[PGO] Profile guided code size optimization.

Summary:
Enable some of the existing size optimizations for cold code under PGO.

A ~5% code size saving in big internal app under PGO.

The way it gets BFI/PSI is discussed in the RFC thread

http://lists.llvm.org/pipermail/llvm-dev/2019-March/130894.html 

Note it doesn't currently touch loop passes.

Reviewers: davidxl, eraman

Reviewed By: eraman

Subscribers: mgorny, javed.absar, smeenai, mehdi_amini, eraman, zzheng, steven_wu, dexonsmith, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D59514

llvm-svn: 358422

1 files changed, 11 insertions, 1 deletions

diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index b26ee96092d..c5fd68299eb 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -575,8 +575,12 @@ void PassBuilder::addPGOInstrPasses(ModulePassManager &MPM, bool DebugLogging,
     Options.DoCounterPromotion = true;
     Options.UseBFIInPromotion = IsCS;
     MPM.addPass(InstrProfiling(Options, IsCS));
-  } else if (!ProfileFile.empty())
+  } else if (!ProfileFile.empty()) {
     MPM.addPass(PGOInstrumentationUse(ProfileFile, ProfileRemappingFile, IsCS));
+    // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
+    // RequireAnalysisPass for PSI before subsequent non-module passes.
+    MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
+  }
 }
 
 static InlineParams
@@ -649,6 +653,9 @@ PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
     MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
                                         PGOOpt->ProfileRemappingFile,
                                         Phase == ThinLTOPhase::PreLink));
+    // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
+    // RequireAnalysisPass for PSI before subsequent non-module passes.
+    MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
     // Do not invoke ICP in the ThinLTOPrelink phase as it makes it hard
     // for the profile annotation to be accurate in the ThinLTO backend.
     if (Phase != ThinLTOPhase::PreLink)
@@ -1065,6 +1072,9 @@ PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level, bool DebugLogging,
     MPM.addPass(SampleProfileLoaderPass(PGOOpt->ProfileFile,
                                         PGOOpt->ProfileRemappingFile,
                                         false /* ThinLTOPhase::PreLink */));
+    // Cache ProfileSummaryAnalysis once to avoid the potential need to insert
+    // RequireAnalysisPass for PSI before subsequent non-module passes.
+    MPM.addPass(RequireAnalysisPass<ProfileSummaryAnalysis, Module>());
   }
 
   // Remove unused virtual tables to improve the quality of code generated by