diff --git a/lib/Analysis/IPA/CallGraphSCCPass.cpp b/lib/Analysis/IPA/CallGraphSCCPass.cpp
index 0e333d1..0f39f44 100644
--- a/lib/Analysis/IPA/CallGraphSCCPass.cpp
+++ b/lib/Analysis/IPA/CallGraphSCCPass.cpp
@@ -17,12 +17,13 @@
 
 #define DEBUG_TYPE "cgscc-passmgr"
 #include "llvm/CallGraphSCCPass.h"
+#include "llvm/IntrinsicInst.h"
+#include "llvm/Function.h"
+#include "llvm/PassManagers.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/ADT/SCCIterator.h"
-#include "llvm/PassManagers.h"
-#include "llvm/Function.h"
 #include "llvm/Support/Debug.h"
-#include "llvm/IntrinsicInst.h"
+#include "llvm/Support/Timer.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
@@ -102,9 +103,10 @@
       CallGraphUpToDate = true;
     }
 
-    Timer *T = StartPassTimer(CGSP);
-    Changed = CGSP->runOnSCC(CurSCC);
-    StopPassTimer(CGSP, T);
+    {
+      TimeRegion PassTimer(getPassTimer(CGSP));
+      Changed = CGSP->runOnSCC(CurSCC);
+    }
     
     // After the CGSCCPass is done, when assertions are enabled, use
     // RefreshCallGraph to verify that the callgraph was correctly updated.
@@ -125,9 +127,8 @@
   for (unsigned i = 0, e = CurSCC.size(); i != e; ++i) {
     if (Function *F = CurSCC[i]->getFunction()) {
       dumpPassInfo(P, EXECUTION_MSG, ON_FUNCTION_MSG, F->getName());
-      Timer *T = StartPassTimer(FPP);
+      TimeRegion PassTimer(getPassTimer(FPP));
       Changed |= FPP->runOnFunction(*F);
-      StopPassTimer(FPP, T);
     }
   }
   
diff --git a/lib/Analysis/LoopPass.cpp b/lib/Analysis/LoopPass.cpp
index 2d613f6..f26c0eb 100644
--- a/lib/Analysis/LoopPass.cpp
+++ b/lib/Analysis/LoopPass.cpp
@@ -14,6 +14,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/LoopPass.h"
+#include "llvm/Support/Timer.h"
 using namespace llvm;
 
 //===----------------------------------------------------------------------===//
@@ -228,9 +229,9 @@
 
       {
         PassManagerPrettyStackEntry X(P, *CurrentLoop->getHeader());
-        Timer *T = StartPassTimer(P);
+        TimeRegion PassTimer(getPassTimer(P));
+
         Changed |= P->runOnLoop(CurrentLoop, *this);
-        StopPassTimer(P, T);
       }
 
       if (Changed)
@@ -245,9 +246,10 @@
         // is a function pass and it's really expensive to verify every
         // loop in the function every time. That level of checking can be
         // enabled with the -verify-loop-info option.
-        Timer *T = StartPassTimer(LI);
-        CurrentLoop->verifyLoop();
-        StopPassTimer(LI, T);
+        {
+          TimeRegion PassTimer(getPassTimer(LI));
+          CurrentLoop->verifyLoop();
+        }
 
         // Then call the regular verifyAnalysis functions.
         verifyPreservedAnalysis(P);
diff --git a/lib/Support/Timer.cpp b/lib/Support/Timer.cpp
index 317d5ac..96f440a 100644
--- a/lib/Support/Timer.cpp
+++ b/lib/Support/Timer.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Support/Format.h"
 #include "llvm/System/Mutex.h"
 #include "llvm/System/Process.h"
+#include "llvm/ADT/StringMap.h"
 #include <map>
 using namespace llvm;
 
@@ -95,37 +96,28 @@
 // Timer Implementation
 //===----------------------------------------------------------------------===//
 
-Timer::Timer(const std::string &N)
-  : Elapsed(0), UserTime(0), SystemTime(0), MemUsed(0), Name(N),
-    Started(false), TG(getDefaultTimerGroup()) {
+void Timer::init(const std::string &N) {
+  assert(TG == 0 && "Timer already initialized");
+  Name = N;
+  Started = false;
+  TG = getDefaultTimerGroup();
   TG->addTimer();
 }
 
-Timer::Timer(const std::string &N, TimerGroup &tg)
-  : Elapsed(0), UserTime(0), SystemTime(0), MemUsed(0), Name(N),
-    Started(false), TG(&tg) {
+void Timer::init(const std::string &N, TimerGroup &tg) {
+  assert(TG == 0 && "Timer already initialized");
+  Name = N;
+  Started = false;
+  TG = &tg;
   TG->addTimer();
 }
 
-Timer::Timer(const Timer &T) {
-  TG = T.TG;
-  if (TG) TG->addTimer();
-  operator=(T);
-}
-
-// Copy ctor, initialize with no TG member.
-Timer::Timer(bool, const Timer &T) {
-  TG = T.TG;     // Avoid assertion in operator=
-  operator=(T);  // Copy contents
-  TG = 0;
-}
-
 Timer::~Timer() {
-  if (!TG) return;
+  if (!TG) return;  // Never initialized.
   
   if (Started) {
     Started = false;
-    TG->addTimerToPrint(*this);
+    TG->addTimerToPrint(Time, Name);
   }
   TG->removeTimer();
 }
@@ -136,12 +128,7 @@
   return 0;
 }
 
-struct TimeRecord {
-  double Elapsed, UserTime, SystemTime;
-  ssize_t MemUsed;
-};
-
-static TimeRecord getTimeRecord(bool Start) {
+TimeRecord TimeRecord::getCurrentTime(bool Start) {
   TimeRecord Result;
 
   sys::TimeValue now(0,0);
@@ -157,9 +144,9 @@
     MemUsed = getMemUsage();
   }
 
-  Result.Elapsed    =  now.seconds()  + now.microseconds() / 1000000.0;
+  Result.WallTime   =  now.seconds() +  now.microseconds() / 1000000.0;
   Result.UserTime   = user.seconds() + user.microseconds() / 1000000.0;
-  Result.SystemTime =  sys.seconds()  + sys.microseconds() / 1000000.0;
+  Result.SystemTime =  sys.seconds() +  sys.microseconds() / 1000000.0;
   Result.MemUsed = MemUsed;
   return Result;
 }
@@ -169,19 +156,11 @@
 void Timer::startTimer() {
   Started = true;
   ActiveTimers->push_back(this);
-  TimeRecord TR = getTimeRecord(true);
-  Elapsed    -= TR.Elapsed;
-  UserTime   -= TR.UserTime;
-  SystemTime -= TR.SystemTime;
-  MemUsed    -= TR.MemUsed;
+  Time -= TimeRecord::getCurrentTime(true);
 }
 
 void Timer::stopTimer() {
-  TimeRecord TR = getTimeRecord(false);
-  Elapsed    += TR.Elapsed;
-  UserTime   += TR.UserTime;
-  SystemTime += TR.SystemTime;
-  MemUsed    += TR.MemUsed;
+  Time += TimeRecord::getCurrentTime(false);
 
   if (ActiveTimers->back() == this) {
     ActiveTimers->pop_back();
@@ -193,25 +172,6 @@
   }
 }
 
-void Timer::sum(const Timer &T) {
-  Elapsed    += T.Elapsed;
-  UserTime   += T.UserTime;
-  SystemTime += T.SystemTime;
-  MemUsed    += T.MemUsed;
-}
-
-const Timer &Timer::operator=(const Timer &T) {
-  Elapsed = T.Elapsed;
-  UserTime = T.UserTime;
-  SystemTime = T.SystemTime;
-  MemUsed = T.MemUsed;
-  Name = T.Name;
-  Started = T.Started;
-  assert(TG == T.TG && "Can only assign timers in the same TimerGroup!");
-  return *this;
-}
-
-
 static void printVal(double Val, double Total, raw_ostream &OS) {
   if (Total < 1e-7)   // Avoid dividing by zero.
     OS << "        -----     ";
@@ -221,23 +181,19 @@
   }
 }
 
-void Timer::print(const Timer &Total, raw_ostream &OS) {
-  if (Total.UserTime)
-    printVal(UserTime, Total.UserTime, OS);
-  if (Total.SystemTime)
-    printVal(SystemTime, Total.SystemTime, OS);
+void TimeRecord::print(const TimeRecord &Total, raw_ostream &OS) const {
+  if (Total.getUserTime())
+    printVal(getUserTime(), Total.getUserTime(), OS);
+  if (Total.getSystemTime())
+    printVal(getSystemTime(), Total.getSystemTime(), OS);
   if (Total.getProcessTime())
     printVal(getProcessTime(), Total.getProcessTime(), OS);
-  printVal(Elapsed, Total.Elapsed, OS);
+  printVal(getWallTime(), Total.getWallTime(), OS);
   
   OS << "  ";
   
-  if (Total.MemUsed)
-    OS << format("%9lld", (long long)MemUsed) << "  ";
-
-  OS << Name << "\n";
-  
-  Started = false;  // Once printed, don't print again
+  if (Total.getMemUsed())
+    OS << format("%9lld", (long long)getMemUsed()) << "  ";
 }
 
 
@@ -245,40 +201,35 @@
 //   NamedRegionTimer Implementation
 //===----------------------------------------------------------------------===//
 
-typedef std::map<std::string, Timer> Name2Timer;
-typedef std::map<std::string, std::pair<TimerGroup, Name2Timer> > Name2Pair;
+typedef StringMap<Timer> Name2TimerMap;
+typedef StringMap<std::pair<TimerGroup, Name2TimerMap> > Name2PairMap;
 
-static ManagedStatic<Name2Timer> NamedTimers;
-static ManagedStatic<Name2Pair> NamedGroupedTimers;
+static ManagedStatic<Name2TimerMap> NamedTimers;
+static ManagedStatic<Name2PairMap> NamedGroupedTimers;
 
 static Timer &getNamedRegionTimer(const std::string &Name) {
   sys::SmartScopedLock<true> L(*TimerLock);
-  Name2Timer::iterator I = NamedTimers->find(Name);
-  if (I != NamedTimers->end())
-    return I->second;
-
-  return NamedTimers->insert(I, std::make_pair(Name, Timer(Name)))->second;
+  
+  Timer &T = (*NamedTimers)[Name];
+  if (!T.isInitialized())
+    T.init(Name);
+  return T;
 }
 
 static Timer &getNamedRegionTimer(const std::string &Name,
                                   const std::string &GroupName) {
   sys::SmartScopedLock<true> L(*TimerLock);
 
-  Name2Pair::iterator I = NamedGroupedTimers->find(GroupName);
-  if (I == NamedGroupedTimers->end()) {
-    TimerGroup TG(GroupName);
-    std::pair<TimerGroup, Name2Timer> Pair(TG, Name2Timer());
-    I = NamedGroupedTimers->insert(I, std::make_pair(GroupName, Pair));
-  }
+  std::pair<TimerGroup, Name2TimerMap> &GroupEntry =
+    (*NamedGroupedTimers)[GroupName];
 
-  Name2Timer::iterator J = I->second.second.find(Name);
-  if (J == I->second.second.end())
-    J = I->second.second.insert(J,
-                                std::make_pair(Name,
-                                               Timer(Name,
-                                                     I->second.first)));
+  if (GroupEntry.second.empty())
+    GroupEntry.first.setName(GroupName);
 
-  return J->second;
+  Timer &T = GroupEntry.second[Name];
+  if (!T.isInitialized())
+    T.init(Name);
+  return T;
 }
 
 NamedRegionTimer::NamedRegionTimer(const std::string &Name)
@@ -298,8 +249,7 @@
     return; // Don't print timing report.
   
   // Sort the timers in descending order by amount of time taken.
-  std::sort(TimersToPrint.begin(), TimersToPrint.end(),
-            std::greater<Timer>());
+  std::sort(TimersToPrint.begin(), TimersToPrint.end());
 
   // Figure out how many spaces to indent TimerGroup name.
   unsigned Padding = (80-Name.length())/2;
@@ -307,50 +257,46 @@
 
   raw_ostream *OutStream = GetLibSupportInfoOutputFile();
 
-  ++NumTimers;
-  {  // Scope to contain Total timer: don't allow total timer to drop us to
-     // zero timers.
-    Timer Total("TOTAL");
+  TimeRecord Total;
+  for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i)
+    Total += TimersToPrint[i].first;
 
-    for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i)
-      Total.sum(TimersToPrint[i]);
+  // Print out timing header.
+  *OutStream << "===" << std::string(73, '-') << "===\n";
+  OutStream->indent(Padding) << Name << '\n';
+  *OutStream << "===" << std::string(73, '-') << "===\n";
 
-    // Print out timing header.
-    *OutStream << "===" << std::string(73, '-') << "===\n"
-               << std::string(Padding, ' ') << Name << "\n"
-               << "===" << std::string(73, '-')
-               << "===\n";
-
-    // If this is not an collection of ungrouped times, print the total time.
-    // Ungrouped timers don't really make sense to add up.  We still print the
-    // TOTAL line to make the percentages make sense.
-    if (this != DefaultTimerGroup) {
-      *OutStream << "  Total Execution Time: ";
-      *OutStream << format("%5.4f", Total.getProcessTime()) << " seconds (";
-      *OutStream << format("%5.4f", Total.getWallTime()) << " wall clock)\n";
-    }
-    *OutStream << "\n";
-
-    if (Total.UserTime)
-      *OutStream << "   ---User Time---";
-    if (Total.SystemTime)
-      *OutStream << "   --System Time--";
-    if (Total.getProcessTime())
-      *OutStream << "   --User+System--";
-    *OutStream << "   ---Wall Time---";
-    if (Total.getMemUsed())
-      *OutStream << "  ---Mem---";
-    *OutStream << "  --- Name ---\n";
-
-    // Loop through all of the timing data, printing it out.
-    for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i)
-      TimersToPrint[i].print(Total, *OutStream);
-
-    Total.print(Total, *OutStream);
-    *OutStream << '\n';
-    OutStream->flush();
+  // If this is not an collection of ungrouped times, print the total time.
+  // Ungrouped timers don't really make sense to add up.  We still print the
+  // TOTAL line to make the percentages make sense.
+  if (this != DefaultTimerGroup) {
+    *OutStream << "  Total Execution Time: ";
+    *OutStream << format("%5.4f", Total.getProcessTime()) << " seconds (";
+    *OutStream << format("%5.4f", Total.getWallTime()) << " wall clock)\n";
   }
-  --NumTimers;
+  *OutStream << "\n";
+
+  if (Total.getUserTime())
+    *OutStream << "   ---User Time---";
+  if (Total.getSystemTime())
+    *OutStream << "   --System Time--";
+  if (Total.getProcessTime())
+    *OutStream << "   --User+System--";
+  *OutStream << "   ---Wall Time---";
+  if (Total.getMemUsed())
+    *OutStream << "  ---Mem---";
+  *OutStream << "  --- Name ---\n";
+
+  // Loop through all of the timing data, printing it out.
+  for (unsigned i = 0, e = TimersToPrint.size(); i != e; ++i) {
+    const std::pair<TimeRecord, std::string> &Entry = TimersToPrint[e-i-1];
+    Entry.first.print(Total, *OutStream);
+    *OutStream << Entry.second << '\n';
+  }
+
+  Total.print(Total, *OutStream);
+  *OutStream << "Total\n\n";
+  OutStream->flush();
 
   TimersToPrint.clear();
 
@@ -363,8 +309,8 @@
   ++NumTimers;
 }
 
-void TimerGroup::addTimerToPrint(const Timer &T) {
+void TimerGroup::addTimerToPrint(const TimeRecord &T, const std::string &Name) {
   sys::SmartScopedLock<true> L(*TimerLock);
-  TimersToPrint.push_back(Timer(true, T));
+  TimersToPrint.push_back(std::make_pair(T, Name));
 }
 
diff --git a/lib/VMCore/PassManager.cpp b/lib/VMCore/PassManager.cpp
index c4dfe14..6d83261 100644
--- a/lib/VMCore/PassManager.cpp
+++ b/lib/VMCore/PassManager.cpp
@@ -378,7 +378,7 @@
 static ManagedStatic<sys::SmartMutex<true> > TimingInfoMutex;
 
 class TimingInfo {
-  std::map<Pass*, Timer> TimingData;
+  DenseMap<Pass*, Timer> TimingData;
   TimerGroup TG;
 
 public:
@@ -397,19 +397,16 @@
   // null.  It may be called multiple times.
   static void createTheTimeInfo();
 
-  /// passStarted - This method creates a timer for the given pass if it doesn't
-  /// already have one, and starts the timer.
-  Timer *passStarted(Pass *P) {
+  /// getPassTimer - Return the timer for the specified pass if it exists.
+  Timer *getPassTimer(Pass *P) {
     if (P->getAsPMDataManager()) 
       return 0;
 
     sys::SmartScopedLock<true> Lock(*TimingInfoMutex);
-    std::map<Pass*, Timer>::iterator I = TimingData.find(P);
-    if (I == TimingData.end())
-      I=TimingData.insert(std::make_pair(P, Timer(P->getPassName(), TG))).first;
-    Timer *T = &I->second;
-    T->startTimer();
-    return T;
+    Timer &T = TimingData[P];
+    if (!T.isInitialized())
+      T.init(P->getPassName(), TG);
+    return &T;
   }
 };
 
@@ -704,11 +701,8 @@
          E = PreservedSet.end(); I != E; ++I) {
     AnalysisID AID = *I;
     if (Pass *AP = findAnalysisPass(AID, true)) {
-
-      Timer *T = 0;
-      if (TheTimeInfo) T = TheTimeInfo->passStarted(AP);
+      TimeRegion PassTimer(getPassTimer(AP));
       AP->verifyAnalysis();
-      if (T) T->stopTimer();
     }
   }
 }
@@ -792,10 +786,9 @@
   {
     // If the pass crashes releasing memory, remember this.
     PassManagerPrettyStackEntry X(P);
-    
-    Timer *T = StartPassTimer(P);
+    TimeRegion PassTimer(getPassTimer(P));
+
     P->releaseMemory();
-    StopPassTimer(P, T);
   }
 
   if (const PassInfo *PI = P->getPassInfo()) {
@@ -1128,10 +1121,9 @@
       {
         // If the pass crashes, remember this.
         PassManagerPrettyStackEntry X(BP, *I);
-      
-        Timer *T = StartPassTimer(BP);
+        TimeRegion PassTimer(getPassTimer(BP));
+
         LocalChanged |= BP->runOnBasicBlock(*I);
-        StopPassTimer(BP, T);
       }
 
       Changed |= LocalChanged;
@@ -1345,10 +1337,9 @@
 
     {
       PassManagerPrettyStackEntry X(FP, F);
+      TimeRegion PassTimer(getPassTimer(FP));
 
-      Timer *T = StartPassTimer(FP);
       LocalChanged |= FP->runOnFunction(F);
-      StopPassTimer(FP, T);
     }
 
     Changed |= LocalChanged;
@@ -1420,9 +1411,9 @@
 
     {
       PassManagerPrettyStackEntry X(MP, M);
-      Timer *T = StartPassTimer(MP);
+      TimeRegion PassTimer(getPassTimer(MP));
+
       LocalChanged |= MP->runOnModule(M);
-      StopPassTimer(MP, T);
     }
 
     Changed |= LocalChanged;
@@ -1559,17 +1550,12 @@
 }
 
 /// If TimingInfo is enabled then start pass timer.
-Timer *llvm::StartPassTimer(Pass *P) {
+Timer *llvm::getPassTimer(Pass *P) {
   if (TheTimeInfo) 
-    return TheTimeInfo->passStarted(P);
+    return TheTimeInfo->getPassTimer(P);
   return 0;
 }
 
-/// If TimingInfo is enabled then stop pass timer.
-void llvm::StopPassTimer(Pass *P, Timer *T) {
-  if (T) T->stopTimer();
-}
-
 //===----------------------------------------------------------------------===//
 // PMStack implementation
 //