[NewPM] Port MergeFunctions pass

This ports the MergeFunctions pass to the NewPM. This was rather
straightforward, as no analyses are used.

Additionally MergeFunctions needs to be conditionally enabled in
the PassBuilder, but I left that part out of this patch.

Differential Revision: https://reviews.llvm.org/D72537

7 files changed, 70 insertions, 16 deletions

diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 831c6882b4a..a5e1310e28b 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -288,7 +288,7 @@ void initializeMemoryDependenceWrapperPassPass(PassRegistry&);
 void initializeMemorySSAPrinterLegacyPassPass(PassRegistry&);
 void initializeMemorySSAWrapperPassPass(PassRegistry&);
 void initializeMemorySanitizerLegacyPassPass(PassRegistry&);
-void initializeMergeFunctionsPass(PassRegistry&);
+void initializeMergeFunctionsLegacyPassPass(PassRegistry&);
 void initializeMergeICmpsLegacyPassPass(PassRegistry &);
 void initializeMergedLoadStoreMotionLegacyPassPass(PassRegistry&);
 void initializeMetaRenamerPass(PassRegistry&);
diff --git a/llvm/include/llvm/Transforms/IPO/MergeFunctions.h b/llvm/include/llvm/Transforms/IPO/MergeFunctions.h
new file mode 100644
index 00000000000..822f0fd9918
--- /dev/null
+++ b/llvm/include/llvm/Transforms/IPO/MergeFunctions.h
@@ -0,0 +1,32 @@
+//===- MergeFunctions.h - Merge Identical Functions -------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass transforms simple global variables that never have their address
+// taken.  If obviously true, it marks read/write globals as constant, deletes
+// variables only stored to, etc.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_TRANSFORMS_IPO_MERGEFUNCTIONS_H
+#define LLVM_TRANSFORMS_IPO_MERGEFUNCTIONS_H
+
+#include "llvm/IR/PassManager.h"
+
+namespace llvm {
+
+class Module;
+
+/// Merge identical functions.
+class MergeFunctionsPass : public PassInfoMixin<MergeFunctionsPass> {
+public:
+  PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
+};
+
+} // end namespace llvm
+
+#endif // LLVM_TRANSFORMS_IPO_MERGEFUNCTIONS_H
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
index b05ee0537eb..53b7db8689c 100644
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -86,6 +86,7 @@
 #include "llvm/Transforms/IPO/Inliner.h"
 #include "llvm/Transforms/IPO/Internalize.h"
 #include "llvm/Transforms/IPO/LowerTypeTests.h"
+#include "llvm/Transforms/IPO/MergeFunctions.h"
 #include "llvm/Transforms/IPO/PartialInlining.h"
 #include "llvm/Transforms/IPO/SCCP.h"
 #include "llvm/Transforms/IPO/SampleProfile.h"
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
index 3efb57cd358..355dd6f9681 100644
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -64,6 +64,7 @@ MODULE_PASS("internalize", InternalizePass())
 MODULE_PASS("invalidate<all>", InvalidateAllAnalysesPass())
 MODULE_PASS("ipsccp", IPSCCPPass())
 MODULE_PASS("lowertypetests", LowerTypeTestsPass(nullptr, nullptr))
+MODULE_PASS("mergefunc", MergeFunctionsPass())
 MODULE_PASS("name-anon-globals", NameAnonGlobalPass())
 MODULE_PASS("no-op-module", NoOpModulePass())
 MODULE_PASS("partial-inliner", PartialInlinerPass())
diff --git a/llvm/lib/Transforms/IPO/IPO.cpp b/llvm/lib/Transforms/IPO/IPO.cpp
index bddf7521159..8a15800cbdb 100644
--- a/llvm/lib/Transforms/IPO/IPO.cpp
+++ b/llvm/lib/Transforms/IPO/IPO.cpp
@@ -43,7 +43,7 @@ void llvm::initializeIPO(PassRegistry &Registry) {
   initializeBlockExtractorPass(Registry);
   initializeSingleLoopExtractorPass(Registry);
   initializeLowerTypeTestsPass(Registry);
-  initializeMergeFunctionsPass(Registry);
+  initializeMergeFunctionsLegacyPassPass(Registry);
   initializePartialInlinerLegacyPassPass(Registry);
   initializeAttributorLegacyPassPass(Registry);
   initializePostOrderFunctionAttrsLegacyPassPass(Registry);
diff --git a/llvm/lib/Transforms/IPO/MergeFunctions.cpp b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
index a702de03e46..06d2a2f3194 100644
--- a/llvm/lib/Transforms/IPO/MergeFunctions.cpp
+++ b/llvm/lib/Transforms/IPO/MergeFunctions.cpp
@@ -122,6 +122,7 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/IPO.h"
+#include "llvm/Transforms/IPO/MergeFunctions.h"
 #include "llvm/Transforms/Utils/FunctionComparator.h"
 #include <algorithm>
 #include <cassert>
@@ -196,16 +197,12 @@ public:
 /// by considering all pointer types to be equivalent. Once identified,
 /// MergeFunctions will fold them by replacing a call to one to a call to a
 /// bitcast of the other.
-class MergeFunctions : public ModulePass {
+class MergeFunctions {
 public:
-  static char ID;
-
-  MergeFunctions()
-    : ModulePass(ID), FnTree(FunctionNodeCmp(&GlobalNumbers)) {
-    initializeMergeFunctionsPass(*PassRegistry::getPassRegistry());
+  MergeFunctions() : FnTree(FunctionNodeCmp(&GlobalNumbers)) {
   }
 
-  bool runOnModule(Module &M) override;
+  bool runOnModule(Module &M);
 
 private:
   // The function comparison operator is provided here so that FunctionNodes do
@@ -298,14 +295,39 @@ private:
   DenseMap<AssertingVH<Function>, FnTreeType::iterator> FNodesInTree;
 };
 
-} // end anonymous namespace
+class MergeFunctionsLegacyPass : public ModulePass {
+public:
+  static char ID;
 
-char MergeFunctions::ID = 0;
+  MergeFunctionsLegacyPass(): ModulePass(ID) {
+    initializeMergeFunctionsLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
 
-INITIALIZE_PASS(MergeFunctions, "mergefunc", "Merge Functions", false, false)
+  bool runOnModule(Module &M) override {
+    if (skipModule(M))
+      return false;
+
+    MergeFunctions MF;
+    return MF.runOnModule(M);
+  }
+};
+
+} // end anonymous namespace
+
+char MergeFunctionsLegacyPass::ID = 0;
+INITIALIZE_PASS(MergeFunctionsLegacyPass, "mergefunc",
+                "Merge Functions", false, false)
 
 ModulePass *llvm::createMergeFunctionsPass() {
-  return new MergeFunctions();
+  return new MergeFunctionsLegacyPass();
+}
+
+PreservedAnalyses MergeFunctionsPass::run(Module &M,
+                                          ModuleAnalysisManager &AM) {
+  MergeFunctions MF;
+  if (!MF.runOnModule(M))
+    return PreservedAnalyses::all();
+  return PreservedAnalyses::none();
 }
 
 #ifndef NDEBUG
@@ -387,9 +409,6 @@ static bool isEligibleForMerging(Function &F) {
 }
 
 bool MergeFunctions::runOnModule(Module &M) {
-  if (skipModule(M))
-    return false;
-
   bool Changed = false;
 
   // All functions in the module, ordered by hash. Functions with a unique
diff --git a/llvm/test/Transforms/MergeFunc/merge-block-address.ll b/llvm/test/Transforms/MergeFunc/merge-block-address.ll
index 4ce13e5da87..d2340a77caf 100644
--- a/llvm/test/Transforms/MergeFunc/merge-block-address.ll
+++ b/llvm/test/Transforms/MergeFunc/merge-block-address.ll
@@ -1,4 +1,5 @@
 ; RUN: opt -S -mergefunc < %s | FileCheck %s
+; RUN: opt -S -passes=mergefunc < %s | FileCheck %s
 
 ; These two functions are identical. The basic block labels are the same, and
 ; induce the same CFG. We are testing that block addresses within different