Index: clang/lib/CodeGen/BackendUtil.cpp
===================================================================
--- clang/lib/CodeGen/BackendUtil.cpp
+++ clang/lib/CodeGen/BackendUtil.cpp
@@ -54,6 +54,7 @@
 #include "llvm/Transforms/ObjCARC.h"
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/Transforms/Scalar/GVN.h"
+#include "llvm/Transforms/Utils/NameAnonGlobals.h"
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
 #include <memory>
 using namespace clang;
@@ -800,6 +801,9 @@
   default:
     llvm_unreachable("Invalid optimization level!");
 
+  case 0:
+    return PassBuilder::O0;
+
   case 1:
     return PassBuilder::O1;
 
@@ -881,17 +885,26 @@
   ModulePassManager MPM;
 
   if (!CodeGenOpts.DisableLLVMPasses) {
+    bool IsThinLTO = CodeGenOpts.EmitSummaryIndex;
+    bool IsLTO = CodeGenOpts.PrepareForLTO;
+
     if (CodeGenOpts.OptimizationLevel == 0) {
-      // Build a minimal pipeline based on the semantics required by Clang,
-      // which is just that always inlining occurs.
       MPM.addPass(AlwaysInlinerPass());
+      if (IsThinLTO)
+        MPM.addPass(NameAnonGlobalPass());
     } else {
-      // Otherwise, use the default pass pipeline. We also have to map our
-      // optimization levels into one of the distinct levels used to configure
-      // the pipeline.
+      // Map our optimization levels into one of the distinct levels used to
+      // configure the pipeline.
       PassBuilder::OptimizationLevel Level = mapToLevel(CodeGenOpts);
 
-      MPM = PB.buildPerModuleDefaultPipeline(Level);
+      if (IsThinLTO) {
+        MPM = PB.buildThinLTOPreLinkDefaultPipeline(Level);
+        MPM.addPass(NameAnonGlobalPass());
+      } else if (IsLTO) {
+        MPM = PB.buildLTOPreLinkDefaultPipeline(Level);
+      } else {
+        MPM = PB.buildPerModuleDefaultPipeline(Level);
+      }
     }
   }
 
Index: llvm/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/lib/Passes/PassBuilder.cpp
+++ llvm/lib/Passes/PassBuilder.cpp
@@ -751,9 +751,6 @@
   // Reduce the size of the IR as much as possible.
   MPM.addPass(GlobalOptPass());
 
-  // Rename anon globals to be able to export them in the summary.
-  MPM.addPass(NameAnonGlobalPass());
-
   return MPM;
 }
 
Index: llvm/test/Other/new-pm-thinlto-defaults.ll
===================================================================
--- llvm/test/Other/new-pm-thinlto-defaults.ll
+++ llvm/test/Other/new-pm-thinlto-defaults.ll
@@ -154,7 +154,6 @@
 ; CHECK-O-NEXT: Finished CGSCC pass manager run.
 ; CHECK-O-NEXT: Finished llvm::Module pass manager run.
 ; CHECK-PRELINK-O-NEXT: Running pass: GlobalOptPass
-; CHECK-PRELINK-O-NEXT: Running pass: NameAnonGlobalPass
 ; CHECK-POSTLINK-O-NEXT: Running pass: PassManager<{{.*}}Module{{.*}}>
 ; CHECK-POSTLINK-O-NEXT: Starting llvm::Module pass manager run.
 ; CHECK-POSTLINK-O-NEXT: Running pass: GlobalOptPass