Index: llvm/include/llvm/IR/ProfileSummary.h
===================================================================
--- llvm/include/llvm/IR/ProfileSummary.h
+++ llvm/include/llvm/IR/ProfileSummary.h
@@ -64,11 +64,12 @@
   ProfileSummary(Kind K, SummaryEntryVector DetailedSummary,
                  uint64_t TotalCount, uint64_t MaxCount,
                  uint64_t MaxInternalCount, uint64_t MaxFunctionCount,
-                 uint32_t NumCounts, uint32_t NumFunctions)
+                 uint32_t NumCounts, uint32_t NumFunctions,
+                 bool Partial = false)
       : PSK(K), DetailedSummary(std::move(DetailedSummary)),
         TotalCount(TotalCount), MaxCount(MaxCount),
         MaxInternalCount(MaxInternalCount), MaxFunctionCount(MaxFunctionCount),
-        NumCounts(NumCounts), NumFunctions(NumFunctions) {}
+        NumCounts(NumCounts), NumFunctions(NumFunctions), Partial(Partial) {}
 
   Kind getKind() const { return PSK; }
   /// Return summary information as metadata.
Index: llvm/lib/IR/ProfileSummary.cpp
===================================================================
--- llvm/lib/IR/ProfileSummary.cpp
+++ llvm/lib/IR/ProfileSummary.cpp
@@ -68,14 +68,15 @@
 Metadata *ProfileSummary::getMD(LLVMContext &Context) {
   const char *KindStr[3] = {"InstrProf", "CSInstrProf", "SampleProfile"};
   Metadata *Components[] = {
-    getKeyValMD(Context, "ProfileFormat", KindStr[PSK]),
-    getKeyValMD(Context, "TotalCount", getTotalCount()),
-    getKeyValMD(Context, "MaxCount", getMaxCount()),
-    getKeyValMD(Context, "MaxInternalCount", getMaxInternalCount()),
-    getKeyValMD(Context, "MaxFunctionCount", getMaxFunctionCount()),
-    getKeyValMD(Context, "NumCounts", getNumCounts()),
-    getKeyValMD(Context, "NumFunctions", getNumFunctions()),
-    getDetailedSummaryMD(Context),
+      getKeyValMD(Context, "ProfileFormat", KindStr[PSK]),
+      getKeyValMD(Context, "TotalCount", getTotalCount()),
+      getKeyValMD(Context, "MaxCount", getMaxCount()),
+      getKeyValMD(Context, "MaxInternalCount", getMaxInternalCount()),
+      getKeyValMD(Context, "MaxFunctionCount", getMaxFunctionCount()),
+      getKeyValMD(Context, "NumCounts", getNumCounts()),
+      getKeyValMD(Context, "NumFunctions", getNumFunctions()),
+      getKeyValMD(Context, "IsPartialProfile", isPartialProfile()),
+      getDetailedSummaryMD(Context),
   };
   return MDTuple::get(Context, Components);
 }
@@ -159,7 +160,7 @@
     return nullptr;
 
   uint64_t NumCounts, TotalCount, NumFunctions, MaxFunctionCount, MaxCount,
-      MaxInternalCount;
+      MaxInternalCount, IsPartialProfile;
   if (!getVal(dyn_cast<MDTuple>(Tuple->getOperand(1)), "TotalCount",
               TotalCount))
     return nullptr;
@@ -176,11 +177,14 @@
   if (!getVal(dyn_cast<MDTuple>(Tuple->getOperand(6)), "NumFunctions",
               NumFunctions))
     return nullptr;
+  if (!getVal(dyn_cast<MDTuple>(Tuple->getOperand(6)), "IsPartialProfile",
+              IsPartialProfile))
+    return nullptr;
 
   SummaryEntryVector Summary;
   if (!getSummaryFromMD(dyn_cast<MDTuple>(Tuple->getOperand(7)), Summary))
     return nullptr;
   return new ProfileSummary(SummaryKind, std::move(Summary), TotalCount,
                             MaxCount, MaxInternalCount, MaxFunctionCount,
-                            NumCounts, NumFunctions);
+                            NumCounts, NumFunctions, IsPartialProfile);
 }
Index: llvm/test/Transforms/SampleProfile/summary.ll
===================================================================
--- llvm/test/Transforms/SampleProfile/summary.ll
+++ llvm/test/Transforms/SampleProfile/summary.ll
@@ -1,6 +1,10 @@
 ; Test that we annotate entire program's summary to IR.
 ; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/summary.prof -S | FileCheck %s
 ; RUN: opt < %s -sample-profile -sample-profile-file=%S/Inputs/summary.prof -S | opt -sample-profile -sample-profile-file=%S/Inputs/summary.prof -S | FileCheck %s
+; Test that we annotate partial profile flag to IR correctly.
+; RUN: llvm-profdata merge --sample --extbinary --partial-profile %S/Inputs/summary.prof --output=%t.prof
+; RUN: opt < %s -sample-profile -sample-profile-file=%t.prof -S | FileCheck %s -check-prefix=PARTIAL
+; RUN: opt < %s -sample-profile -sample-profile-file=%t.prof -S | opt -sample-profile -sample-profile-file=%t.prof -S | FileCheck %s -check-prefix=PARTIAL
 
 define i32 @bar() #0 !dbg !1 {
 entry:
@@ -18,6 +22,8 @@
 ; CHECK-DAG: {{![0-9]+}} = !{!"NumCounts", i64 5}
 ; CHECK-DAG: {{![0-9]+}} = !{!"NumFunctions", i64 3}
 ; CHECK-DAG: {{![0-9]+}} = !{!"MaxFunctionCount", i64 3}
+; CHECK-DAG: {{![0-9]+}} = !{!"IsPartialProfile", i64 0}
+; PARTIAL: {{![0-9]+}} = !{!"IsPartialProfile", i64 1}
 
 !1 = distinct !DISubprogram(name: "bar")
 !2 = !DILocation(line: 2, scope: !2)