[MI] Change the array of `MachineMemOperand` pointers to be

a generically extensible collection of extra info attached to
a `MachineInstr`.

The primary change here is cleaning up the APIs used for setting and
manipulating the `MachineMemOperand` pointer arrays so chat we can
change how they are allocated.

Then we introduce an extra info object that using the trailing object
pattern to attach some number of MMOs but also other extra info. The
design of this is specifically so that this extra info has a fixed
necessary cost (the header tracking what extra info is included) and
everything else can be tail allocated. This pattern works especially
well with a `BumpPtrAllocator` which we use here.

I've also added the basic scaffolding for putting interesting pointers
into this, namely pre- and post-instruction symbols. These aren't used
anywhere yet, they're just there to ensure I've actually gotten the data
structure types correct. I'll flesh out support for these in
a subsequent patch (MIR dumping, parsing, the works).

Finally, I've included an optimization where we store any single pointer
inline in the `MachineInstr` to avoid the allocation overhead. This is
expected to be the overwhelmingly most common case and so should avoid
any memory usage growth due to slightly less clever / dense allocation
when dealing with >1 MMO. This did require several ergonomic
improvements to the `PointerSumType` to reasonably support the various
usage models.

This also has a side effect of freeing up 8 bits within the
`MachineInstr` which could be repurposed for something else.

The suggested direction here came largely from Hal Finkel. I hope it was
worth it. ;] It does hopefully clear a path for subsequent extensions
w/o nearly as much leg work. Lots of thanks to Reid and Justin for
careful reviews and ideas about how to do all of this.

Differential Revision: https://reviews.llvm.org/D50701

llvm-svn: 339940

12 files changed, 192 insertions, 162 deletions

diff --git a/llvm/lib/CodeGen/BranchFolding.cpp b/llvm/lib/CodeGen/BranchFolding.cpp
index c7a0c645716..fa027eedd4d 100644
--- a/llvm/lib/CodeGen/BranchFolding.cpp
+++ b/llvm/lib/CodeGen/BranchFolding.cpp
@@ -865,7 +865,7 @@ mergeOperations(MachineBasicBlock::iterator MBBIStartPos,
 
     // Merge MMOs from memory operations in the common block.
     if (MBBICommon->mayLoad() || MBBICommon->mayStore())
-      MBBICommon->setMemRefs(MBBICommon->mergeMemRefsWith(*MBBI));
+      MBBICommon->cloneMergedMemRefs(*MBB->getParent(), {&*MBBICommon, &*MBBI});
     // Drop undef flags if they aren't present in all merged instructions.
     for (unsigned I = 0, E = MBBICommon->getNumOperands(); I != E; ++I) {
       MachineOperand &MO = MBBICommon->getOperand(I);
diff --git a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
index 8559d6055cc..74f51cc7292 100644
--- a/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/IRTranslator.cpp
@@ -706,13 +706,12 @@ void IRTranslator::getStackGuard(unsigned DstReg,
     return;
 
   MachinePointerInfo MPInfo(Global);
-  MachineInstr::mmo_iterator MemRefs = MF->allocateMemRefsArray(1);
   auto Flags = MachineMemOperand::MOLoad | MachineMemOperand::MOInvariant |
                MachineMemOperand::MODereferenceable;
-  *MemRefs =
+  MachineMemOperand *MemRef =
       MF->getMachineMemOperand(MPInfo, Flags, DL->getPointerSizeInBits() / 8,
                                DL->getPointerABIAlignment(0));
-  MIB.setMemRefs(MemRefs, MemRefs + 1);
+  MIB.setMemRefs({MemRef});
 }
 
 bool IRTranslator::translateOverflowIntrinsic(const CallInst &CI, unsigned Op,
diff --git a/llvm/lib/CodeGen/ImplicitNullChecks.cpp b/llvm/lib/CodeGen/ImplicitNullChecks.cpp
index 0a447bc613b..558dbb08b22 100644
--- a/llvm/lib/CodeGen/ImplicitNullChecks.cpp
+++ b/llvm/lib/CodeGen/ImplicitNullChecks.cpp
@@ -651,7 +651,7 @@ MachineInstr *ImplicitNullChecks::insertFaultingInstr(
     }
   }
 
-  MIB.setMemRefs(MI->memoperands_begin(), MI->memoperands_end());
+  MIB.setMemRefs(MI->memoperands());
 
   return MIB;
 }
diff --git a/llvm/lib/CodeGen/MIRParser/MIParser.cpp b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
index a61e7872f1a..86d4a380ac7 100644
--- a/llvm/lib/CodeGen/MIRParser/MIParser.cpp
+++ b/llvm/lib/CodeGen/MIRParser/MIParser.cpp
@@ -797,10 +797,7 @@ bool MIParser::parse(MachineInstr *&MI) {
     return true;
   if (MemOperands.empty())
     return false;
-  MachineInstr::mmo_iterator MemRefs =
-      MF.allocateMemRefsArray(MemOperands.size());
-  std::copy(MemOperands.begin(), MemOperands.end(), MemRefs);
-  MI->setMemRefs(MemRefs, MemRefs + MemOperands.size());
+  MI->setMemRefs(MF, MemOperands);
   return false;
 }
 
diff --git a/llvm/lib/CodeGen/MachineFunction.cpp b/llvm/lib/CodeGen/MachineFunction.cpp
index dd668bcf619..1b15819cd50 100644
--- a/llvm/lib/CodeGen/MachineFunction.cpp
+++ b/llvm/lib/CodeGen/MachineFunction.cpp
@@ -406,77 +406,12 @@ MachineFunction::getMachineMemOperand(const MachineMemOperand *MMO,
                                MMO->getOrdering(), MMO->getFailureOrdering());
 }
 
-MachineInstr::mmo_iterator
-MachineFunction::allocateMemRefsArray(unsigned long Num) {
-  return Allocator.Allocate<MachineMemOperand *>(Num);
-}
-
-std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
-MachineFunction::extractLoadMemRefs(MachineInstr::mmo_iterator Begin,
-                                    MachineInstr::mmo_iterator End) {
-  // Count the number of load mem refs.
-  unsigned Num = 0;
-  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
-    if ((*I)->isLoad())
-      ++Num;
-
-  // Allocate a new array and populate it with the load information.
-  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
-  unsigned Index = 0;
-  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
-    if ((*I)->isLoad()) {
-      if (!(*I)->isStore())
-        // Reuse the MMO.
-        Result[Index] = *I;
-      else {
-        // Clone the MMO and unset the store flag.
-        MachineMemOperand *JustLoad =
-          getMachineMemOperand((*I)->getPointerInfo(),
-                               (*I)->getFlags() & ~MachineMemOperand::MOStore,
-                               (*I)->getSize(), (*I)->getBaseAlignment(),
-                               (*I)->getAAInfo(), nullptr,
-                               (*I)->getSyncScopeID(), (*I)->getOrdering(),
-                               (*I)->getFailureOrdering());
-        Result[Index] = JustLoad;
-      }
-      ++Index;
-    }
-  }
-  return std::make_pair(Result, Result + Num);
-}
-
-std::pair<MachineInstr::mmo_iterator, MachineInstr::mmo_iterator>
-MachineFunction::extractStoreMemRefs(MachineInstr::mmo_iterator Begin,
-                                     MachineInstr::mmo_iterator End) {
-  // Count the number of load mem refs.
-  unsigned Num = 0;
-  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I)
-    if ((*I)->isStore())
-      ++Num;
-
-  // Allocate a new array and populate it with the store information.
-  MachineInstr::mmo_iterator Result = allocateMemRefsArray(Num);
-  unsigned Index = 0;
-  for (MachineInstr::mmo_iterator I = Begin; I != End; ++I) {
-    if ((*I)->isStore()) {
-      if (!(*I)->isLoad())
-        // Reuse the MMO.
-        Result[Index] = *I;
-      else {
-        // Clone the MMO and unset the load flag.
-        MachineMemOperand *JustStore =
-          getMachineMemOperand((*I)->getPointerInfo(),
-                               (*I)->getFlags() & ~MachineMemOperand::MOLoad,
-                               (*I)->getSize(), (*I)->getBaseAlignment(),
-                               (*I)->getAAInfo(), nullptr,
-                               (*I)->getSyncScopeID(), (*I)->getOrdering(),
-                               (*I)->getFailureOrdering());
-        Result[Index] = JustStore;
-      }
-      ++Index;
-    }
-  }
-  return std::make_pair(Result, Result + Num);
+MachineInstr::ExtraInfo *
+MachineFunction::createMIExtraInfo(ArrayRef<MachineMemOperand *> MMOs,
+                                   MCSymbol *PreInstrSymbol,
+                                   MCSymbol *PostInstrSymbol) {
+  return MachineInstr::ExtraInfo::create(Allocator, MMOs, PreInstrSymbol,
+                                         PostInstrSymbol);
 }
 
 const char *MachineFunction::createExternalSymbolName(StringRef Name) {
diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 96fcfdb72ad..fb1d392e01b 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -131,8 +131,7 @@ MachineInstr::MachineInstr(MachineFunction &MF, const MCInstrDesc &tid,
 /// MachineInstr ctor - Copies MachineInstr arg exactly
 ///
 MachineInstr::MachineInstr(MachineFunction &MF, const MachineInstr &MI)
-    : MCID(&MI.getDesc()), NumMemRefs(MI.NumMemRefs), MemRefs(MI.MemRefs),
-      debugLoc(MI.getDebugLoc()) {
+    : MCID(&MI.getDesc()), Info(MI.Info), debugLoc(MI.getDebugLoc()) {
   assert(debugLoc.hasTrivialDestructor() && "Expected trivial destructor");
 
   CapOperands = OperandCapacity::get(MI.getNumOperands());
@@ -315,71 +314,178 @@ void MachineInstr::RemoveOperand(unsigned OpNo) {
   --NumOperands;
 }
 
-/// addMemOperand - Add a MachineMemOperand to the machine instruction.
-/// This function should be used only occasionally. The setMemRefs function
-/// is the primary method for setting up a MachineInstr's MemRefs list.
+void MachineInstr::dropMemRefs(MachineFunction &MF) {
+  if (memoperands_empty())
+    return;
+
+  // See if we can just drop all of our extra info.
+  if (!getPreInstrSymbol() && !getPostInstrSymbol()) {
+    Info.clear();
+    return;
+  }
+  if (!getPostInstrSymbol()) {
+    Info.set<EIIK_PreInstrSymbol>(getPreInstrSymbol());
+    return;
+  }
+  if (!getPreInstrSymbol()) {
+    Info.set<EIIK_PostInstrSymbol>(getPostInstrSymbol());
+    return;
+  }
+
+  // Otherwise allocate a fresh extra info with just these symbols.
+  Info.set<EIIK_OutOfLine>(
+      MF.createMIExtraInfo({}, getPreInstrSymbol(), getPostInstrSymbol()));
+}
+
+void MachineInstr::setMemRefs(MachineFunction &MF,
+                              ArrayRef<MachineMemOperand *> MMOs) {
+  if (MMOs.empty()) {
+    dropMemRefs(MF);
+    return;
+  }
+
+  // Try to store a single MMO inline.
+  if (MMOs.size() == 1 && !getPreInstrSymbol() && !getPostInstrSymbol()) {
+    Info.set<EIIK_MMO>(MMOs[0]);
+    return;
+  }
+
+  // Otherwise create an extra info struct with all of our info.
+  Info.set<EIIK_OutOfLine>(
+      MF.createMIExtraInfo(MMOs, getPreInstrSymbol(), getPostInstrSymbol()));
+}
+
 void MachineInstr::addMemOperand(MachineFunction &MF,
                                  MachineMemOperand *MO) {
-  mmo_iterator OldMemRefs = MemRefs;
-  unsigned OldNumMemRefs = NumMemRefs;
+  SmallVector<MachineMemOperand *, 2> MMOs;
+  MMOs.append(memoperands_begin(), memoperands_end());
+  MMOs.push_back(MO);
+  setMemRefs(MF, MMOs);
+}
 
-  unsigned NewNum = NumMemRefs + 1;
-  mmo_iterator NewMemRefs = MF.allocateMemRefsArray(NewNum);
+void MachineInstr::cloneMemRefs(MachineFunction &MF, const MachineInstr &MI) {
+  if (this == &MI)
+    // Nothing to do for a self-clone!
+    return;
+
+  assert(&MF == MI.getMF() &&
+         "Invalid machine functions when cloning memory refrences!");
+  // See if we can just steal the extra info already allocated for the
+  // instruction. We can do this whenever the pre- and post-instruction symbols
+  // are the same (including null).
+  if (getPreInstrSymbol() == MI.getPreInstrSymbol() &&
+      getPostInstrSymbol() == MI.getPostInstrSymbol()) {
+    Info = MI.Info;
+    return;
+  }
 
-  std::copy(OldMemRefs, OldMemRefs + OldNumMemRefs, NewMemRefs);
-  NewMemRefs[NewNum - 1] = MO;
-  setMemRefs(NewMemRefs, NewMemRefs + NewNum);
+  // Otherwise, fall back on a copy-based clone.
+  setMemRefs(MF, MI.memoperands());
 }
 
 /// Check to see if the MMOs pointed to by the two MemRefs arrays are
 /// identical.
-static bool hasIdenticalMMOs(const MachineInstr &MI1, const MachineInstr &MI2) {
-  auto I1 = MI1.memoperands_begin(), E1 = MI1.memoperands_end();
-  auto I2 = MI2.memoperands_begin(), E2 = MI2.memoperands_end();
-  if ((E1 - I1) != (E2 - I2))
+static bool hasIdenticalMMOs(ArrayRef<MachineMemOperand *> LHS,
+                             ArrayRef<MachineMemOperand *> RHS) {
+  if (LHS.size() != RHS.size())
     return false;
-  for (; I1 != E1; ++I1, ++I2) {
-    if (**I1 != **I2)
-      return false;
+
+  auto LHSPointees = make_pointee_range(LHS);
+  auto RHSPointees = make_pointee_range(RHS);
+  return std::equal(LHSPointees.begin(), LHSPointees.end(),
+                    RHSPointees.begin());
+}
+
+void MachineInstr::cloneMergedMemRefs(MachineFunction &MF,
+                                      ArrayRef<const MachineInstr *> MIs) {
+  // Try handling easy numbers of MIs with simpler mechanisms.
+  if (MIs.empty()) {
+    dropMemRefs(MF);
+    return;
   }
-  return true;
+  if (MIs.size() == 1) {
+    cloneMemRefs(MF, *MIs[0]);
+    return;
+  }
+  // Because an empty memoperands list provides *no* information and must be
+  // handled conservatively (assuming the instruction can do anything), the only
+  // way to merge with it is to drop all other memoperands.
+  if (MIs[0]->memoperands_empty()) {
+    dropMemRefs(MF);
+    return;
+  }
+
+  // Handle the general case.
+  SmallVector<MachineMemOperand *, 2> MergedMMOs;
+  // Start with the first instruction.
+  assert(&MF == MIs[0]->getMF() &&
+         "Invalid machine functions when cloning memory references!");
+  MergedMMOs.append(MIs[0]->memoperands_begin(), MIs[0]->memoperands_end());
+  // Now walk all the other instructions and accumulate any different MMOs.
+  for (const MachineInstr &MI : make_pointee_range(MIs.slice(1))) {
+    assert(&MF == MI.getMF() &&
+           "Invalid machine functions when cloning memory references!");
+
+    // Skip MIs with identical operands to the first. This is a somewhat
+    // arbitrary hack but will catch common cases without being quadratic.
+    // TODO: We could fully implement merge semantics here if needed.
+    if (hasIdenticalMMOs(MIs[0]->memoperands(), MI.memoperands()))
+      continue;
+
+    // Because an empty memoperands list provides *no* information and must be
+    // handled conservatively (assuming the instruction can do anything), the
+    // only way to merge with it is to drop all other memoperands.
+    if (MI.memoperands_empty()) {
+      dropMemRefs(MF);
+      return;
+    }
+
+    // Otherwise accumulate these into our temporary buffer of the merged state.
+    MergedMMOs.append(MI.memoperands_begin(), MI.memoperands_end());
+  }
+
+  setMemRefs(MF, MergedMMOs);
 }
 
-std::pair<MachineInstr::mmo_iterator, unsigned>
-MachineInstr::mergeMemRefsWith(const MachineInstr& Other) {
-
-  // If either of the incoming memrefs are empty, we must be conservative and
-  // treat this as if we've exhausted our space for memrefs and dropped them.
-  if (memoperands_empty() || Other.memoperands_empty())
-    return std::make_pair(nullptr, 0);
-
-  // If both instructions have identical memrefs, we don't need to merge them.
-  // Since many instructions have a single memref, and we tend to merge things
-  // like pairs of loads from the same location, this catches a large number of
-  // cases in practice.
-  if (hasIdenticalMMOs(*this, Other))
-    return std::make_pair(MemRefs, NumMemRefs);
-
-  // TODO: consider uniquing elements within the operand lists to reduce
-  // space usage and fall back to conservative information less often.
-  size_t CombinedNumMemRefs = NumMemRefs + Other.NumMemRefs;
-
-  // If we don't have enough room to store this many memrefs, be conservative
-  // and drop them.  Otherwise, we'd fail asserts when trying to add them to
-  // the new instruction.
-  if (CombinedNumMemRefs != uint8_t(CombinedNumMemRefs))
-    return std::make_pair(nullptr, 0);
-
-  MachineFunction *MF = getMF();
-  mmo_iterator MemBegin = MF->allocateMemRefsArray(CombinedNumMemRefs);
-  mmo_iterator MemEnd = std::copy(memoperands_begin(), memoperands_end(),
-                                  MemBegin);
-  MemEnd = std::copy(Other.memoperands_begin(), Other.memoperands_end(),
-                     MemEnd);
-  assert(MemEnd - MemBegin == (ptrdiff_t)CombinedNumMemRefs &&
-         "missing memrefs");
-
-  return std::make_pair(MemBegin, CombinedNumMemRefs);
+MCSymbol *MachineInstr::getOrCreatePreInstrTempSymbol(MCContext &MCCtx) {
+  MCSymbol *S = getPreInstrSymbol();
+  if (S)
+    return S;
+
+  // Create a new temp symbol.
+  S = MCCtx.createTempSymbol();
+
+  if (!Info) {
+    // If we don't have any other extra info, we can store this inline.
+    Info.set<EIIK_PreInstrSymbol>(S);
+    return S;
+  }
+
+  // Otherwise, allocate a fully set of extra info.
+  Info.set<EIIK_OutOfLine>(
+      getMF()->createMIExtraInfo(memoperands(), S, getPostInstrSymbol()));
+
+  return S;
+}
+
+MCSymbol *MachineInstr::getOrCreatePostInstrTempSymbol(MCContext &MCCtx) {
+  MCSymbol *S = getPostInstrSymbol();
+  if (S)
+    return S;
+
+  // Create a new temp symbol.
+  S = MCCtx.createTempSymbol();
+
+  if (!Info) {
+    // If we don't have any other extra info, we can store this inline.
+    Info.set<EIIK_PostInstrSymbol>(S);
+    return S;
+  }
+
+  // Otherwise, allocate a fully set of extra info.
+  Info.set<EIIK_OutOfLine>(
+      getMF()->createMIExtraInfo(memoperands(), getPreInstrSymbol(), S));
+  return S;
 }
 
 uint16_t MachineInstr::mergeFlagsWith(const MachineInstr &Other) const {
diff --git a/llvm/lib/CodeGen/MachineOutliner.cpp b/llvm/lib/CodeGen/MachineOutliner.cpp
index a712afec095..b5a4dbf6af6 100644
--- a/llvm/lib/CodeGen/MachineOutliner.cpp
+++ b/llvm/lib/CodeGen/MachineOutliner.cpp
@@ -1197,7 +1197,7 @@ MachineOutliner::createOutlinedFunction(Module &M, const OutlinedFunction &OF,
   for (unsigned Str : OF.Sequence) {
     MachineInstr *NewMI =
         MF.CloneMachineInstr(Mapper.IntegerInstructionMap.find(Str)->second);
-    NewMI->dropMemRefs();
+    NewMI->dropMemRefs(MF);
 
     // Don't keep debug information for outlined instructions.
     NewMI->setDebugLoc(DebugLoc());
diff --git a/llvm/lib/CodeGen/MachinePipeliner.cpp b/llvm/lib/CodeGen/MachinePipeliner.cpp
index 9bb00aaef86..943a2b42200 100644
--- a/llvm/lib/CodeGen/MachinePipeliner.cpp
+++ b/llvm/lib/CodeGen/MachinePipeliner.cpp
@@ -3175,28 +3175,26 @@ void SwingSchedulerDAG::updateMemOperands(MachineInstr &NewMI,
     return;
   // If the instruction has memory operands, then adjust the offset
   // when the instruction appears in different stages.
-  unsigned NumRefs = NewMI.memoperands_end() - NewMI.memoperands_begin();
-  if (NumRefs == 0)
+  if (NewMI.memoperands_empty())
     return;
-  MachineInstr::mmo_iterator NewMemRefs = MF.allocateMemRefsArray(NumRefs);
-  unsigned Refs = 0;
+  SmallVector<MachineMemOperand *, 2> NewMMOs;
   for (MachineMemOperand *MMO : NewMI.memoperands()) {
     if (MMO->isVolatile() || (MMO->isInvariant() && MMO->isDereferenceable()) ||
         (!MMO->getValue())) {
-      NewMemRefs[Refs++] = MMO;
+      NewMMOs.push_back(MMO);
       continue;
     }
     unsigned Delta;
     if (Num != UINT_MAX && computeDelta(OldMI, Delta)) {
       int64_t AdjOffset = Delta * Num;
-      NewMemRefs[Refs++] =
-          MF.getMachineMemOperand(MMO, AdjOffset, MMO->getSize());
+      NewMMOs.push_back(
+          MF.getMachineMemOperand(MMO, AdjOffset, MMO->getSize()));
     } else {
-      NewMI.dropMemRefs();
+      NewMI.dropMemRefs(MF);
       return;
     }
   }
-  NewMI.setMemRefs(NewMemRefs, NewMemRefs + NumRefs);
+  NewMI.setMemRefs(MF, NewMMOs);
 }
 
 /// Clone the instruction for the new pipelined loop and update the
diff --git a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
index 1b0dac76613..6b843f9db59 100644
--- a/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/InstrEmitter.cpp
@@ -886,12 +886,9 @@ EmitMachineNode(SDNode *Node, bool IsClone, bool IsCloned,
       MIB.addReg(ScratchRegs[i], RegState::ImplicitDefine |
                                  RegState::EarlyClobber);
 
-  // Transfer all of the memory reference descriptions of this instruction.
-  ArrayRef<MachineMemOperand *> SDNodeMemRefs =
-      cast<MachineSDNode>(Node)->memoperands();
-  MachineMemOperand **MemRefs = MF->allocateMemRefsArray(SDNodeMemRefs.size());
-  std::copy(SDNodeMemRefs.begin(), SDNodeMemRefs.end(), MemRefs);
-  MIB.setMemRefs({MemRefs, SDNodeMemRefs.size()});
+  // Set the memory reference descriptions of this instruction now that it is
+  // part of the function.
+  MIB.setMemRefs(cast<MachineSDNode>(Node)->memoperands());
 
   // Insert the instruction into position in the block. This needs to
   // happen before any custom inserter hook is called so that the
diff --git a/llvm/lib/CodeGen/StackColoring.cpp b/llvm/lib/CodeGen/StackColoring.cpp
index ff7dc211025..33733661ea6 100644
--- a/llvm/lib/CodeGen/StackColoring.cpp
+++ b/llvm/lib/CodeGen/StackColoring.cpp
@@ -1022,9 +1022,7 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
       }
 
       // We adjust AliasAnalysis information for merged stack slots.
-      MachineInstr::mmo_iterator NewMemOps =
-          MF->allocateMemRefsArray(I.getNumMemOperands());
-      unsigned MemOpIdx = 0;
+      SmallVector<MachineMemOperand *, 2> NewMMOs;
       bool ReplaceMemOps = false;
       for (MachineMemOperand *MMO : I.memoperands()) {
         // If this memory location can be a slot remapped here,
@@ -1051,17 +1049,17 @@ void StackColoring::remapInstructions(DenseMap<int, int> &SlotRemap) {
           }
         }
         if (MayHaveConflictingAAMD) {
-          NewMemOps[MemOpIdx++] = MF->getMachineMemOperand(MMO, AAMDNodes());
+          NewMMOs.push_back(MF->getMachineMemOperand(MMO, AAMDNodes()));
           ReplaceMemOps = true;
+        } else {
+          NewMMOs.push_back(MMO);
         }
-        else
-          NewMemOps[MemOpIdx++] = MMO;
       }
 
       // If any memory operand is updated, set memory references of
       // this instruction.
       if (ReplaceMemOps)
-        I.setMemRefs(std::make_pair(NewMemOps, I.getNumMemOperands()));
+        I.setMemRefs(*MF, NewMMOs);
     }
 
   // Update the location of C++ catch objects for the MSVC personality routine.
diff --git a/llvm/lib/CodeGen/TargetInstrInfo.cpp b/llvm/lib/CodeGen/TargetInstrInfo.cpp
index 034ad9a4982..19670c24ae8 100644
--- a/llvm/lib/CodeGen/TargetInstrInfo.cpp
+++ b/llvm/lib/CodeGen/TargetInstrInfo.cpp
@@ -583,7 +583,7 @@ MachineInstr *TargetInstrInfo::foldMemoryOperand(MachineInstr &MI,
   }
 
   if (NewMI) {
-    NewMI->setMemRefs(MI.memoperands_begin(), MI.memoperands_end());
+    NewMI->setMemRefs(MF, MI.memoperands());
     // Add a memory operand, foldMemoryOperandImpl doesn't do that.
     assert((!(Flags & MachineMemOperand::MOStore) ||
             NewMI->mayStore()) &&
@@ -653,10 +653,10 @@ MachineInstr *TargetInstrInfo::foldMemoryOperand(MachineInstr &MI,
 
   // Copy the memoperands from the load to the folded instruction.
   if (MI.memoperands_empty()) {
-    NewMI->setMemRefs(LoadMI.memoperands_begin(), LoadMI.memoperands_end());
+    NewMI->setMemRefs(MF, LoadMI.memoperands());
   } else {
     // Handle the rare case of folding multiple loads.
-    NewMI->setMemRefs(MI.memoperands_begin(), MI.memoperands_end());
+    NewMI->setMemRefs(MF, MI.memoperands());
     for (MachineInstr::mmo_iterator I = LoadMI.memoperands_begin(),
                                     E = LoadMI.memoperands_end();
          I != E; ++I) {
diff --git a/llvm/lib/CodeGen/TargetLoweringBase.cpp b/llvm/lib/CodeGen/TargetLoweringBase.cpp
index 7b1b76821da..aeb321f4a42 100644
--- a/llvm/lib/CodeGen/TargetLoweringBase.cpp
+++ b/llvm/lib/CodeGen/TargetLoweringBase.cpp
@@ -968,7 +968,7 @@ TargetLoweringBase::emitPatchPoint(MachineInstr &InitialMI,
       MIB.add(MI->getOperand(i));
 
     // Inherit previous memory operands.
-    MIB->setMemRefs(MI->memoperands_begin(), MI->memoperands_end());
+    MIB.cloneMemRefs(*MI);
     assert(MIB->mayLoad() && "Folded a stackmap use to a non-load!");
 
     // Add a new memory operand for this FI.