Index: llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp
===================================================================
--- llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp
+++ llvm/trunk/lib/Analysis/ProfileSummaryInfo.cpp
@@ -51,6 +51,18 @@
              " blocks required to reach the -profile-summary-cutoff-hot"
              " percentile exceeds this count."));
 
+// The next two options override the counts derived from summary computation and
+// are useful for debugging purposes.
+static cl::opt<int> ProfileSummaryHotCount(
+    "profile-summary-hot-count", cl::ReallyHidden, cl::ZeroOrMore,
+    cl::desc("A fixed hot count that overrides the count derived from"
+             " profile-summary-cutoff-hot"));
+
+static cl::opt<int> ProfileSummaryColdCount(
+    "profile-summary-cold-count", cl::ReallyHidden, cl::ZeroOrMore,
+    cl::desc("A fixed cold count that overrides the count derived from"
+             " profile-summary-cutoff-cold"));
+
 // Find the summary entry for a desired percentile of counts.
 static const ProfileSummaryEntry &getEntryForPercentile(SummaryEntryVector &DS,
                                                         uint64_t Percentile) {
@@ -198,9 +210,15 @@
   auto &HotEntry =
       getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffHot);
   HotCountThreshold = HotEntry.MinCount;
+  if (ProfileSummaryHotCount.getNumOccurrences() > 0)
+    HotCountThreshold = ProfileSummaryHotCount;
   auto &ColdEntry =
       getEntryForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
   ColdCountThreshold = ColdEntry.MinCount;
+  if (ProfileSummaryColdCount.getNumOccurrences() > 0)
+    ColdCountThreshold = ProfileSummaryColdCount;
+  assert(ColdCountThreshold <= HotCountThreshold &&
+         "Cold count threshold cannot exceed hot count threshold!");
   HasHugeWorkingSetSize =
       HotEntry.NumCounts > ProfileSummaryHugeWorkingSetSizeThreshold;
 }
Index: llvm/trunk/test/Analysis/ProfileSummary/basic.ll
===================================================================
--- llvm/trunk/test/Analysis/ProfileSummary/basic.ll
+++ llvm/trunk/test/Analysis/ProfileSummary/basic.ll
@@ -1,19 +1,31 @@
 ; RUN: opt < %s -disable-output -passes=print-profile-summary -S 2>&1 | FileCheck %s
+; RUN: opt < %s -disable-output -profile-summary-hot-count=500 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-HOT
+; RUN: opt < %s -disable-output -profile-summary-cold-count=0 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-COLD
+; RUN: opt < %s -disable-output -profile-summary-cold-count=200 -profile-summary-hot-count=1000 -passes=print-profile-summary -S 2>&1 | FileCheck %s -check-prefixes=OVERRIDE-BOTH
 
 define void @f1() !prof !20 {
 ; CHECK-LABEL: f1 :hot
+; OVERRIDE-HOT-LABEL: f1
+; OVERRIDE-COLD-LABEL: f1 :hot
+; OVERRIDE-BOTH-LABEL: f1
 
   ret void
 }
 
 define void @f2() !prof !21 {
 ; CHECK-LABEL: f2 :cold
+; OVERRIDE-HOT-LABEL: f2 :cold
+; OVERRIDE-COLD-LABEL: f2
+; OVERRIDE-BOTH-LABEL: f2
 
   ret void
 }
 
 define void @f3() !prof !22 {
 ; CHECK-LABEL: f3
+; OVERRIDE-HOT-LABEL: f3
+; OVERRIDE-COLD-LABEL: f3
+; OVERRIDE-BOTH-LABEL: f3
 
   ret void
 }