Index: llvm/trunk/include/llvm/Passes/PassBuilder.h
===================================================================
--- llvm/trunk/include/llvm/Passes/PassBuilder.h
+++ llvm/trunk/include/llvm/Passes/PassBuilder.h
@@ -85,6 +85,9 @@
   /// is that of the flag: `vectorize-slp`.
   bool SLPVectorization;
 
+  /// Tuning option to enable/disable loop unrolling. Its default value is true.
+  bool LoopUnrolling;
+
   /// Tuning option to cap the number of calls to retrive clobbering accesses in
   /// MemorySSA, in LICM.
   unsigned LicmMssaOptCap;
Index: llvm/trunk/lib/Passes/PassBuilder.cpp
===================================================================
--- llvm/trunk/lib/Passes/PassBuilder.cpp
+++ llvm/trunk/lib/Passes/PassBuilder.cpp
@@ -217,6 +217,7 @@
   LoopInterleaving = EnableLoopInterleaving;
   LoopVectorization = EnableLoopVectorization;
   SLPVectorization = RunSLPVectorization;
+  LoopUnrolling = true;
   LicmMssaOptCap = SetLicmMssaOptCap;
   LicmMssaNoAccForPromotionCap = SetLicmMssaNoAccForPromotionCap;
 }
@@ -459,8 +460,9 @@
   // Do not enable unrolling in PreLinkThinLTO phase during sample PGO
   // because it changes IR to makes profile annotation in back compile
   // inaccurate.
-  if (Phase != ThinLTOPhase::PreLink || !PGOOpt ||
-      PGOOpt->Action != PGOOptions::SampleUse)
+  if ((Phase != ThinLTOPhase::PreLink || !PGOOpt ||
+       PGOOpt->Action != PGOOptions::SampleUse) &&
+      PTO.LoopUnrolling)
     LPM2.addPass(LoopFullUnrollPass(Level));
 
   for (auto &C : LoopOptimizerEndEPCallbacks)
@@ -907,7 +909,8 @@
     OptimizePM.addPass(
         createFunctionToLoopPassAdaptor(LoopUnrollAndJamPass(Level)));
   }
-  OptimizePM.addPass(LoopUnrollPass(LoopUnrollOptions(Level)));
+  if (PTO.LoopUnrolling)
+    OptimizePM.addPass(LoopUnrollPass(LoopUnrollOptions(Level)));
   OptimizePM.addPass(WarnMissedTransformationsPass());
   OptimizePM.addPass(InstCombinePass());
   OptimizePM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());