diff --git a/llvm/include/llvm/IR/PassInstrumentation.h b/llvm/include/llvm/IR/PassInstrumentation.h
--- a/llvm/include/llvm/IR/PassInstrumentation.h
+++ b/llvm/include/llvm/IR/PassInstrumentation.h
@@ -232,6 +232,14 @@
                   ExtraArgsT...) {
     return false;
   }
+
+  template <typename CallableT>
+  void pushBeforeNonSkippedPassCallback(CallableT C) {
+    Callbacks->BeforeNonSkippedPassCallbacks.emplace_back(std::move(C));
+  }
+  void popBeforeNonSkippedPassCallback() {
+    Callbacks->BeforeNonSkippedPassCallbacks.pop_back();
+  }
 };
 
 bool isSpecialPass(StringRef PassID, const std::vector<StringRef> &Specials);
diff --git a/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h b/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
--- a/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
+++ b/llvm/include/llvm/Transforms/Scalar/LoopPassManager.h
@@ -50,6 +50,7 @@
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Dominators.h"
+#include "llvm/IR/PassInstrumentation.h"
 #include "llvm/IR/PassManager.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
@@ -296,6 +297,21 @@
     // declaration.
     appendLoopsToWorklist(LI, Worklist);
 
+#ifndef NDEBUG
+    PI.pushBeforeNonSkippedPassCallback([&LAR, &LI](StringRef PassID, Any IR) {
+      if (isSpecialPass(PassID, {"PassManager"}))
+        return;
+      assert(any_isa<const Loop *>(IR));
+      const Loop *L = any_cast<const Loop *>(IR);
+      assert(L && "Loop should be valid for printing");
+
+      // Verify the loop structure and LCSSA form before visiting the loop.
+      L->verifyLoop();
+      assert(L->isRecursivelyLCSSAForm(LAR.DT, LI) &&
+             "Loops must remain in LCSSA form!");
+    });
+#endif
+
     do {
       Loop *L = Worklist.pop_back_val();
 
@@ -306,11 +322,6 @@
 #ifndef NDEBUG
       // Save a parent loop pointer for asserts.
       Updater.ParentL = L->getParentLoop();
-
-      // Verify the loop structure and LCSSA form before visiting the loop.
-      L->verifyLoop();
-      assert(L->isRecursivelyLCSSAForm(LAR.DT, LI) &&
-             "Loops must remain in LCSSA form!");
 #endif
       // Check the PassInstrumentation's BeforePass callbacks before running the
       // pass, skip its execution completely if asked to (callback returns
@@ -345,6 +356,10 @@
       PA.intersect(std::move(PassPA));
     } while (!Worklist.empty());
 
+#ifndef NDEBUG
+    PI.popBeforeNonSkippedPassCallback();
+#endif
+
     // By definition we preserve the proxy. We also preserve all analyses on
     // Loops. This precludes *any* invalidation of loop analyses by the proxy,
     // but that's OK because we've taken care to invalidate analyses in the
diff --git a/llvm/test/Feature/optnone-opt.ll b/llvm/test/Feature/optnone-opt.ll
--- a/llvm/test/Feature/optnone-opt.ll
+++ b/llvm/test/Feature/optnone-opt.ll
@@ -34,7 +34,7 @@
   br label %while.cond
 
 while.end:                                        ; preds = %while.cond
-  ret i32 0
+  ret i32 %dec
 }
 
 attributes #0 = { optnone noinline }