diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -13981,9 +13981,6 @@
     for (auto &V : Values) {
       auto CachedDisposition = V.getInt();
       const auto *Loop = V.getPointer();
-      // TODO: Make sure LoopDispositions contains no invalid loops.
-      if (!ValidLoops.contains(Loop))
-        continue;
       const auto RecomputedDisposition = SE2.getLoopDisposition(S, Loop);
       if (CachedDisposition != RecomputedDisposition) {
         dbgs() << "Cached disposition of " << *S << " for loop " << *Loop
diff --git a/llvm/lib/Transforms/Utils/LoopUtils.cpp b/llvm/lib/Transforms/Utils/LoopUtils.cpp
--- a/llvm/lib/Transforms/Utils/LoopUtils.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUtils.cpp
@@ -696,6 +696,7 @@
   Loop *OutermostLoop = L->getOutermostLoop();
 
   SE.forgetLoop(L);
+  SE.forgetBlockAndLoopDispositions();
 
   std::unique_ptr<MemorySSAUpdater> MSSAU;
   if (MSSA)