Index: lib/Transforms/Scalar/LICM.cpp
===================================================================
--- lib/Transforms/Scalar/LICM.cpp
+++ lib/Transforms/Scalar/LICM.cpp
@@ -1191,30 +1191,39 @@
     } else { // MSSAU
       if (isOnlyMemoryAccess(SI, CurLoop, MSSAU))
         return true;
+      // If there are more accesses than the Promotion cap, give up, we're not
+      // walking a list that long.
+      if (NoOfMemAccTooLarge)
+        return false;
+      // Check store only if there's still "quota" to check clobber.
       if (*LicmMssaOptCounter < LicmMssaOptCap) {
-        auto *Source = MSSA->getSkipSelfWalker()->getClobberingMemoryAccess(SI);
-        (*LicmMssaOptCounter)++;
-        // If there are no clobbering Defs in the loop, we still need to check
-        // for interfering Uses. If there are more accesses than the Promotion
-        // cap, give up, we're not walking a list that long. Otherwise, walk the
-        // list, check each Use if it's optimized to an access outside the loop.
-        // If yes, store is safe to hoist. This is fairly restrictive, but
-        // conservatively correct.
+        // If there are interfering Uses (i.e. their defining access is in the
+        // loop), or ordered loads (stored as Defs!), don't move this store.
+        // Could do better here, but this is conservatively correct.
         // TODO: Cache set of Uses on the first walk in runOnLoop, update when
         // moving accesses. Can also extend to dominating uses.
-        if ((!MSSA->isLiveOnEntryDef(Source) &&
-             CurLoop->contains(Source->getBlock())) ||
-            NoOfMemAccTooLarge)
-          return false;
         for (auto *BB : CurLoop->getBlocks())
           if (auto *Accesses = MSSA->getBlockAccesses(BB))
-            for (const auto &MA : *Accesses)
+            for (const auto &MA : *Accesses) {
               if (const auto *MU = dyn_cast<MemoryUse>(&MA)) {
                 auto *MD = MU->getDefiningAccess();
                 if (!MSSA->isLiveOnEntryDef(MD) &&
                     CurLoop->contains(MD->getBlock()))
                   return false;
+              } else {
+                if (const auto *MD = dyn_cast<MemoryDef>(&MA))
+                  if (auto *LI= dyn_cast<LoadInst>(MD->getMemoryInst()))
+                    if (!LI->isUnordered())
+                      return false;
               }
+            }
+
+        auto *Source = MSSA->getSkipSelfWalker()->getClobberingMemoryAccess(SI);
+        (*LicmMssaOptCounter)++;
+        // If there are no clobbering Defs in the loop, store is safe to hoist.
+        if (!MSSA->isLiveOnEntryDef(Source) &&
+             CurLoop->contains(Source->getBlock()))
+          return false;
         return true;
       }
       return false;
Index: test/Transforms/LICM/hoist-debuginvariant.ll
===================================================================
--- test/Transforms/LICM/hoist-debuginvariant.ll
+++ test/Transforms/LICM/hoist-debuginvariant.ll
@@ -1,6 +1,6 @@
 ; RUN: opt < %s -licm -S | FileCheck %s
 ; RUN: opt < %s -strip-debug -licm -S | FileCheck %s
-; RUN: opt < %s -licm -enable-mssa-loop-dependency=true -verify-memoryssa -S | FileCheck %s --check-prefixes=CHECK,MSSA
+; RUN: opt < %s -licm -enable-mssa-loop-dependency=true -verify-memoryssa -S | FileCheck %s --check-prefixes=CHECK
 
 target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
 target triple = "x86_64-unknown-linux-gnu"
@@ -17,7 +17,6 @@
 ; CHECK-NEXT: [[_TMP2:%.*]] = load i32, i32* @a, align 4
 ; CHECK-NEXT: [[_TMP3:%.*]] = load i32, i32* @b, align 4
 ; CHECK-NEXT: [[_TMP4:%.*]] = sdiv i32 [[_TMP2]], [[_TMP3]]
-; MSSA-NEXT: store i32 [[_TMP4:%.*]], i32* @c, align 4
 ; CHECK-NEXT: br label [[BB3:%.*]]
 
   br label %bb3