Revert 112442 and 112440 until the compile time problems introduced

by 112440 are resolved.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112692 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 134 insertions, 204 deletions

diff --git a/include/llvm/Analysis/IVUsers.h b/include/llvm/Analysis/IVUsers.h
index 7aa34f1cff..578e6aba83 100644
--- a/include/llvm/Analysis/IVUsers.h
+++ b/include/llvm/Analysis/IVUsers.h
@@ -27,7 +27,6 @@ class Value;
 class IVUsers;
 class ScalarEvolution;
 class SCEV;
-class SCEVAddRecExpr;
 class IVUsers;
 
 /// IVStrideUse - Keep track of one use of a strided induction variable.
@@ -123,7 +122,7 @@ class IVUsers : public LoopPass {
   LoopInfo *LI;
   DominatorTree *DT;
   ScalarEvolution *SE;
-  SmallPtrSet<Instruction *, 16> Processed;
+  SmallPtrSet<Instruction*,16> Processed;
 
   /// IVUses - A list of all tracked IV uses of induction variable expressions
   /// we are interested in.
@@ -135,16 +134,14 @@ class IVUsers : public LoopPass {
 
   virtual void releaseMemory();
 
-  const SCEVAddRecExpr *findInterestingAddRec(const SCEV *S) const;
-  bool isInterestingUser(const Instruction *User) const;
-
 public:
   static char ID; // Pass ID, replacement for typeid
   IVUsers();
 
-  /// AddUsersIfInteresting - Inspect the def-use graph starting at the
-  /// specified Instruction and add IVUsers.
-  void AddUsersIfInteresting(Instruction *I);
+  /// AddUsersIfInteresting - Inspect the specified Instruction.  If it is a
+  /// reducible SCEV, recursively add its users to the IVUsesByStride set and
+  /// return true.  Otherwise, return false.
+  bool AddUsersIfInteresting(Instruction *I);
 
   IVStrideUse &AddUser(Instruction *User, Value *Operand);
 
diff --git a/lib/Analysis/IVUsers.cpp b/lib/Analysis/IVUsers.cpp
index d9bdf5cbb0..fd514336be 100644
--- a/lib/Analysis/IVUsers.cpp
+++ b/lib/Analysis/IVUsers.cpp
@@ -35,123 +35,112 @@ Pass *llvm::createIVUsersPass() {
   return new IVUsers();
 }
 
-/// findInterestingAddRec - Test whether the given expression is interesting.
-/// Return the addrec with the current loop which makes it interesting, or
-/// null if it is not interesting.
-const SCEVAddRecExpr *IVUsers::findInterestingAddRec(const SCEV *S) const {
+/// isInteresting - Test whether the given expression is "interesting" when
+/// used by the given expression, within the context of analyzing the
+/// given loop.
+static bool isInteresting(const SCEV *S, const Instruction *I, const Loop *L,
+                          ScalarEvolution *SE) {
   // An addrec is interesting if it's affine or if it has an interesting start.
   if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(S)) {
     // Keep things simple. Don't touch loop-variant strides.
     if (AR->getLoop() == L)
-      return AR;
-    // We don't yet know how to do effective SCEV expansions for addrecs
-    // with interesting steps.
-    if (findInterestingAddRec(AR->getStepRecurrence(*SE)))
-      return 0;
-    // Otherwise recurse to see if the start value is interesting.
-    return findInterestingAddRec(AR->getStart());
+      return AR->isAffine() || !L->contains(I);
+    // Otherwise recurse to see if the start value is interesting, and that
+    // the step value is not interesting, since we don't yet know how to
+    // do effective SCEV expansions for addrecs with interesting steps.
+    return isInteresting(AR->getStart(), I, L, SE) &&
+          !isInteresting(AR->getStepRecurrence(*SE), I, L, SE);
   }
 
   // An add is interesting if exactly one of its operands is interesting.
   if (const SCEVAddExpr *Add = dyn_cast<SCEVAddExpr>(S)) {
+    bool AnyInterestingYet = false;
     for (SCEVAddExpr::op_iterator OI = Add->op_begin(), OE = Add->op_end();
          OI != OE; ++OI)
-      if (const SCEVAddRecExpr *AR = findInterestingAddRec(*OI))
-        return AR;
-    return 0;
+      if (isInteresting(*OI, I, L, SE)) {
+        if (AnyInterestingYet)
+          return false;
+        AnyInterestingYet = true;
+      }
+    return AnyInterestingYet;
   }
 
   // Nothing else is interesting here.
-  return 0;
+  return false;
 }
 
-bool IVUsers::isInterestingUser(const Instruction *User) const {
-  // Void and FP expressions cannot be reduced.
-  if (!SE->isSCEVable(User->getType()))
-    return false;
+/// AddUsersIfInteresting - Inspect the specified instruction.  If it is a
+/// reducible SCEV, recursively add its users to the IVUsesByStride set and
+/// return true.  Otherwise, return false.
+bool IVUsers::AddUsersIfInteresting(Instruction *I) {
+  if (!SE->isSCEVable(I->getType()))
+    return false;   // Void and FP expressions cannot be reduced.
 
   // LSR is not APInt clean, do not touch integers bigger than 64-bits.
-  if (SE->getTypeSizeInBits(User->getType()) > 64)
+  if (SE->getTypeSizeInBits(I->getType()) > 64)
     return false;
 
-  // Don't descend into PHI nodes outside the current loop.
-  if (LI->getLoopFor(User->getParent()) != L &&
-      isa<PHINode>(User))
-    return false;
+  if (!Processed.insert(I))
+    return true;    // Instruction already handled.
 
-  // Otherwise, it may be interesting.
-  return true;
-}
+  // Get the symbolic expression for this instruction.
+  const SCEV *ISE = SE->getSCEV(I);
 
-/// AddUsersIfInteresting - Inspect the specified instruction.  If it is a
-/// reducible SCEV, recursively add its users to the IVUsesByStride set and
-/// return true.  Otherwise, return false.
-void IVUsers::AddUsersIfInteresting(Instruction *I) {
-  // Stop if we've seen this before.
-  if (!Processed.insert(I))
-    return;
+  // If we've come to an uninteresting expression, stop the traversal and
+  // call this a user.
+  if (!isInteresting(ISE, I, L, SE))
+    return false;
 
-  // If this PHI node is not SCEVable, ignore it.
-  if (!SE->isSCEVable(I->getType()))
-    return;
-
-  // If this PHI node is not an addrec for this loop, ignore it.
-  const SCEVAddRecExpr *Expr = findInterestingAddRec(SE->getSCEV(I));
-  if (!Expr)
-    return;
-
-  // Walk the def-use graph.
-  SmallVector<std::pair<Instruction *, const SCEVAddRecExpr *>, 16> Worklist;
-  Worklist.push_back(std::make_pair(I, Expr));
-  do {
-    std::pair<Instruction *, const SCEVAddRecExpr *> P =
-      Worklist.pop_back_val();
-    Instruction *Op = P.first;
-    const SCEVAddRecExpr *OpAR = P.second;
-
-    // Visit Op's users.
-    SmallPtrSet<Instruction *, 8> VisitedUsers;
-    for (Value::use_iterator UI = Op->use_begin(), E = Op->use_end();
-         UI != E; ++UI) {
-      // Don't visit any individual user more than once.
-      Instruction *User = cast<Instruction>(*UI);
-      if (!VisitedUsers.insert(User))
-        continue;
-
-      // If it's an affine addrec (which we can pretty safely re-expand) inside
-      // the loop, or a potentially non-affine addrec outside the loop (which
-      // we can evaluate outside of the loop), follow it.
-      if (OpAR->isAffine() || !L->contains(User)) {
-        if (isInterestingUser(User)) {
-          const SCEV *UserExpr = SE->getSCEV(User);
-
-          if (const SCEVAddRecExpr *AR = findInterestingAddRec(UserExpr)) {
-            // Interesting. Keep searching.
-            if (Processed.insert(User))
-              Worklist.push_back(std::make_pair(User, AR));
-            continue;
-          }
-        }
+  SmallPtrSet<Instruction *, 4> UniqueUsers;
+  for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+       UI != E; ++UI) {
+    Instruction *User = cast<Instruction>(*UI);
+    if (!UniqueUsers.insert(User))
+      continue;
+
+    // Do not infinitely recurse on PHI nodes.
+    if (isa<PHINode>(User) && Processed.count(User))
+      continue;
+
+    // Descend recursively, but not into PHI nodes outside the current loop.
+    // It's important to see the entire expression outside the loop to get
+    // choices that depend on addressing mode use right, although we won't
+    // consider references outside the loop in all cases.
+    // If User is already in Processed, we don't want to recurse into it again,
+    // but do want to record a second reference in the same instruction.
+    bool AddUserToIVUsers = false;
+    if (LI->getLoopFor(User->getParent()) != L) {
+      if (isa<PHINode>(User) || Processed.count(User) ||
+          !AddUsersIfInteresting(User)) {
+        DEBUG(dbgs() << "FOUND USER in other loop: " << *User << '\n'
+                     << "   OF SCEV: " << *ISE << '\n');
+        AddUserToIVUsers = true;
       }
+    } else if (Processed.count(User) ||
+               !AddUsersIfInteresting(User)) {
+      DEBUG(dbgs() << "FOUND USER: " << *User << '\n'
+                   << "   OF SCEV: " << *ISE << '\n');
+      AddUserToIVUsers = true;
+    }
 
-      // Otherwise, this is the point where the def-use chain
-      // becomes uninteresting. Call it an IV User.
-      AddUser(User, Op);
+    if (AddUserToIVUsers) {
+      // Okay, we found a user that we cannot reduce.
+      IVUses.push_back(new IVStrideUse(this, User, I));
+      IVStrideUse &NewUse = IVUses.back();
+      // Transform the expression into a normalized form.
+      ISE = TransformForPostIncUse(NormalizeAutodetect,
+                                   ISE, User, I,
+                                   NewUse.PostIncLoops,
+                                   *SE, *DT);
+      DEBUG(dbgs() << "   NORMALIZED TO: " << *ISE << '\n');
     }
-  } while (!Worklist.empty());
+  }
+  return true;
 }
 
 IVStrideUse &IVUsers::AddUser(Instruction *User, Value *Operand) {
   IVUses.push_back(new IVStrideUse(this, User, Operand));
-  IVStrideUse &NewUse = IVUses.back();
-
-  // Auto-detect and remember post-inc loops for this expression.
-  const SCEV *S = SE->getSCEV(Operand);
-  (void)TransformForPostIncUse(NormalizeAutodetect,
-                               S, User, Operand,
-                               NewUse.PostIncLoops,
-                               *SE, *DT);
-  return NewUse;
+  return IVUses.back();
 }
 
 IVUsers::IVUsers()
@@ -176,7 +165,7 @@ bool IVUsers::runOnLoop(Loop *l, LPPassManager &LPM) {
   // them by stride.  Start by finding all of the PHI nodes in the header for
   // this loop.  If they are induction variables, inspect their uses.
   for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I)
-    AddUsersIfInteresting(I);
+    (void)AddUsersIfInteresting(I);
 
   return false;
 }
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 4fe93b9d41..e8dc5d3a64 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -113,7 +113,6 @@ class RegUseTracker {
 public:
   void CountRegister(const SCEV *Reg, size_t LUIdx);
   void DropRegister(const SCEV *Reg, size_t LUIdx);
-  void DropUse(size_t LUIdx, size_t NewLUIdx);
   void DropUse(size_t LUIdx);
 
   bool isRegUsedByUsesOtherThan(const SCEV *Reg, size_t LUIdx) const;
@@ -152,24 +151,6 @@ RegUseTracker::DropRegister(const SCEV *Reg, size_t LUIdx) {
   RSD.UsedByIndices.reset(LUIdx);
 }
 
-/// DropUse - Clear out reference by use LUIdx, and prepare for use NewLUIdx
-/// to be swapped into LUIdx's position.
-void
-RegUseTracker::DropUse(size_t LUIdx, size_t NewLUIdx) {
-  // Remove the use index from every register's use list.
-  for (RegUsesTy::iterator I = RegUsesMap.begin(), E = RegUsesMap.end();
-       I != E; ++I) {
-    SmallBitVector &UsedByIndices = I->second.UsedByIndices;
-    UsedByIndices.resize(std::max(UsedByIndices.size(), NewLUIdx + 1));
-    if (LUIdx < UsedByIndices.size()) {
-      UsedByIndices[LUIdx] = UsedByIndices[NewLUIdx];
-      UsedByIndices.reset(NewLUIdx);
-    } else
-      UsedByIndices.reset(LUIdx);
-  }
-}
-
-/// DropUse - Clear out reference by use LUIdx.
 void
 RegUseTracker::DropUse(size_t LUIdx) {
   // Remove the use index from every register's use list.
@@ -1353,9 +1334,7 @@ class LSRInstance {
                    UseMapDenseMapInfo> UseMapTy;
   UseMapTy UseMap;
 
-  bool reconcileNewOffset(LSRUse &LU,
-                          int64_t NewMinOffset, int64_t NewMaxOffset,
-                          bool HasBaseReg,
+  bool reconcileNewOffset(LSRUse &LU, int64_t NewOffset, bool HasBaseReg,
                           LSRUse::KindType Kind, const Type *AccessTy);
 
   std::pair<size_t, int64_t> getUse(const SCEV *&Expr,
@@ -1364,8 +1343,7 @@ class LSRInstance {
 
   void DeleteUse(LSRUse &LU);
 
-  LSRUse *FindUseWithSimilarFormula(const Formula &F, const LSRUse &OrigLU,
-                                    int64_t &NewBaseOffs);
+  LSRUse *FindUseWithSimilarFormula(const Formula &F, const LSRUse &OrigLU);
 
 public:
   void InsertInitialFormula(const SCEV *S, LSRUse &LU, size_t LUIdx);
@@ -1866,13 +1844,11 @@ LSRInstance::OptimizeLoopTermCond() {
 /// at the given offset and other details. If so, update the use and
 /// return true.
 bool
-LSRInstance::reconcileNewOffset(LSRUse &LU,
-                                int64_t NewMinOffset, int64_t NewMaxOffset,
-                                bool HasBaseReg,
+LSRInstance::reconcileNewOffset(LSRUse &LU, int64_t NewOffset, bool HasBaseReg,
                                 LSRUse::KindType Kind, const Type *AccessTy) {
-  int64_t ResultMinOffset = LU.MinOffset;
-  int64_t ResultMaxOffset = LU.MaxOffset;
-  const Type *ResultAccessTy = AccessTy;
+  int64_t NewMinOffset = LU.MinOffset;
+  int64_t NewMaxOffset = LU.MaxOffset;
+  const Type *NewAccessTy = AccessTy;
 
   // Check for a mismatched kind. It's tempting to collapse mismatched kinds to
   // something conservative, however this can pessimize in the case that one of
@@ -1880,27 +1856,29 @@ LSRInstance::reconcileNewOffset(LSRUse &LU,
   if (LU.Kind != Kind)
     return false;
   // Conservatively assume HasBaseReg is true for now.
-  if (NewMinOffset < LU.MinOffset) {
-    if (!isAlwaysFoldable(LU.MaxOffset - NewMinOffset, 0, HasBaseReg,
+  if (NewOffset < LU.MinOffset) {
+    if (!isAlwaysFoldable(LU.MaxOffset - NewOffset, 0, HasBaseReg,
                           Kind, AccessTy, TLI))
       return false;
-    ResultMinOffset = NewMinOffset;
-  } else if (NewMaxOffset > LU.MaxOffset) {
-    if (!isAlwaysFoldable(NewMaxOffset - LU.MinOffset, 0, HasBaseReg,
+    NewMinOffset = NewOffset;
+  } else if (NewOffset > LU.MaxOffset) {
+    if (!isAlwaysFoldable(NewOffset - LU.MinOffset, 0, HasBaseReg,
                           Kind, AccessTy, TLI))
       return false;
-    ResultMaxOffset = NewMaxOffset;
+    NewMaxOffset = NewOffset;
   }
   // Check for a mismatched access type, and fall back conservatively as needed.
   // TODO: Be less conservative when the type is similar and can use the same
   // addressing modes.
   if (Kind == LSRUse::Address && AccessTy != LU.AccessTy)
-    ResultAccessTy = Type::getVoidTy(AccessTy->getContext());
+    NewAccessTy = Type::getVoidTy(AccessTy->getContext());
 
   // Update the use.
-  LU.MinOffset = ResultMinOffset;
-  LU.MaxOffset = ResultMaxOffset;
-  LU.AccessTy = ResultAccessTy;
+  LU.MinOffset = NewMinOffset;
+  LU.MaxOffset = NewMaxOffset;
+  LU.AccessTy = NewAccessTy;
+  if (NewOffset != LU.Offsets.back())
+    LU.Offsets.push_back(NewOffset);
   return true;
 }
 
@@ -1925,12 +1903,9 @@ LSRInstance::getUse(const SCEV *&Expr,
     // A use already existed with this base.
     size_t LUIdx = P.first->second;
     LSRUse &LU = Uses[LUIdx];
-    if (reconcileNewOffset(LU, Offset, Offset,
-                           /*HasBaseReg=*/true, Kind, AccessTy)) {
-      LU.Offsets.push_back(Offset);
+    if (reconcileNewOffset(LU, Offset, /*HasBaseReg=*/true, Kind, AccessTy))
       // Reuse this use.
       return std::make_pair(LUIdx, Offset);
-    }
   }
 
   // Create a new use.
@@ -1939,7 +1914,11 @@ LSRInstance::getUse(const SCEV *&Expr,
   Uses.push_back(LSRUse(Kind, AccessTy));
   LSRUse &LU = Uses[LUIdx];
 
-  LU.Offsets.push_back(Offset);
+  // We don't need to track redundant offsets, but we don't need to go out
+  // of our way here to avoid them.
+  if (LU.Offsets.empty() || Offset != LU.Offsets.back())
+    LU.Offsets.push_back(Offset);
+
   LU.MinOffset = Offset;
   LU.MaxOffset = Offset;
   return std::make_pair(LUIdx, Offset);
@@ -1947,12 +1926,8 @@ LSRInstance::getUse(const SCEV *&Expr,
 
 /// DeleteUse - Delete the given use from the Uses list.
 void LSRInstance::DeleteUse(LSRUse &LU) {
-  if (&LU != &Uses.back()) {
+  if (&LU != &Uses.back())
     std::swap(LU, Uses.back());
-    RegUses.DropUse(&LU - Uses.begin(), Uses.size() - 1);
-  } else {
-    RegUses.DropUse(&LU - Uses.begin());
-  }
   Uses.pop_back();
 }
 
@@ -1960,9 +1935,8 @@ void LSRInstance::DeleteUse(LSRUse &LU) {
 /// a formula that has the same registers as the given formula.
 LSRUse *
 LSRInstance::FindUseWithSimilarFormula(const Formula &OrigF,
-                                       const LSRUse &OrigLU,
-                                       int64_t &NewBaseOffs) {
-  // Search all uses for a formula similar to OrigF. This could be more clever.
+                                       const LSRUse &OrigLU) {
+  // Search all uses for the formula. This could be more clever.
   for (size_t LUIdx = 0, NumUses = Uses.size(); LUIdx != NumUses; ++LUIdx) {
     LSRUse &LU = Uses[LUIdx];
     // Check whether this use is close enough to OrigLU, to see whether it's
@@ -1985,15 +1959,8 @@ LSRInstance::FindUseWithSimilarFormula(const Formula &OrigF,
             F.ScaledReg == OrigF.ScaledReg &&
             F.AM.BaseGV == OrigF.AM.BaseGV &&
             F.AM.Scale == OrigF.AM.Scale) {
-          // Ok, all the registers and symbols matched. Check to see if the
-          // immediate looks nicer than our old one.
-          if (OrigF.AM.BaseOffs == INT64_MIN ||
-              (F.AM.BaseOffs != INT64_MIN &&
-               abs64(F.AM.BaseOffs) < abs64(OrigF.AM.BaseOffs))) {
-            // Looks good. Take it.
-            NewBaseOffs = F.AM.BaseOffs;
+          if (F.AM.BaseOffs == 0)
             return &LU;
-          }
           // This is the formula where all the registers and symbols matched;
           // there aren't going to be any others. Since we declined it, we
           // can skip the rest of the formulae and procede to the next LSRUse.
@@ -2634,17 +2601,6 @@ struct WorkItem {
   WorkItem(size_t LI, int64_t I, const SCEV *R)
     : LUIdx(LI), Imm(I), OrigReg(R) {}
 
-  bool operator==(const WorkItem &that) const {
-    return LUIdx == that.LUIdx && Imm == that.Imm && OrigReg == that.OrigReg;
-  }
-  bool operator<(const WorkItem &that) const {
-    if (LUIdx != that.LUIdx)
-      return LUIdx < that.LUIdx;
-    if (Imm != that.Imm)
-      return Imm < that.Imm;
-    return OrigReg < that.OrigReg;
-  }
-
   void print(raw_ostream &OS) const;
   void dump() const;
 };
@@ -2684,7 +2640,8 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
   // Now examine each set of registers with the same base value. Build up
   // a list of work to do and do the work in a separate step so that we're
   // not adding formulae and register counts while we're searching.
-  SmallSetVector<WorkItem, 32> WorkItems;
+  SmallVector<WorkItem, 32> WorkItems;
+  SmallSet<std::pair<size_t, int64_t>, 32> UniqueItems;
   for (SmallVectorImpl<const SCEV *>::const_iterator I = Sequence.begin(),
        E = Sequence.end(); I != E; ++I) {
     const SCEV *Reg = *I;
@@ -2727,10 +2684,10 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
         // Compute the difference between the two.
         int64_t Imm = (uint64_t)JImm - M->first;
         for (int LUIdx = UsedByIndices.find_first(); LUIdx != -1;
-             LUIdx = UsedByIndices.find_next(LUIdx)) {
+             LUIdx = UsedByIndices.find_next(LUIdx))
           // Make a memo of this use, offset, and register tuple.
-          WorkItems.insert(WorkItem(LUIdx, Imm, OrigReg));
-        }
+          if (UniqueItems.insert(std::make_pair(LUIdx, Imm)))
+            WorkItems.push_back(WorkItem(LUIdx, Imm, OrigReg));
       }
     }
   }
@@ -2738,6 +2695,7 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
   Map.clear();
   Sequence.clear();
   UsedByIndicesMap.clear();
+  UniqueItems.clear();
 
   // Now iterate through the worklist and add new formulae.
   for (SmallVectorImpl<WorkItem>::const_iterator I = WorkItems.begin(),
@@ -3034,12 +2992,8 @@ void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() {
            E = LU.Formulae.end(); I != E; ++I) {
         const Formula &F = *I;
         if (F.AM.BaseOffs != 0 && F.AM.Scale == 0) {
-          int64_t NewBaseOffs;
-          if (LSRUse *LUThatHas = FindUseWithSimilarFormula(F, LU,
-                                                            NewBaseOffs)) {
-            if (reconcileNewOffset(*LUThatHas,
-                                   F.AM.BaseOffs + LU.MinOffset - NewBaseOffs,
-                                   F.AM.BaseOffs + LU.MaxOffset - NewBaseOffs,
+          if (LSRUse *LUThatHas = FindUseWithSimilarFormula(F, LU)) {
+            if (reconcileNewOffset(*LUThatHas, F.AM.BaseOffs,
                                    /*HasBaseReg=*/false,
                                    LU.Kind, LU.AccessTy)) {
               DEBUG(dbgs() << "  Deleting use "; LU.print(dbgs());
@@ -3047,30 +3001,6 @@ void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() {
 
               LUThatHas->AllFixupsOutsideLoop &= LU.AllFixupsOutsideLoop;
 
-              // Update the relocs to reference the new use.
-              // Do this first so that MinOffset and MaxOffset are updated
-              // before we begin to determine which formulae to delete.
-              for (SmallVectorImpl<LSRFixup>::iterator I = Fixups.begin(),
-                   E = Fixups.end(); I != E; ++I) {
-                LSRFixup &Fixup = *I;
-                if (Fixup.LUIdx == LUIdx) {
-                  Fixup.LUIdx = LUThatHas - &Uses.front();
-                  Fixup.Offset += F.AM.BaseOffs - NewBaseOffs;
-                  DEBUG(dbgs() << "New fixup has offset "
-                               << Fixup.Offset << '\n');
-                  LUThatHas->Offsets.push_back(Fixup.Offset);
-                  if (Fixup.Offset > LUThatHas->MaxOffset)
-                    LUThatHas->MaxOffset = Fixup.Offset;
-                  if (Fixup.Offset < LUThatHas->MinOffset)
-                    LUThatHas->MinOffset = Fixup.Offset;
-                }
-                // DeleteUse will do a swap+pop_back, so if this fixup is
-                // now pointing to the last LSRUse, update it to point to the
-                // position it'll be swapped to.
-                if (Fixup.LUIdx == NumUses-1)
-                  Fixup.LUIdx = LUIdx;
-              }
-
               // Delete formulae from the new use which are no longer legal.
               bool Any = false;
               for (size_t i = 0, e = LUThatHas->Formulae.size(); i != e; ++i) {
@@ -3089,6 +3019,20 @@ void LSRInstance::NarrowSearchSpaceByCollapsingUnrolledCode() {
               if (Any)
                 LUThatHas->RecomputeRegs(LUThatHas - &Uses.front(), RegUses);
 
+              // Update the relocs to reference the new use.
+              for (SmallVectorImpl<LSRFixup>::iterator I = Fixups.begin(),
+                   E = Fixups.end(); I != E; ++I) {
+                LSRFixup &Fixup = *I;
+                if (Fixup.LUIdx == LUIdx) {
+                  Fixup.LUIdx = LUThatHas - &Uses.front();
+                  Fixup.Offset += F.AM.BaseOffs;
+                  DEBUG(dbgs() << "New fixup has offset "
+                               << Fixup.Offset << '\n');
+                }
+                if (Fixup.LUIdx == NumUses-1)
+                  Fixup.LUIdx = LUIdx;
+              }
+
               // Delete the old use.
               DeleteUse(LU);
               --LUIdx;
diff --git a/test/CodeGen/X86/lsr-reuse.ll b/test/CodeGen/X86/lsr-reuse.ll
index 98afc3e215..d2ff58be10 100644
--- a/test/CodeGen/X86/lsr-reuse.ll
+++ b/test/CodeGen/X86/lsr-reuse.ll
@@ -452,8 +452,8 @@ bb5:                                              ; preds = %bb3, %entry
 ; CHECK-NEXT:   addss   %xmm{{.*}}, %xmm{{.*}}
 ; CHECK-NEXT:   mulss   (%r{{[^,]*}}), %xmm{{.*}}
 ; CHECK-NEXT:   movss   %xmm{{.*}}, (%r{{[^,]*}})
-; CHECK-NEXT:   decq    %r{{.*}}
 ; CHECK-NEXT:   addq    $4, %r{{.*}}
+; CHECK-NEXT:   decq    %r{{.*}}
 ; CHECK-NEXT:   addq    $4, %r{{.*}}
 ; CHECK-NEXT:   movaps  %xmm{{.*}}, %xmm{{.*}}
 ; CHECK-NEXT: BB10_2: