[llvm] r254021 - [PGO] MST based PGO instrumentation infrastructure

Rong Xu via llvm-commits llvm-commits at lists.llvm.org
Tue Nov 24 13:31:26 PST 2015


Author: xur
Date: Tue Nov 24 15:31:25 2015
New Revision: 254021

URL: http://llvm.org/viewvc/llvm-project?rev=254021&view=rev
Log:
[PGO] MST based PGO instrumentation infrastructure

This patch implements a minimum spanning tree (MST) based instrumentation for
PGO. The use of MST guarantees minimum number of CFG edges getting
instrumented. An addition optimization is to instrument the less executed
edges to further reduce the instrumentation overhead. The patch contains both the
instrumentation and the use of the profile to set the branch weights.

Differential Revision: http://reviews.llvm.org/D12781

Added:
    llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h
    llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
    llvm/trunk/test/Transforms/PGOProfile/
    llvm/trunk/test/Transforms/PGOProfile/Inputs/
    llvm/trunk/test/Transforms/PGOProfile/Inputs/branch1.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/branch2.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/criticaledge.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/landingpad.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/loop1.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/loop2.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/loop3.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/single_bb.proftext
    llvm/trunk/test/Transforms/PGOProfile/Inputs/switch.proftext
    llvm/trunk/test/Transforms/PGOProfile/branch1_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/branch1_use.ll
    llvm/trunk/test/Transforms/PGOProfile/branch2_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/branch2_use.ll
    llvm/trunk/test/Transforms/PGOProfile/checksum_mismatch.ll
    llvm/trunk/test/Transforms/PGOProfile/criticaledge_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/criticaledge_use.ll
    llvm/trunk/test/Transforms/PGOProfile/landingpad_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/landingpad_use.ll
    llvm/trunk/test/Transforms/PGOProfile/loop1_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/loop1_use.ll
    llvm/trunk/test/Transforms/PGOProfile/loop2_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/loop2_use.ll
    llvm/trunk/test/Transforms/PGOProfile/loop3_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/loop3_use.ll
    llvm/trunk/test/Transforms/PGOProfile/noprofile_use.ll
    llvm/trunk/test/Transforms/PGOProfile/single_bb_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/switch_gen.ll
    llvm/trunk/test/Transforms/PGOProfile/switch_use.ll
Modified:
    llvm/trunk/include/llvm/IR/DiagnosticInfo.h
    llvm/trunk/include/llvm/InitializePasses.h
    llvm/trunk/include/llvm/LinkAllPasses.h
    llvm/trunk/include/llvm/Transforms/Instrumentation.h
    llvm/trunk/lib/IR/DiagnosticInfo.cpp
    llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt
    llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt
    llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp
    llvm/trunk/lib/Transforms/Instrumentation/LLVMBuild.txt

Modified: llvm/trunk/include/llvm/IR/DiagnosticInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/DiagnosticInfo.h?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/DiagnosticInfo.h (original)
+++ llvm/trunk/include/llvm/IR/DiagnosticInfo.h Tue Nov 24 15:31:25 2015
@@ -60,6 +60,7 @@ enum DiagnosticKind {
   DK_OptimizationRemarkAnalysisAliasing,
   DK_OptimizationFailure,
   DK_MIRParser,
+  DK_PGOProfile,
   DK_FirstPluginKind
 };
 
@@ -248,6 +249,31 @@ private:
 
   /// Message to report.
   const Twine &Msg;
+};
+
+/// Diagnostic information for the PGO profiler.
+class DiagnosticInfoPGOProfile : public DiagnosticInfo {
+public:
+  DiagnosticInfoPGOProfile(const char *FileName, const Twine &Msg,
+                           DiagnosticSeverity Severity = DS_Error)
+      : DiagnosticInfo(DK_PGOProfile, Severity), FileName(FileName), Msg(Msg) {}
+
+  /// \see DiagnosticInfo::print.
+  void print(DiagnosticPrinter &DP) const override;
+
+  static bool classof(const DiagnosticInfo *DI) {
+    return DI->getKind() == DK_PGOProfile;
+  }
+
+  const char *getFileName() const { return FileName; }
+  const Twine &getMsg() const { return Msg; }
+
+private:
+  /// Name of the input file associated with this diagnostic.
+  const char *FileName;
+
+  /// Message to report.
+  const Twine &Msg;
 };
 
 /// Common features for diagnostics dealing with optimization remarks.

Modified: llvm/trunk/include/llvm/InitializePasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/InitializePasses.h?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/include/llvm/InitializePasses.h (original)
+++ llvm/trunk/include/llvm/InitializePasses.h Tue Nov 24 15:31:25 2015
@@ -117,6 +117,8 @@ void initializeEdgeBundlesPass(PassRegis
 void initializeExpandPostRAPass(PassRegistry&);
 void initializeAAResultsWrapperPassPass(PassRegistry &);
 void initializeGCOVProfilerPass(PassRegistry&);
+void initializePGOInstrumentationGenPass(PassRegistry&);
+void initializePGOInstrumentationUsePass(PassRegistry&);
 void initializeInstrProfilingPass(PassRegistry&);
 void initializeAddressSanitizerPass(PassRegistry&);
 void initializeAddressSanitizerModulePass(PassRegistry&);

Modified: llvm/trunk/include/llvm/LinkAllPasses.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/LinkAllPasses.h?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/include/llvm/LinkAllPasses.h (original)
+++ llvm/trunk/include/llvm/LinkAllPasses.h Tue Nov 24 15:31:25 2015
@@ -85,6 +85,8 @@ namespace {
       (void) llvm::createDomOnlyViewerPass();
       (void) llvm::createDomViewerPass();
       (void) llvm::createGCOVProfilerPass();
+      (void) llvm::createPGOInstrumentationGenPass();
+      (void) llvm::createPGOInstrumentationUsePass();
       (void) llvm::createInstrProfilingPass();
       (void) llvm::createFunctionInliningPass();
       (void) llvm::createAlwaysInlinerPass();

Modified: llvm/trunk/include/llvm/Transforms/Instrumentation.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Transforms/Instrumentation.h?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Transforms/Instrumentation.h (original)
+++ llvm/trunk/include/llvm/Transforms/Instrumentation.h Tue Nov 24 15:31:25 2015
@@ -79,6 +79,11 @@ struct GCOVOptions {
 ModulePass *createGCOVProfilerPass(const GCOVOptions &Options =
                                    GCOVOptions::getDefault());
 
+// PGO Instrumention
+ModulePass *createPGOInstrumentationGenPass();
+ModulePass *
+createPGOInstrumentationUsePass(StringRef Filename = StringRef(""));
+
 /// Options for the frontend instrumentation based profiling pass.
 struct InstrProfOptions {
   InstrProfOptions() : NoRedZone(false) {}
@@ -149,6 +154,24 @@ FunctionPass *createBoundsCheckingPass()
 /// protect against stack-based overflow vulnerabilities.
 FunctionPass *createSafeStackPass(const TargetMachine *TM = nullptr);
 
+/// \brief Calculate what to divide by to scale counts.
+///
+/// Given the maximum count, calculate a divisor that will scale all the
+/// weights to strictly less than UINT32_MAX.
+static inline uint64_t calculateCountScale(uint64_t MaxCount) {
+  return MaxCount < UINT32_MAX ? 1 : MaxCount / UINT32_MAX + 1;
+}
+
+/// \brief Scale an individual branch count.
+///
+/// Scale a 64-bit weight down to 32-bits using \c Scale.
+///
+static inline uint32_t scaleBranchCount(uint64_t Count, uint64_t Scale) {
+  uint64_t Scaled = Count / Scale;
+  assert(Scaled <= UINT32_MAX && "overflow 32-bits");
+  return Scaled;
+}
+
 } // End llvm namespace
 
 #endif

Modified: llvm/trunk/lib/IR/DiagnosticInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/IR/DiagnosticInfo.cpp?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/lib/IR/DiagnosticInfo.cpp (original)
+++ llvm/trunk/lib/IR/DiagnosticInfo.cpp Tue Nov 24 15:31:25 2015
@@ -132,6 +132,12 @@ void DiagnosticInfoSampleProfile::print(
   DP << getMsg();
 }
 
+void DiagnosticInfoPGOProfile::print(DiagnosticPrinter &DP) const {
+  if (getFileName())
+    DP << getFileName() << ": ";
+  DP << getMsg();
+}
+
 bool DiagnosticInfoOptimizationBase::isLocationAvailable() const {
   return getDebugLoc();
 }

Modified: llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt (original)
+++ llvm/trunk/lib/Transforms/IPO/LLVMBuild.txt Tue Nov 24 15:31:25 2015
@@ -20,4 +20,4 @@ type = Library
 name = IPO
 parent = Transforms
 library_name = ipo
-required_libraries = Analysis Core InstCombine IRReader Linker Object ProfileData Scalar Support TransformUtils Vectorize
+required_libraries = Analysis Core InstCombine IRReader Linker Object ProfileData Scalar Support TransformUtils Vectorize Instrumentation

Added: llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h?rev=254021&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h (added)
+++ llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h Tue Nov 24 15:31:25 2015
@@ -0,0 +1,210 @@
+//===-- CFGMST.h - Minimum Spanning Tree for CFG -------*- C++ -*-===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements Union-find algorithm to compute Minimum Spanning Tree
+// for a given CFG.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/raw_ostream.h"
+#include "llvm/Support/BranchProbability.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include <string>
+#include <vector>
+#include <utility>
+
+namespace llvm {
+
+#define DEBUG_TYPE "cfgmst"
+
+template <class Edge, class BBInfo> class CFGMST {
+public:
+  Function &F;
+
+  // Store all the edges in CFG. It may contain some stale edges
+  // when Removed is set.
+  std::vector<std::unique_ptr<Edge>> AllEdges;
+
+  // This map records the auxiliary information for each BB.
+  DenseMap<const BasicBlock *, std::unique_ptr<BBInfo>> BBInfos;
+
+  // Find the root group of the G and compress the path from G to the root.
+  BBInfo *findAndCompressGroup(BBInfo *G) {
+    if (G->Group != G)
+      G->Group = findAndCompressGroup(static_cast<BBInfo *>(G->Group));
+    return static_cast<BBInfo *>(G->Group);
+  }
+
+  // Union BB1 and BB2 into the same group and return true.
+  // Returns false if BB1 and BB2 are already in the same group.
+  bool unionGroups(const BasicBlock *BB1, const BasicBlock *BB2) {
+    BBInfo *BB1G = findAndCompressGroup(&getBBInfo(BB1));
+    BBInfo *BB2G = findAndCompressGroup(&getBBInfo(BB2));
+
+    if (BB1G == BB2G)
+      return false;
+
+    // Make the smaller rank tree a direct child or the root of high rank tree.
+    if (BB1G->Rank < BB2G->Rank)
+      BB1G->Group = BB2G;
+    else {
+      BB2G->Group = BB1G;
+      // If the ranks are the same, increment root of one tree by one.
+      if (BB1G->Rank == BB2G->Rank)
+        BB1G->Rank++;
+    }
+    return true;
+  }
+
+  // Give BB, return the auxiliary information.
+  BBInfo &getBBInfo(const BasicBlock *BB) const {
+    auto It = BBInfos.find(BB);
+    assert(It->second.get() != nullptr);
+    return *It->second.get();
+  }
+
+  // Traverse the CFG using a stack. Find all the edges and assign the weight.
+  // Edges with large weight will be put into MST first so they are less likely
+  // to be instrumented.
+  void buildEdges() {
+    DEBUG(dbgs() << "Build Edge on " << F.getName() << "\n");
+
+    const BasicBlock *BB = &(F.getEntryBlock());
+    // Add a fake edge to the entry.
+    addEdge(nullptr, BB, BFI->getEntryFreq());
+
+    // Special handling for single BB functions.
+    if (succ_empty(BB)) {
+      addEdge(BB, nullptr, BFI->getEntryFreq());
+      return;
+    }
+
+    static const uint32_t CriticalEdgeMultiplier = 1000;
+
+    for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+      TerminatorInst *TI = BB->getTerminator();
+      uint64_t BBWeight = BFI->getBlockFreq(&*BB).getFrequency();
+      uint64_t Weight;
+      if (int successors = TI->getNumSuccessors()) {
+        for (uint32_t i = 0; i != successors; ++i) {
+          BasicBlock *TargetBB = TI->getSuccessor(i);
+          bool Critical = isCriticalEdge(TI, i);
+          uint64_t scaleFactor = BBWeight;
+          if (Critical) {
+            if (scaleFactor < UINT64_MAX / CriticalEdgeMultiplier)
+              scaleFactor *= CriticalEdgeMultiplier;
+            else
+              scaleFactor = UINT64_MAX;
+          }
+          Weight = BPI->getEdgeProbability(&*BB, TargetBB).scale(scaleFactor);
+          addEdge(&*BB, TargetBB, Weight).IsCritical = Critical;
+          DEBUG(dbgs() << "  Edge: from " << BB->getName() << " to "
+                       << TargetBB->getName() << "  w=" << Weight << "\n");
+        }
+      } else {
+        addEdge(&*BB, nullptr, BBWeight);
+        DEBUG(dbgs() << "  Edge: from " << BB->getName() << " to exit"
+                     << " w = " << BBWeight << "\n");
+      }
+    }
+  }
+
+  // Sort CFG edges based on its weight.
+  void sortEdgesByWeight() {
+    std::sort(
+        AllEdges.begin(), AllEdges.end(),
+        [](const std::unique_ptr<Edge> &lhs, const std::unique_ptr<Edge> &rhs) {
+          return lhs->Weight > rhs->Weight;
+        });
+  }
+
+  // Traverse all the edges and compute the Minimum Weight Spanning Tree
+  // using union-find algorithm.
+  void computeMinimumSpanningTree() {
+    // First, put all the critical edge with landing-pad as the Dest to MST.
+    // This works around the insufficient support of critical edges split
+    // when destination BB is a landing pad.
+    for (auto &Ei : AllEdges) {
+      if (Ei->Removed)
+        continue;
+      if (Ei->IsCritical) {
+        if (Ei->DestBB && Ei->DestBB->isLandingPad()) {
+          if (unionGroups(Ei->SrcBB, Ei->DestBB))
+            Ei->InMST = true;
+        }
+      }
+    }
+
+    for (auto &Ei : AllEdges) {
+      if (Ei->Removed)
+        continue;
+      if (unionGroups(Ei->SrcBB, Ei->DestBB))
+        Ei->InMST = true;
+    }
+  }
+
+  // Dump the Debug information about the instrumentation.
+  void dumpEdges(raw_ostream &OS, const StringRef Message = StringRef()) const {
+    if (!Message.empty())
+      OS << Message << "\n";
+    OS << "  Number of Basic Blocks: " << BBInfos.size() << "\n";
+    for (auto &BI : BBInfos) {
+      const BasicBlock *BB = BI.first;
+      OS << "  BB: " << (BB == nullptr ? "FakeNode" : BB->getName()) << "  "
+         << BI.second->infoString() << "\n";
+    }
+
+    OS << "  Number of Edges: " << AllEdges.size()
+       << " (*: Instrument, C: CriticalEdge, -: Removed)\n";
+    uint32_t Count = 0;
+    for (auto &EI : AllEdges) {
+      OS << "  Edge " << Count++ << ": " << getBBInfo(EI->SrcBB).Index << "-->"
+         << getBBInfo(EI->DestBB).Index << EI->infoString() << "\n";
+    };
+  }
+
+  // Add an edge to AllEdges with weight W.
+  Edge &addEdge(const BasicBlock *Src, const BasicBlock *Dest, uint64_t W) {
+    uint32_t Index = BBInfos.size();
+    auto Iter = BBInfos.end();
+    bool Inserted;
+    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Src, nullptr));
+    if (Inserted) {
+      // Newly inserted, update the real info.
+      Iter->second = std::move(llvm::make_unique<BBInfo>(Index));
+      Index++;
+    }
+    std::tie(Iter, Inserted) = BBInfos.insert(std::make_pair(Dest, nullptr));
+    if (Inserted)
+      // Newly inserted, update the real info.
+      Iter->second = std::move(llvm::make_unique<BBInfo>(Index));
+    AllEdges.emplace_back(new Edge(Src, Dest, W));
+    return *AllEdges.back();
+  }
+
+  BranchProbabilityInfo *BPI;
+  BlockFrequencyInfo *BFI;
+
+public:
+  CFGMST(Function &Func, BranchProbabilityInfo *BPI_ = nullptr,
+         BlockFrequencyInfo *BFI_ = nullptr)
+      : F(Func), BPI(BPI_), BFI(BFI_) {
+    buildEdges();
+    sortEdgesByWeight();
+    computeMinimumSpanningTree();
+  }
+};
+
+#undef DEBUG_TYPE // "cfgmst"
+} // end namespace llvm

Modified: llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/CMakeLists.txt Tue Nov 24 15:31:25 2015
@@ -6,6 +6,7 @@ add_llvm_library(LLVMInstrumentation
   MemorySanitizer.cpp
   Instrumentation.cpp
   InstrProfiling.cpp
+  PGOInstrumentation.cpp
   SafeStack.cpp
   SanitizerCoverage.cpp
   ThreadSanitizer.cpp

Modified: llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/Instrumentation.cpp Tue Nov 24 15:31:25 2015
@@ -60,6 +60,8 @@ void llvm::initializeInstrumentation(Pas
   initializeAddressSanitizerModulePass(Registry);
   initializeBoundsCheckingPass(Registry);
   initializeGCOVProfilerPass(Registry);
+  initializePGOInstrumentationGenPass(Registry);
+  initializePGOInstrumentationUsePass(Registry);
   initializeInstrProfilingPass(Registry);
   initializeMemorySanitizerPass(Registry);
   initializeThreadSanitizerPass(Registry);

Modified: llvm/trunk/lib/Transforms/Instrumentation/LLVMBuild.txt
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/LLVMBuild.txt?rev=254021&r1=254020&r2=254021&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/LLVMBuild.txt (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/LLVMBuild.txt Tue Nov 24 15:31:25 2015
@@ -19,4 +19,4 @@
 type = Library
 name = Instrumentation
 parent = Transforms
-required_libraries = Analysis Core MC Support TransformUtils
+required_libraries = Analysis Core MC Support TransformUtils ProfileData

Added: llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp?rev=254021&view=auto
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (added)
+++ llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp Tue Nov 24 15:31:25 2015
@@ -0,0 +1,718 @@
+//===- PGOInstru.cpp - PGO Instrumentation --------===//
+//
+//                      The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements PGO instrumentation using a minimum spanning tree based
+// on the  following paper.
+//   [1] Donald E. Knuth, Francis R. Stevenson. Optimal measurement of points
+//   for program frequency counts. BIT Numerical Mathematics 1973, Volume 13,
+//   Issue 3, pp 313-322
+// The idea of the algorithm based on the fact that for each node (except for
+// the entry and exit), the sum of incoming edge counts equals the sum of
+// outgoing edge counts. The count of edge on spanning tree can be derived from
+// those edges not on the spanning tree. Knuth proves this method instruments
+// the minimum number of edges.
+//
+// The minimal spanning tree here is actually a maximum weight tree -- on-tree
+// edges have higher frequencies (most likely to execute). The idea is to
+// instrument those less frequently executed edges which speeds up the
+// instrumented binaries.
+//
+// This file contains two passes:
+// (1) Pass PGOInstrumentationGen which instruments the IR to generate edge
+// count profile, and
+// (2) Pass PGOInstrumentationUse which reads the edge count profile and
+// annotates the branch weight.
+// These two passes are mutually exclusive, and they are called at the same
+// compilation point (so they see the same IR). For PGOInstrumentationGen,
+// the real work is done instrumentOneFunc(). For PGOInstrumentationUse, the
+// real work in done in class PGOUseFunc and the profile is opened in module
+// level and passed to each PGOUseFunc instance.
+// The shared code for PGOInstrumentationGen and PGOInstrumentationUse is put
+// in class FuncPGOInstrumentation.
+//
+// Class PGOEdge represents a CFG edge and some auxiliary information. Class
+// BBInfo contains auxiliary information for a BB. These two classes are used
+// in PGOGenFunc. Class PGOUseEdge and UseBBInfo are the derived class of
+// PGOEdge and BBInfo, respectively. They contains extra data structure used
+// in populating profile counters.
+// The MST implementation is in Class CFGMST.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Instrumentation.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/STLExtras.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/IRBuilder.h"
+#include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/DiagnosticInfo.h"
+#include "llvm/Pass.h"
+#include "llvm/IR/Module.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Support/BranchProbability.h"
+#include "llvm/Support/JamCRC.h"
+#include "llvm/Transforms/Utils/BasicBlockUtils.h"
+#include "llvm/ProfileData/InstrProfReader.h"
+#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/BranchProbabilityInfo.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include <string>
+#include <vector>
+#include <utility>
+#include "CFGMST.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "pgo-instr"
+
+STATISTIC(NumOfPGOInstrument, "Number of edges instrumented.");
+STATISTIC(NumOfPGOEdge, "Number of edges.");
+STATISTIC(NumOfPGOBB, "Number of basic-blocks.");
+STATISTIC(NumOfPGOSplit, "Number of critical edge splits.");
+STATISTIC(NumOfPGOFunc, "Number of functions having valid profile counts.");
+STATISTIC(NumOfPGOMismatch, "Number of functions having mismatch profile.");
+STATISTIC(NumOfPGOMissing, "Number of functions without profile.");
+
+static cl::opt<std::string>
+    PGOProfileFile("pgo-profile-file", cl::init(""), cl::Hidden,
+                   cl::value_desc("filename"),
+                   cl::desc("Specify the path of profile data file"));
+
+namespace {
+class PGOInstrumentationGen : public ModulePass {
+public:
+  static char ID;
+
+  PGOInstrumentationGen() : ModulePass(ID) {
+    initializePGOInstrumentationGenPass(*PassRegistry::getPassRegistry());
+  }
+
+  const char *getPassName() const override {
+    return "PGOInstrumentationGenPass";
+  }
+
+private:
+  bool runOnModule(Module &M) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<BlockFrequencyInfoWrapperPass>();
+    AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  }
+};
+
+class PGOInstrumentationUse : public ModulePass {
+public:
+  static char ID;
+
+  // Provide the profile filename as the parameter.
+  PGOInstrumentationUse(StringRef Filename = StringRef(""))
+      : ModulePass(ID), ProfileFileName(Filename) {
+    if (!PGOProfileFile.empty())
+      ProfileFileName = StringRef(PGOProfileFile);
+    initializePGOInstrumentationUsePass(*PassRegistry::getPassRegistry());
+  }
+
+  const char *getPassName() const override {
+    return "PGOInstrumentationUsePass";
+  }
+
+private:
+  StringRef ProfileFileName;
+  std::unique_ptr<IndexedInstrProfReader> PGOReader;
+  bool runOnModule(Module &M) override;
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<BlockFrequencyInfoWrapperPass>();
+    AU.addRequired<BranchProbabilityInfoWrapperPass>();
+  }
+};
+} // end anonymous namespace
+
+char PGOInstrumentationGen::ID = 0;
+INITIALIZE_PASS_BEGIN(PGOInstrumentationGen, "pgo-instr-gen",
+                      "PGO instrumentation.", false, false)
+INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_END(PGOInstrumentationGen, "pgo-instr-gen",
+                    "PGO instrumentation.", false, false)
+
+ModulePass *llvm::createPGOInstrumentationGenPass() {
+  return new PGOInstrumentationGen();
+}
+
+char PGOInstrumentationUse::ID = 0;
+INITIALIZE_PASS_BEGIN(PGOInstrumentationUse, "pgo-instr-use",
+                      "Read PGO instrumentation profile.", false, false)
+INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_END(PGOInstrumentationUse, "pgo-instr-use",
+                    "Read PGO instrumentation profile.", false, false)
+
+ModulePass *llvm::createPGOInstrumentationUsePass(StringRef Filename) {
+  return new PGOInstrumentationUse(Filename);
+}
+
+namespace {
+/// \brief An MST based instrumentation for PGO
+///
+/// Implements a Minimum Spanning Tree (MST) based instrumentation for PGO
+/// in the function level.
+//
+// This class implements the CFG edges. Note the CFG can be a multi-graph.
+struct PGOEdge {
+  const BasicBlock *SrcBB;
+  const BasicBlock *DestBB;
+  uint64_t Weight;
+  bool InMST;
+  bool Removed;
+  bool IsCritical;
+  PGOEdge(const BasicBlock *Src, const BasicBlock *Dest, unsigned W = 1)
+      : SrcBB(Src), DestBB(Dest), Weight(W), InMST(false), Removed(false),
+        IsCritical(false) {}
+  // Return the information string of an edge.
+  const std::string infoString() const {
+    std::string Str = (Removed ? "-" : " ");
+    Str += (InMST ? " " : "*");
+    Str += (IsCritical ? "c" : " ");
+    Str += "  W=" + std::to_string(Weight);
+    return Str;
+  }
+};
+
+// This class stores the auxiliary information for each BB.
+struct BBInfo {
+  BBInfo *Group;
+  uint32_t Index;
+  uint32_t Rank;
+
+  BBInfo(unsigned IX) : Group(this), Index(IX), Rank(0) {}
+
+  // Return the information string of this object.
+  const std::string infoString() const {
+    return "Index=" + std::to_string(Index);
+  }
+};
+
+// This class implements the CFG edges. Note the CFG can be a multi-graph.
+template <class Edge, class BBInfo> class FuncPGOInstrumentation {
+private:
+  Function &F;
+  void computeCFGHash();
+
+public:
+  std::string FuncName;
+  GlobalVariable *FuncNameVar;
+  // CFG hash value for this function.
+  uint64_t FunctionHash;
+
+  // The Minimum Spanning Tree of function CFG.
+  CFGMST<Edge, BBInfo> MST;
+
+  // Give an edge, find the BB that will be instrumented.
+  // Return nullptr if there is no BB to be instrumented.
+  BasicBlock *getInstrBB(Edge *E);
+
+  // Return the auxiliary BB information.
+  BBInfo &getBBInfo(const BasicBlock *BB) const { return MST.getBBInfo(BB); }
+
+  // Dump edges and BB information.
+  void dumpInfo(std::string Str = "") const {
+    std::string Message = "Dump Function " + FuncName + " Hash: " +
+                          std::to_string(FunctionHash) + "\t" + Str;
+    MST.dumpEdges(dbgs(), Message);
+  }
+
+  FuncPGOInstrumentation(Function &Func, bool CreateGlobalVar = false,
+                         BranchProbabilityInfo *BPI_ = nullptr,
+                         BlockFrequencyInfo *BFI_ = nullptr)
+      : F(Func), FunctionHash(0), MST(F, BPI_, BFI_) {
+    FuncName = getPGOFuncName(F);
+    computeCFGHash();
+    DEBUG(dumpInfo("after CFGMST"));
+
+    NumOfPGOBB += MST.BBInfos.size();
+    for (auto &Ei : MST.AllEdges) {
+      if (Ei->Removed)
+        continue;
+      NumOfPGOEdge++;
+      if (!Ei->InMST)
+        NumOfPGOInstrument++;
+    }
+
+    if (CreateGlobalVar)
+      FuncNameVar = createPGOFuncNameVar(F, FuncName);
+  };
+};
+
+// Compute Hash value for the CFG: the lower 32 bits are CRC32 of the index
+// value of each BB in the CFG. The higher 32 bits record the number of edges.
+template <class Edge, class BBInfo>
+void FuncPGOInstrumentation<Edge, BBInfo>::computeCFGHash() {
+  std::vector<char> Indexes;
+  JamCRC JC;
+  for (auto &BB : F) {
+    const TerminatorInst *TI = BB.getTerminator();
+    for (unsigned s = 0, e = TI->getNumSuccessors(); s != e; ++s) {
+      BasicBlock *Succ = TI->getSuccessor(s);
+      uint32_t Index = getBBInfo(Succ).Index;
+      for (int i = 0; i < sizeof(uint32_t) / sizeof(char); i++)
+        Indexes.push_back((char)(Index >> (i * sizeof(char))));
+    }
+  }
+  JC.update(Indexes);
+  FunctionHash = MST.AllEdges.size() << 32 | JC.getCRC();
+}
+
+template <class Edge, class BBInfo>
+BasicBlock *FuncPGOInstrumentation<Edge, BBInfo>::getInstrBB(Edge *E) {
+  if (E->InMST || E->Removed)
+    return nullptr;
+
+  BasicBlock *SrcBB = const_cast<BasicBlock *>(E->SrcBB);
+  BasicBlock *DestBB = const_cast<BasicBlock *>(E->DestBB);
+  // For a fake edge, instrument the real BB.
+  if (SrcBB == nullptr)
+    return DestBB;
+  if (DestBB == nullptr)
+    return SrcBB;
+
+  // Instrument the SrcBB if it has a single successor,
+  // otherwise, the DestBB if this is not a critical edge.
+  TerminatorInst *TI = SrcBB->getTerminator();
+  if (TI->getNumSuccessors() <= 1)
+    return SrcBB;
+  if (!E->IsCritical)
+    return DestBB;
+
+  // For a critical edge, we have to split. Instrument the newly
+  // created BB.
+  NumOfPGOSplit++;
+  DEBUG(dbgs() << "Split critical edge: " << getBBInfo(SrcBB).Index << " --> "
+               << getBBInfo(DestBB).Index << "\n");
+  unsigned SuccNum = GetSuccessorNumber(SrcBB, DestBB);
+  BasicBlock *InstrBB = SplitCriticalEdge(TI, SuccNum);
+  assert(InstrBB && "Critical edge is not split");
+
+  E->Removed = true;
+  return InstrBB;
+}
+
+// Visit all edge and instrument the edges not in MST.
+// Critical edges will be split.
+static void instrumentOneFunc(Function &F, Module *M,
+                              BranchProbabilityInfo *BPI,
+                              BlockFrequencyInfo *BFI) {
+  unsigned NumCounters = 0;
+  FuncPGOInstrumentation<PGOEdge, BBInfo> FuncInfo(F, true, BPI, BFI);
+  for (auto &Ei : FuncInfo.MST.AllEdges) {
+    if (!Ei->InMST && !Ei->Removed)
+      NumCounters++;
+  }
+
+  uint32_t j = 0;
+  for (auto &Ei : FuncInfo.MST.AllEdges) {
+    BasicBlock *InstrBB = FuncInfo.getInstrBB(Ei.get());
+    if (!InstrBB)
+      continue;
+
+    IRBuilder<> Builder(InstrBB, InstrBB->getFirstInsertionPt());
+    assert(Builder.GetInsertPoint() != InstrBB->end() &&
+           "Cannot get the Instrumentation point");
+    auto *I8PtrTy = Type::getInt8PtrTy(M->getContext());
+    Builder.CreateCall(
+        Intrinsic::getDeclaration(M, Intrinsic::instrprof_increment),
+        {llvm::ConstantExpr::getBitCast(FuncInfo.FuncNameVar, I8PtrTy),
+         Builder.getInt64(FuncInfo.FunctionHash), Builder.getInt32(NumCounters),
+         Builder.getInt32(j++)});
+  }
+}
+
+struct PGOUseEdge : public PGOEdge {
+  bool CountValid;
+  uint64_t CountValue;
+  PGOUseEdge(const BasicBlock *Src, const BasicBlock *Dest, unsigned W = 1)
+      : PGOEdge(Src, Dest, W), CountValid(false), CountValue(0) {}
+
+  // Set edge count value
+  void setEdgeCount(uint64_t Value) {
+    CountValue = Value;
+    CountValid = true;
+  }
+
+  // Return the information string for this object.
+  const std::string infoString() const {
+    if (!CountValid)
+      return PGOEdge::infoString();
+    return PGOEdge::infoString() + "  Count=" + std::to_string(CountValue);
+  }
+};
+
+typedef SmallVector<PGOUseEdge *, 2> DirectEdges;
+
+// This class stores the auxiliary information for each BB.
+struct UseBBInfo : public BBInfo {
+  uint64_t CountValue;
+  bool CountValid;
+  int32_t UnknownCountInEdge;
+  int32_t UnknownCountOutEdge;
+  DirectEdges InEdges;
+  DirectEdges OutEdges;
+  UseBBInfo(unsigned IX)
+      : BBInfo(IX), CountValue(0), CountValid(false), UnknownCountInEdge(0),
+        UnknownCountOutEdge(0) {}
+  UseBBInfo(unsigned IX, uint64_t C)
+      : BBInfo(IX), CountValue(C), CountValid(true), UnknownCountInEdge(0),
+        UnknownCountOutEdge(0) {}
+
+  // Set the profile count value for this BB.
+  void setBBInfoCount(uint64_t Value) {
+    CountValue = Value;
+    CountValid = true;
+  }
+
+  // Return the information string of this object.
+  const std::string infoString() const {
+    if (!CountValid)
+      return BBInfo::infoString();
+    return BBInfo::infoString() + "  Count=" + std::to_string(CountValue);
+  }
+};
+
+// Sum up the count values for all the edges.
+static uint64_t sumEdgeCount(const ArrayRef<PGOUseEdge *> Edges) {
+  uint64_t Total = 0;
+  for (auto &Ei : Edges) {
+    if (Ei->Removed)
+      continue;
+    Total += Ei->CountValue;
+  }
+  return Total;
+}
+
+class PGOUseFunc {
+private:
+  Function &F;
+  Module *M;
+  // This member stores the shared information with class PGOGenFunc.
+  FuncPGOInstrumentation<PGOUseEdge, UseBBInfo> FuncInfo;
+
+  // Return the auxiliary BB information.
+  UseBBInfo &getBBInfo(const BasicBlock *BB) const {
+    return FuncInfo.getBBInfo(BB);
+  }
+
+  // The maximum count value in the profile. This is only used in PGO use
+  // compilation.
+  uint64_t ProgramMaxCount;
+
+  // Find the Instrumented BB and set the value.
+  void setInstrumentedCounts(const std::vector<uint64_t> &CountFromProfile);
+
+  // Set the edge counter value for the unknown edge -- there should be only
+  // one unknown edge.
+  void setEdgeCount(DirectEdges &Edges, uint64_t Value);
+
+  // Return FuncName string;
+  const std::string getFuncName() const { return FuncInfo.FuncName; }
+
+  // Set the hot/cold inline hints based on the count values.
+  void applyFunctionAttributes(uint64_t EntryCount, uint64_t MaxCount) {
+    if (ProgramMaxCount == 0)
+      return;
+    // Threshold of the hot functions.
+    const BranchProbability HotFunctionThreshold(1, 100);
+    // Threshold of the cold functions.
+    const BranchProbability ColdFunctionThreshold(2, 10000);
+    if (EntryCount >= HotFunctionThreshold.scale(ProgramMaxCount))
+      F.addFnAttr(llvm::Attribute::InlineHint);
+    else if (MaxCount <= ColdFunctionThreshold.scale(ProgramMaxCount))
+      F.addFnAttr(llvm::Attribute::Cold);
+  }
+
+public:
+  PGOUseFunc(Function &Func, Module *Modu,
+             BranchProbabilityInfo *BPI_ = nullptr,
+             BlockFrequencyInfo *BFI_ = nullptr)
+      : F(Func), M(Modu), FuncInfo(Func, false, BPI_, BFI_) {}
+
+  // Read counts for the instrumented BB from profile.
+  bool readCounters(IndexedInstrProfReader *PGOReader);
+
+  // Populate the counts for all BBs.
+  void populateCounters();
+
+  // Set the branch weights based on the count values.
+  void setBranchWeights();
+};
+
+// Visit all the edges and assign the count value for the instrumented
+// edges and the BB.
+void PGOUseFunc::setInstrumentedCounts(
+    const std::vector<uint64_t> &CountFromProfile) {
+
+  // Use a worklist as we will update the vector during the iteration.
+  std::vector<PGOUseEdge *> WorkList;
+  for (auto &Ei : FuncInfo.MST.AllEdges)
+    WorkList.push_back(Ei.get());
+
+  uint32_t j = 0;
+  for (auto &Ei : WorkList) {
+    BasicBlock *InstrBB = FuncInfo.getInstrBB(Ei);
+    if (!InstrBB)
+      continue;
+    uint64_t CountValue = CountFromProfile[j++];
+    if (!Ei->Removed) {
+      getBBInfo(InstrBB).setBBInfoCount(CountValue);
+      Ei->setEdgeCount(CountValue);
+      continue;
+    }
+
+    // Need to add two new edges.
+    BasicBlock *SrcBB = const_cast<BasicBlock *>(Ei->SrcBB);
+    BasicBlock *DestBB = const_cast<BasicBlock *>(Ei->DestBB);
+    // Add new edge of SrcBB->InstrBB.
+    PGOUseEdge &NewEdge = FuncInfo.MST.addEdge(SrcBB, InstrBB, 0);
+    NewEdge.setEdgeCount(CountValue);
+    // Add new edge of InstrBB->DestBB.
+    PGOUseEdge &NewEdge1 = FuncInfo.MST.addEdge(InstrBB, DestBB, 0);
+    NewEdge1.setEdgeCount(CountValue);
+    NewEdge1.InMST = true;
+    getBBInfo(InstrBB).setBBInfoCount(CountValue);
+  }
+}
+
+// Set the count value for the unknown edges. There should be one and only one
+// unknown edge in Edges vector.
+void PGOUseFunc::setEdgeCount(DirectEdges &Edges, uint64_t Value) {
+  for (auto &Ei : Edges) {
+    if (Ei->CountValid)
+      continue;
+    Ei->setEdgeCount(Value);
+
+    getBBInfo(Ei->SrcBB).UnknownCountOutEdge--;
+    getBBInfo(Ei->DestBB).UnknownCountInEdge--;
+    return;
+  }
+  llvm_unreachable("Cannot find the unknown count edge");
+}
+
+// Read the profile from ProfileFileName and assign the value to the
+// instrumented BB and the edges. This function also updates ProgramMaxCount.
+// Return true if the profile are successfully read, and false on errors.
+bool PGOUseFunc::readCounters(IndexedInstrProfReader *PGOReader) {
+  auto &Ctx = M->getContext();
+  ErrorOr<InstrProfRecord> Result =
+      PGOReader->getInstrProfRecord(FuncInfo.FuncName, FuncInfo.FunctionHash);
+  if (std::error_code EC = Result.getError()) {
+    if (EC == instrprof_error::unknown_function)
+      NumOfPGOMissing++;
+    else if (EC == instrprof_error::hash_mismatch ||
+             EC == llvm::instrprof_error::malformed)
+      NumOfPGOMismatch++;
+
+    std::string Msg = EC.message() + std::string(" ") + F.getName().str();
+    Ctx.diagnose(
+        DiagnosticInfoPGOProfile(M->getName().data(), Msg, DS_Warning));
+    return false;
+  }
+  std::vector<uint64_t> &CountFromProfile = Result.get().Counts;
+
+  NumOfPGOFunc++;
+  DEBUG(dbgs() << CountFromProfile.size() << " counts\n");
+  uint64_t ValueSum = 0;
+  for (unsigned i = 0, e = CountFromProfile.size(); i < e; i++) {
+    DEBUG(dbgs() << "  " << i << ": " << CountFromProfile[i] << "\n");
+    ValueSum += CountFromProfile[i];
+  }
+
+  DEBUG(dbgs() << "SUM =  " << ValueSum << "\n");
+
+  getBBInfo(nullptr).UnknownCountOutEdge = 2;
+  getBBInfo(nullptr).UnknownCountInEdge = 2;
+
+  setInstrumentedCounts(CountFromProfile);
+  ProgramMaxCount = PGOReader->getMaximumFunctionCount();
+  return true;
+}
+
+// Populate the counters from instrumented BBs to all BBs.
+// In the end of this operation, all BBs should have a valid count value.
+void PGOUseFunc::populateCounters() {
+  // First set up Count variable for all BBs.
+  for (auto &Ei : FuncInfo.MST.AllEdges) {
+    if (Ei->Removed)
+      continue;
+
+    const BasicBlock *SrcBB = Ei->SrcBB;
+    const BasicBlock *DestBB = Ei->DestBB;
+    UseBBInfo &SrcInfo = getBBInfo(SrcBB);
+    UseBBInfo &DestInfo = getBBInfo(DestBB);
+    SrcInfo.OutEdges.push_back(Ei.get());
+    DestInfo.InEdges.push_back(Ei.get());
+    SrcInfo.UnknownCountOutEdge++;
+    DestInfo.UnknownCountInEdge++;
+
+    if (!Ei->CountValid)
+      continue;
+    DestInfo.UnknownCountInEdge--;
+    SrcInfo.UnknownCountOutEdge--;
+  }
+
+  bool Changes = true;
+  unsigned NumPasses = 0;
+  while (Changes) {
+    NumPasses++;
+    Changes = false;
+
+    // For efficient traversal, it's better to start from the end as most
+    // of the instrumented edges are at the end.
+    for (auto &BB : reverse(F)) {
+      UseBBInfo &Count = getBBInfo(&BB);
+      if (!Count.CountValid) {
+        if (Count.UnknownCountOutEdge == 0) {
+          Count.CountValue = sumEdgeCount(Count.OutEdges);
+          Count.CountValid = true;
+          Changes = true;
+        } else if (Count.UnknownCountInEdge == 0) {
+          Count.CountValue = sumEdgeCount(Count.InEdges);
+          Count.CountValid = true;
+          Changes = true;
+        }
+      }
+      if (Count.CountValid) {
+        if (Count.UnknownCountOutEdge == 1) {
+          uint64_t Total = Count.CountValue - sumEdgeCount(Count.OutEdges);
+          setEdgeCount(Count.OutEdges, Total);
+          Changes = true;
+        }
+        if (Count.UnknownCountInEdge == 1) {
+          uint64_t Total = Count.CountValue - sumEdgeCount(Count.InEdges);
+          setEdgeCount(Count.InEdges, Total);
+          Changes = true;
+        }
+      }
+    }
+  }
+
+  DEBUG(dbgs() << "Populate counts in " << NumPasses << " passes.\n");
+  // Assert every BB has a valid counter.
+  uint64_t FuncEntryCount = getBBInfo(&*F.begin()).CountValue;
+  uint64_t FuncMaxCount = FuncEntryCount;
+  for (auto &BB : F) {
+    assert(getBBInfo(&BB).CountValid && "BB count is not valid");
+    uint64_t Count = getBBInfo(&BB).CountValue;
+    if (Count > FuncMaxCount)
+      FuncMaxCount = Count;
+  }
+  applyFunctionAttributes(FuncEntryCount, FuncMaxCount);
+
+  DEBUG(FuncInfo.dumpInfo("after reading profile."));
+}
+
+// Assign the scaled count values to the BB with multiple out edges.
+void PGOUseFunc::setBranchWeights() {
+  // Generate MD_prof metadata for every branch instruction.
+  DEBUG(dbgs() << "\nSetting branch weights.\n");
+  MDBuilder MDB(M->getContext());
+  for (auto &BB : F) {
+    TerminatorInst *TI = BB.getTerminator();
+    if (TI->getNumSuccessors() < 2)
+      continue;
+    if (!isa<BranchInst>(TI) && !isa<SwitchInst>(TI))
+      continue;
+    if (getBBInfo(&BB).CountValue == 0)
+      continue;
+
+    // We have a non-zero Branch BB.
+    const UseBBInfo &BBCountInfo = getBBInfo(&BB);
+    unsigned Size = BBCountInfo.OutEdges.size();
+    SmallVector<unsigned, 2> EdgeCounts(Size, 0);
+    uint64_t MaxCount = 0;
+    for (unsigned s = 0; s < Size; s++) {
+      const PGOUseEdge *E = BBCountInfo.OutEdges[s];
+      const BasicBlock *SrcBB = E->SrcBB;
+      const BasicBlock *DestBB = E->DestBB;
+      if (DestBB == 0)
+        continue;
+      unsigned SuccNum = GetSuccessorNumber(SrcBB, DestBB);
+      uint64_t EdgeCount = E->CountValue;
+      if (EdgeCount > MaxCount)
+        MaxCount = EdgeCount;
+      EdgeCounts[SuccNum] = EdgeCount;
+    }
+    assert(MaxCount > 0 && "Bad max count");
+    uint64_t Scale = calculateCountScale(MaxCount);
+    SmallVector<unsigned, 4> Weights;
+    for (const auto &ECI : EdgeCounts)
+      Weights.push_back(scaleBranchCount(ECI, Scale));
+
+    TI->setMetadata(llvm::LLVMContext::MD_prof,
+                    MDB.createBranchWeights(Weights));
+    DEBUG(dbgs() << "Weight is: "; for (const auto &W
+                                        : Weights) dbgs()
+                                   << W << " ";
+          dbgs() << "\n";);
+  }
+}
+} // end anonymous namespace
+
+bool PGOInstrumentationGen::runOnModule(Module &M) {
+  for (auto &F : M) {
+    if (F.isDeclaration())
+      continue;
+    BranchProbabilityInfo *BPI =
+        &(getAnalysis<BranchProbabilityInfoWrapperPass>(F).getBPI());
+    BlockFrequencyInfo *BFI =
+        &(getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI());
+    instrumentOneFunc(F, &M, BPI, BFI);
+  }
+  return true;
+}
+
+static void setPGOCountOnFunc(PGOUseFunc &Func,
+                              IndexedInstrProfReader *PGOReader) {
+  if (Func.readCounters(PGOReader)) {
+    Func.populateCounters();
+    Func.setBranchWeights();
+  }
+}
+
+bool PGOInstrumentationUse::runOnModule(Module &M) {
+  DEBUG(dbgs() << "Read in profile counters: ");
+  auto &Ctx = M.getContext();
+  // Read the counter array from file.
+  auto ReaderOrErr = IndexedInstrProfReader::create(ProfileFileName);
+  if (std::error_code EC = ReaderOrErr.getError()) {
+    Ctx.diagnose(
+        DiagnosticInfoPGOProfile(ProfileFileName.data(), EC.message()));
+    return false;
+  }
+
+  PGOReader = std::move(ReaderOrErr.get());
+  if (!PGOReader) {
+    Ctx.diagnose(DiagnosticInfoPGOProfile(ProfileFileName.data(),
+                                          "Cannot get PGOReader"));
+    return false;
+  }
+
+  for (auto &F : M) {
+    if (F.isDeclaration())
+      continue;
+    BranchProbabilityInfo *BPI =
+        &(getAnalysis<BranchProbabilityInfoWrapperPass>(F).getBPI());
+    BlockFrequencyInfo *BFI =
+        &(getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI());
+    PGOUseFunc Func(F, &M, BPI, BFI);
+    setPGOCountOnFunc(Func, PGOReader.get());
+  }
+  return true;
+}

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/branch1.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/branch1.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/branch1.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/branch1.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,6 @@
+_Z9test_br_1i
+23925403969
+2
+3
+2
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/branch2.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/branch2.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/branch2.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/branch2.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,6 @@
+_Z9test_br_2i
+29368252703
+2
+1
+1
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/criticaledge.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/criticaledge.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/criticaledge.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/criticaledge.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,17 @@
+_Z17test_criticalEdgeii
+82348442248
+8
+2
+1
+2
+2
+0
+1
+2
+1
+
+<stdin>:_ZL3bari
+12884901887
+1
+7
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/landingpad.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/landingpad.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/landingpad.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/landingpad.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,14 @@
+_Z3fooi
+57451243578
+4
+3
+1
+2
+0
+
+_Z3bari
+23319865734
+2
+1
+2
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/loop1.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/loop1.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/loop1.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/loop1.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,6 @@
+_Z15test_simple_fori
+32052181608
+2
+96
+4
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/loop2.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/loop2.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/loop2.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/loop2.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,6 @@
+_Z13test_do_whilei
+29706172832
+2
+96
+4
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/loop3.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/loop3.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/loop3.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/loop3.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,8 @@
+_Z15test_nested_foriii
+75296580464
+4
+186
+33
+10
+6
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/single_bb.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/single_bb.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/single_bb.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/single_bb.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,5 @@
+_Z9single_bbv
+12884999999
+1
+1
+

Added: llvm/trunk/test/Transforms/PGOProfile/Inputs/switch.proftext
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/Inputs/switch.proftext?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/Inputs/switch.proftext (added)
+++ llvm/trunk/test/Transforms/PGOProfile/Inputs/switch.proftext Tue Nov 24 15:31:25 2015
@@ -0,0 +1,8 @@
+_Z13test_switch_1i
+46628225222
+4
+0
+0
+0
+3
+

Added: llvm/trunk/test/Transforms/PGOProfile/branch1_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/branch1_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/branch1_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/branch1_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,21 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z9test_br_1i = private constant [13 x i8] c"_Z9test_br_1i"
+
+define i32 @_Z9test_br_1i(i32 %i) {
+entry:
+  %cmp = icmp sgt i32 %i, 0
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @__llvm_profile_name__Z9test_br_1i, i32 0, i32 0), i64 23925403969, i32 2, i32 1)
+  %add = add nsw i32 %i, 2
+  br label %if.end
+
+if.end:
+  %retv = phi i32 [ %add, %if.then ], [ %i, %entry ]
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @__llvm_profile_name__Z9test_br_1i, i32 0, i32 0), i64 23925403969, i32 2, i32 0)
+  ret i32 %retv
+}

Added: llvm/trunk/test/Transforms/PGOProfile/branch1_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/branch1_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/branch1_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/branch1_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,21 @@
+; RUN: llvm-profdata merge %S/Inputs/branch1.proftext -o %T/branch1.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/branch1.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z9test_br_1i(i32 %i) {
+entry:
+  %cmp = icmp sgt i32 %i, 0
+  br i1 %cmp, label %if.then, label %if.end
+; CHECK: !prof !0
+
+if.then:
+  %add = add nsw i32 %i, 2
+  br label %if.end
+
+if.end:
+  %retv = phi i32 [ %add, %if.then ], [ %i, %entry ]
+  ret i32 %retv
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 2, i32 1}

Added: llvm/trunk/test/Transforms/PGOProfile/branch2_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/branch2_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/branch2_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/branch2_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,25 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z9test_br_2i = private constant [13 x i8] c"_Z9test_br_2i"
+
+define i32 @_Z9test_br_2i(i32 %i) {
+entry:
+  %cmp = icmp sgt i32 %i, 0
+  br i1 %cmp, label %if.then, label %if.else
+
+if.then:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @__llvm_profile_name__Z9test_br_2i, i32 0, i32 0), i64 29368252703, i32 2, i32 0)
+  %add = add nsw i32 %i, 2
+  br label %if.end
+
+if.else:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @__llvm_profile_name__Z9test_br_2i, i32 0, i32 0), i64 29368252703, i32 2, i32 1)
+  %sub = sub nsw i32 %i, 2
+  br label %if.end
+
+if.end:
+  %retv = phi i32 [ %add, %if.then ], [ %sub, %if.else ]
+  ret i32 %retv
+}

Added: llvm/trunk/test/Transforms/PGOProfile/branch2_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/branch2_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/branch2_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/branch2_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,25 @@
+; RUN: llvm-profdata merge %S/Inputs/branch2.proftext -o %T/branch2.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/branch2.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z9test_br_2i(i32 %i) {
+entry:
+  %cmp = icmp sgt i32 %i, 0
+  br i1 %cmp, label %if.then, label %if.else
+; CHECK: !prof !0
+
+if.then:
+  %add = add nsw i32 %i, 2
+  br label %if.end
+
+if.else:
+  %sub = sub nsw i32 %i, 2
+  br label %if.end
+
+if.end:
+  %retv = phi i32 [ %add, %if.then ], [ %sub, %if.else ]
+  ret i32 %retv
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 1, i32 1}

Added: llvm/trunk/test/Transforms/PGOProfile/checksum_mismatch.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/checksum_mismatch.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/checksum_mismatch.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/checksum_mismatch.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,18 @@
+; RUN: llvm-profdata merge %S/Inputs/single_bb.proftext -o %T/single_bb.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/single_bb.profdata -S 2>&1 | FileCheck %s
+
+; CHECK: Function control flow change detected (hash mismatch) _Z9single_bbv
+; CHECK: No profile data available for function _ZL8uncalledii
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z9single_bbv() {
+entry:
+  ret i32 0
+}
+
+define i32 @_ZL8uncalledii(i32 %i, i32 %j) {
+  %mul = mul nsw i32 %i, %j
+  ret i32 %mul
+}

Added: llvm/trunk/test/Transforms/PGOProfile/criticaledge_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/criticaledge_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/criticaledge_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/criticaledge_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,80 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z17test_criticalEdgeii = private constant [23 x i8] c"_Z17test_criticalEdgeii"
+; CHECK: @"__llvm_profile_name_<stdin>:_ZL3bari" = private constant [16 x i8] c"<stdin>:_ZL3bari"
+
+define i32 @_Z17test_criticalEdgeii(i32 %i, i32 %j) {
+entry:
+  switch i32 %i, label %sw.default [
+    i32 1, label %sw.bb
+    i32 2, label %sw.bb1
+    i32 3, label %sw.bb3
+    i32 4, label %sw.bb3
+; CHECK:    i32 3, label %entry.sw.bb3_crit_edge
+; CHECK:    i32 4, label %entry.sw.bb3_crit_edge1
+    i32 5, label %sw.bb3
+  ]
+
+; CHECK: entry.sw.bb3_crit_edge1:
+; CHECK:   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 1)
+; CHECK:   br label %sw.bb3
+
+; CHECK: entry.sw.bb3_crit_edge:
+; CHECK:   call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 0)
+; CHECK:   br label %sw.bb3
+
+sw.bb:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 5)
+  %call = call i32 @_ZL3bari(i32 2)
+  br label %sw.epilog
+
+sw.bb1:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 4)
+  %call2 = call i32 @_ZL3bari(i32 1024)
+  br label %sw.epilog
+
+sw.bb3:
+  %cmp = icmp eq i32 %j, 2
+  br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 2)
+  %call4 = call i32 @_ZL3bari(i32 4)
+  br label %return
+
+if.end:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 3)
+  %call5 = call i32 @_ZL3bari(i32 8)
+  br label %sw.epilog
+
+sw.default:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 6)
+  %call6 = call i32 @_ZL3bari(i32 32)
+  %cmp7 = icmp sgt i32 %j, 10
+  br i1 %cmp7, label %if.then8, label %if.end9
+
+if.then8:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([23 x i8], [23 x i8]* @__llvm_profile_name__Z17test_criticalEdgeii, i32 0, i32 0), i64 82348442248, i32 8, i32 7)
+  %add = add nsw i32 %call6, 10
+  br label %if.end9
+
+if.end9:
+  %res.0 = phi i32 [ %add, %if.then8 ], [ %call6, %sw.default ]
+  br label %sw.epilog
+
+sw.epilog:
+  %res.1 = phi i32 [ %res.0, %if.end9 ], [ %call5, %if.end ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ]
+  br label %return
+
+return:
+  %retval = phi i32 [ %res.1, %sw.epilog ], [ %call4, %if.then ]
+  ret i32 %retval
+}
+
+define internal i32 @_ZL3bari(i32 %i) {
+entry:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([16 x i8], [16 x i8]* @"__llvm_profile_name_<stdin>:_ZL3bari", i32 0, i32 0), i64 12884901887, i32 1, i32 0)
+  ret i32 %i
+}

Added: llvm/trunk/test/Transforms/PGOProfile/criticaledge_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/criticaledge_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/criticaledge_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/criticaledge_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,75 @@
+; RUN: llvm-profdata merge %S/Inputs/criticaledge.proftext -o %T/criticaledge.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/criticaledge.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z17test_criticalEdgeii(i32 %i, i32 %j) {
+entry:
+  switch i32 %i, label %sw.default [
+    i32 1, label %sw.bb
+    i32 2, label %sw.bb1
+    i32 3, label %sw.bb3
+    i32 4, label %sw.bb3
+; CHECK:    i32 3, label %entry.sw.bb3_crit_edge
+; CHECK:    i32 4, label %entry.sw.bb3_crit_edge1
+    i32 5, label %sw.bb3
+  ]
+; CHECK: !prof !0
+
+; CHECK: entry.sw.bb3_crit_edge1:
+; CHECK:   br label %sw.bb3
+; CHECK: entry.sw.bb3_crit_edge:
+; CHECK:   br label %sw.bb3
+
+sw.bb:
+  %call = call i32 @_ZL3bari(i32 2)
+  br label %sw.epilog
+
+sw.bb1:
+  %call2 = call i32 @_ZL3bari(i32 1024)
+  br label %sw.epilog
+
+sw.bb3:
+  %cmp = icmp eq i32 %j, 2
+  br i1 %cmp, label %if.then, label %if.end
+; CHECK: !prof !1
+
+if.then:
+  %call4 = call i32 @_ZL3bari(i32 4)
+  br label %return
+
+if.end:
+  %call5 = call i32 @_ZL3bari(i32 8)
+  br label %sw.epilog
+
+sw.default:
+  %call6 = call i32 @_ZL3bari(i32 32)
+  %cmp7 = icmp sgt i32 %j, 10
+  br i1 %cmp7, label %if.then8, label %if.end9
+; CHECK: !prof !2
+
+if.then8:
+  %add = add nsw i32 %call6, 10
+  br label %if.end9
+
+if.end9:
+  %res.0 = phi i32 [ %add, %if.then8 ], [ %call6, %sw.default ]
+  br label %sw.epilog
+
+sw.epilog:
+  %res.1 = phi i32 [ %res.0, %if.end9 ], [ %call5, %if.end ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ]
+  br label %return
+
+return:
+  %retval = phi i32 [ %res.1, %sw.epilog ], [ %call4, %if.then ]
+  ret i32 %retval
+}
+
+define internal i32 @_ZL3bari(i32 %i) {
+entry:
+  ret i32 %i
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 2, i32 1, i32 0, i32 2, i32 1, i32 1}
+; CHECK: !1 = !{!"branch_weights", i32 2, i32 2}
+; CHECK: !2 = !{!"branch_weights", i32 1, i32 1}

Added: llvm/trunk/test/Transforms/PGOProfile/landingpad_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/landingpad_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/landingpad_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/landingpad_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,95 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at val = global i32 0, align 4
+ at _ZTIi = external constant i8*
+; CHECK: @__llvm_profile_name__Z3bari = private constant [7 x i8] c"_Z3bari"
+; CHECK: @__llvm_profile_name__Z3fooi = private constant [7 x i8] c"_Z3fooi"
+
+define i32 @_Z3bari(i32 %i) {
+entry:
+  %rem = srem i32 %i, 3
+  %tobool = icmp ne i32 %rem, 0
+  br i1 %tobool, label %if.then, label %if.end
+
+if.then:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3bari, i32 0, i32 0), i64 23319865734, i32 2, i32 1)
+  %exception = call i8* @__cxa_allocate_exception(i64 4)
+  %tmp = bitcast i8* %exception to i32*
+  store i32 %i, i32* %tmp, align 16
+  call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null)
+  unreachable
+
+if.end:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3bari, i32 0, i32 0), i64 23319865734, i32 2, i32 0)
+  ret i32 0
+}
+
+declare i8* @__cxa_allocate_exception(i64)
+
+declare void @__cxa_throw(i8*, i8*, i8*)
+
+define i32 @_Z3fooi(i32 %i) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %rem = srem i32 %i, 2
+  %tobool = icmp ne i32 %rem, 0
+  br i1 %tobool, label %if.then, label %if.end
+
+if.then:
+  %mul = mul nsw i32 %i, 7
+  %call = invoke i32 @_Z3bari(i32 %mul)
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3fooi, i32 0, i32 0), i64 57451243578, i32 4, i32 1)
+  br label %if.end
+
+lpad:
+  %tmp = landingpad { i8*, i32 }
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+  %tmp1 = extractvalue { i8*, i32 } %tmp, 0
+  %tmp2 = extractvalue { i8*, i32 } %tmp, 1
+  br label %catch.dispatch
+
+catch.dispatch:
+  %tmp3 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %tmp2, %tmp3
+  br i1 %matches, label %catch, label %eh.resume
+
+catch:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3fooi, i32 0, i32 0), i64 57451243578, i32 4, i32 2)
+  %tmp4 = call i8* @__cxa_begin_catch(i8* %tmp1)
+  %tmp5 = bitcast i8* %tmp4 to i32*
+  %tmp6 = load i32, i32* %tmp5, align 4
+  %tmp7 = load i32, i32* @val, align 4
+  %sub = sub nsw i32 %tmp7, %tmp6
+  store i32 %sub, i32* @val, align 4
+  call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:
+  ret i32 -1
+
+if.end:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3fooi, i32 0, i32 0), i64 57451243578, i32 4, i32 0)
+  %tmp8 = load i32, i32* @val, align 4
+  %add = add nsw i32 %tmp8, %i
+  store i32 %add, i32* @val, align 4
+  br label %try.cont
+
+eh.resume:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([7 x i8], [7 x i8]* @__llvm_profile_name__Z3fooi, i32 0, i32 0), i64 57451243578, i32 4, i32 3)
+  %lpad.val = insertvalue { i8*, i32 } undef, i8* %tmp1, 0
+  %lpad.val3 = insertvalue { i8*, i32 } %lpad.val, i32 %tmp2, 1
+  resume { i8*, i32 } %lpad.val3
+}
+
+declare i32 @__gxx_personality_v0(...)
+
+declare i32 @llvm.eh.typeid.for(i8*)
+
+declare i8* @__cxa_begin_catch(i8*)
+
+declare void @__cxa_end_catch()
+

Added: llvm/trunk/test/Transforms/PGOProfile/landingpad_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/landingpad_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/landingpad_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/landingpad_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,94 @@
+; RUN: llvm-profdata merge %S/Inputs/landingpad.proftext -o %T/landingpad.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/landingpad.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at val = global i32 0, align 4
+ at _ZTIi = external constant i8*
+
+define i32 @_Z3bari(i32 %i) {
+entry:
+  %rem = srem i32 %i, 3
+  %tobool = icmp ne i32 %rem, 0
+  br i1 %tobool, label %if.then, label %if.end
+; CHECK: !prof !0
+
+if.then:
+  %exception = call i8* @__cxa_allocate_exception(i64 4)
+  %tmp = bitcast i8* %exception to i32*
+  store i32 %i, i32* %tmp, align 16
+  call void @__cxa_throw(i8* %exception, i8* bitcast (i8** @_ZTIi to i8*), i8* null)
+  unreachable
+
+if.end:
+  ret i32 0
+}
+
+declare i8* @__cxa_allocate_exception(i64)
+
+declare void @__cxa_throw(i8*, i8*, i8*)
+
+define i32 @_Z3fooi(i32 %i) personality i8* bitcast (i32 (...)* @__gxx_personality_v0 to i8*) {
+entry:
+  %rem = srem i32 %i, 2
+  %tobool = icmp ne i32 %rem, 0
+  br i1 %tobool, label %if.then, label %if.end
+; CHECK: !prof !1
+
+if.then:
+  %mul = mul nsw i32 %i, 7
+  %call = invoke i32 @_Z3bari(i32 %mul)
+          to label %invoke.cont unwind label %lpad
+
+invoke.cont:
+  br label %if.end
+
+lpad:
+  %tmp = landingpad { i8*, i32 }
+          catch i8* bitcast (i8** @_ZTIi to i8*)
+  %tmp1 = extractvalue { i8*, i32 } %tmp, 0
+  %tmp2 = extractvalue { i8*, i32 } %tmp, 1
+  br label %catch.dispatch
+
+catch.dispatch:
+  %tmp3 = call i32 @llvm.eh.typeid.for(i8* bitcast (i8** @_ZTIi to i8*))
+  %matches = icmp eq i32 %tmp2, %tmp3
+  br i1 %matches, label %catch, label %eh.resume
+; CHECK: !prof !2
+
+catch:
+  %tmp4 = call i8* @__cxa_begin_catch(i8* %tmp1)
+  %tmp5 = bitcast i8* %tmp4 to i32*
+  %tmp6 = load i32, i32* %tmp5, align 4
+  %tmp7 = load i32, i32* @val, align 4
+  %sub = sub nsw i32 %tmp7, %tmp6
+  store i32 %sub, i32* @val, align 4
+  call void @__cxa_end_catch()
+  br label %try.cont
+
+try.cont:
+  ret i32 -1
+
+if.end:
+  %tmp8 = load i32, i32* @val, align 4
+  %add = add nsw i32 %tmp8, %i
+  store i32 %add, i32* @val, align 4
+  br label %try.cont
+
+eh.resume:
+  %lpad.val = insertvalue { i8*, i32 } undef, i8* %tmp1, 0
+  %lpad.val3 = insertvalue { i8*, i32 } %lpad.val, i32 %tmp2, 1
+  resume { i8*, i32 } %lpad.val3
+}
+
+declare i32 @__gxx_personality_v0(...)
+
+declare i32 @llvm.eh.typeid.for(i8*)
+
+declare i8* @__cxa_begin_catch(i8*)
+
+declare void @__cxa_end_catch()
+
+; CHECK: !0 = !{!"branch_weights", i32 2, i32 1}
+; CHECK: !1 = !{!"branch_weights", i32 3, i32 2}
+; CHECK: !2 = !{!"branch_weights", i32 2, i32 0}

Added: llvm/trunk/test/Transforms/PGOProfile/loop1_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop1_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop1_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop1_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,29 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z15test_simple_fori = private constant [20 x i8] c"_Z15test_simple_fori"
+
+define i32 @_Z15test_simple_fori(i32 %n) {
+entry:
+  br label %for.cond
+
+for.cond:
+  %i = phi i32 [ 0, %entry ], [ %inc1, %for.inc ]
+  %sum = phi i32 [ 1, %entry ], [ %inc, %for.inc ]
+  %cmp = icmp slt i32 %i, %n
+  br i1 %cmp, label %for.body, label %for.end
+
+for.body:
+  %inc = add nsw i32 %sum, 1
+  br label %for.inc
+
+for.inc:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @__llvm_profile_name__Z15test_simple_fori, i32 0, i32 0), i64 32052181608, i32 2, i32 0)
+  %inc1 = add nsw i32 %i, 1
+  br label %for.cond
+
+for.end:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([20 x i8], [20 x i8]* @__llvm_profile_name__Z15test_simple_fori, i32 0, i32 0), i64 32052181608, i32 2, i32 1)
+  ret i32 %sum
+}

Added: llvm/trunk/test/Transforms/PGOProfile/loop1_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop1_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop1_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop1_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,29 @@
+; RUN: llvm-profdata merge %S/Inputs/loop1.proftext -o %T/loop1.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/loop1.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z15test_simple_fori(i32 %n) {
+entry:
+  br label %for.cond
+
+for.cond:
+  %i = phi i32 [ 0, %entry ], [ %inc1, %for.inc ]
+  %sum = phi i32 [ 1, %entry ], [ %inc, %for.inc ]
+  %cmp = icmp slt i32 %i, %n
+  br i1 %cmp, label %for.body, label %for.end
+; CHECK: !prof !0
+
+for.body:
+  %inc = add nsw i32 %sum, 1
+  br label %for.inc
+
+for.inc:
+  %inc1 = add nsw i32 %i, 1
+  br label %for.cond
+
+for.end:
+  ret i32 %sum
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 96, i32 4}

Added: llvm/trunk/test/Transforms/PGOProfile/loop2_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop2_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop2_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop2_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,26 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z13test_do_whilei = private constant [18 x i8] c"_Z13test_do_whilei"
+
+define i32 @_Z13test_do_whilei(i32 %n) {
+entry:
+  br label %do.body
+
+do.body:
+  %i.0 = phi i32 [ 0, %entry ], [ %inc1, %do.cond ]
+  %sum = phi i32 [ 1, %entry ], [ %inc, %do.cond ]
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_do_whilei, i32 0, i32 0), i64 29706172832, i32 2, i32 0)
+  %inc = add nsw i32 %sum, 1
+  br label %do.cond
+
+do.cond:
+  %inc1 = add nsw i32 %i.0, 1
+  %cmp = icmp slt i32 %i.0, %n
+  br i1 %cmp, label %do.body, label %do.end
+
+do.end:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_do_whilei, i32 0, i32 0), i64 29706172832, i32 2, i32 1)
+  ret i32 %inc
+}

Added: llvm/trunk/test/Transforms/PGOProfile/loop2_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop2_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop2_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop2_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,26 @@
+; RUN: llvm-profdata merge %S/Inputs/loop2.proftext -o %T/loop2.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/loop2.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z13test_do_whilei(i32 %n) {
+entry:
+  br label %do.body
+
+do.body:
+  %i.0 = phi i32 [ 0, %entry ], [ %inc1, %do.cond ]
+  %sum = phi i32 [ 1, %entry ], [ %inc, %do.cond ]
+  %inc = add nsw i32 %sum, 1
+  br label %do.cond
+
+do.cond:
+  %inc1 = add nsw i32 %i.0, 1
+  %cmp = icmp slt i32 %i.0, %n
+  br i1 %cmp, label %do.body, label %do.end
+; CHECK: !prof !0
+
+do.end:
+  ret i32 %inc
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 92, i32 4}

Added: llvm/trunk/test/Transforms/PGOProfile/loop3_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop3_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop3_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop3_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,63 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z15test_nested_foriii = private constant [22 x i8] c"_Z15test_nested_foriii"
+
+define i32 @_Z15test_nested_foriii(i32 %r, i32 %s, i32 %t) {
+entry:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__llvm_profile_name__Z15test_nested_foriii, i32 0, i32 0), i64 75296580464, i32 4, i32 3)
+  br label %for.cond
+
+for.cond:
+  %i.0 = phi i32 [ 0, %entry ], [ %inc12, %for.inc11 ]
+  %nested_for_sum.0 = phi i32 [ 1, %entry ], [ %nested_for_sum.1, %for.inc11 ]
+  %cmp = icmp slt i32 %i.0, %r
+  br i1 %cmp, label %for.body, label %for.end13
+
+for.body:
+  br label %for.cond1
+
+for.cond1:
+  %j.0 = phi i32 [ 0, %for.body ], [ %inc9, %for.inc8 ]
+  %nested_for_sum.1 = phi i32 [ %nested_for_sum.0, %for.body ], [ %nested_for_sum.2, %for.inc8 ]
+  %cmp2 = icmp slt i32 %j.0, %s
+  br i1 %cmp2, label %for.body3, label %for.end10
+
+for.body3:
+  br label %for.cond4
+
+for.cond4:
+  %k.0 = phi i32 [ 0, %for.body3 ], [ %inc7, %for.inc ]
+  %nested_for_sum.2 = phi i32 [ %nested_for_sum.1, %for.body3 ], [ %inc, %for.inc ]
+  %cmp5 = icmp slt i32 %k.0, %t
+  br i1 %cmp5, label %for.body6, label %for.end
+
+for.body6:
+  %inc = add nsw i32 %nested_for_sum.2, 1
+  br label %for.inc
+
+for.inc:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__llvm_profile_name__Z15test_nested_foriii, i32 0, i32 0), i64 75296580464, i32 4, i32 0)
+  %inc7 = add nsw i32 %k.0, 1
+  br label %for.cond4
+
+for.end:
+  br label %for.inc8
+
+for.inc8:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__llvm_profile_name__Z15test_nested_foriii, i32 0, i32 0), i64 75296580464, i32 4, i32 1)
+  %inc9 = add nsw i32 %j.0, 1
+  br label %for.cond1
+
+for.end10:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([22 x i8], [22 x i8]* @__llvm_profile_name__Z15test_nested_foriii, i32 0, i32 0), i64 75296580464, i32 4, i32 2)
+  br label %for.inc11
+
+for.inc11:
+  %inc12 = add nsw i32 %i.0, 1
+  br label %for.cond
+
+for.end13:
+  ret i32 %nested_for_sum.0
+}

Added: llvm/trunk/test/Transforms/PGOProfile/loop3_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/loop3_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/loop3_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/loop3_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,65 @@
+; RUN: llvm-profdata merge %S/Inputs/loop3.proftext -o %T/loop3.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/loop3.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z15test_nested_foriii(i32 %r, i32 %s, i32 %t) {
+entry:
+  br label %for.cond
+
+for.cond:
+  %i.0 = phi i32 [ 0, %entry ], [ %inc12, %for.inc11 ]
+  %nested_for_sum.0 = phi i32 [ 1, %entry ], [ %nested_for_sum.1, %for.inc11 ]
+  %cmp = icmp slt i32 %i.0, %r
+  br i1 %cmp, label %for.body, label %for.end13
+; CHECK: !prof !0
+
+for.body:
+  br label %for.cond1
+
+for.cond1:
+  %j.0 = phi i32 [ 0, %for.body ], [ %inc9, %for.inc8 ]
+  %nested_for_sum.1 = phi i32 [ %nested_for_sum.0, %for.body ], [ %nested_for_sum.2, %for.inc8 ]
+  %cmp2 = icmp slt i32 %j.0, %s
+  br i1 %cmp2, label %for.body3, label %for.end10
+; CHECK: !prof !1
+
+for.body3:
+  br label %for.cond4
+
+for.cond4:
+  %k.0 = phi i32 [ 0, %for.body3 ], [ %inc7, %for.inc ]
+  %nested_for_sum.2 = phi i32 [ %nested_for_sum.1, %for.body3 ], [ %inc, %for.inc ]
+  %cmp5 = icmp slt i32 %k.0, %t
+  br i1 %cmp5, label %for.body6, label %for.end
+; CHECK: !prof !2
+
+for.body6:
+  %inc = add nsw i32 %nested_for_sum.2, 1
+  br label %for.inc
+
+for.inc:
+  %inc7 = add nsw i32 %k.0, 1
+  br label %for.cond4
+
+for.end:
+  br label %for.inc8
+
+for.inc8:
+  %inc9 = add nsw i32 %j.0, 1
+  br label %for.cond1
+
+for.end10:
+  br label %for.inc11
+
+for.inc11:
+  %inc12 = add nsw i32 %i.0, 1
+  br label %for.cond
+
+for.end13:
+  ret i32 %nested_for_sum.0
+}
+
+; CHECK: !0 = !{!"branch_weights", i32 10, i32 6}
+; CHECK: !1 = !{!"branch_weights", i32 33, i32 10}
+; CHECK: !2 = !{!"branch_weights", i32 186, i32 33}

Added: llvm/trunk/test/Transforms/PGOProfile/noprofile_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/noprofile_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/noprofile_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/noprofile_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,9 @@
+; RUN: not opt < %s -pgo-instr-use -pgo-profile-file=%T/notexisting.profdata -S  2>&1 |grep 'notexisting.profdata: No such file or directory'
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z9single_bbv() {
+entry:
+  ret i32 0
+}

Added: llvm/trunk/test/Transforms/PGOProfile/single_bb_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/single_bb_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/single_bb_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/single_bb_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,11 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z9single_bbv = private constant [13 x i8] c"_Z9single_bbv"
+
+define i32 @_Z9single_bbv() {
+entry:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([13 x i8], [13 x i8]* @__llvm_profile_name__Z9single_bbv, i32 0, i32 0), i64 12884901887, i32 1, i32 0)
+  ret i32 0
+}

Added: llvm/trunk/test/Transforms/PGOProfile/switch_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/switch_gen.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/switch_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/switch_gen.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,38 @@
+; RUN: opt < %s -pgo-instr-gen -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; CHECK: @__llvm_profile_name__Z13test_switch_1i = private constant [18 x i8] c"_Z13test_switch_1i"
+
+define i32 @_Z13test_switch_1i(i32 %i) {
+entry:
+  switch i32 %i, label %sw.default [
+    i32 1, label %sw.bb
+    i32 2, label %sw.bb1
+    i32 3, label %sw.bb3
+  ]
+
+sw.bb:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_switch_1i, i32 0, i32 0), i64 46628225222, i32 4, i32 2)
+  %add = add nsw i32 %i, 2
+  br label %sw.epilog
+
+sw.bb1:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_switch_1i, i32 0, i32 0), i64 46628225222, i32 4, i32 0)
+  %add2 = add nsw i32 %i, 100
+  br label %sw.epilog
+
+sw.bb3:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_switch_1i, i32 0, i32 0), i64 46628225222, i32 4, i32 1)
+  %add4 = add nsw i32 %i, 4
+  br label %sw.epilog
+
+sw.default:
+; CHECK: call void @llvm.instrprof.increment(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @__llvm_profile_name__Z13test_switch_1i, i32 0, i32 0), i64 46628225222, i32 4, i32 3)
+  %add5 = add nsw i32 %i, 1
+  br label %sw.epilog
+
+sw.epilog:
+  %retv = phi i32 [ %add5, %sw.default ], [ %add4, %sw.bb3 ], [ %add2, %sw.bb1 ], [ %add, %sw.bb ]
+  ret i32 %retv
+}

Added: llvm/trunk/test/Transforms/PGOProfile/switch_use.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/switch_use.ll?rev=254021&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/switch_use.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/switch_use.ll Tue Nov 24 15:31:25 2015
@@ -0,0 +1,36 @@
+; RUN: llvm-profdata merge %S/Inputs/switch.proftext -o %T/switch.profdata
+; RUN: opt < %s -pgo-instr-use -pgo-profile-file=%T/switch.profdata -S | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define i32 @_Z13test_switch_1i(i32 %i) {
+entry:
+  switch i32 %i, label %sw.default [
+    i32 1, label %sw.bb
+    i32 2, label %sw.bb1
+    i32 3, label %sw.bb3
+  ]
+; CHECK: !prof !0
+
+sw.bb:
+  %add = add nsw i32 %i, 2
+  br label %sw.epilog
+
+sw.bb1:
+  %add2 = add nsw i32 %i, 100
+  br label %sw.epilog
+
+sw.bb3:
+  %add4 = add nsw i32 %i, 4
+  br label %sw.epilog
+
+sw.default:
+  %add5 = add nsw i32 %i, 1
+  br label %sw.epilog
+
+sw.epilog:
+  %retv = phi i32 [ %add5, %sw.default ], [ %add4, %sw.bb3 ], [ %add2, %sw.bb1 ], [ %add, %sw.bb ]
+  ret i32 %retv
+}
+
+;CHECK: !0 = !{!"branch_weights", i32 3, i32 0, i32 0, i32 0}




More information about the llvm-commits mailing list