diff --git a/llvm/docs/LangRef.rst b/llvm/docs/LangRef.rst
--- a/llvm/docs/LangRef.rst
+++ b/llvm/docs/LangRef.rst
@@ -6257,6 +6257,15 @@
    !3 = distinct !{} ; access group for instructions in the inner loop (which are implicitly contained in outer loop as well)
    !4 = distinct !{} ; access group for instructions in the outer, but not the inner loop
 
+'``llvm.loop.mustprogress``' Metadata
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``llvm.loop.mustprogress`` metadata indicates that this loop is required to
+terminate, unwind, or interact with the environment in an observable way e.g.
+via a volatile memory access, I/O, or other synchronization. If such a loop is
+not found to interact with the environment in an observable way, the loop may
+be removed. This corresponds to the ``mustprogress`` function attribute.
+
 '``irr_loop``' Metadata
 ^^^^^^^^^^^^^^^^^^^^^^^
 
diff --git a/llvm/include/llvm/Analysis/LoopInfo.h b/llvm/include/llvm/Analysis/LoopInfo.h
--- a/llvm/include/llvm/Analysis/LoopInfo.h
+++ b/llvm/include/llvm/Analysis/LoopInfo.h
@@ -840,6 +840,9 @@
   /// unrolling pass is run more than once (which it generally is).
   void setLoopAlreadyUnrolled();
 
+  /// Add llvm.loop.mustprogress to this loop's loop id metadata.
+  void setLoopMustProgress();
+
   void dump() const;
   void dumpVerbose() const;
 
diff --git a/llvm/include/llvm/Transforms/Utils/Cloning.h b/llvm/include/llvm/Transforms/Utils/Cloning.h
--- a/llvm/include/llvm/Transforms/Utils/Cloning.h
+++ b/llvm/include/llvm/Transforms/Utils/Cloning.h
@@ -176,9 +176,9 @@
       function_ref<AssumptionCache &(Function &)> GetAssumptionCache = nullptr,
       ProfileSummaryInfo *PSI = nullptr,
       BlockFrequencyInfo *CallerBFI = nullptr,
-      BlockFrequencyInfo *CalleeBFI = nullptr)
+      BlockFrequencyInfo *CalleeBFI = nullptr, LoopInfo *CalleeLI = nullptr)
       : CG(cg), GetAssumptionCache(GetAssumptionCache), PSI(PSI),
-        CallerBFI(CallerBFI), CalleeBFI(CalleeBFI) {}
+        CallerBFI(CallerBFI), CalleeBFI(CalleeBFI), CalleeLI(CalleeLI) {}
 
   /// If non-null, InlineFunction will update the callgraph to reflect the
   /// changes it makes.
@@ -186,6 +186,7 @@
   function_ref<AssumptionCache &(Function &)> GetAssumptionCache;
   ProfileSummaryInfo *PSI;
   BlockFrequencyInfo *CallerBFI, *CalleeBFI;
+  LoopInfo *CalleeLI;
 
   /// InlineFunction fills this in with all static allocas that get copied into
   /// the caller.
diff --git a/llvm/lib/Analysis/LoopInfo.cpp b/llvm/lib/Analysis/LoopInfo.cpp
--- a/llvm/lib/Analysis/LoopInfo.cpp
+++ b/llvm/lib/Analysis/LoopInfo.cpp
@@ -535,6 +535,22 @@
   setLoopID(NewLoopID);
 }
 
+void Loop::setLoopMustProgress() {
+  LLVMContext &Context = getHeader()->getContext();
+
+  MDNode *MustProgress = findOptionMDForLoop(this, "llvm.loop.mustprogress");
+
+  if (MustProgress)
+    return;
+
+  MDNode *MustProgressMD =
+      MDNode::get(Context, MDString::get(Context, "llvm.loop.mustprogress"));
+  MDNode *LoopID = getLoopID();
+  MDNode *NewLoopID =
+      makePostTransformationMetadata(Context, LoopID, {}, {MustProgressMD});
+  setLoopID(NewLoopID);
+}
+
 bool Loop::isAnnotatedParallel() const {
   MDNode *DesiredLoopIdMetadata = getLoopID();