diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp
--- a/clang/lib/CodeGen/BackendUtil.cpp
+++ b/clang/lib/CodeGen/BackendUtil.cpp
@@ -1063,6 +1063,16 @@
                           const LangOptions &LangOpts, PassBuilder &PB) {
   PB.registerOptimizerLastEPCallback([&](ModulePassManager &MPM,
                                          PassBuilder::OptimizationLevel Level) {
+    if (CodeGenOpts.OptimizationLevel == 0) {
+      if (!CodeGenOpts.ThinLTOIndexFile.empty())
+        llvm::report_fatal_error(
+            "Unexpected optimizer in non-optimized ThinLTO PostLink");
+    } else {
+      if (CodeGenOpts.PrepareForThinLTO)
+        llvm::report_fatal_error(
+            "Unexpected optimizer in optimized ThinLTO PreLink");
+    }
+
     if (CodeGenOpts.SanitizeCoverageType ||
         CodeGenOpts.SanitizeCoverageIndirectCalls ||
         CodeGenOpts.SanitizeCoverageTraceCmp) {
@@ -1313,7 +1323,12 @@
             FPM.addPass(BoundsCheckingPass());
           });
 
-    addSanitizers(TargetTriple, CodeGenOpts, LangOpts, PB);
+    if (CodeGenOpts.OptimizationLevel != 0 ||
+        CodeGenOpts.ThinLTOIndexFile.empty()) {
+      // This is testing distributed ThinLTO PostLink. O0 called optimized in
+      // PreLink.
+      addSanitizers(TargetTriple, CodeGenOpts, LangOpts, PB);
+    }
 
     if (Optional<GCOVOptions> Options = getGCOVOptions(CodeGenOpts, LangOpts))
       PB.registerPipelineStartEPCallback(
@@ -1522,6 +1537,10 @@
     Conf.CGFileType = getCodeGenFileType(Action);
     break;
   }
+  Triple TargetTriple(M->getTargetTriple());
+  Conf.OptimizerLastPassBuilderHook = [&](PassBuilder &PB) {
+    addSanitizers(TargetTriple, CGOpts, LOpts, PB);
+  };
   if (Error E =
           thinBackend(Conf, -1, AddStream, *M, *CombinedIndex, ImportList,
                       ModuleToDefinedGVSummaries[M->getModuleIdentifier()],
diff --git a/clang/test/CodeGen/thinlto-distributed-sanitizers.ll b/clang/test/CodeGen/thinlto-distributed-sanitizers.ll
new file mode 100644
--- /dev/null
+++ b/clang/test/CodeGen/thinlto-distributed-sanitizers.ll
@@ -0,0 +1,164 @@
+; REQUIRES: x86-registered-target
+
+; Validate ThinLTO post link pipeline with sanitizers
+
+; RUN: opt -thinlto-bc -o %t.o %s
+
+; RUN: llvm-lto2 run -thinlto-distributed-indexes %t.o \
+; RUN:   -o %t2.index \
+; RUN:   -r=%t.o,main,px
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=address \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,ASAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=address \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,ASAN2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=address \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,ASAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=address \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,ASAN2 %s
+
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=memory \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,MSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=memory \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,MSAN2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=memory \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,MSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=memory \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,MSAN2 %s
+
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=thread \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,TSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=thread \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,TSAN2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=thread \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,TSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=thread \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,TSAN2 %s
+
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=hwaddress \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,HWASAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=hwaddress \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,HWASAN2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=hwaddress \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,HWASAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=hwaddress \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,HWASAN2 %s
+
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=dataflow \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,DFSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=dataflow \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,DFSAN2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=dataflow \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,DFSAN0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize=dataflow \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,DFSAN2 %s
+
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize-coverage=trace-pc-guard \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,SANCOV0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize-coverage=trace-pc-guard \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=%t.o.thinlto.bc \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,SANCOV2 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize-coverage=trace-pc-guard \
+; RUN:   -O0 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,SANCOV0 %s
+
+; RUN: %clang -target x86_64-grtev4-linux-gnu -fsanitize-coverage=trace-pc-guard \
+; RUN:   -O2 -fexperimental-new-pass-manager -Xclang -fdebug-pass-manager \
+; RUN:   -c -fthinlto-index=/dev/null \
+; RUN:   -o %t.native.o -x ir %t.o 2>&1 | FileCheck -check-prefixes=CHECK,SANCOV2 %s
+
+
+; CHECK: Starting llvm::Module pass manager
+; ASAN0-NOT: MemorySanitizer
+; MSAN0-NOT: AddressSanitizer
+; TSAN0-NOT: ThreadSanitizer
+; HWASAN0-NOT: HWAddressSanitizer
+; DFSAN0-NOT: DataFlowSanitizer
+; SANCOV0-NOT: SanitizerCoverage
+
+; ASAN2: Running analysis: ASanGlobalsMetadataAnalysis on {{.*}}.o
+; ASAN2: Running pass: ModuleAddressSanitizerPass on {{.*}}.o
+; ASAN2: Running pass: AddressSanitizerPass on main
+; MSAN2: Running pass: MemorySanitizerPass on {{.*}}.o
+; MSAN2: Running pass: MemorySanitizerPass on main
+; TSAN2: Running pass: ThreadSanitizerPass on {{.*}}.o
+; TSAN2: Running pass: ThreadSanitizerPass on main
+; HWASAN2: Running pass: HWAddressSanitizerPass on {{.*}}.o
+; DFSAN2: Running pass: DataFlowSanitizerPass on {{.*}}.o
+; SANCOV2: Running pass: ModuleSanitizerCoveragePass on {{.*}}.o
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-grtev4-linux-gnu"
+
+define i32 @main() {
+  br label %b
+b:
+  br label %b
+  ret i32 0
+}
diff --git a/clang/test/Driver/asan.c b/clang/test/Driver/asan.c
--- a/clang/test/Driver/asan.c
+++ b/clang/test/Driver/asan.c
@@ -3,7 +3,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-ASAN
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-ASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-ASAN
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-ASAN
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-NOASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-ASAN
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=address %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-ASAN
 
@@ -21,7 +21,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-KASAN
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-KASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KASAN
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KASAN
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-NOASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KASAN
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target i386-unknown-linux -fsanitize=kernel-address %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KASAN
 
@@ -39,7 +39,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-HWASAN
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-HWASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-HWASAN
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-HWASAN
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-NOHWASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-HWASAN
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-HWASAN
 
@@ -57,7 +57,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-NOHWASAN
 // RUN: %clang     -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 
@@ -68,7 +68,7 @@
 // RUN: %clang     -fno-experimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // RUN: %clang -O2 -fno-experimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // RUN: %clang     -fno-experimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
-// FIX: %clang -O2 -fno-experimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target aarch64-unknown-linux -fsanitize=kernel-hwaddress %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefix=CHECK-KHWASAN
 // Verify that -fsanitize={address,hwaddres,kernel-address,kernel-hwaddress} invokes ASan, HWAsan, KASan or KHWASan instrumentation.
 
 int foo(int *a) { return *a; }
@@ -76,3 +76,6 @@
 // CHECK-KASAN: __asan_{{.*}}load4_noabort
 // CHECK-HWASAN: __hwasan_init
 // CHECK-KHWASAN: __hwasan_tls
+
+// CHECK-NOASAN-NOT: __asan
+// CHECK-NOHWASAN-NOT: __asan
diff --git a/clang/test/Driver/dfsan.c b/clang/test/Driver/dfsan.c
--- a/clang/test/Driver/dfsan.c
+++ b/clang/test/Driver/dfsan.c
@@ -3,7 +3,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -flto=thin -o - | FileCheck %s
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=NODFSAN
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -flto -o - | FileCheck %s
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=dataflow %s -S -emit-llvm -flto -o - | FileCheck %s
 
@@ -20,3 +20,4 @@
 
 int foo(int *a) { return *a; }
 // CHECK: __dfsan
+// NODFSAN-NOT: __dfsan
diff --git a/clang/test/Driver/msan.c b/clang/test/Driver/msan.c
--- a/clang/test/Driver/msan.c
+++ b/clang/test/Driver/msan.c
@@ -1,49 +1,50 @@
 // REQUIRES: x86-registered-target
 
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O1 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O3 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O1 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O3 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s
 
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O1 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O3 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O1 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O3 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang     -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s
+// RUN: %clang -O2 -fno-experimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s
 
-// RUN: %clang -target mips64-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -target mips64el-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -target powerpc64-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -target powerpc64le-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
+// RUN: %clang -target mips64-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -target mips64el-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -target powerpc64-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -target powerpc64le-unknown-linux-gnu -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
 
 // Verify that -fsanitize=memory and -fsanitize=kernel-memory invoke MSan/KMSAN instrumentation.
 
 // Also check that this works with the new pass manager with and without
 // optimization
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O1 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O1 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=NOMSAN
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=memory %s -S -emit-llvm -flto -o - | FileCheck %s
 
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O1 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
-// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s --check-prefixes=CHECK
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O1 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory  %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=NOMSAN
+// RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=kernel-memory %s -S -emit-llvm -flto -o - | FileCheck %s
 
 int foo(int *a) { return *a; }
 // CHECK: @__msan_
+// NOMSAN-NOT: __msan
diff --git a/clang/test/Driver/sancov.c b/clang/test/Driver/sancov.c
--- a/clang/test/Driver/sancov.c
+++ b/clang/test/Driver/sancov.c
@@ -3,7 +3,7 @@
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -flto=thin -o - | FileCheck %s
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=NOSANCOV
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -flto -o - | FileCheck %s
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize-coverage=trace-pc-guard %s -S -emit-llvm -flto -o - | FileCheck %s
 
@@ -20,3 +20,4 @@
 
 int foo(int *a) { return *a; }
 // CHECK: _sancov_
+// NOSANCOV-NOT: _sancov
\ No newline at end of file
diff --git a/clang/test/Driver/tsan.c b/clang/test/Driver/tsan.c
--- a/clang/test/Driver/tsan.c
+++ b/clang/test/Driver/tsan.c
@@ -19,9 +19,10 @@
 // RUN: %clang -O3 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -o - | FileCheck %s
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -flto=thin -o - | FileCheck %s
-// FIX: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -flto=thin -o - | FileCheck %s
+// RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -flto=thin -o - | FileCheck %s --check-prefixes=NOTSAN
 // RUN: %clang     -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -flto -o - | FileCheck %s
 // RUN: %clang -O2 -fexperimental-new-pass-manager -target x86_64-unknown-linux -fsanitize=thread %s -S -emit-llvm -flto -o - | FileCheck %s
 
 int foo(int *a) { return *a; }
 // CHECK: __tsan_init
+// NOTSAN-NOT: __tsan
diff --git a/llvm/include/llvm/LTO/Config.h b/llvm/include/llvm/LTO/Config.h
--- a/llvm/include/llvm/LTO/Config.h
+++ b/llvm/include/llvm/LTO/Config.h
@@ -48,7 +48,9 @@
   TargetOptions Options;
   std::vector<std::string> MAttrs;
   std::vector<std::string> PassPlugins;
-  /// For adding passes that run right before codegen.
+  /// For adding passes that run by optimizer.
+  std::function<void(PassBuilder &)> OptimizerLastPassBuilderHook;
+  /// For adding passes that run right before codegen (NewPM only).
   std::function<void(legacy::PassManager &)> PreCodeGenPassesHook;
   Optional<Reloc::Model> RelocModel = Reloc::PIC_;
   Optional<CodeModel::Model> CodeModel = None;
diff --git a/llvm/lib/LTO/LTOBackend.cpp b/llvm/lib/LTO/LTOBackend.cpp
--- a/llvm/lib/LTO/LTOBackend.cpp
+++ b/llvm/lib/LTO/LTOBackend.cpp
@@ -253,6 +253,9 @@
   PB.registerLoopAnalyses(LAM);
   PB.crossRegisterProxies(LAM, FAM, CGAM, MAM);
 
+  if (Conf.OptimizerLastPassBuilderHook)
+    Conf.OptimizerLastPassBuilderHook(PB);
+
   ModulePassManager MPM(Conf.DebugPassManager);
 
   if (!Conf.DisableVerify)