Index: lib/Analysis/ProfileSummaryInfo.cpp
===================================================================
--- lib/Analysis/ProfileSummaryInfo.cpp
+++ lib/Analysis/ProfileSummaryInfo.cpp
@@ -78,10 +78,12 @@
   if (hasSampleProfile()) {
     // In sample PGO mode, check if there is a profile metadata on the
     // instruction. If it is present, determine hotness solely based on that,
-    // since the sampled entry count may not be accurate.
+    // since the sampled entry count may not be accurate. If there is no
+    // annotated on the instruction, it means that it is a cold callsite.
     uint64_t TotalCount;
     if (Inst->extractProfTotalWeight(TotalCount))
       return TotalCount;
+    return 0;
   }
   if (BFI)
     return BFI->getBlockProfileCount(Inst->getParent());
Index: test/Bitcode/Inputs/thinlto-function-summary-callgraph-sample-profile-summary.ll
===================================================================
--- /dev/null
+++ test/Bitcode/Inputs/thinlto-function-summary-callgraph-sample-profile-summary.ll
@@ -0,0 +1,31 @@
+; ModuleID = 'thinlto-function-summary-callgraph-profile-summary2.ll'
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define void @hot1() #1 {
+  ret void
+}
+define void @hot2() #1 {
+  ret void
+}
+define void @hot3() #1 {
+  ret void
+}
+define void @cold1() #1 {
+  ret void
+}
+define void @cold2() #1 {
+  ret void
+}
+define void @cold3() #1 {
+  ret void
+}
+define void @none1() #1 {
+  ret void
+}
+define void @none2() #1 {
+  ret void
+}
+define void @none3() #1 {
+  ret void
+}
Index: test/Bitcode/thinlto-function-summary-callgraph-sample-profile-summary.ll
===================================================================
--- test/Bitcode/thinlto-function-summary-callgraph-sample-profile-summary.ll
+++ test/Bitcode/thinlto-function-summary-callgraph-sample-profile-summary.ll
@@ -1,7 +1,7 @@
 ; Test to check the callgraph in summary when there is PGO
 ; RUN: opt -module-summary %s -o %t.o
 ; RUN: llvm-bcanalyzer -dump %t.o | FileCheck %s
-; RUN: opt -module-summary %p/Inputs/thinlto-function-summary-callgraph-profile-summary.ll -o %t2.o
+; RUN: opt -module-summary %p/Inputs/thinlto-function-summary-callgraph-sample-profile-summary.ll -o %t2.o
 ; RUN: llvm-lto -thinlto -o %t3 %t.o %t2.o
 ; RUN: llvm-bcanalyzer -dump %t3.thinlto.bc | FileCheck %s --check-prefix=COMBINED
 
@@ -16,24 +16,26 @@
 ; "hot3"
 ; CHECK-NEXT: <FUNCTION op0=20 op1=4
 ; "hot4"
-; CHECK-NEXT: <FUNCTION op0=24 op1=4
+; CHECK-NEXT: <FUNCTION op0=24 op1=5
 ; "cold"
-; CHECK-NEXT: <FUNCTION op0=28 op1=4
+; CHECK-NEXT: <FUNCTION op0=29 op1=5
 ; "none1"
-; CHECK-NEXT: <FUNCTION op0=32 op1=5
+; CHECK-NEXT: <FUNCTION op0=34 op1=5
 ; "none2"
-; CHECK-NEXT: <FUNCTION op0=37 op1=5
+; CHECK-NEXT: <FUNCTION op0=39 op1=5
 ; "none3"
-; CHECK-NEXT: <FUNCTION op0=42 op1=5
+; CHECK-NEXT: <FUNCTION op0=44 op1=5
+; CHECK-NEXT: <FUNCTION op0=49 op1=5
+
 ; CHECK-LABEL:       <GLOBALVAL_SUMMARY_BLOCK
 ; CHECK-NEXT:    <VERSION
-; CHECK-NEXT:    <VALUE_GUID op0=25 op1=123/>
-; op4=hot1 op6=cold op8=hot2 op10=hot4 op12=none1 op14=hot3 op16=none2 op18=none3 op20=123
-; CHECK-NEXT:    <PERMODULE_PROFILE {{.*}} op4=1 op5=3 op6=5 op7=1 op8=2 op9=3 op10=4 op11=3 op12=6 op13=2 op14=3 op15=3 op16=7 op17=2 op18=8 op19=2 op20=25 op21=4/>
+; CHECK-NEXT:    <VALUE_GUID op0=26 op1=123/>
+; op4=none1 op6=hot1 op8=cold1 op10=none2 op12=hot2 op14=cold2 op16=none3 op18=hot3 op20=cold3 op22=123
+; CHECK-NEXT:    <PERMODULE_PROFILE {{.*}} op4=7 op5=1 op6=1 op7=3 op8=4 op9=1 op10=8 op11=1 op12=2 op13=3 op14=5 op15=1 op16=9 op17=1 op18=3 op19=3 op20=6 op21=1 op22=26 op23=4/>
 ; CHECK-NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 
 ; CHECK: <STRTAB_BLOCK
-; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3hot4coldnone1none2none3{{.*}}'
+; CHECK-NEXT: blob data = 'hot_functionhot1hot2hot3cold1cold2cold3none1none2none3{{.*}}'
 
 ; COMBINED:       <GLOBALVAL_SUMMARY_BLOCK
 ; COMBINED-NEXT:    <VERSION
@@ -45,13 +47,17 @@
 ; COMBINED-NEXT:    <VALUE_GUID
 ; COMBINED-NEXT:    <VALUE_GUID
 ; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <VALUE_GUID
+; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
 ; COMBINED-NEXT:    <COMBINED abbrevid=
-; COMBINED-NEXT:    <COMBINED_PROFILE {{.*}} op5=[[HOT1:.*]] op6=3 op7=[[COLD:.*]] op8=1 op9=[[HOT2:.*]] op10=3 op11=[[NONE1:.*]] op12=2 op13=[[HOT3:.*]] op14=3 op15=[[NONE2:.*]] op16=2 op17=[[NONE3:.*]] op18=2/>
+; COMBINED-NEXT:    <COMBINED abbrevid=
+; COMBINED-NEXT:    <COMBINED_PROFILE {{.*}} op5=[[NONE1:.*]] op6=1 op7=[[HOT1:.*]] op8=3 op9=[[COLD1:.*]] op10=1 op11=[[NONE2:.*]] op12=1 op13=[[HOT2:.*]] op14=3 op15=[[COLD2:.*]] op16=1 op17=[[NONE3:.*]] op18=1 op19=[[HOT3:.*]] op20=3 op21=[[COLD3:.*]] op22=1/>
 ; COMBINED_NEXT:    <COMBINED abbrevid=
 ; COMBINED_NEXT:  </GLOBALVAL_SUMMARY_BLOCK>
 
@@ -63,24 +69,19 @@
 ; This function have high profile count, so entry block is hot.
 define void @hot_function(i1 %a, i1 %a2) !prof !20 {
 entry:
-    call void @hot1()
-    br i1 %a, label %Cold, label %Hot, !prof !41
-Cold:           ; 1/1000 goes here
-  call void @cold()
-  call void @hot2()
-  call void @hot4(), !prof !15
-  call void @none1()
-  br label %exit
-Hot:            ; 999/1000 goes here
-  call void @hot2()
-  call void @hot3()
-  br i1 %a2, label %None1, label %None2, !prof !42
-None1:          ; half goes here
   call void @none1()
+  call void @hot1(), !prof !15
+  call void @cold1(), !prof !16
+  br i1 %a, label %Cold, label %Hot, !prof !41
+Cold:           ; 1/1000 goes here
   call void @none2()
+  call void @hot2(), !prof !15
+  call void @cold2(), !prof !16
   br label %exit
-None2:          ; half goes here
+Hot:            ; 999/1000 goes here
   call void @none3()
+  call void @hot3(), !prof !15
+  call void @cold3(), !prof !16
   br label %exit
 exit:
   ret void
@@ -89,17 +90,14 @@
 declare void @hot1() #1
 declare void @hot2() #1
 declare void @hot3() #1
-declare void @hot4() #1
-declare void @cold() #1
+declare void @cold1() #1
+declare void @cold2() #1
+declare void @cold3() #1
 declare void @none1() #1
 declare void @none2() #1
 declare void @none3() #1
 
-
 !41 = !{!"branch_weights", i32 1, i32 1000}
-!42 = !{!"branch_weights", i32 1, i32 1}
-
-
 
 !llvm.module.flags = !{!1}
 !20 = !{!"function_entry_count", i64 110, i64 123}
@@ -119,3 +117,4 @@
 !13 = !{i32 999000, i64 100, i32 1}
 !14 = !{i32 999999, i64 1, i32 2}
 !15 = !{!"branch_weights", i32 100}
+!16 = !{!"branch_weights", i32 1}
Index: unittests/Analysis/ProfileSummaryInfoTest.cpp
===================================================================
--- unittests/Analysis/ProfileSummaryInfoTest.cpp
+++ unittests/Analysis/ProfileSummaryInfoTest.cpp
@@ -196,14 +196,18 @@
 
   CallSite CS1(BB1->getFirstNonPHI());
   auto *CI2 = BB2->getFirstNonPHI();
+  // Manually attach branch weights metadata to the call instruction.
+  SmallVector<uint32_t, 1> Weights;
+  Weights.push_back(1000);
+  MDBuilder MDB(M->getContext());
+  CI2->setMetadata(LLVMContext::MD_prof, MDB.createBranchWeights(Weights));
   CallSite CS2(CI2);
 
-  EXPECT_TRUE(PSI.isHotCallSite(CS1, &BFI));
-  EXPECT_FALSE(PSI.isHotCallSite(CS2, &BFI));
+  EXPECT_FALSE(PSI.isHotCallSite(CS1, &BFI));
+  EXPECT_TRUE(PSI.isHotCallSite(CS2, &BFI));
 
   // Test that CS2 is considered hot when it gets an MD_prof metadata with
   // weights that exceed the hot count threshold.
-  MDBuilder MDB(M->getContext());
   CI2->setMetadata(llvm::LLVMContext::MD_prof, MDB.createBranchWeights({400}));
   EXPECT_TRUE(PSI.isHotCallSite(CS2, &BFI));
 }