Index: lib/Analysis/MemorySSA.cpp
===================================================================
--- lib/Analysis/MemorySSA.cpp
+++ lib/Analysis/MemorySSA.cpp
@@ -84,7 +84,7 @@
 #endif
 /// Enables memory ssa as a dependency for loop passes in legacy pass manager.
 cl::opt<bool> llvm::EnableMSSALoopDependency(
-    "enable-mssa-loop-dependency", cl::Hidden, cl::init(false),
+    "enable-mssa-loop-dependency", cl::Hidden, cl::init(true),
     cl::desc("Enable MemorySSA dependency for loop pass manager"));
 
 static cl::opt<bool, true>
Index: lib/Transforms/Utils/LoopUtils.cpp
===================================================================
--- lib/Transforms/Utils/LoopUtils.cpp
+++ lib/Transforms/Utils/LoopUtils.cpp
@@ -19,6 +19,7 @@
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/MemorySSA.h"
 #include "llvm/Analysis/MemorySSAUpdater.h"
 #include "llvm/Analysis/MustExecute.h"
 #include "llvm/Analysis/ScalarEvolution.h"
@@ -170,6 +171,8 @@
   AU.addPreserved<SCEVAAWrapperPass>();
   AU.addRequired<ScalarEvolutionWrapperPass>();
   AU.addPreserved<ScalarEvolutionWrapperPass>();
+  // FIXME: When all loop passes preserve MemorySSA, it can be required and
+  // preserved here instead of the individual handling in each pass.
 }
 
 /// Manually defined generic "LoopPass" dependency initialization. This is used
@@ -190,6 +193,7 @@
   INITIALIZE_PASS_DEPENDENCY(GlobalsAAWrapperPass)
   INITIALIZE_PASS_DEPENDENCY(SCEVAAWrapperPass)
   INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
+  INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
 }
 
 /// Create MDNode for input string.
Index: test/CodeGen/PowerPC/sms-grp-order.ll
===================================================================
--- test/CodeGen/PowerPC/sms-grp-order.ll
+++ test/CodeGen/PowerPC/sms-grp-order.ll
@@ -4,25 +4,24 @@
 
 define void @lame_encode_buffer_interleaved() local_unnamed_addr {
 ; CHECK-LABEL: lame_encode_buffer_interleaved:
-; CHECK:       # %bb.0:
-; CHECK-NEXT:    lhz 3, 0(0)
-; CHECK-NEXT:    li 5, 1
-; CHECK-NEXT:    sldi 5, 5, 62
-; CHECK-NEXT:    lhz 4, 0(3)
-; CHECK-NEXT:    mtctr 5
-; CHECK-NEXT:    .p2align 5
-; CHECK-NEXT:  .LBB0_1: #
-; CHECK-NEXT:    extsh 3, 3
-; CHECK-NEXT:    extsh 4, 4
-; CHECK-NEXT:    srawi 3, 3, 1
-; CHECK-NEXT:    addze 3, 3
-; CHECK-NEXT:    srawi 4, 4, 1
-; CHECK-NEXT:    addze 4, 4
-; CHECK-NEXT:    bdnz .LBB0_1
-; CHECK-NEXT:  # %bb.2:
-; CHECK-NEXT:    sth 3, 0(0)
-; CHECK-NEXT:    sth 4, 0(3)
-; CHECK-NEXT:    blr
+; CHECK:      # %bb.0:
+; CHECK-NEXT:   lha 3, 0(3)
+; CHECK-NEXT:   li 5, 1
+; CHECK-NEXT:   sldi 5, 5, 62
+; CHECK-NEXT:   lhz 4, 0(0)
+; CHECK-NEXT:   mtctr 5
+; CHECK-NEXT:   srawi 3, 3, 1
+; CHECK-NEXT:   addze 3, 3
+; CHECK-NEXT:   .p2align 4
+; CHECK-NEXT: .LBB0_1:
+; CHECK-NEXT:   extsh 4, 4
+; CHECK-NEXT:   srawi 4, 4, 1
+; CHECK-NEXT:   addze 4, 4
+; CHECK-NEXT:   bdnz .LBB0_1
+; CHECK-NEXT: # %bb.2:
+; CHECK-NEXT:   sth 4, 0(0)
+; CHECK-NEXT:   sth 3, 0(3)
+; CHECK-NEXT:   blr
   br label %1
 
 1:                                                ; preds = %1, %0
Index: test/Other/opt-O2-pipeline.ll
===================================================================
--- test/Other/opt-O2-pipeline.ll
+++ test/Other/opt-O2-pipeline.ll
@@ -93,12 +93,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -153,12 +154,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -185,12 +187,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -246,6 +249,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
Index: test/Other/opt-O3-pipeline.ll
===================================================================
--- test/Other/opt-O3-pipeline.ll
+++ test/Other/opt-O3-pipeline.ll
@@ -98,12 +98,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -158,12 +159,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -190,12 +192,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -251,6 +254,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
Index: test/Other/opt-Os-pipeline.ll
===================================================================
--- test/Other/opt-Os-pipeline.ll
+++ test/Other/opt-Os-pipeline.ll
@@ -80,12 +80,13 @@
 ; CHECK-NEXT:         Simplify the CFG
 ; CHECK-NEXT:         Reassociate expressions
 ; CHECK-NEXT:         Dominator Tree Construction
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Rotate Loops
@@ -140,12 +141,13 @@
 ; CHECK-NEXT:         Phi Values Analysis
 ; CHECK-NEXT:         Memory Dependence Analysis
 ; CHECK-NEXT:         Dead Store Elimination
+; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:         Function Alias Analysis Results
+; CHECK-NEXT:         Memory SSA
 ; CHECK-NEXT:         Natural Loop Information
 ; CHECK-NEXT:         Canonicalize natural loops
 ; CHECK-NEXT:         LCSSA Verifier
 ; CHECK-NEXT:         Loop-Closed SSA Form Pass
-; CHECK-NEXT:         Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:         Function Alias Analysis Results
 ; CHECK-NEXT:         Scalar Evolution Analysis
 ; CHECK-NEXT:         Loop Pass Manager
 ; CHECK-NEXT:           Loop Invariant Code Motion
@@ -172,12 +174,13 @@
 ; CHECK-NEXT:     FunctionPass Manager
 ; CHECK-NEXT:       Float to int
 ; CHECK-NEXT:       Dominator Tree Construction
+; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
+; CHECK-NEXT:       Function Alias Analysis Results
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Natural Loop Information
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass
-; CHECK-NEXT:       Basic Alias Analysis (stateless AA impl)
-; CHECK-NEXT:       Function Alias Analysis Results
 ; CHECK-NEXT:       Scalar Evolution Analysis
 ; CHECK-NEXT:       Loop Pass Manager
 ; CHECK-NEXT:         Rotate Loops
@@ -233,6 +236,7 @@
 ; CHECK-NEXT:       Lazy Block Frequency Analysis
 ; CHECK-NEXT:       Optimization Remark Emitter
 ; CHECK-NEXT:       Combine redundant instructions
+; CHECK-NEXT:       Memory SSA
 ; CHECK-NEXT:       Canonicalize natural loops
 ; CHECK-NEXT:       LCSSA Verifier
 ; CHECK-NEXT:       Loop-Closed SSA Form Pass