[PATCH] D93002: [NPM] Support -fmerge-functions

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks created this revision.
aeubanks added reviewers: ychen, asbirlea, nikic.
Herald added a subscriber: hiraditya.
aeubanks requested review of this revision.
Herald added projects: clang, LLVM.
Herald added subscribers: llvm-commits, cfe-commits.

I tried to put it in the same place in the pipeline as the legacy PM.

Fixes PR48399.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D93002

Files:
  clang/lib/CodeGen/BackendUtil.cpp
  clang/test/CodeGenCXX/merge-functions.cpp
  llvm/include/llvm/Passes/PassBuilder.h
  llvm/lib/Passes/PassBuilder.cpp


Index: llvm/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/lib/Passes/PassBuilder.cpp
+++ llvm/lib/Passes/PassBuilder.cpp
@@ -282,6 +282,7 @@
   LicmMssaOptCap = SetLicmMssaOptCap;
   LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
   CallGraphProfile = true;
+  MergeFunctions = false;
 }
 
 extern cl::opt<bool> EnableConstraintElimination;
@@ -1316,6 +1317,10 @@
   if (EnableHotColdSplit && !LTOPreLink)
     MPM.addPass(HotColdSplittingPass());
 
+  // Merge functions if requested.
+  if (PTO.MergeFunctions)
+    MPM.addPass(MergeFunctionsPass());
+
   // LoopSink pass sinks instructions hoisted by LICM, which serves as a
   // canonicalization pass that enables other optimizations. As a result,
   // LoopSink pass needs to be a very late IR pass to avoid undoing LICM
@@ -1767,6 +1772,9 @@
         /* RunProfileGen */ (PGOOpt->Action == PGOOptions::IRInstr),
         /* IsCS */ false, PGOOpt->ProfileFile, PGOOpt->ProfileRemappingFile);
 
+  if (PTO.MergeFunctions)
+    MPM.addPass(MergeFunctionsPass());
+
   for (auto &C : PipelineStartEPCallbacks)
     C(MPM, Level);
   for (auto &C : PipelineEarlySimplificationEPCallbacks)
Index: llvm/include/llvm/Passes/PassBuilder.h
===================================================================
--- llvm/include/llvm/Passes/PassBuilder.h
+++ llvm/include/llvm/Passes/PassBuilder.h
@@ -123,6 +123,10 @@
   /// Tuning option to enable/disable call graph profile. Its default value is
   /// that of the flag: `-enable-npm-call-graph-profile`.
   bool CallGraphProfile;
+
+  /// Tuning option to enable/disable function merging. Its default value is
+  /// false.
+  bool MergeFunctions;
 };
 
 /// This class provides access to building LLVM's passes.
Index: clang/test/CodeGenCXX/merge-functions.cpp
===================================================================
--- clang/test/CodeGenCXX/merge-functions.cpp
+++ clang/test/CodeGenCXX/merge-functions.cpp
@@ -1,5 +1,8 @@
 // REQUIRES: x86-registered-target
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -O0 -fno-experimental-new-pass-manager -fmerge-functions -emit-llvm -o - -x c++ < %s | FileCheck %s -implicit-check-not=_ZN1A1gEiPi
 // RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -O1 -fno-experimental-new-pass-manager -fmerge-functions -emit-llvm -o - -x c++ < %s | FileCheck %s -implicit-check-not=_ZN1A1gEiPi
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -O0 -fexperimental-new-pass-manager -fmerge-functions -emit-llvm -o - -x c++ < %s | FileCheck %s -implicit-check-not=_ZN1A1gEiPi
+// RUN: %clang_cc1 -triple x86_64-pc-linux-gnu -O1 -fexperimental-new-pass-manager -fmerge-functions -emit-llvm -o - -x c++ < %s | FileCheck %s -implicit-check-not=_ZN1A1gEiPi
 
 // Basic functionality test. Function merging doesn't kick in on functions that
 // are too simple.
Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -1139,6 +1139,7 @@
   PTO.LoopInterleaving = CodeGenOpts.UnrollLoops;
   PTO.LoopVectorization = CodeGenOpts.VectorizeLoop;
   PTO.SLPVectorization = CodeGenOpts.VectorizeSLP;
+  PTO.MergeFunctions = CodeGenOpts.MergeFunctions;
   // Only enable CGProfilePass when using integrated assembler, since
   // non-integrated assemblers don't recognize .cgprofile section.
   PTO.CallGraphProfile = !CodeGenOpts.DisableIntegratedAS;


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