diff --git a/llvm/include/llvm/Transforms/Scalar.h b/llvm/include/llvm/Transforms/Scalar.h
--- a/llvm/include/llvm/Transforms/Scalar.h
+++ b/llvm/include/llvm/Transforms/Scalar.h
@@ -211,7 +211,7 @@
 //
 // LoopRotate - This pass is a simple loop rotating pass.
 //
-Pass *createLoopRotatePass(int MaxHeaderSize = -1, bool PrepareForLTO = false);
+Pass *createLoopRotatePass(bool PrepareForLTO = false);
 
 //===----------------------------------------------------------------------===//
 //
diff --git a/llvm/include/llvm/Transforms/Scalar/LoopRotation.h b/llvm/include/llvm/Transforms/Scalar/LoopRotation.h
--- a/llvm/include/llvm/Transforms/Scalar/LoopRotation.h
+++ b/llvm/include/llvm/Transforms/Scalar/LoopRotation.h
@@ -22,13 +22,11 @@
 /// A simple loop rotation transformation.
 class LoopRotatePass : public PassInfoMixin<LoopRotatePass> {
 public:
-  LoopRotatePass(bool EnableHeaderDuplication = true,
-                 bool PrepareForLTO = false);
+  LoopRotatePass(bool PrepareForLTO = false);
   PreservedAnalyses run(Loop &L, LoopAnalysisManager &AM,
                         LoopStandardAnalysisResults &AR, LPMUpdater &U);
 
 private:
-  const bool EnableHeaderDuplication;
   const bool PrepareForLTO;
 };
 }
diff --git a/llvm/lib/Passes/PassBuilderPipelines.cpp b/llvm/lib/Passes/PassBuilderPipelines.cpp
--- a/llvm/lib/Passes/PassBuilderPipelines.cpp
+++ b/llvm/lib/Passes/PassBuilderPipelines.cpp
@@ -295,8 +295,9 @@
   // TODO: Investigate promotion cap for O1.
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap));
 
-  LPM1.addPass(LoopRotatePass(/* Disable header duplication */ true,
-                              isLTOPreLink(Phase)));
+  // Note that this LoopRotate pass doesn't disable header duplication, but
+  // perhaps it should.
+  LPM1.addPass(LoopRotatePass(isLTOPreLink(Phase)));
   // TODO: Investigate promotion cap for O1.
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap));
   LPM1.addPass(SimpleLoopUnswitchPass());
@@ -467,9 +468,7 @@
   // TODO: Investigate promotion cap for O1.
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap));
 
-  // Disable header duplication in loop rotation at -Oz.
-  LPM1.addPass(
-      LoopRotatePass(Level != OptimizationLevel::Oz, isLTOPreLink(Phase)));
+  LPM1.addPass(LoopRotatePass(isLTOPreLink(Phase)));
   // TODO: Investigate promotion cap for O1.
   LPM1.addPass(LICMPass(PTO.LicmMssaOptCap, PTO.LicmMssaNoAccForPromotionCap));
   LPM1.addPass(
@@ -641,10 +640,9 @@
   MPM.addPass(PGOInstrumentationGen(IsCS));
 
   FunctionPassManager FPM;
-  // Disable header duplication in loop rotation at -Oz.
-  FPM.addPass(createFunctionToLoopPassAdaptor(
-      LoopRotatePass(Level != OptimizationLevel::Oz), /*UseMemorySSA=*/false,
-      /*UseBlockFrequencyInfo=*/false));
+  FPM.addPass(createFunctionToLoopPassAdaptor(LoopRotatePass(),
+                                              /*UseMemorySSA=*/false,
+                                              /*UseBlockFrequencyInfo=*/false));
   MPM.addPass(createModuleToFunctionPassAdaptor(std::move(FPM),
                                                 PTO.EagerlyInvalidateAnalyses));
 
@@ -1163,8 +1161,7 @@
 
   LoopPassManager LPM;
   // First rotate loops that may have been un-rotated by prior passes.
-  // Disable header duplication at -Oz.
-  LPM.addPass(LoopRotatePass(Level != OptimizationLevel::Oz, LTOPreLink));
+  LPM.addPass(LoopRotatePass(LTOPreLink));
   // Some loops may have become dead by now. Try to delete them.
   // FIXME: see discussion in https://reviews.llvm.org/D112851,
   //        this may need to be revisited once we run GVN before loop deletion
diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -454,8 +454,8 @@
   // to reduce amount of IR that will have to be duplicated.
   // TODO: Investigate promotion cap for O1.
   MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
-  // Rotate Loop - disable header duplication at -Oz
-  MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, PrepareForLTO));
+  // Rotate Loop - header duplication is disabled if minsize is set.
+  MPM.add(createLoopRotatePass(PrepareForLTO));
   // TODO: Investigate promotion cap for O1.
   MPM.add(createLICMPass(LicmMssaOptCap, LicmMssaNoAccForPromotionCap));
   if (EnableSimpleLoopUnswitch)
@@ -921,8 +921,8 @@
 
   // Re-rotate loops in all our loop nests. These may have fallout out of
   // rotated form due to GVN or other transformations, and the vectorizer relies
-  // on the rotated form. Disable header duplication at -Oz.
-  MPM.add(createLoopRotatePass(SizeLevel == 2 ? 0 : -1, PrepareForLTO));
+  // on the rotated form.
+  MPM.add(createLoopRotatePass(PrepareForLTO));
 
   // Distribute loops to allow partial vectorization.  I.e. isolate dependences
   // into separate loop that would otherwise inhibit vectorization.  This is
diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -40,17 +40,16 @@
     cl::desc("Run loop-rotation in the prepare-for-lto stage. This option "
              "should be used for testing only."));
 
-LoopRotatePass::LoopRotatePass(bool EnableHeaderDuplication, bool PrepareForLTO)
-    : EnableHeaderDuplication(EnableHeaderDuplication),
-      PrepareForLTO(PrepareForLTO) {}
+LoopRotatePass::LoopRotatePass(bool PrepareForLTO)
+    : PrepareForLTO(PrepareForLTO) {}
 
 PreservedAnalyses LoopRotatePass::run(Loop &L, LoopAnalysisManager &AM,
                                       LoopStandardAnalysisResults &AR,
                                       LPMUpdater &) {
   // Vectorization requires loop-rotation. Use default threshold for loops the
-  // user explicitly marked for vectorization, even when header duplication is
-  // disabled.
-  int Threshold = EnableHeaderDuplication ||
+  // user explicitly marked for vectorization, even when the minsize attribute
+  // is set.
+  int Threshold = !L.getHeader()->getParent()->hasMinSize() ||
                           hasVectorizeTransformation(&L) == TM_ForcedByUser
                       ? DefaultRotationThreshold
                       : 0;
@@ -80,19 +79,13 @@
 namespace {
 
 class LoopRotateLegacyPass : public LoopPass {
-  unsigned MaxHeaderSize;
   bool PrepareForLTO;
 
 public:
   static char ID; // Pass ID, replacement for typeid
-  LoopRotateLegacyPass(int SpecifiedMaxHeaderSize = -1,
-                       bool PrepareForLTO = false)
+  LoopRotateLegacyPass(bool PrepareForLTO = false)
       : LoopPass(ID), PrepareForLTO(PrepareForLTO) {
     initializeLoopRotateLegacyPassPass(*PassRegistry::getPassRegistry());
-    if (SpecifiedMaxHeaderSize == -1)
-      MaxHeaderSize = DefaultRotationThreshold;
-    else
-      MaxHeaderSize = unsigned(SpecifiedMaxHeaderSize);
   }
 
   // LCSSA form makes instruction renaming easier.
@@ -126,11 +119,12 @@
     if (MSSAA)
       MSSAU = MemorySSAUpdater(&MSSAA->getMSSA());
     // Vectorization requires loop-rotation. Use default threshold for loops the
-    // user explicitly marked for vectorization, even when header duplication is
-    // disabled.
-    int Threshold = hasVectorizeTransformation(L) == TM_ForcedByUser
-                        ? DefaultRotationThreshold
-                        : MaxHeaderSize;
+    // user explicitly marked for vectorization, even when the minsize attribute
+    // is set.
+    int Threshold =
+        !F.hasMinSize() || hasVectorizeTransformation(L) == TM_ForcedByUser
+            ? DefaultRotationThreshold
+            : 0;
 
     return LoopRotation(L, LI, TTI, AC, &DT, &SE,
                         MSSAU.hasValue() ? MSSAU.getPointer() : nullptr, SQ,
@@ -150,6 +144,6 @@
 INITIALIZE_PASS_END(LoopRotateLegacyPass, "loop-rotate", "Rotate Loops", false,
                     false)
 
-Pass *llvm::createLoopRotatePass(int MaxHeaderSize, bool PrepareForLTO) {
-  return new LoopRotateLegacyPass(MaxHeaderSize, PrepareForLTO);
+Pass *llvm::createLoopRotatePass(bool PrepareForLTO) {
+  return new LoopRotateLegacyPass(PrepareForLTO);
 }
diff --git a/llvm/test/Transforms/LoopRotate/minsize-disable.ll b/llvm/test/Transforms/LoopRotate/minsize-disable.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/LoopRotate/minsize-disable.ll
@@ -0,0 +1,33 @@
+; REQUIRES: asserts
+; RUN: opt < %s -S -O2 -debug -debug-only=loop-rotate 2>&1 | FileCheck %s
+; RUN: opt < %s -S -passes='default<O2>' -debug -debug-only=loop-rotate 2>&1 | FileCheck %s
+
+; Loop should not be rotated for functions with the minsize attribute.
+; This is mostly useful for LTO which doesn't (yet) understand -Oz.
+; CHECK: LoopRotation: NOT rotating - contains 2 instructions, which is more
+
+@e = global i32 10
+
+declare void @use(i32)
+
+; Function attrs: minsize optsize
+define void @test() #0 {
+entry:
+  %end = load i32, i32* @e
+  br label %loop
+
+loop:
+  %n.phi = phi i32 [ %n, %loop.fin ], [ 0, %entry ]
+  %cond = icmp eq i32 %n.phi, %end
+  br i1 %cond, label %exit, label %loop.fin
+
+loop.fin:
+  %n = add i32 %n.phi, 1
+  call void @use(i32 %n)
+  br label %loop
+
+exit:
+  ret void
+}
+
+attributes #0 = { minsize optsize }
diff --git a/llvm/test/Transforms/LoopRotate/oz-disable.ll b/llvm/test/Transforms/LoopRotate/oz-disable.ll
deleted file mode 100644
--- a/llvm/test/Transforms/LoopRotate/oz-disable.ll
+++ /dev/null
@@ -1,32 +0,0 @@
-; REQUIRES: asserts
-; RUN: opt < %s -S -Os -debug -debug-only=loop-rotate 2>&1 | FileCheck %s -check-prefix=OS
-; RUN: opt < %s -S -Oz -debug -debug-only=loop-rotate 2>&1 | FileCheck %s -check-prefix=OZ
-; RUN: opt < %s -S -passes='default<Os>' -debug -debug-only=loop-rotate 2>&1 | FileCheck %s -check-prefix=OS
-; RUN: opt < %s -S -passes='default<Oz>' -debug -debug-only=loop-rotate 2>&1 | FileCheck %s -check-prefix=OZ
-
-; Loop should be rotated for -Os but not for -Oz.
-; OS: rotating Loop at depth 1
-; OZ-NOT: rotating Loop at depth 1
-
-@e = global i32 10
-
-declare void @use(i32)
-
-define void @test() {
-entry:
-  %end = load i32, i32* @e
-  br label %loop
-
-loop:
-  %n.phi = phi i32 [ %n, %loop.fin ], [ 0, %entry ]
-  %cond = icmp eq i32 %n.phi, %end
-  br i1 %cond, label %exit, label %loop.fin
-
-loop.fin:
-  %n = add i32 %n.phi, 1
-  call void @use(i32 %n)
-  br label %loop
-
-exit:
-  ret void
-}