvm/llvm-project/commit/347a599e5f03ab708943559d0a131127b206b576
DIFF: https://github.com/llvm/llvm-project/commit/347a599e5f03ab708943559d0a131127b206b576.diff

LOG: [Inlining] Introduce -enable-npm-pgo-inline-deferral

Summary:
Experiments show that inline deferral past pre-inlining slightly
pessimizes the performance.

This patch introduces an option to control inline deferral during PGO.
The option defaults to true for now (that is, NFC).

Reviewers: davidxl

Reviewed By: davidxl

Subscribers: eraman, hiraditya, haicheng, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D80776

Added: 
    

Modified: 
    llvm/include/llvm/Analysis/InlineAdvisor.h
    llvm/include/llvm/Analysis/InlineCost.h
    llvm/lib/Analysis/InlineAdvisor.cpp
    llvm/lib/Analysis/InlineCost.cpp
    llvm/lib/Passes/PassBuilder.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Analysis/InlineAdvisor.h b/llvm/include/llvm/Analysis/InlineAdvisor.h
index e9f08a69a5af..0a11bd04777d 100644
--- a/llvm/include/llvm/Analysis/InlineAdvisor.h
+++ b/llvm/include/llvm/Analysis/InlineAdvisor.h
@@ -203,7 +203,7 @@ class InlineAdvisorAnalysis : public AnalysisInfoMixin<InlineAdvisorAnalysis> {
 /// inlining should not be attempted.
 Optional<InlineCost>
 shouldInline(CallBase &CB, function_ref<InlineCost(CallBase &CB)> GetInlineCost,
-             OptimizationRemarkEmitter &ORE);
+             OptimizationRemarkEmitter &ORE, bool EnableDeferral = true);
 
 /// Emit ORE message.
 void emitInlinedInto(OptimizationRemarkEmitter &ORE, DebugLoc DLoc,

diff  --git a/llvm/include/llvm/Analysis/InlineCost.h b/llvm/include/llvm/Analysis/InlineCost.h
index 0d67f9f32859..a1f49d45789c 100644
--- a/llvm/include/llvm/Analysis/InlineCost.h
+++ b/llvm/include/llvm/Analysis/InlineCost.h
@@ -182,6 +182,9 @@ struct InlineParams {
 
   /// Compute inline cost even when the cost has exceeded the threshold.
   Optional<bool> ComputeFullInlineCost;
+
+  /// Indicate whether we should allow inline deferral.
+  Optional<bool> EnableDeferral = true;
 };
 
 /// Generate the parameters to tune the inline cost analysis based only on the

diff  --git a/llvm/lib/Analysis/InlineAdvisor.cpp b/llvm/lib/Analysis/InlineAdvisor.cpp
index 7af8a4dffcba..4d8a241ef9fe 100644
--- a/llvm/lib/Analysis/InlineAdvisor.cpp
+++ b/llvm/lib/Analysis/InlineAdvisor.cpp
@@ -117,7 +117,9 @@ std::unique_ptr<InlineAdvice> DefaultInlineAdvisor::getAdvice(CallBase &CB) {
     return getInlineCost(CB, Params, CalleeTTI, GetAssumptionCache, GetTLI,
                          GetBFI, PSI, RemarksEnabled ? &ORE : nullptr);
   };
-  auto OIC = llvm::shouldInline(CB, GetInlineCost, ORE);
+  auto OIC = llvm::shouldInline(CB, GetInlineCost, ORE,
+                                Params.EnableDeferral.hasValue() &&
+                                    Params.EnableDeferral.getValue());
   return std::make_unique<DefaultInlineAdvice>(this, CB, OIC, ORE);
 }
 
@@ -298,7 +300,7 @@ void llvm::setInlineRemark(CallBase &CB, StringRef Message) {
 Optional<InlineCost>
 llvm::shouldInline(CallBase &CB,
                    function_ref<InlineCost(CallBase &CB)> GetInlineCost,
-                   OptimizationRemarkEmitter &ORE) {
+                   OptimizationRemarkEmitter &ORE, bool EnableDeferral) {
   using namespace ore;
 
   InlineCost IC = GetInlineCost(CB);
@@ -335,7 +337,8 @@ llvm::shouldInline(CallBase &CB,
   }
 
   int TotalSecondaryCost = 0;
-  if (shouldBeDeferred(Caller, IC, TotalSecondaryCost, GetInlineCost)) {
+  if (EnableDeferral &&
+      shouldBeDeferred(Caller, IC, TotalSecondaryCost, GetInlineCost)) {
     LLVM_DEBUG(dbgs() << "    NOT Inlining: " << CB
                       << " Cost = " << IC.getCost()
                       << ", outer Cost = " << TotalSecondaryCost << '\n');

diff  --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 7377b0880ec9..9eea2e945a85 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -2250,7 +2250,8 @@ Optional<int> llvm::getInliningCostEstimate(
                                /*HotCallSiteThreshold*/ {},
                                /*LocallyHotCallSiteThreshold*/ {},
                                /*ColdCallSiteThreshold*/ {},
-                               /* ComputeFullInlineCost*/ true};
+                               /*ComputeFullInlineCost*/ true,
+                               /*EnableDeferral*/ true};
 
   InlineCostCallAnalyzer CA(*Call.getCalledFunction(), Call, Params, CalleeTTI,
                             GetAssumptionCache, GetBFI, PSI, ORE, true,

diff  --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index 10f92f714802..1c93adee50dd 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -254,6 +254,12 @@ static cl::opt<bool> EnableCallGraphProfile(
     "enable-npm-call-graph-profile", cl::init(true), cl::Hidden,
     cl::desc("Enable call graph profile pass for the new PM (default = on)"));
 
+/// Flag to enable inline deferral during PGO.
+static cl::opt<bool>
+    EnablePGOInlineDeferral("enable-npm-pgo-inline-deferral", cl::init(true),
+                            cl::Hidden,
+                            cl::desc("Enable inline deferral during PGO"));
+
 PipelineTuningOptions::PipelineTuningOptions() {
   LoopInterleaving = true;
   LoopVectorization = true;
@@ -832,6 +838,9 @@ PassBuilder::buildInlinerPipeline(OptimizationLevel Level, ThinLTOPhase Phase,
       PGOOpt->Action == PGOOptions::SampleUse)
     IP.HotCallSiteThreshold = 0;
 
+  if (PGOOpt)
+    IP.EnableDeferral = EnablePGOInlineDeferral;
+
   ModuleInlinerWrapperPass MIWP(IP, DebugLogging, UseInlineAdvisor,
                                 MaxDevirtIterations);