Index: include/llvm/CodeGen/MachineInstr.h
===================================================================
--- include/llvm/CodeGen/MachineInstr.h
+++ include/llvm/CodeGen/MachineInstr.h
@@ -1169,6 +1169,12 @@
     assert(NumMemRefs == NewMemRefsEnd - NewMemRefs && "Too many memrefs");
   }
 
+  /// clearMemRefs - Clear this MachineInstr's memory reference descriptor list.
+  void clearMemRefs() {
+    MemRefs = nullptr;
+    NumMemRefs = 0;
+  }
+
 private:
   /// getRegInfo - If this instruction is embedded into a MachineFunction,
   /// return the MachineRegisterInfo object for the current function, otherwise
Index: lib/CodeGen/BranchFolding.cpp
===================================================================
--- lib/CodeGen/BranchFolding.cpp
+++ lib/CodeGen/BranchFolding.cpp
@@ -24,6 +24,7 @@
 #include "llvm/CodeGen/MachineBranchProbabilityInfo.h"
 #include "llvm/CodeGen/MachineFunctionPass.h"
 #include "llvm/CodeGen/MachineJumpTableInfo.h"
+#include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/MachineModuleInfo.h"
 #include "llvm/CodeGen/MachineRegisterInfo.h"
 #include "llvm/CodeGen/Passes.h"
@@ -727,6 +728,99 @@
   return true;
 }
 
+static bool hasIdenticalMMOs(const MachineInstr *MI1,
+                             const MachineInstr *MI2) {
+  auto MMOI1 = MI1->memoperands_begin(), MMOE1 = MI1->memoperands_end();
+  auto MMOI2 = MI2->memoperands_begin(), MMOE2 = MI2->memoperands_end();
+
+  if ((MMOE1 - MMOI1) != (MMOE2 - MMOI2))
+    return false;
+
+  for (; MMOI1 != MMOE1; ++MMOI1, ++MMOI2) {
+    const Value *V1 = (*MMOI1)->getValue();
+    const Value *V2 = (*MMOI2)->getValue();
+
+    if (V1 != V2)
+      return false;
+
+    // And check all other MMO fields.
+    if ((*MMOI1)->getPseudoValue() != (*MMOI2)->getPseudoValue())
+      return false;
+
+    if ((*MMOI1)->getSize() != (*MMOI2)->getSize())
+      return false;
+
+    if ((*MMOI1)->getOffset() != (*MMOI2)->getOffset())
+      return false;
+
+    if ((*MMOI1)->getFlags() != (*MMOI2)->getFlags())
+      return false;
+
+    if ((*MMOI1)->getAAInfo() != (*MMOI2)->getAAInfo())
+      return false;
+
+    if ((*MMOI1)->getRanges() != (*MMOI2)->getRanges())
+      return false;
+
+    if ((*MMOI1)->getAlignment() != (*MMOI2)->getAlignment())
+      return false;
+
+    if ((*MMOI1)->getBaseAlignment() != (*MMOI2)->getBaseAlignment())
+      return false;
+
+    if ((*MMOI1)->getAddrSpace() != (*MMOI2)->getAddrSpace())
+      return false;
+  }
+
+  return true;
+}
+
+static void removeMMOsFromMemoryOperations(
+ MachineBasicBlock::iterator MBBIStartPos,
+ MachineBasicBlock &MBBCommon) {
+  // Remove MMOs from memory operations in the common block
+  // when they do not match the ones from the block being tail-merged.
+  // This ensures later passes conservatively compute dependencies.
+  MachineBasicBlock *MBB = MBBIStartPos->getParent();
+  // Note CommonTailLen does not necessarily matches the size of
+  // the common BB nor all its instructions because of debug
+  // instructions differences.
+  unsigned CommonTailLen = 0;
+  for (auto E = MBB->end(); MBBIStartPos != E; ++MBBIStartPos)
+    ++CommonTailLen;
+
+  MachineBasicBlock::reverse_iterator MBBI = MBB->rbegin();
+  MachineBasicBlock::reverse_iterator MBBICommon = MBBCommon.rbegin();
+  MachineBasicBlock::reverse_iterator MBBIE = MBB->rend();
+  MachineBasicBlock::reverse_iterator MBBIECommon = MBBCommon.rend();
+
+  while (CommonTailLen--) {
+    assert(MBBI != MBBIE && "Reached BB end within common tail length!");
+    (void)MBBIE;
+
+    if (MBBI->isDebugValue()) {
+      ++MBBI;
+      continue;
+    }
+
+    while (MBBICommon->isDebugValue())
+      ++MBBICommon;
+
+    assert(MBBICommon != MBBIECommon &&
+      "Reached BB end within common tail length!");
+    (void)MBBIECommon;
+
+    assert(MBBICommon->isIdenticalTo(&*MBBI) && "Expected matching MIIs!");
+
+    if (MBBICommon->mayLoad() || MBBICommon->mayStore())
+      if (!hasIdenticalMMOs(&*MBBI, &*MBBICommon))
+        MBBICommon->clearMemRefs();
+
+    ++MBBI;
+    ++MBBICommon;
+  }
+}
+
 // See if any of the blocks in MergePotentials (which all have a common single
 // successor, or all have no successor) can be tail-merged.  If there is a
 // successor, any blocks in MergePotentials that are not tail-merged and
@@ -840,6 +934,8 @@
         continue;
       DEBUG(dbgs() << "BB#" << SameTails[i].getBlock()->getNumber()
                    << (i == e-1 ? "" : ", "));
+      // Remove MMOs from memory operations as needed.
+      removeMMOsFromMemoryOperations(SameTails[i].getTailStartPos(), *MBB);
       // Hack the end off BB i, making it jump to BB commonTailIndex instead.
       ReplaceTailWithBranchTo(SameTails[i].getTailStartPos(), MBB);
       // BB i is no longer a predecessor of SuccBB; remove it from the worklist.