Index: lib/CodeGen/BackendUtil.cpp
===================================================================
--- lib/CodeGen/BackendUtil.cpp
+++ lib/CodeGen/BackendUtil.cpp
@@ -1136,6 +1136,8 @@
   Conf.SampleProfile = std::move(SampleProfile);
   Conf.UseNewPM = CGOpts.ExperimentalNewPassManager;
   Conf.DebugPassManager = CGOpts.DebugPassManager;
+  Conf.RemarksWithHotness = CGOpts.DiagnosticsWithHotness;
+  Conf.RemarksFilename = CGOpts.OptRecordFile;
   switch (Action) {
   case Backend_EmitNothing:
     Conf.PreCodeGenModuleHook = [](size_t Task, const Module &Mod) {
Index: lib/Frontend/CompilerInvocation.cpp
===================================================================
--- lib/Frontend/CompilerInvocation.cpp
+++ lib/Frontend/CompilerInvocation.cpp
@@ -1075,7 +1075,9 @@
   bool UsingProfile = UsingSampleProfile ||
       (Opts.getProfileUse() != CodeGenOptions::ProfileNone);
 
-  if (Opts.DiagnosticsWithHotness && !UsingProfile)
+  if (Opts.DiagnosticsWithHotness && !UsingProfile &&
+      // An IR file will contain PGO as metadata
+      IK.getLanguage() != InputKind::LLVM_IR)
     Diags.Report(diag::warn_drv_diagnostics_hotness_requires_pgo)
         << "-fdiagnostics-show-hotness";
 
Index: test/CodeGen/thinlto-diagnostic-handler-remarks-with-hotness.ll
===================================================================
--- /dev/null
+++ test/CodeGen/thinlto-diagnostic-handler-remarks-with-hotness.ll
@@ -0,0 +1,47 @@
+; Test to ensure -fdiagnostics-show-hotness and -fsave-optimization-record
+; work when invoking the ThinLTO backend path.
+; RUN: opt -module-summary -o %t.o %s
+; RUN: llvm-lto -thinlto -o %t %t.o
+
+; First try with pass remarks to stderr
+; RUN: %clang -O2 -x ir %t.o -fthinlto-index=%t.thinlto.bc -mllvm -pass-remarks=inline -fdiagnostics-show-hotness -o %t2.o -c 2>&1 | FileCheck %s
+
+; CHECK: tinkywinky inlined into main with cost=0 (threshold=337) (hotness: 300)
+
+; Next try YAML pass remarks file
+; RUN: rm -f %t2.opt.yaml.thin.0.yaml
+; RUN: %clang -O2 -x ir %t.o -fthinlto-index=%t.thinlto.bc -fsave-optimization-record -fdiagnostics-show-hotness -o %t2.o -c
+; RUN: cat %t2.opt.yaml.thin.0.yaml | FileCheck %s -check-prefix=YAML
+
+; YAML: --- !Passed
+; YAML-NEXT: Pass:            inline
+; YAML-NEXT: Name:            Inlined
+; YAML-NEXT: Function:        main
+; YAML-NEXT: Hotness:         300
+; YAML-NEXT: Args:
+; YAML-NEXT:   - Callee:          tinkywinky
+; YAML-NEXT:   - String:          ' inlined into '
+; YAML-NEXT:   - Caller:          main
+; YAML-NEXT:   - String:          ' with cost='
+; YAML-NEXT:   - Cost:            '0'
+; YAML-NEXT:   - String:          ' (threshold='
+; YAML-NEXT:   - Threshold:       '337'
+; YAML-NEXT:   - String:          ')'
+; YAML-NEXT: ...
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-scei-ps4"
+
+declare i32 @patatino()
+
+define i32 @tinkywinky() {
+  %a = call i32 @patatino()
+  ret i32 %a
+}
+
+define i32 @main() !prof !0 {
+  %i = call i32 @tinkywinky()
+  ret i32 %i
+}
+
+!0 = !{!"function_entry_count", i64 300}