diff --git a/llvm/include/llvm/IR/StructuralHash.h b/llvm/include/llvm/IR/StructuralHash.h
--- a/llvm/include/llvm/IR/StructuralHash.h
+++ b/llvm/include/llvm/IR/StructuralHash.h
@@ -1,4 +1,4 @@
-//===- llvm/IR/StructuralHash.h - IR Hash for expensive checks --*- C++ -*-===//
+//===- llvm/IR/StructuralHash.h - IR Hashing --------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
@@ -14,11 +14,8 @@
 #ifndef LLVM_IR_STRUCTURALHASH_H
 #define LLVM_IR_STRUCTURALHASH_H
 
-#ifdef EXPENSIVE_CHECKS
-
 #include <cstdint>
 
-// This header is only meant to be used when -DEXPENSIVE_CHECKS is set
 namespace llvm {
 
 class Function;
@@ -30,5 +27,3 @@
 } // end namespace llvm
 
 #endif
-
-#endif // LLVM_IR_STRUCTURALHASH_H
diff --git a/llvm/lib/IR/StructuralHash.cpp b/llvm/lib/IR/StructuralHash.cpp
--- a/llvm/lib/IR/StructuralHash.cpp
+++ b/llvm/lib/IR/StructuralHash.cpp
@@ -1,13 +1,10 @@
-//===-- StructuralHash.cpp - IR Hash for expensive checks -------*- C++ -*-===//
+//===-- StructuralHash.cpp - IR Hashing -------------------------*- C++ -*-===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
-//
-
-#ifdef EXPENSIVE_CHECKS
 
 #include "llvm/IR/StructuralHash.h"
 #include "llvm/IR/Function.h"
@@ -77,5 +74,3 @@
   H.update(M);
   return H.getHash();
 }
-
-#endif
diff --git a/llvm/lib/Passes/StandardInstrumentations.cpp b/llvm/lib/Passes/StandardInstrumentations.cpp
--- a/llvm/lib/Passes/StandardInstrumentations.cpp
+++ b/llvm/lib/Passes/StandardInstrumentations.cpp
@@ -24,6 +24,7 @@
 #include "llvm/IR/PassInstrumentation.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/IR/PrintPasses.h"
+#include "llvm/IR/StructuralHash.h"
 #include "llvm/IR/Verifier.h"
 #include "llvm/Support/CommandLine.h"
 #include "llvm/Support/CrashRecoveryContext.h"
@@ -1049,6 +1050,23 @@
 
 AnalysisKey PreservedCFGCheckerAnalysis::Key;
 
+struct PreservedFunctionHashAnalysis
+    : public AnalysisInfoMixin<PreservedFunctionHashAnalysis> {
+  static AnalysisKey Key;
+
+  struct FunctionHash {
+    uint64_t Hash;
+  };
+
+  using Result = FunctionHash;
+
+  Result run(Function &F, FunctionAnalysisManager &FAM) {
+    return Result{StructuralHash(F)};
+  }
+};
+
+AnalysisKey PreservedFunctionHashAnalysis::Key;
+
 bool PreservedCFGCheckerInstrumentation::CFG::invalidate(
     Function &F, const PreservedAnalyses &PA,
     FunctionAnalysisManager::Invalidator &) {
@@ -1063,6 +1081,7 @@
     return;
 
   FAM.registerPass([&] { return PreservedCFGCheckerAnalysis(); });
+  FAM.registerPass([&] { return PreservedFunctionHashAnalysis(); });
 
   PIC.registerBeforeNonSkippedPassCallback(
       [this, &FAM](StringRef P, Any IR) {
@@ -1076,6 +1095,8 @@
 
         // Make sure a fresh CFG snapshot is available before the pass.
         FAM.getResult<PreservedCFGCheckerAnalysis>(*const_cast<Function *>(*F));
+        FAM.getResult<PreservedFunctionHashAnalysis>(
+            *const_cast<Function *>(*F));
       });
 
   PIC.registerAfterPassInvalidatedCallback(
@@ -1095,9 +1116,19 @@
 #endif
     (void)this;
 
-    const auto **F = any_cast<const Function *>(&IR);
-    if (!F)
+    const auto **MaybeF = any_cast<const Function *>(&IR);
+    if (!MaybeF)
       return;
+    Function &F = *const_cast<Function *>(*MaybeF);
+
+    if (auto *HashBefore =
+            FAM.getCachedResult<PreservedFunctionHashAnalysis>(F)) {
+      if (HashBefore->Hash != StructuralHash(F)) {
+        report_fatal_error(formatv(
+            "Function @{0} changed by {1} without invalidating analyses",
+            F.getName(), P));
+      }
+    }
 
     auto CheckCFG = [](StringRef Pass, StringRef FuncName,
                        const CFG &GraphBefore, const CFG &GraphAfter) {
@@ -1112,10 +1143,9 @@
       report_fatal_error(Twine("CFG unexpectedly changed by ", Pass));
     };
 
-    if (auto *GraphBefore = FAM.getCachedResult<PreservedCFGCheckerAnalysis>(
-            *const_cast<Function *>(*F)))
-      CheckCFG(P, (*F)->getName(), *GraphBefore,
-               CFG(*F, /* TrackBBLifetime */ false));
+    if (auto *GraphBefore = FAM.getCachedResult<PreservedCFGCheckerAnalysis>(F))
+      CheckCFG(P, F.getName(), *GraphBefore,
+               CFG(&F, /* TrackBBLifetime */ false));
   });
 }
 
@@ -2151,18 +2181,17 @@
   TimePasses.registerCallbacks(PIC);
   OptNone.registerCallbacks(PIC);
   OptPassGate.registerCallbacks(PIC);
-  if (FAM)
-    PreservedCFGChecker.registerCallbacks(PIC, *FAM);
   PrintChangedIR.registerCallbacks(PIC);
   PseudoProbeVerification.registerCallbacks(PIC);
   if (VerifyEach)
     Verify.registerCallbacks(PIC);
   PrintChangedDiff.registerCallbacks(PIC);
   WebsiteChangeReporter.registerCallbacks(PIC);
-
   ChangeTester.registerCallbacks(PIC);
-
   PrintCrashIR.registerCallbacks(PIC);
+  if (FAM)
+    PreservedCFGChecker.registerCallbacks(PIC, *FAM);
+
   // TimeProfiling records the pass running time cost.
   // Its 'BeforePassCallback' can be appended at the tail of all the
   // BeforeCallbacks by calling `registerCallbacks` in the end.
diff --git a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-markloopasdeleted.ll b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-markloopasdeleted.ll
--- a/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-markloopasdeleted.ll
+++ b/llvm/test/Transforms/SimpleLoopUnswitch/nontrivial-unswitch-markloopasdeleted.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -enable-loop-distribute -passes='loop-distribute,loop-mssa(simple-loop-unswitch<nontrivial>),loop-distribute' -o /dev/null -S -verify-analysis-invalidation -debug-pass-manager=verbose 2>&1 | FileCheck %s
+; RUN: opt < %s -enable-loop-distribute -passes='loop-distribute,loop-mssa(simple-loop-unswitch<nontrivial>),loop-distribute' -o /dev/null -S -verify-analysis-invalidation=0 -debug-pass-manager=verbose 2>&1 | FileCheck %s
 
 
 ; Running loop-distribute will result in LoopAccessAnalysis being required and
@@ -29,7 +29,6 @@
 ;
 ; CHECK: Invalidating analysis: LoopAccessAnalysis on test6
 ; CHECK-NEXT: Running pass: LoopDistributePass on test6
-; CHECK-NEXT: Running analysis: PreservedCFGCheckerAnalysis on test6
 ; CHECK-NEXT: Running analysis: LoopAccessAnalysis on test6
 
 
diff --git a/llvm/unittests/IR/PassManagerTest.cpp b/llvm/unittests/IR/PassManagerTest.cpp
--- a/llvm/unittests/IR/PassManagerTest.cpp
+++ b/llvm/unittests/IR/PassManagerTest.cpp
@@ -950,4 +950,37 @@
   FPM.addPass(TestSimplifyCFGWrapperPass(InnerFPM));
   FPM.run(*F, FAM);
 }
+
+#ifdef EXPENSIVE_CHECKS
+
+struct WrongFunctionPass : PassInfoMixin<WrongFunctionPass> {
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM) {
+    F.getEntryBlock().begin()->eraseFromParent();
+    return PreservedAnalyses::all();
+  }
+  static StringRef name() { return "WrongFunctionPass"; }
+};
+
+TEST_F(PassManagerTest, FunctionAnalysisMissedInvalidation) {
+  LLVMContext Context;
+  auto M = parseIR(Context, "define void @foo() {\n"
+                            "  %a = add i32 0, 0\n"
+                            "  ret void\n"
+                            "}\n");
+
+  FunctionAnalysisManager FAM;
+  PassInstrumentationCallbacks PIC;
+  StandardInstrumentations SI(M->getContext(), /*DebugLogging*/ false);
+  SI.registerCallbacks(PIC, &FAM);
+  FAM.registerPass([&] { return PassInstrumentationAnalysis(&PIC); });
+
+  FunctionPassManager FPM;
+  FPM.addPass(WrongFunctionPass());
+
+  auto *F = M->getFunction("foo");
+  EXPECT_DEATH(FPM.run(*F, FAM), "Function @foo changed by WrongFunctionPass without invalidating analyses");
+}
+
+#endif
+
 }