diff --git a/include/llvm/Transforms/Vectorize.h b/include/llvm/Transforms/Vectorize.h
index 8d0db161160..823c5fba745 100644
--- a/include/llvm/Transforms/Vectorize.h
+++ b/include/llvm/Transforms/Vectorize.h
@@ -114,7 +114,7 @@ createBBVectorizePass(const VectorizeConfig &C = VectorizeConfig());
 //
 // LoopVectorize - Create a loop vectorization pass.
 //
-Pass *createLoopVectorizePass();
+Pass *createLoopVectorizePass(bool NoUnrolling = false);
 
 //===----------------------------------------------------------------------===//
 //
diff --git a/lib/Transforms/IPO/PassManagerBuilder.cpp b/lib/Transforms/IPO/PassManagerBuilder.cpp
index 743dc423434..d4c0c2caeaa 100644
--- a/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -196,7 +196,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
   MPM.add(createLoopDeletionPass());          // Delete dead loops
 
   if (!LateVectorize && LoopVectorize)
-      MPM.add(createLoopVectorizePass());
+      MPM.add(createLoopVectorizePass(DisableUnrollLoops));
 
   if (!DisableUnrollLoops)
     MPM.add(createLoopUnrollPass());          // Unroll small loops
@@ -250,7 +250,7 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
     // Add the various vectorization passes and relevant cleanup passes for
     // them since we are no longer in the middle of the main scalar pipeline.
     if (LoopVectorize) {
-      MPM.add(createLoopVectorizePass());
+      MPM.add(createLoopVectorizePass(DisableUnrollLoops));
 
       if (!DisableUnrollLoops)
         MPM.add(createLoopUnrollPass());    // Unroll small loops
diff --git a/lib/Transforms/Vectorize/LoopVectorize.cpp b/lib/Transforms/Vectorize/LoopVectorize.cpp
index 2ee1441e4b5..0afc73e5098 100644
--- a/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -761,9 +761,9 @@ struct LoopVectorizeHints {
   /// Vectorization unroll factor.
   unsigned Unroll;
 
-  LoopVectorizeHints(const Loop *L)
+  LoopVectorizeHints(const Loop *L, bool DisableUnrolling)
   : Width(VectorizationFactor)
-  , Unroll(VectorizationUnroll)
+  , Unroll(DisableUnrolling ? 1 : VectorizationUnroll)
   , LoopID(L->getLoopID()) {
     getHints(L);
     // The command line options override any loop metadata except for when
@@ -772,6 +772,9 @@ struct LoopVectorizeHints {
       Width = VectorizationFactor;
     if (VectorizationUnroll.getNumOccurrences() > 0)
       Unroll = VectorizationUnroll;
+
+    DEBUG(if (DisableUnrolling && Unroll == 1)
+            dbgs() << "LV: Unrolling disabled by the pass manager\n");
   }
 
   /// Return the loop vectorizer metadata prefix.
@@ -878,7 +881,8 @@ struct LoopVectorize : public LoopPass {
   /// Pass identification, replacement for typeid
   static char ID;
 
-  explicit LoopVectorize() : LoopPass(ID) {
+  explicit LoopVectorize(bool NoUnrolling = false)
+    : LoopPass(ID), DisableUnrolling(NoUnrolling) {
     initializeLoopVectorizePass(*PassRegistry::getPassRegistry());
   }
 
@@ -888,6 +892,7 @@ struct LoopVectorize : public LoopPass {
   TargetTransformInfo *TTI;
   DominatorTree *DT;
   TargetLibraryInfo *TLI;
+  bool DisableUnrolling;
 
   virtual bool runOnLoop(Loop *L, LPPassManager &LPM) {
     // We only vectorize innermost loops.
@@ -909,7 +914,7 @@ struct LoopVectorize : public LoopPass {
     DEBUG(dbgs() << "LV: Checking a loop in \"" <<
           L->getHeader()->getParent()->getName() << "\"\n");
 
-    LoopVectorizeHints Hints(L);
+    LoopVectorizeHints Hints(L, DisableUnrolling);
 
     if (Hints.Width == 1 && Hints.Unroll == 1) {
       DEBUG(dbgs() << "LV: Not vectorizing.\n");
@@ -4786,8 +4791,8 @@ INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_END(LoopVectorize, LV_NAME, lv_name, false, false)
 
 namespace llvm {
-  Pass *createLoopVectorizePass() {
-    return new LoopVectorize();
+  Pass *createLoopVectorizePass(bool NoUnrolling) {
+    return new LoopVectorize(NoUnrolling);
   }
 }
 
diff --git a/test/Transforms/LoopVectorize/X86/unroll-pm.ll b/test/Transforms/LoopVectorize/X86/unroll-pm.ll
new file mode 100644
index 00000000000..5064fec286c
--- /dev/null
+++ b/test/Transforms/LoopVectorize/X86/unroll-pm.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -O2 -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -S | FileCheck %s
+; RUN: opt < %s -O2 -mtriple=x86_64-apple-macosx10.8.0 -mcpu=corei7-avx -force-vector-width=4 -disable-loop-unrolling -S | FileCheck %s -check-prefix=CHECK-NOUNRL
+
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.8.0"
+;CHECK-LABEL: @bar(
+;CHECK: store <4 x i32>
+;CHECK: store <4 x i32>
+;CHECK: ret
+;CHECK-NOUNRL-LABEL: @bar(
+;CHECK-NOUNRL: store <4 x i32>
+;CHECK-NOUNRL-NOT: store <4 x i32>
+;CHECK-NOUNRL: ret
+define i32 @bar(i32* nocapture %A, i32 %n) nounwind uwtable ssp {
+  %1 = icmp sgt i32 %n, 0
+  br i1 %1, label %.lr.ph, label %._crit_edge
+
+.lr.ph:                                           ; preds = %0, %.lr.ph
+  %indvars.iv = phi i64 [ %indvars.iv.next, %.lr.ph ], [ 0, %0 ]
+  %2 = getelementptr inbounds i32* %A, i64 %indvars.iv
+  %3 = load i32* %2, align 4
+  %4 = add nsw i32 %3, 6
+  store i32 %4, i32* %2, align 4
+  %indvars.iv.next = add i64 %indvars.iv, 1
+  %lftr.wideiv = trunc i64 %indvars.iv.next to i32
+  %exitcond = icmp eq i32 %lftr.wideiv, %n
+  br i1 %exitcond, label %._crit_edge, label %.lr.ph
+
+._crit_edge:                                      ; preds = %.lr.ph, %0
+  ret i32 undef
+}
diff --git a/test/Transforms/LoopVectorize/global_alias.ll b/test/Transforms/LoopVectorize/global_alias.ll
index ae72d3c6082..4fd4c989de4 100644
--- a/test/Transforms/LoopVectorize/global_alias.ll
+++ b/test/Transforms/LoopVectorize/global_alias.ll
@@ -1,4 +1,4 @@
-; RUN: opt < %s -O3 -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s
+; RUN: opt < %s -O1 -loop-vectorize -force-vector-unroll=1 -force-vector-width=4 -dce -instcombine -S | FileCheck %s
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:64:128-a0:0:64-n32-S64"
 
diff --git a/tools/opt/opt.cpp b/tools/opt/opt.cpp
index ca820617861..691080aba37 100644
--- a/tools/opt/opt.cpp
+++ b/tools/opt/opt.cpp
@@ -135,6 +135,11 @@ UnitAtATime("funit-at-a-time",
             cl::desc("Enable IPO. This is same as llvm-gcc's -funit-at-a-time"),
             cl::init(true));
 
+static cl::opt<bool>
+DisableLoopUnrolling("disable-loop-unrolling",
+                     cl::desc("Disable loop unrolling in all relevant passes"),
+                     cl::init(false));
+
 static cl::opt<bool>
 DisableSimplifyLibCalls("disable-simplify-libcalls",
                         cl::desc("Disable simplify-libcalls"));
@@ -447,12 +452,13 @@ static void AddOptimizationPasses(PassManagerBase &MPM,FunctionPassManager &FPM,
     Builder.Inliner = createAlwaysInlinerPass();
   }
   Builder.DisableUnitAtATime = !UnitAtATime;
-  Builder.DisableUnrollLoops = OptLevel == 0;
+  Builder.DisableUnrollLoops = (DisableLoopUnrolling.getNumOccurrences() > 0) ?
+                               DisableLoopUnrolling : OptLevel == 0;
   
+  Builder.LoopVectorize = OptLevel > 1 && SizeLevel < 2;
+
   Builder.populateFunctionPassManager(FPM);
   Builder.populateModulePassManager(MPM);
-
-  Builder.LoopVectorize = OptLevel > 1 && SizeLevel < 2;
 }
 
 static void AddStandardCompilePasses(PassManagerBase &PM) {