diff --git a/llvm/include/llvm/Transforms/Scalar/LoopUnrollPass.h b/llvm/include/llvm/Transforms/Scalar/LoopUnrollPass.h
--- a/llvm/include/llvm/Transforms/Scalar/LoopUnrollPass.h
+++ b/llvm/include/llvm/Transforms/Scalar/LoopUnrollPass.h
@@ -64,6 +64,7 @@
   Optional<bool> AllowRuntime;
   Optional<bool> AllowUpperBound;
   Optional<bool> AllowProfileBasedPeeling;
+  Optional<unsigned> Threshold;
   Optional<unsigned> FullUnrollMaxCount;
   int OptLevel;
 
@@ -120,6 +121,12 @@
     return *this;
   }
 
+  // Sets "cost threshold" tuning parameter for loop unrolling.
+  LoopUnrollOptions &setThreshold(unsigned T) {
+    Threshold = T;
+    return *this;
+  }
+
   // Sets the max full unroll count.
   LoopUnrollOptions &setFullUnrollMaxCount(unsigned O) {
     FullUnrollMaxCount = O;
diff --git a/llvm/lib/Passes/PassBuilder.cpp b/llvm/lib/Passes/PassBuilder.cpp
--- a/llvm/lib/Passes/PassBuilder.cpp
+++ b/llvm/lib/Passes/PassBuilder.cpp
@@ -536,6 +536,15 @@
       UnrollOpts.setOptLevel(OptLevel);
       continue;
     }
+    if (ParamName.consume_front("threshold=")) {
+      unsigned Threshold;
+      if (ParamName.getAsInteger(0, Threshold))
+        return make_error<StringError>(
+            formatv("invalid LoopUnrollPass parameter '{0}' ", ParamName).str(),
+            inconvertibleErrorCode());
+      UnrollOpts.setThreshold(Threshold);
+      continue;
+    }
     if (ParamName.consume_front("full-unroll-max=")) {
       int Count;
       if (ParamName.getAsInteger(0, Count))
diff --git a/llvm/lib/Passes/PassRegistry.def b/llvm/lib/Passes/PassRegistry.def
--- a/llvm/lib/Passes/PassRegistry.def
+++ b/llvm/lib/Passes/PassRegistry.def
@@ -401,7 +401,7 @@
                              return LoopUnrollPass(Opts);
                            },
                           parseLoopUnrollOptions,
-                          "O0;O1;O2;O3;full-unroll-max=N;"
+                          "O0;O1;O2;O3;threshold=N;full-unroll-max=N;"
                           "no-partial;partial;"
                           "no-peeling;peeling;"
                           "no-profile-peeling;profile-peeling;"
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -1602,8 +1602,8 @@
     LoopUnrollResult Result = tryToUnrollLoop(
         &L, DT, &LI, SE, TTI, AC, ORE, BFI, PSI,
         /*PreserveLCSSA*/ true, UnrollOpts.OptLevel, UnrollOpts.OnlyWhenForced,
-        UnrollOpts.ForgetSCEV, /*Count*/ None,
-        /*Threshold*/ None, UnrollOpts.AllowPartial, UnrollOpts.AllowRuntime,
+        UnrollOpts.ForgetSCEV, /*Count*/ None, UnrollOpts.Threshold,
+        UnrollOpts.AllowPartial, UnrollOpts.AllowRuntime,
         UnrollOpts.AllowUpperBound, LocalAllowPeeling,
         UnrollOpts.AllowProfileBasedPeeling, UnrollOpts.FullUnrollMaxCount);
     Changed |= Result != LoopUnrollResult::Unmodified;
@@ -1641,6 +1641,8 @@
   if (UnrollOpts.AllowProfileBasedPeeling != None)
     OS << (UnrollOpts.AllowProfileBasedPeeling.getValue() ? "" : "no-")
        << "profile-peeling;";
+  if (UnrollOpts.Threshold != None)
+    OS << "threshold=" << UnrollOpts.Threshold << ";";
   if (UnrollOpts.FullUnrollMaxCount != None)
     OS << "full-unroll-max=" << UnrollOpts.FullUnrollMaxCount << ";";
   OS << "O" << UnrollOpts.OptLevel;
diff --git a/llvm/test/Other/new-pm-print-pipeline.ll b/llvm/test/Other/new-pm-print-pipeline.ll
--- a/llvm/test/Other/new-pm-print-pipeline.ll
+++ b/llvm/test/Other/new-pm-print-pipeline.ll
@@ -31,8 +31,8 @@
 ; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(lower-matrix-intrinsics<>,lower-matrix-intrinsics<minimal>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-9
 ; CHECK-9: function(lower-matrix-intrinsics<>,lower-matrix-intrinsics<minimal>)
 
-; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(loop-unroll<>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;full-unroll-max=7;O1>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-10
-; CHECK-10: function(loop-unroll<O2>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;full-unroll-max=7;O1>)
+; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(loop-unroll<>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;threshold=32;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;threshold=32;full-unroll-max=7;O1>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-10
+; CHECK-10: function(loop-unroll<O2>,loop-unroll<partial;peeling;runtime;upperbound;profile-peeling;threshold=32;full-unroll-max=5;O1>,loop-unroll<no-partial;no-peeling;no-runtime;no-upperbound;no-profile-peeling;threshold=32;full-unroll-max=7;O1>)
 
 ; RUN: opt -disable-output -disable-verify -print-pipeline-passes -passes='function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep>)' < %s | FileCheck %s --match-full-lines --check-prefixes=CHECK-11
 ; CHECK-11: function(gvn<>,gvn<pre;load-pre;split-backedge-load-pre;memdep>,gvn<no-pre;no-load-pre;no-split-backedge-load-pre;no-memdep>)
diff --git a/llvm/test/Other/print-passes.ll b/llvm/test/Other/print-passes.ll
--- a/llvm/test/Other/print-passes.ll
+++ b/llvm/test/Other/print-passes.ll
@@ -13,7 +13,7 @@
 ; CHECK: Function passes:
 ; CHECK: no-op-function
 ; CHECK: Function passes with params:
-; CHECK: loop-unroll<O0;O1;O2;O3;full-unroll-max=N;no-partial;partial;no-peeling;peeling;no-profile-peeling;profile-peeling;no-runtime;runtime;no-upperbound;upperbound>
+; CHECK: loop-unroll<O0;O1;O2;O3;threshold=N;full-unroll-max=N;no-partial;partial;no-peeling;peeling;no-profile-peeling;profile-peeling;no-runtime;runtime;no-upperbound;upperbound>
 ; CHECK: Function analyses:
 ; CHECK: no-op-function
 ; CHECK: Function alias analyses: