Update MemorySSA in LoopUnswitch.

Summary:
Update MemorySSA in old LoopUnswitch pass.
Actual dependency and update is disabled by default.

Subscribers: sanjoy, jlebar, Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D45301

llvm-svn: 341984

lib/Transforms/Scalar/LoopUnswitch.cpp

@@ -28,18 +28,19 @@
 
 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SmallPtrSet.h"
-#include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CodeMetrics.h"
-#include "llvm/Analysis/LegacyDivergenceAnalysis.h"
 #include "llvm/Analysis/InstructionSimplify.h"
+#include "llvm/Analysis/LegacyDivergenceAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/LoopIterator.h"
 #include "llvm/Analysis/LoopPass.h"
+#include "llvm/Analysis/MemorySSA.h"
+#include "llvm/Analysis/MemorySSAUpdater.h"
 #include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
-#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/BasicBlock.h"
 #include "llvm/IR/CallSite.h"
@@ -65,8 +66,10 @@
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Cloning.h"
+#include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
 #include <algorithm>
@@ -180,6 +183,8 @@ namespace {
 
     Loop *currentLoop = nullptr;
     DominatorTree *DT = nullptr;
+    MemorySSA *MSSA = nullptr;
+    std::unique_ptr<MemorySSAUpdater> MSSAU;
     BasicBlock *loopHeader = nullptr;
     BasicBlock *loopPreheader = nullptr;
 
@@ -214,6 +219,10 @@ namespace {
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.addRequired<AssumptionCacheTracker>();
       AU.addRequired<TargetTransformInfoWrapperPass>();
+      if (EnableMSSALoopDependency) {
+        AU.addRequired<MemorySSAWrapperPass>();
+        AU.addPreserved<MemorySSAWrapperPass>();
+      }
       if (hasBranchDivergence)
         AU.addRequired<LegacyDivergenceAnalysis>();
       getLoopAnalysisUsage(AU);
@@ -384,6 +393,7 @@ INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(LoopPass)
 INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(LegacyDivergenceAnalysis)
+INITIALIZE_PASS_DEPENDENCY(MemorySSAWrapperPass)
 INITIALIZE_PASS_END(LoopUnswitch, "loop-unswitch", "Unswitch loops",
                       false, false)
 
@@ -515,6 +525,11 @@ bool LoopUnswitch::runOnLoop(Loop *L, LPPassManager &LPM_Ref) {
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   LPM = &LPM_Ref;
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+  if (EnableMSSALoopDependency) {
+    MSSA = &getAnalysis<MemorySSAWrapperPass>().getMSSA();
+    MSSAU = make_unique<MemorySSAUpdater>(MSSA);
+    assert(DT && "Cannot update MemorySSA without a valid DomTree.");
+  }
   currentLoop = L;
   Function *F = currentLoop->getHeader()->getParent();
 
@@ -522,13 +537,21 @@ bool LoopUnswitch::runOnLoop(Loop *L, LPPassManager &LPM_Ref) {
   if (SanitizeMemory)
     SafetyInfo.computeLoopSafetyInfo(L);
 
+  if (MSSA && VerifyMemorySSA)
+    MSSA->verifyMemorySSA();
+
   bool Changed = false;
   do {
     assert(currentLoop->isLCSSAForm(*DT));
+    if (MSSA && VerifyMemorySSA)
+      MSSA->verifyMemorySSA();
     redoLoop = false;
     Changed |= processCurrentLoop();
   } while(redoLoop);
 
+  if (MSSA && VerifyMemorySSA)
+    MSSA->verifyMemorySSA();
+
   return Changed;
 }
 
@@ -952,13 +975,16 @@ void LoopUnswitch::EmitPreheaderBranchOnCondition(Value *LIC, Constant *Val,
     if (OldBranchSucc != TrueDest && OldBranchSucc != FalseDest) {
       Updates.push_back({DominatorTree::Delete, OldBranchParent, OldBranchSucc});
     }
-
     DT->applyUpdates(Updates);
+
+    if (MSSAU)
+      MSSAU->applyUpdates(Updates, *DT);
   }
 
   // If either edge is critical, split it. This helps preserve LoopSimplify
   // form for enclosing loops.
-  auto Options = CriticalEdgeSplittingOptions(DT, LI).setPreserveLCSSA();
+  auto Options =
+      CriticalEdgeSplittingOptions(DT, LI, MSSAU.get()).setPreserveLCSSA();
   SplitCriticalEdge(BI, 0, Options);
   SplitCriticalEdge(BI, 1, Options);
 }
@@ -984,7 +1010,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
   // First step, split the preheader, so that we know that there is a safe place
   // to insert the conditional branch.  We will change loopPreheader to have a
   // conditional branch on Cond.
-  BasicBlock *NewPH = SplitEdge(loopPreheader, loopHeader, DT, LI);
+  BasicBlock *NewPH = SplitEdge(loopPreheader, loopHeader, DT, LI, MSSAU.get());
 
   // Now that we have a place to insert the conditional branch, create a place
   // to branch to: this is the exit block out of the loop that we should
@@ -995,7 +1021,8 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
   // without actually branching to it (the exit block should be dominated by the
   // loop header, not the preheader).
   assert(!L->contains(ExitBlock) && "Exit block is in the loop?");
-  BasicBlock *NewExit = SplitBlock(ExitBlock, &ExitBlock->front(), DT, LI);
+  BasicBlock *NewExit =
+      SplitBlock(ExitBlock, &ExitBlock->front(), DT, LI, MSSAU.get());
 
   // Okay, now we have a position to branch from and a position to branch to,
   // insert the new conditional branch.
@@ -1015,6 +1042,7 @@ void LoopUnswitch::UnswitchTrivialCondition(Loop *L, Value *Cond, Constant *Val,
   // particular value, rewrite the loop with this info.  We know that this will
   // at least eliminate the old branch.
   RewriteLoopBodyWithConditionConstant(L, Cond, Val, false);
+
   ++NumTrivial;
 }
 
@@ -1190,7 +1218,7 @@ void LoopUnswitch::SplitExitEdges(Loop *L,
 
     // Although SplitBlockPredecessors doesn't preserve loop-simplify in
     // general, if we call it on all predecessors of all exits then it does.
-    SplitBlockPredecessors(ExitBlock, Preds, ".us-lcssa", DT, LI, nullptr,
+    SplitBlockPredecessors(ExitBlock, Preds, ".us-lcssa", DT, LI, MSSAU.get(),
                            /*PreserveLCSSA*/ true);
   }
 }
@@ -1216,7 +1244,8 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
 
   // First step, split the preheader and exit blocks, and add these blocks to
   // the LoopBlocks list.
-  BasicBlock *NewPreheader = SplitEdge(loopPreheader, loopHeader, DT, LI);
+  BasicBlock *NewPreheader =
+      SplitEdge(loopPreheader, loopHeader, DT, LI, MSSAU.get());
   LoopBlocks.push_back(NewPreheader);
 
   // We want the loop to come after the preheader, but before the exit blocks.
@@ -1318,10 +1347,24 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   assert(OldBR->isUnconditional() && OldBR->getSuccessor(0) == LoopBlocks[0] &&
          "Preheader splitting did not work correctly!");
 
+  if (MSSAU) {
+    // Update MemorySSA after cloning, and before splitting to unreachables,
+    // since that invalidates the 1:1 mapping of clones in VMap.
+    LoopBlocksRPO LBRPO(L);
+    LBRPO.perform(LI);
+    MSSAU->updateForClonedLoop(LBRPO, ExitBlocks, VMap);
+  }
+
   // Emit the new branch that selects between the two versions of this loop.
   EmitPreheaderBranchOnCondition(LIC, Val, NewBlocks[0], LoopBlocks[0], OldBR,
                                  TI);
   LPM->deleteSimpleAnalysisValue(OldBR, L);
+  if (MSSAU) {
+    // Update MemoryPhis in Exit blocks.
+    MSSAU->updateExitBlocksForClonedLoop(ExitBlocks, VMap, *DT);
+    if (VerifyMemorySSA)
+      MSSA->verifyMemorySSA();
+  }
 
   // The OldBr was replaced by a new one and removed (but not erased) by
   // EmitPreheaderBranchOnCondition. It is no longer needed, so delete it.
@@ -1347,6 +1390,9 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   if (!LoopProcessWorklist.empty() && LoopProcessWorklist.back() == NewLoop &&
       LICHandle && !isa<Constant>(LICHandle))
     RewriteLoopBodyWithConditionConstant(NewLoop, LICHandle, Val, true);
+
+  if (MSSA && VerifyMemorySSA)
+    MSSA->verifyMemorySSA();
 }
 
 /// Remove all instances of I from the worklist vector specified.
@@ -1485,7 +1531,7 @@ void LoopUnswitch::RewriteLoopBodyWithConditionConstant(Loop *L, Value *LIC,
     // and hooked up so as to preserve the loop structure, because
     // trying to update it is complicated.  So instead we preserve the
     // loop structure and put the block on a dead code path.
-    SplitEdge(Switch, SISucc, DT, LI);
+    SplitEdge(Switch, SISucc, DT, LI, MSSAU.get());
     // Compute the successors instead of relying on the return value
     // of SplitEdge, since it may have split the switch successor
     // after PHI nodes.
@@ -1539,6 +1585,8 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
           Worklist.push_back(Use);
       LPM->deleteSimpleAnalysisValue(I, L);
       RemoveFromWorklist(I, Worklist);
+      if (MSSAU)
+        MSSAU->removeMemoryAccess(I);
       I->eraseFromParent();
       ++NumSimplify;
       continue;
@@ -1578,6 +1626,8 @@ void LoopUnswitch::SimplifyCode(std::vector<Instruction*> &Worklist, Loop *L) {
         // Move all of the successor contents from Succ to Pred.
         Pred->getInstList().splice(BI->getIterator(), Succ->getInstList(),
                                    Succ->begin(), Succ->end());
+        if (MSSAU)
+          MSSAU->moveAllAfterMergeBlocks(Succ, Pred, BI);
         LPM->deleteSimpleAnalysisValue(BI, L);
         RemoveFromWorklist(BI, Worklist);
         BI->eraseFromParent();

test/Transforms/LoopUnswitch/2006-06-13-SingleEntryPHI.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 
 	%struct.BLEND_MAP = type { i16, i16, i16, i32, %struct.BLEND_MAP_ENTRY* }
 	%struct.BLEND_MAP_ENTRY = type { float, i8, { [5 x float], [4 x i8] } }

test/Transforms/LoopUnswitch/2006-06-27-DeadSwitchCase.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 
 define void @init_caller_save() {
 entry:

test/Transforms/LoopUnswitch/2007-05-09-Unreachable.ll

@@ -1,5 +1,6 @@
 ; PR1333
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 
 target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64"
 target triple = "i686-pc-linux-gnu"

test/Transforms/LoopUnswitch/2007-05-09-tl.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 ; PR1333
 
 define void @pp_cxx_expression() {

test/Transforms/LoopUnswitch/2007-07-12-ExitDomInfo.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -instcombine -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -instcombine -disable-output
 
 @str3 = external constant [3 x i8]		; <[3 x i8]*> [#uses=1]
 

test/Transforms/LoopUnswitch/2007-07-13-DomInfo.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 
 define i32 @main(i32 %argc, i8** %argv) {
 entry:

test/Transforms/LoopUnswitch/2007-07-18-DomInfo.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 ; PR1559
 
 target triple = "i686-pc-linux-gnu"

test/Transforms/LoopUnswitch/2007-08-01-LCSSA.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -instcombine -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -instcombine -disable-output
 	%struct.ClassDef = type { %struct.QByteArray, %struct.QByteArray, %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", i8, i8, %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QList<ArgumentDef>", %"struct.QMap<QByteArray,QByteArray>", %"struct.QList<ArgumentDef>", %"struct.QMap<QByteArray,QByteArray>", i32, i32 }
 	%struct.FILE = type { i32, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, i8*, %struct._IO_marker*, %struct.FILE*, i32, i32, i32, i16, i8, [1 x i8], i8*, i64, i8*, i8*, i8*, i8*, i32, i32, [40 x i8] }
 	%struct.Generator = type { %struct.FILE*, %struct.ClassDef*, %"struct.QList<ArgumentDef>", %struct.QByteArray, %"struct.QList<ArgumentDef>" }

test/Transforms/LoopUnswitch/2008-06-02-DomInfo.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -instcombine -gvn -disable-output
+; RUN: opt < %s -loop-unswitch -instcombine -gvn -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 ; PR2372
 target triple = "i386-pc-linux-gnu"
 

test/Transforms/LoopUnswitch/2008-11-03-Invariant.ll

@@ -1,5 +1,6 @@
 ; REQUIRES: asserts
 ; RUN: opt < %s -loop-unswitch -stats -disable-output 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -stats -disable-output 2>&1 | FileCheck %s
 ; PR 3170
 
 define i32 @a(i32 %x, i32 %y) nounwind {

test/Transforms/LoopUnswitch/2010-11-18-LCSSA.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa
 ; PR8622
 @g_38 = external global i32, align 4
 

test/Transforms/LoopUnswitch/2011-09-26-EHCrash.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -sroa -loop-unswitch -disable-output
+; RUN: opt < %s -sroa -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 ; PR11016
 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"
 target triple = "x86_64-apple-macosx10.7.2"

test/Transforms/LoopUnswitch/2011-11-18-SimpleSwitch.ll

@@ -1,6 +1,7 @@
 ; REQUIRES: asserts
 ; RUN: opt -loop-unswitch -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
 ; RUN: opt -S -loop-unswitch -verify-loop-info -verify-dom-info < %s | FileCheck %s
+; RUN: opt -S -loop-unswitch -verify-loop-info -verify-dom-info -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 
 ; STATS: 2 loop-unswitch - Number of switches unswitched
 

test/Transforms/LoopUnswitch/2011-11-18-TwoSwitches-Threshold.ll

@@ -1,6 +1,7 @@
 ; REQUIRES: asserts
 ; RUN: opt -loop-unswitch -loop-unswitch-threshold 13 -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
 ; RUN: opt -S -loop-unswitch -loop-unswitch-threshold 13 -verify-loop-info -verify-dom-info < %s | FileCheck %s
+; RUN: opt -S -loop-unswitch -loop-unswitch-threshold 13 -verify-loop-info -verify-dom-info -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 
 ; STATS: 1 loop-unswitch - Number of switches unswitched
 

test/Transforms/LoopUnswitch/2011-11-18-TwoSwitches.ll

@@ -1,6 +1,7 @@
 ; REQUIRES: asserts
 ; RUN: opt -loop-unswitch -loop-unswitch-threshold 1000 -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
 ; RUN: opt -S -loop-unswitch -loop-unswitch-threshold 1000 -verify-loop-info -verify-dom-info < %s | FileCheck %s
+; RUN: opt -S -loop-unswitch -loop-unswitch-threshold 1000 -verify-loop-info -verify-dom-info -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 
 ; STATS: 3 loop-unswitch - Number of switches unswitched
 

test/Transforms/LoopUnswitch/2012-04-02-IndirectBr.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -S -loop-unswitch -verify-loop-info -verify-dom-info | FileCheck %s
+; RUN: opt < %s -S -loop-unswitch -verify-loop-info -verify-dom-info -enable-mssa-loop-dependency=true -verify-memoryssa | FileCheck %s
 ; PR12343: -loop-unswitch crash on indirect branch
 
 ; CHECK:       %0 = icmp eq i64 undef, 0

test/Transforms/LoopUnswitch/2012-05-20-Phi.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 ; PR12887
 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-unknown-linux-gnu"

test/Transforms/LoopUnswitch/2015-09-18-Addrspace.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -S | FileCheck %s
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -S | FileCheck %s
 
 ; In cases where two address spaces do not have the same size pointer, the
 ; input for the addrspacecast should not be used as a substitute for itself

test/Transforms/LoopUnswitch/LIV-loop-condtion.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -S 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -enable-mssa-loop-dependency=true -verify-memoryssa -S 2>&1 | FileCheck %s
 
 ; This is to test trivial loop unswitch only happens when trivial condition
 ; itself is an LIV loop condition (not partial LIV which could occur in and/or).
@@ -25,4 +26,4 @@ loop_exit:
   ret i32 0
 }
 
-declare void @some_func() noreturn 
+declare void @some_func() noreturn 

test/Transforms/LoopUnswitch/basictest.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -verify-loop-info -S < %s 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -verify-loop-info -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
 
 define i32 @test(i32* %A, i1 %C) {
 entry:

test/Transforms/LoopUnswitch/cleanuppad.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -S -loop-unswitch < %s | FileCheck %s
+; RUN: opt -S -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 target triple = "x86_64-pc-win32"
 
 define void @f(i32 %doit, i1 %x, i1 %y) personality i32 (...)* @__CxxFrameHandler3 {

test/Transforms/LoopUnswitch/copy-metadata.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -S < %s 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
 
 ; This test checks if unswitched condition preserve make.implicit metadata.
 

test/Transforms/LoopUnswitch/crash.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -disable-output
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output
 
 define void @test1(i32* %S2) {
 entry:

test/Transforms/LoopUnswitch/elseif-non-exponential-behavior.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -loop-unswitch -S - < %s | FileCheck %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -S - < %s | FileCheck %s
 
 ;CHECK-LABEL: @b
 ;CHECK: [[Loop1:for\.end.*]]:                              ; preds = %for.cond.us

test/Transforms/LoopUnswitch/exponential-behavior.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -loop-unswitch -S < %s | FileCheck %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s | FileCheck %s
 
 define void @f(i32 %n, i32* %ptr) {
 ; CHECK-LABEL: @f(

test/Transforms/LoopUnswitch/guards.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -S -loop-unswitch < %s | FileCheck %s
+; RUN: opt -S -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 
 declare void @llvm.experimental.guard(i1, ...)
 

test/Transforms/LoopUnswitch/infinite-loop.ll

@@ -1,5 +1,6 @@
 ; REQUIRES: asserts
 ; RUN: opt -loop-unswitch -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output -stats -info-output-file - < %s | FileCheck --check-prefix=STATS %s
 ; RUN: opt -loop-unswitch -simplifycfg -S < %s | FileCheck %s
 ; PR5373
 

test/Transforms/LoopUnswitch/invalidate-scev.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -S -indvars -loop-unswitch < %s | FileCheck %s
+; RUN: opt -S -indvars -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa < %s | FileCheck %s
 
 target triple = "x86_64-unknown-linux-gnu"
 

test/Transforms/LoopUnswitch/msan.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -verify-loop-info -S < %s 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -verify-loop-info -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
 
 @sink = global i32 0, align 4
 @y = global i64 0, align 8

test/Transforms/LoopUnswitch/pr32818.ll

@@ -1,6 +1,7 @@
 ; Check that the call doesn't get removed even if
 ; it has no uses. It could have side-effects.
 ; RUN: opt -loop-unswitch -S %s | FileCheck %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -S %s | FileCheck %s
 
 ; CHECK-LABEL: @tinky
 define i32 @tinkywinky(i8 %patatino) {

test/Transforms/LoopUnswitch/preserve-analyses.ll

@@ -1,4 +1,5 @@
 ; RUN: opt -loop-unswitch -verify-loop-info -verify-dom-info -disable-output < %s
+; RUN: opt -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -verify-loop-info -verify-dom-info -disable-output < %s
 
 ; Loop unswitch should be able to unswitch these loops and
 ; preserve LCSSA and LoopSimplify forms.

test/Transforms/LoopUnswitch/simplify-with-nonvalness.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -verify-loop-info -S < %s 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -verify-loop-info -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
 
 ; There are 1 case and 1 default case in the switch. after we unswitch, we know the
 ; %a is definitely not 0 in one of the unswitched loop, make sure we take advantage

test/Transforms/LoopUnswitch/trivial-unswitch.ll

@@ -1,4 +1,5 @@
 ; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -verify-loop-info -S < %s 2>&1 | FileCheck %s
+; RUN: opt < %s -loop-unswitch -loop-unswitch-threshold=0 -verify-loop-info -enable-mssa-loop-dependency=true -verify-memoryssa -S < %s 2>&1 | FileCheck %s
 
 ; This test contains two trivial unswitch condition in one loop. 
 ; LoopUnswitch pass should be able to unswitch the second one 

test/Transforms/LoopUnswitch/unswitch-equality-undef.ll

@@ -1,5 +1,5 @@
 ; REQUIRES: asserts
-; RUN: opt < %s -instcombine -licm -loop-unswitch -loop-unswitch-threshold=1000 -disable-output -stats 2>&1| FileCheck %s
+; RUN: opt < %s -instcombine -licm -loop-unswitch -loop-unswitch-threshold=1000 -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output -stats 2>&1| FileCheck %s
 ; Check no loop unswitch is done because unswitching of equality expr with
 ; undef is unsafe before the freeze patch is committed.
 ; CHECK-NOT: Number of branches unswitched

test/Transforms/LoopUnswitch/unswitch-select.ll

@@ -1,5 +1,6 @@
 ; REQUIRES: asserts
 ; RUN: opt < %s -loop-unswitch -disable-output -stats 2>&1| FileCheck %s
+; RUN: opt < %s -loop-unswitch -enable-mssa-loop-dependency=true -verify-memoryssa -disable-output -stats 2>&1| FileCheck %s
 
 ; Check the select statement in the loop will be unswitched.
 ; CHECK: 1 loop-unswitch - Number of selects unswitched