Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release:

MFC r309142 (by emaste):

Add WITH_LLD_AS_LD build knob

If set it installs LLD as /usr/bin/ld.  LLD (as of version 3.9) is not
capable of linking the world and kernel, but can self-host and link many
substantial applications. GNU ld continues to be used for the world and
kernel build, regardless of how this knob is set.

It is on by default for arm64, and off for all other CPU architectures.

Sponsored by:	The FreeBSD Foundation

MFC r310840:

Reapply 310775, now it also builds correctly if lldb is disabled:

Move llvm-objdump from CLANG_EXTRAS to installed by default

We currently install three tools from binutils 2.17.50: as, ld, and
objdump. Work is underway to migrate to a permissively-licensed
tool-chain, with one goal being the retirement of binutils 2.17.50.

LLVM's llvm-objdump is intended to be compatible with GNU objdump
although it is currently missing some options and may have formatting
differences. Enable it by default for testing and further investigation.
It may later be changed to install as /usr/bin/objdump, it becomes a
fully viable replacement.

Reviewed by:	emaste
Differential Revision:	https://reviews.freebsd.org/D8879

MFC r312855 (by emaste):

Rename LLD_AS_LD to LLD_IS_LD, for consistency with CLANG_IS_CC

Reported by:	Dan McGregor <dan.mcgregor usask.ca>

MFC r313559 | glebius | 2017-02-10 18:34:48 +0100 (Fri, 10 Feb 2017) | 5 lines

Don't check struct rtentry on FreeBSD, it is an internal kernel structure.
On other systems it may be API structure for SIOCADDRT/SIOCDELRT.

Reviewed by:	emaste, dim

MFC r314152 (by jkim):

Remove an assembler flag, which is redundant since r309124.  The upstream
took care of it by introducing a macro NO_EXEC_STACK_DIRECTIVE.

http://llvm.org/viewvc/llvm-project?rev=273500&view=rev

Reviewed by:	dim

MFC r314564:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
4.0.0 (branches/release_40 296509).  The release will follow soon.

Please note that from 3.5.0 onwards, clang, llvm and lldb require C++11
support to build; see UPDATING for more information.

Also note that as of 4.0.0, lld should be able to link the base system
on amd64 and aarch64.  See the WITH_LLD_IS_LLD setting in src.conf(5).
Though please be aware that this is work in progress.

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/4.0.0/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/4.0.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Jan Beich, Antoine Brodin and Eric Fiselier for
their help.

Relnotes:	yes
Exp-run:	antoine
PR:		215969, 216008

MFC r314708:

For now, revert r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

This commit is the cause of excessive compile times on skein_block.c
(and possibly other files) during kernel builds on amd64.

We never saw the problematic behavior described in this upstream commit,
so for now it is better to revert it.  An upstream bug has been filed
here: https://bugs.llvm.org/show_bug.cgi?id=32142

Reported by:	mjg

MFC r314795:

Reapply r287232 from upstream llvm trunk (by Daniil Fukalov):

  [SCEV] limit recursion depth of CompareSCEVComplexity

  Summary:
  CompareSCEVComplexity goes too deep (50+ on a quite a big unrolled
  loop) and runs almost infinite time.

  Added cache of "equal" SCEV pairs to earlier cutoff of further
  estimation. Recursion depth limit was also introduced as a parameter.

  Reviewers: sanjoy

  Subscribers: mzolotukhin, tstellarAMD, llvm-commits

  Differential Revision: https://reviews.llvm.org/D26389

Pull in r296992 from upstream llvm trunk (by Sanjoy Das):

  [SCEV] Decrease the recursion threshold for CompareValueComplexity

  Fixes PR32142.

  r287232 accidentally increased the recursion threshold for
  CompareValueComplexity from 2 to 32.  This change reverses that
  change by introducing a separate flag for CompareValueComplexity's
  threshold.

The latter revision fixes the excessive compile times for skein_block.c.

MFC r314907 | mmel | 2017-03-08 12:40:27 +0100 (Wed, 08 Mar 2017) | 7 lines

Unbreak ARMv6 world.

The new compiler_rt library imported with clang 4.0.0 have several fatal
issues (non-functional __udivsi3 for example) with ARM specific instrict
functions. As temporary workaround, until upstream solve these problems,
disable all thumb[1][2] related feature.

MFC r315016:

Update clang, llvm, lld, lldb, compiler-rt and libc++ to 4.0.0 release.
We were already very close to the last release candidate, so this is a
pretty minor update.

Relnotes:	yes

MFC r316005:

Revert r314907, and pull in r298713 from upstream compiler-rt trunk (by
Weiming Zhao):

  builtins: Select correct code fragments when compiling for Thumb1/Thum2/ARM ISA.

  Summary:
  Value of __ARM_ARCH_ISA_THUMB isn't based on the actual compilation
  mode (-mthumb, -marm), it reflect's capability of given CPU.

  Due to this:
   - use  __tbumb__ and __thumb2__ insteand of __ARM_ARCH_ISA_THUMB
   - use '.thumb' directive consistently  in all affected files
   - decorate all thumb functions using
     DEFINE_COMPILERRT_THUMB_FUNCTION()

  ---------
  Note: This patch doesn't fix broken Thumb1 variant of __udivsi3 !

  Reviewers: weimingz, rengolin, compnerd

  Subscribers: aemerson, dim

  Differential Revision: https://reviews.llvm.org/D30938

Discussed with:	mmel

1 files changed, 500 insertions, 464 deletions

diff --git a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
index 3ce667f..d442310 100644
--- a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -26,6 +26,7 @@
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/PatternMatch.h"
 #include "llvm/IR/ValueHandle.h"
@@ -50,7 +51,7 @@ namespace llvm {
   FunctionPass *createLazyValueInfoPass() { return new LazyValueInfoWrapperPass(); }
 }
 
-char LazyValueAnalysis::PassID;
+AnalysisKey LazyValueAnalysis::Key;
 
 //===----------------------------------------------------------------------===//
 //                               LVILatticeVal
@@ -70,12 +71,14 @@ class LVILatticeVal {
     /// "nothing known yet".
     undefined,
 
-    /// This Value has a specific constant value.  (For integers, constantrange
-    /// is used instead.)
+    /// This Value has a specific constant value.  (For constant integers,
+    /// constantrange is used instead.  Integer typed constantexprs can appear
+    /// as constant.) 
     constant,
 
-    /// This Value is known to not have the specified value.  (For integers,
-    /// constantrange is used instead.)
+    /// This Value is known to not have the specified value.  (For constant
+    /// integers, constantrange is used instead.  As above, integer typed
+    /// constantexprs can appear here.)
     notconstant,
 
     /// The Value falls within this range. (Used only for integer typed values.)
@@ -139,37 +142,37 @@ public:
     return Range;
   }
 
-  /// Return true if this is a change in status.
-  bool markOverdefined() {
+private:
+  void markOverdefined() {
     if (isOverdefined())
-      return false;
+      return;
     Tag = overdefined;
-    return true;
   }
 
-  /// Return true if this is a change in status.
-  bool markConstant(Constant *V) {
+  void markConstant(Constant *V) {
     assert(V && "Marking constant with NULL");
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
-      return markConstantRange(ConstantRange(CI->getValue()));
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      markConstantRange(ConstantRange(CI->getValue()));
+      return;
+    }
     if (isa<UndefValue>(V))
-      return false;
+      return;
 
     assert((!isConstant() || getConstant() == V) &&
            "Marking constant with different value");
     assert(isUndefined());
     Tag = constant;
     Val = V;
-    return true;
   }
 
-  /// Return true if this is a change in status.
-  bool markNotConstant(Constant *V) {
+  void markNotConstant(Constant *V) {
     assert(V && "Marking constant with NULL");
-    if (ConstantInt *CI = dyn_cast<ConstantInt>(V))
-      return markConstantRange(ConstantRange(CI->getValue()+1, CI->getValue()));
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
+      markConstantRange(ConstantRange(CI->getValue()+1, CI->getValue()));
+      return;
+    }
     if (isa<UndefValue>(V))
-      return false;
+      return;
 
     assert((!isConstant() || getConstant() != V) &&
            "Marking constant !constant with same value");
@@ -178,100 +181,70 @@ public:
     assert(isUndefined() || isConstant());
     Tag = notconstant;
     Val = V;
-    return true;
   }
 
-  /// Return true if this is a change in status.
-  bool markConstantRange(ConstantRange NewR) {
+  void markConstantRange(ConstantRange NewR) {
     if (isConstantRange()) {
       if (NewR.isEmptySet())
-        return markOverdefined();
-
-      bool changed = Range != NewR;
-      Range = std::move(NewR);
-      return changed;
+        markOverdefined();
+      else {
+        Range = std::move(NewR);
+      }
+      return;
     }
 
     assert(isUndefined());
     if (NewR.isEmptySet())
-      return markOverdefined();
-
-    Tag = constantrange;
-    Range = std::move(NewR);
-    return true;
+      markOverdefined();
+    else {
+      Tag = constantrange;
+      Range = std::move(NewR);
+    }
   }
 
+public:
+
   /// Merge the specified lattice value into this one, updating this
   /// one and returning true if anything changed.
-  bool mergeIn(const LVILatticeVal &RHS, const DataLayout &DL) {
-    if (RHS.isUndefined() || isOverdefined()) return false;
-    if (RHS.isOverdefined()) return markOverdefined();
+  void mergeIn(const LVILatticeVal &RHS, const DataLayout &DL) {
+    if (RHS.isUndefined() || isOverdefined())
+      return;
+    if (RHS.isOverdefined()) {
+      markOverdefined();
+      return;
+    }
 
     if (isUndefined()) {
-      Tag = RHS.Tag;
-      Val = RHS.Val;
-      Range = RHS.Range;
-      return true;
+      *this = RHS;
+      return;
     }
 
     if (isConstant()) {
-      if (RHS.isConstant()) {
-        if (Val == RHS.Val)
-          return false;
-        return markOverdefined();
-      }
-
-      if (RHS.isNotConstant()) {
-        if (Val == RHS.Val)
-          return markOverdefined();
-
-        // Unless we can prove that the two Constants are different, we must
-        // move to overdefined.
-        if (ConstantInt *Res =
-                dyn_cast<ConstantInt>(ConstantFoldCompareInstOperands(
-                    CmpInst::ICMP_NE, getConstant(), RHS.getNotConstant(), DL)))
-          if (Res->isOne())
-            return markNotConstant(RHS.getNotConstant());
-
-        return markOverdefined();
-      }
-
-      return markOverdefined();
+      if (RHS.isConstant() && Val == RHS.Val)
+          return;
+      markOverdefined();
+      return;
     }
 
     if (isNotConstant()) {
-      if (RHS.isConstant()) {
-        if (Val == RHS.Val)
-          return markOverdefined();
-
-        // Unless we can prove that the two Constants are different, we must
-        // move to overdefined.
-        if (ConstantInt *Res =
-                dyn_cast<ConstantInt>(ConstantFoldCompareInstOperands(
-                    CmpInst::ICMP_NE, getNotConstant(), RHS.getConstant(), DL)))
-          if (Res->isOne())
-            return false;
-
-        return markOverdefined();
-      }
-
-      if (RHS.isNotConstant()) {
-        if (Val == RHS.Val)
-          return false;
-        return markOverdefined();
-      }
-
-      return markOverdefined();
+      if (RHS.isNotConstant() && Val == RHS.Val)
+          return;
+      markOverdefined();
+      return;
     }
 
     assert(isConstantRange() && "New LVILattice type?");
-    if (!RHS.isConstantRange())
-      return markOverdefined();
-
+    if (!RHS.isConstantRange()) {
+      // We can get here if we've encountered a constantexpr of integer type
+      // and merge it with a constantrange.
+      markOverdefined();
+      return;
+    }
     ConstantRange NewR = Range.unionWith(RHS.getConstantRange());
     if (NewR.isFullSet())
-      return markOverdefined();
-    return markConstantRange(NewR);
+      markOverdefined();
+    else
+      markConstantRange(NewR);
   }
 };
 
@@ -366,6 +339,9 @@ namespace {
   /// A callback value handle updates the cache when values are erased.
   class LazyValueInfoCache;
   struct LVIValueHandle final : public CallbackVH {
+    // Needs to access getValPtr(), which is protected.
+    friend struct DenseMapInfo<LVIValueHandle>;
+
     LazyValueInfoCache *Parent;
 
     LVIValueHandle(Value *V, LazyValueInfoCache *P)
@@ -376,7 +352,7 @@ namespace {
       deleted();
     }
   };
-}
+} // end anonymous namespace
 
 namespace {
   /// This is the cache kept by LazyValueInfo which
@@ -387,12 +363,15 @@ namespace {
     /// entries, allowing us to do a lookup with a binary search.
     /// Over-defined lattice values are recorded in OverDefinedCache to reduce
     /// memory overhead.
-    typedef SmallDenseMap<AssertingVH<BasicBlock>, LVILatticeVal, 4>
-        ValueCacheEntryTy;
+    struct ValueCacheEntryTy {
+      ValueCacheEntryTy(Value *V, LazyValueInfoCache *P) : Handle(V, P) {}
+      LVIValueHandle Handle;
+      SmallDenseMap<AssertingVH<BasicBlock>, LVILatticeVal, 4> BlockVals;
+    };
 
     /// This is all of the cached information for all values,
     /// mapped from Value* to key information.
-    std::map<LVIValueHandle, ValueCacheEntryTy> ValueCache;
+    DenseMap<Value *, std::unique_ptr<ValueCacheEntryTy>> ValueCache;
 
     /// This tracks, on a per-block basis, the set of values that are
     /// over-defined at the end of that block.
@@ -404,6 +383,183 @@ namespace {
     /// don't spend time removing unused blocks from our caches.
     DenseSet<AssertingVH<BasicBlock> > SeenBlocks;
 
+  public:
+    void insertResult(Value *Val, BasicBlock *BB, const LVILatticeVal &Result) {
+      SeenBlocks.insert(BB);
+
+      // Insert over-defined values into their own cache to reduce memory
+      // overhead.
+      if (Result.isOverdefined())
+        OverDefinedCache[BB].insert(Val);
+      else {
+        auto It = ValueCache.find_as(Val);
+        if (It == ValueCache.end()) {
+          ValueCache[Val] = make_unique<ValueCacheEntryTy>(Val, this);
+          It = ValueCache.find_as(Val);
+          assert(It != ValueCache.end() && "Val was just added to the map!");
+        }
+        It->second->BlockVals[BB] = Result;
+      }
+    }
+
+    bool isOverdefined(Value *V, BasicBlock *BB) const {
+      auto ODI = OverDefinedCache.find(BB);
+
+      if (ODI == OverDefinedCache.end())
+        return false;
+
+      return ODI->second.count(V);
+    }
+
+    bool hasCachedValueInfo(Value *V, BasicBlock *BB) const {
+      if (isOverdefined(V, BB))
+        return true;
+
+      auto I = ValueCache.find_as(V);
+      if (I == ValueCache.end())
+        return false;
+
+      return I->second->BlockVals.count(BB);
+    }
+
+    LVILatticeVal getCachedValueInfo(Value *V, BasicBlock *BB) const {
+      if (isOverdefined(V, BB))
+        return LVILatticeVal::getOverdefined();
+
+      auto I = ValueCache.find_as(V);
+      if (I == ValueCache.end())
+        return LVILatticeVal();
+      auto BBI = I->second->BlockVals.find(BB);
+      if (BBI == I->second->BlockVals.end())
+        return LVILatticeVal();
+      return BBI->second;
+    }
+
+    /// clear - Empty the cache.
+    void clear() {
+      SeenBlocks.clear();
+      ValueCache.clear();
+      OverDefinedCache.clear();
+    }
+
+    /// Inform the cache that a given value has been deleted.
+    void eraseValue(Value *V);
+
+    /// This is part of the update interface to inform the cache
+    /// that a block has been deleted.
+    void eraseBlock(BasicBlock *BB);
+
+    /// Updates the cache to remove any influence an overdefined value in
+    /// OldSucc might have (unless also overdefined in NewSucc).  This just
+    /// flushes elements from the cache and does not add any.
+    void threadEdgeImpl(BasicBlock *OldSucc,BasicBlock *NewSucc);
+
+    friend struct LVIValueHandle;
+  };
+}
+
+void LazyValueInfoCache::eraseValue(Value *V) {
+  SmallVector<AssertingVH<BasicBlock>, 4> ToErase;
+  for (auto &I : OverDefinedCache) {
+    SmallPtrSetImpl<Value *> &ValueSet = I.second;
+    ValueSet.erase(V);
+    if (ValueSet.empty())
+      ToErase.push_back(I.first);
+  }
+  for (auto &BB : ToErase)
+    OverDefinedCache.erase(BB);
+
+  ValueCache.erase(V);
+}
+
+void LVIValueHandle::deleted() {
+  // This erasure deallocates *this, so it MUST happen after we're done
+  // using any and all members of *this.
+  Parent->eraseValue(*this);
+}
+
+void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
+  // Shortcut if we have never seen this block.
+  DenseSet<AssertingVH<BasicBlock> >::iterator I = SeenBlocks.find(BB);
+  if (I == SeenBlocks.end())
+    return;
+  SeenBlocks.erase(I);
+
+  auto ODI = OverDefinedCache.find(BB);
+  if (ODI != OverDefinedCache.end())
+    OverDefinedCache.erase(ODI);
+
+  for (auto &I : ValueCache)
+    I.second->BlockVals.erase(BB);
+}
+
+void LazyValueInfoCache::threadEdgeImpl(BasicBlock *OldSucc,
+                                        BasicBlock *NewSucc) {
+  // When an edge in the graph has been threaded, values that we could not
+  // determine a value for before (i.e. were marked overdefined) may be
+  // possible to solve now. We do NOT try to proactively update these values.
+  // Instead, we clear their entries from the cache, and allow lazy updating to
+  // recompute them when needed.
+
+  // The updating process is fairly simple: we need to drop cached info
+  // for all values that were marked overdefined in OldSucc, and for those same
+  // values in any successor of OldSucc (except NewSucc) in which they were
+  // also marked overdefined.
+  std::vector<BasicBlock*> worklist;
+  worklist.push_back(OldSucc);
+
+  auto I = OverDefinedCache.find(OldSucc);
+  if (I == OverDefinedCache.end())
+    return; // Nothing to process here.
+  SmallVector<Value *, 4> ValsToClear(I->second.begin(), I->second.end());
+
+  // Use a worklist to perform a depth-first search of OldSucc's successors.
+  // NOTE: We do not need a visited list since any blocks we have already
+  // visited will have had their overdefined markers cleared already, and we
+  // thus won't loop to their successors.
+  while (!worklist.empty()) {
+    BasicBlock *ToUpdate = worklist.back();
+    worklist.pop_back();
+
+    // Skip blocks only accessible through NewSucc.
+    if (ToUpdate == NewSucc) continue;
+
+    // If a value was marked overdefined in OldSucc, and is here too...
+    auto OI = OverDefinedCache.find(ToUpdate);
+    if (OI == OverDefinedCache.end())
+      continue;
+    SmallPtrSetImpl<Value *> &ValueSet = OI->second;
+
+    bool changed = false;
+    for (Value *V : ValsToClear) {
+      if (!ValueSet.erase(V))
+        continue;
+
+      // If we removed anything, then we potentially need to update
+      // blocks successors too.
+      changed = true;
+
+      if (ValueSet.empty()) {
+        OverDefinedCache.erase(OI);
+        break;
+      }
+    }
+
+    if (!changed) continue;
+
+    worklist.insert(worklist.end(), succ_begin(ToUpdate), succ_end(ToUpdate));
+  }
+}
+
+namespace {
+  // The actual implementation of the lazy analysis and update.  Note that the
+  // inheritance from LazyValueInfoCache is intended to be temporary while
+  // splitting the code and then transitioning to a has-a relationship.
+  class LazyValueInfoImpl {
+
+    /// Cached results from previous queries
+    LazyValueInfoCache TheCache;
+
     /// This stack holds the state of the value solver during a query.
     /// It basically emulates the callstack of the naive
     /// recursive value lookup process.
@@ -428,19 +584,6 @@ namespace {
     const DataLayout &DL; ///< A mandatory DataLayout
     DominatorTree *DT;    ///< An optional DT pointer.
 
-    friend struct LVIValueHandle;
-
-    void insertResult(Value *Val, BasicBlock *BB, const LVILatticeVal &Result) {
-      SeenBlocks.insert(BB);
-
-      // Insert over-defined values into their own cache to reduce memory
-      // overhead.
-      if (Result.isOverdefined())
-        OverDefinedCache[BB].insert(Val);
-      else
-        lookup(Val)[BB] = Result;
-    }
-
   LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB);
   bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T,
                     LVILatticeVal &Result, Instruction *CxtI = nullptr);
@@ -450,6 +593,7 @@ namespace {
   // returned means that the work item was not completely processed and must
   // be revisited after going through the new items.
   bool solveBlockValue(Value *Val, BasicBlock *BB);
+  bool solveBlockValueImpl(LVILatticeVal &Res, Value *Val, BasicBlock *BB);
   bool solveBlockValueNonLocal(LVILatticeVal &BBLV, Value *Val, BasicBlock *BB);
   bool solveBlockValuePHINode(LVILatticeVal &BBLV, PHINode *PN, BasicBlock *BB);
   bool solveBlockValueSelect(LVILatticeVal &BBLV, SelectInst *S,
@@ -458,43 +602,12 @@ namespace {
                                BasicBlock *BB);
   bool solveBlockValueCast(LVILatticeVal &BBLV, Instruction *BBI,
                            BasicBlock *BB);
-  void intersectAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
+  void intersectAssumeOrGuardBlockValueConstantRange(Value *Val,
+                                                     LVILatticeVal &BBLV,
                                               Instruction *BBI);
 
   void solve();
 
-  ValueCacheEntryTy &lookup(Value *V) {
-    return ValueCache[LVIValueHandle(V, this)];
-  }
-
-    bool isOverdefined(Value *V, BasicBlock *BB) const {
-      auto ODI = OverDefinedCache.find(BB);
-
-      if (ODI == OverDefinedCache.end())
-        return false;
-
-      return ODI->second.count(V);
-    }
-
-    bool hasCachedValueInfo(Value *V, BasicBlock *BB) {
-      if (isOverdefined(V, BB))
-        return true;
-
-      LVIValueHandle ValHandle(V, this);
-      auto I = ValueCache.find(ValHandle);
-      if (I == ValueCache.end())
-        return false;
-
-      return I->second.count(BB);
-    }
-
-    LVILatticeVal getCachedValueInfo(Value *V, BasicBlock *BB) {
-      if (isOverdefined(V, BB))
-        return LVILatticeVal::getOverdefined();
-
-      return lookup(V)[BB];
-    }
-
   public:
     /// This is the query interface to determine the lattice
     /// value for the specified Value* at the end of the specified block.
@@ -511,60 +624,28 @@ namespace {
     LVILatticeVal getValueOnEdge(Value *V, BasicBlock *FromBB,BasicBlock *ToBB,
                                  Instruction *CxtI = nullptr);
 
-    /// This is the update interface to inform the cache that an edge from
-    /// PredBB to OldSucc has been threaded to be from PredBB to NewSucc.
-    void threadEdge(BasicBlock *PredBB,BasicBlock *OldSucc,BasicBlock *NewSucc);
+    /// Complete flush all previously computed values
+    void clear() {
+      TheCache.clear();
+    }
 
     /// This is part of the update interface to inform the cache
     /// that a block has been deleted.
-    void eraseBlock(BasicBlock *BB);
-
-    /// clear - Empty the cache.
-    void clear() {
-      SeenBlocks.clear();
-      ValueCache.clear();
-      OverDefinedCache.clear();
+    void eraseBlock(BasicBlock *BB) {
+      TheCache.eraseBlock(BB);
     }
 
-    LazyValueInfoCache(AssumptionCache *AC, const DataLayout &DL,
+    /// This is the update interface to inform the cache that an edge from
+    /// PredBB to OldSucc has been threaded to be from PredBB to NewSucc.
+    void threadEdge(BasicBlock *PredBB,BasicBlock *OldSucc,BasicBlock *NewSucc);
+
+    LazyValueInfoImpl(AssumptionCache *AC, const DataLayout &DL,
                        DominatorTree *DT = nullptr)
         : AC(AC), DL(DL), DT(DT) {}
   };
 } // end anonymous namespace
 
-void LVIValueHandle::deleted() {
-  SmallVector<AssertingVH<BasicBlock>, 4> ToErase;
-  for (auto &I : Parent->OverDefinedCache) {
-    SmallPtrSetImpl<Value *> &ValueSet = I.second;
-    if (ValueSet.count(getValPtr()))
-      ValueSet.erase(getValPtr());
-    if (ValueSet.empty())
-      ToErase.push_back(I.first);
-  }
-  for (auto &BB : ToErase)
-    Parent->OverDefinedCache.erase(BB);
-
-  // This erasure deallocates *this, so it MUST happen after we're done
-  // using any and all members of *this.
-  Parent->ValueCache.erase(*this);
-}
-
-void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
-  // Shortcut if we have never seen this block.
-  DenseSet<AssertingVH<BasicBlock> >::iterator I = SeenBlocks.find(BB);
-  if (I == SeenBlocks.end())
-    return;
-  SeenBlocks.erase(I);
-
-  auto ODI = OverDefinedCache.find(BB);
-  if (ODI != OverDefinedCache.end())
-    OverDefinedCache.erase(ODI);
-
-  for (auto &I : ValueCache)
-    I.second.erase(BB);
-}
-
-void LazyValueInfoCache::solve() {
+void LazyValueInfoImpl::solve() {
   while (!BlockValueStack.empty()) {
     std::pair<BasicBlock*, Value*> &e = BlockValueStack.top();
     assert(BlockValueSet.count(e) && "Stack value should be in BlockValueSet!");
@@ -572,11 +653,11 @@ void LazyValueInfoCache::solve() {
     if (solveBlockValue(e.second, e.first)) {
       // The work item was completely processed.
       assert(BlockValueStack.top() == e && "Nothing should have been pushed!");
-      assert(hasCachedValueInfo(e.second, e.first) &&
+      assert(TheCache.hasCachedValueInfo(e.second, e.first) &&
              "Result should be in cache!");
 
       DEBUG(dbgs() << "POP " << *e.second << " in " << e.first->getName()
-                   << " = " << getCachedValueInfo(e.second, e.first) << "\n");
+                   << " = " << TheCache.getCachedValueInfo(e.second, e.first) << "\n");
 
       BlockValueStack.pop();
       BlockValueSet.erase(e);
@@ -587,21 +668,20 @@ void LazyValueInfoCache::solve() {
   }
 }
 
-bool LazyValueInfoCache::hasBlockValue(Value *Val, BasicBlock *BB) {
+bool LazyValueInfoImpl::hasBlockValue(Value *Val, BasicBlock *BB) {
   // If already a constant, there is nothing to compute.
   if (isa<Constant>(Val))
     return true;
 
-  return hasCachedValueInfo(Val, BB);
+  return TheCache.hasCachedValueInfo(Val, BB);
 }
 
-LVILatticeVal LazyValueInfoCache::getBlockValue(Value *Val, BasicBlock *BB) {
+LVILatticeVal LazyValueInfoImpl::getBlockValue(Value *Val, BasicBlock *BB) {
   // If already a constant, there is nothing to compute.
   if (Constant *VC = dyn_cast<Constant>(Val))
     return LVILatticeVal::get(VC);
 
-  SeenBlocks.insert(BB);
-  return getCachedValueInfo(Val, BB);
+  return TheCache.getCachedValueInfo(Val, BB);
 }
 
 static LVILatticeVal getFromRangeMetadata(Instruction *BBI) {
@@ -610,7 +690,7 @@ static LVILatticeVal getFromRangeMetadata(Instruction *BBI) {
   case Instruction::Load:
   case Instruction::Call:
   case Instruction::Invoke:
-    if (MDNode *Ranges = BBI->getMetadata(LLVMContext::MD_range)) 
+    if (MDNode *Ranges = BBI->getMetadata(LLVMContext::MD_range))
       if (isa<IntegerType>(BBI->getType())) {
         return LVILatticeVal::getRange(getConstantRangeFromMetadata(*Ranges));
       }
@@ -620,14 +700,14 @@ static LVILatticeVal getFromRangeMetadata(Instruction *BBI) {
   return LVILatticeVal::getOverdefined();
 }
 
-bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
+bool LazyValueInfoImpl::solveBlockValue(Value *Val, BasicBlock *BB) {
   if (isa<Constant>(Val))
     return true;
 
-  if (hasCachedValueInfo(Val, BB)) {
+  if (TheCache.hasCachedValueInfo(Val, BB)) {
     // If we have a cached value, use that.
     DEBUG(dbgs() << "  reuse BB '" << BB->getName()
-                 << "' val=" << getCachedValueInfo(Val, BB) << '\n');
+                 << "' val=" << TheCache.getCachedValueInfo(Val, BB) << '\n');
 
     // Since we're reusing a cached value, we don't need to update the
     // OverDefinedCache. The cache will have been properly updated whenever the
@@ -638,28 +718,26 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
   // Hold off inserting this value into the Cache in case we have to return
   // false and come back later.
   LVILatticeVal Res;
+  if (!solveBlockValueImpl(Res, Val, BB))
+    // Work pushed, will revisit
+    return false;
+
+  TheCache.insertResult(Val, BB, Res);
+  return true;
+}
+
+bool LazyValueInfoImpl::solveBlockValueImpl(LVILatticeVal &Res,
+                                            Value *Val, BasicBlock *BB) {
 
   Instruction *BBI = dyn_cast<Instruction>(Val);
-  if (!BBI || BBI->getParent() != BB) {
-    if (!solveBlockValueNonLocal(Res, Val, BB))
-      return false;
-   insertResult(Val, BB, Res);
-   return true;
-  }
+  if (!BBI || BBI->getParent() != BB)
+    return solveBlockValueNonLocal(Res, Val, BB);
 
-  if (PHINode *PN = dyn_cast<PHINode>(BBI)) {
-    if (!solveBlockValuePHINode(Res, PN, BB))
-      return false;
-    insertResult(Val, BB, Res);
-    return true;
-  }
+  if (PHINode *PN = dyn_cast<PHINode>(BBI))
+    return solveBlockValuePHINode(Res, PN, BB);
 
-  if (auto *SI = dyn_cast<SelectInst>(BBI)) {
-    if (!solveBlockValueSelect(Res, SI, BB))
-      return false;
-    insertResult(Val, BB, Res);
-    return true;
-  }
+  if (auto *SI = dyn_cast<SelectInst>(BBI))
+    return solveBlockValueSelect(Res, SI, BB);
 
   // If this value is a nonnull pointer, record it's range and bailout.  Note
   // that for all other pointer typed values, we terminate the search at the
@@ -673,29 +751,20 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
   PointerType *PT = dyn_cast<PointerType>(BBI->getType());
   if (PT && isKnownNonNull(BBI)) {
     Res = LVILatticeVal::getNot(ConstantPointerNull::get(PT));
-    insertResult(Val, BB, Res);
     return true;
   }
   if (BBI->getType()->isIntegerTy()) {
-    if (isa<CastInst>(BBI)) {
-      if (!solveBlockValueCast(Res, BBI, BB))
-        return false;
-      insertResult(Val, BB, Res);
-      return true;
-    }
+    if (isa<CastInst>(BBI))
+      return solveBlockValueCast(Res, BBI, BB);
+    
     BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI);
-    if (BO && isa<ConstantInt>(BO->getOperand(1))) { 
-      if (!solveBlockValueBinaryOp(Res, BBI, BB))
-        return false;
-      insertResult(Val, BB, Res);
-      return true;
-    }
+    if (BO && isa<ConstantInt>(BO->getOperand(1)))
+      return solveBlockValueBinaryOp(Res, BBI, BB);
   }
 
   DEBUG(dbgs() << " compute BB '" << BB->getName()
                  << "' - unknown inst def found.\n");
   Res = getFromRangeMetadata(BBI);
-  insertResult(Val, BB, Res);
   return true;
 }
 
@@ -748,7 +817,7 @@ static bool isObjectDereferencedInBlock(Value *Val, BasicBlock *BB) {
   return false;
 }
 
-bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
+bool LazyValueInfoImpl::solveBlockValueNonLocal(LVILatticeVal &BBLV,
                                                  Value *Val, BasicBlock *BB) {
   LVILatticeVal Result;  // Start Undefined.
 
@@ -763,7 +832,7 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
       PointerType *PTy = cast<PointerType>(Val->getType());
       Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
     } else {
-      Result.markOverdefined();
+      Result = LVILatticeVal::getOverdefined();
     }
     BBLV = Result;
     return true;
@@ -785,7 +854,7 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
     if (Result.isOverdefined()) {
       DEBUG(dbgs() << " compute BB '" << BB->getName()
             << "' - overdefined because of pred (non local).\n");
-      // Bofore giving up, see if we can prove the pointer non-null local to
+      // Before giving up, see if we can prove the pointer non-null local to
       // this particular block.
       if (Val->getType()->isPointerTy() &&
           isObjectDereferencedInBlock(Val, BB)) {
@@ -806,7 +875,7 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
   return true;
 }
 
-bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV,
+bool LazyValueInfoImpl::solveBlockValuePHINode(LVILatticeVal &BBLV,
                                                 PHINode *PN, BasicBlock *BB) {
   LVILatticeVal Result;  // Start Undefined.
 
@@ -845,64 +914,70 @@ bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV,
   return true;
 }
 
-static bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
-                                      LVILatticeVal &Result,
-                                      bool isTrueDest = true);
+static LVILatticeVal getValueFromCondition(Value *Val, Value *Cond,
+                                           bool isTrueDest = true);
 
 // If we can determine a constraint on the value given conditions assumed by
 // the program, intersect those constraints with BBLV
-void LazyValueInfoCache::intersectAssumeBlockValueConstantRange(Value *Val,
-                                                            LVILatticeVal &BBLV,
-                                                            Instruction *BBI) {
+void LazyValueInfoImpl::intersectAssumeOrGuardBlockValueConstantRange(
+        Value *Val, LVILatticeVal &BBLV, Instruction *BBI) {
   BBI = BBI ? BBI : dyn_cast<Instruction>(Val);
   if (!BBI)
     return;
 
-  for (auto &AssumeVH : AC->assumptions()) {
+  for (auto &AssumeVH : AC->assumptionsFor(Val)) {
     if (!AssumeVH)
       continue;
     auto *I = cast<CallInst>(AssumeVH);
     if (!isValidAssumeForContext(I, BBI, DT))
       continue;
 
-    Value *C = I->getArgOperand(0);
-    if (ICmpInst *ICI = dyn_cast<ICmpInst>(C)) {
-      LVILatticeVal Result;
-      if (getValueFromFromCondition(Val, ICI, Result))
-        BBLV = intersect(BBLV, Result);
-    }
+    BBLV = intersect(BBLV, getValueFromCondition(Val, I->getArgOperand(0)));
+  }
+
+  // If guards are not used in the module, don't spend time looking for them
+  auto *GuardDecl = BBI->getModule()->getFunction(
+          Intrinsic::getName(Intrinsic::experimental_guard));
+  if (!GuardDecl || GuardDecl->use_empty())
+    return;
+
+  for (Instruction &I : make_range(BBI->getIterator().getReverse(),
+                                   BBI->getParent()->rend())) {
+    Value *Cond = nullptr;
+    if (match(&I, m_Intrinsic<Intrinsic::experimental_guard>(m_Value(Cond))))
+      BBLV = intersect(BBLV, getValueFromCondition(Val, Cond));
   }
 }
 
-bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
+bool LazyValueInfoImpl::solveBlockValueSelect(LVILatticeVal &BBLV,
                                                SelectInst *SI, BasicBlock *BB) {
 
   // Recurse on our inputs if needed
   if (!hasBlockValue(SI->getTrueValue(), BB)) {
     if (pushBlockValue(std::make_pair(BB, SI->getTrueValue())))
       return false;
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
   LVILatticeVal TrueVal = getBlockValue(SI->getTrueValue(), BB);
   // If we hit overdefined, don't ask more queries.  We want to avoid poisoning
   // extra slots in the table if we can.
   if (TrueVal.isOverdefined()) {
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
 
   if (!hasBlockValue(SI->getFalseValue(), BB)) {
     if (pushBlockValue(std::make_pair(BB, SI->getFalseValue())))
       return false;
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
   LVILatticeVal FalseVal = getBlockValue(SI->getFalseValue(), BB);
   // If we hit overdefined, don't ask more queries.  We want to avoid poisoning
   // extra slots in the table if we can.
   if (FalseVal.isOverdefined()) {
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
 
@@ -916,22 +991,22 @@ bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
     // ValueTracking getting smarter looking back past our immediate inputs.)
     if (SelectPatternResult::isMinOrMax(SPR.Flavor) &&
         LHS == SI->getTrueValue() && RHS == SI->getFalseValue()) {
-      switch (SPR.Flavor) {
-      default:
-        llvm_unreachable("unexpected minmax type!");
-      case SPF_SMIN:                   /// Signed minimum
-        BBLV.markConstantRange(TrueCR.smin(FalseCR));
-        return true;
-      case SPF_UMIN:                   /// Unsigned minimum
-        BBLV.markConstantRange(TrueCR.umin(FalseCR));
-        return true;
-      case SPF_SMAX:                   /// Signed maximum
-        BBLV.markConstantRange(TrueCR.smax(FalseCR));
-        return true;
-      case SPF_UMAX:                   /// Unsigned maximum
-        BBLV.markConstantRange(TrueCR.umax(FalseCR));
-        return true;
-      };
+      ConstantRange ResultCR = [&]() {
+        switch (SPR.Flavor) {
+        default:
+          llvm_unreachable("unexpected minmax type!");
+        case SPF_SMIN:                   /// Signed minimum
+          return TrueCR.smin(FalseCR);
+        case SPF_UMIN:                   /// Unsigned minimum
+          return TrueCR.umin(FalseCR);
+        case SPF_SMAX:                   /// Signed maximum
+          return TrueCR.smax(FalseCR);
+        case SPF_UMAX:                   /// Unsigned maximum
+          return TrueCR.umax(FalseCR);
+        };
+      }();
+      BBLV = LVILatticeVal::getRange(ResultCR);
+      return true;
     }
 
     // TODO: ABS, NABS from the SelectPatternResult
@@ -940,27 +1015,21 @@ bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
   // Can we constrain the facts about the true and false values by using the
   // condition itself?  This shows up with idioms like e.g. select(a > 5, a, 5).
   // TODO: We could potentially refine an overdefined true value above.
-  if (auto *ICI = dyn_cast<ICmpInst>(SI->getCondition())) {
-    LVILatticeVal TrueValTaken, FalseValTaken;
-    if (!getValueFromFromCondition(SI->getTrueValue(), ICI,
-                                   TrueValTaken, true))
-      TrueValTaken.markOverdefined();
-    if (!getValueFromFromCondition(SI->getFalseValue(), ICI,
-                                   FalseValTaken, false))
-      FalseValTaken.markOverdefined();
-
-    TrueVal = intersect(TrueVal, TrueValTaken);
-    FalseVal = intersect(FalseVal, FalseValTaken);
-
-
-    // Handle clamp idioms such as:
-    //   %24 = constantrange<0, 17>
-    //   %39 = icmp eq i32 %24, 0
-    //   %40 = add i32 %24, -1
-    //   %siv.next = select i1 %39, i32 16, i32 %40
-    //   %siv.next = constantrange<0, 17> not <-1, 17>
-    // In general, this can handle any clamp idiom which tests the edge
-    // condition via an equality or inequality.
+  Value *Cond = SI->getCondition();
+  TrueVal = intersect(TrueVal,
+                      getValueFromCondition(SI->getTrueValue(), Cond, true));
+  FalseVal = intersect(FalseVal,
+                       getValueFromCondition(SI->getFalseValue(), Cond, false));
+
+  // Handle clamp idioms such as:
+  //   %24 = constantrange<0, 17>
+  //   %39 = icmp eq i32 %24, 0
+  //   %40 = add i32 %24, -1
+  //   %siv.next = select i1 %39, i32 16, i32 %40
+  //   %siv.next = constantrange<0, 17> not <-1, 17>
+  // In general, this can handle any clamp idiom which tests the edge
+  // condition via an equality or inequality.
+  if (auto *ICI = dyn_cast<ICmpInst>(Cond)) {
     ICmpInst::Predicate Pred = ICI->getPredicate();
     Value *A = ICI->getOperand(0);
     if (ConstantInt *CIBase = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
@@ -1001,13 +1070,13 @@ bool LazyValueInfoCache::solveBlockValueSelect(LVILatticeVal &BBLV,
   return true;
 }
 
-bool LazyValueInfoCache::solveBlockValueCast(LVILatticeVal &BBLV,
+bool LazyValueInfoImpl::solveBlockValueCast(LVILatticeVal &BBLV,
                                              Instruction *BBI,
                                              BasicBlock *BB) {
   if (!BBI->getOperand(0)->getType()->isSized()) {
     // Without knowing how wide the input is, we can't analyze it in any useful
     // way.
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
 
@@ -1024,7 +1093,7 @@ bool LazyValueInfoCache::solveBlockValueCast(LVILatticeVal &BBLV,
     // Unhandled instructions are overdefined.
     DEBUG(dbgs() << " compute BB '" << BB->getName()
                  << "' - overdefined (unknown cast).\n");
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   }
 
@@ -1041,7 +1110,8 @@ bool LazyValueInfoCache::solveBlockValueCast(LVILatticeVal &BBLV,
   ConstantRange LHSRange = ConstantRange(OperandBitWidth);
   if (hasBlockValue(BBI->getOperand(0), BB)) {
     LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
-    intersectAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
+    intersectAssumeOrGuardBlockValueConstantRange(BBI->getOperand(0), LHSVal,
+                                                  BBI);
     if (LHSVal.isConstantRange())
       LHSRange = LHSVal.getConstantRange();
   }
@@ -1052,31 +1122,12 @@ bool LazyValueInfoCache::solveBlockValueCast(LVILatticeVal &BBLV,
   // NOTE: We're currently limited by the set of operations that ConstantRange
   // can evaluate symbolically.  Enhancing that set will allows us to analyze
   // more definitions.
-  LVILatticeVal Result;
-  switch (BBI->getOpcode()) {
-  case Instruction::Trunc:
-    Result.markConstantRange(LHSRange.truncate(ResultBitWidth));
-    break;
-  case Instruction::SExt:
-    Result.markConstantRange(LHSRange.signExtend(ResultBitWidth));
-    break;
-  case Instruction::ZExt:
-    Result.markConstantRange(LHSRange.zeroExtend(ResultBitWidth));
-    break;
-  case Instruction::BitCast:
-    Result.markConstantRange(LHSRange);
-    break;
-  default:
-    // Should be dead if the code above is correct
-    llvm_unreachable("inconsistent with above");
-    break;
-  }
-
-  BBLV = Result;
+  auto CastOp = (Instruction::CastOps) BBI->getOpcode();
+  BBLV = LVILatticeVal::getRange(LHSRange.castOp(CastOp, ResultBitWidth));
   return true;
 }
 
-bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
+bool LazyValueInfoImpl::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
                                                  Instruction *BBI,
                                                  BasicBlock *BB) {
 
@@ -1101,7 +1152,7 @@ bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
     // Unhandled instructions are overdefined.
     DEBUG(dbgs() << " compute BB '" << BB->getName()
                  << "' - overdefined (unknown binary operator).\n");
-    BBLV.markOverdefined();
+    BBLV = LVILatticeVal::getOverdefined();
     return true;
   };
 
@@ -1118,7 +1169,8 @@ bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
   ConstantRange LHSRange = ConstantRange(OperandBitWidth);
   if (hasBlockValue(BBI->getOperand(0), BB)) {
     LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
-    intersectAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
+    intersectAssumeOrGuardBlockValueConstantRange(BBI->getOperand(0), LHSVal,
+                                                  BBI);
     if (LHSVal.isConstantRange())
       LHSRange = LHSVal.getConstantRange();
   }
@@ -1129,82 +1181,114 @@ bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
   // NOTE: We're currently limited by the set of operations that ConstantRange
   // can evaluate symbolically.  Enhancing that set will allows us to analyze
   // more definitions.
-  LVILatticeVal Result;
-  switch (BBI->getOpcode()) {
-  case Instruction::Add:
-    Result.markConstantRange(LHSRange.add(RHSRange));
-    break;
-  case Instruction::Sub:
-    Result.markConstantRange(LHSRange.sub(RHSRange));
-    break;
-  case Instruction::Mul:
-    Result.markConstantRange(LHSRange.multiply(RHSRange));
-    break;
-  case Instruction::UDiv:
-    Result.markConstantRange(LHSRange.udiv(RHSRange));
-    break;
-  case Instruction::Shl:
-    Result.markConstantRange(LHSRange.shl(RHSRange));
-    break;
-  case Instruction::LShr:
-    Result.markConstantRange(LHSRange.lshr(RHSRange));
-    break;
-  case Instruction::And:
-    Result.markConstantRange(LHSRange.binaryAnd(RHSRange));
-    break;
-  case Instruction::Or:
-    Result.markConstantRange(LHSRange.binaryOr(RHSRange));
-    break;
-  default:
-    // Should be dead if the code above is correct
-    llvm_unreachable("inconsistent with above");
-    break;
-  }
-
-  BBLV = Result;
+  auto BinOp = (Instruction::BinaryOps) BBI->getOpcode();
+  BBLV = LVILatticeVal::getRange(LHSRange.binaryOp(BinOp, RHSRange));
   return true;
 }
 
-bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
-                               LVILatticeVal &Result, bool isTrueDest) {
-  assert(ICI && "precondition");
-  if (isa<Constant>(ICI->getOperand(1))) {
-    if (ICI->isEquality() && ICI->getOperand(0) == Val) {
+static LVILatticeVal getValueFromICmpCondition(Value *Val, ICmpInst *ICI,
+                                               bool isTrueDest) {
+  Value *LHS = ICI->getOperand(0);
+  Value *RHS = ICI->getOperand(1);
+  CmpInst::Predicate Predicate = ICI->getPredicate();
+
+  if (isa<Constant>(RHS)) {
+    if (ICI->isEquality() && LHS == Val) {
       // We know that V has the RHS constant if this is a true SETEQ or
       // false SETNE.
-      if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
-        Result = LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
+      if (isTrueDest == (Predicate == ICmpInst::ICMP_EQ))
+        return LVILatticeVal::get(cast<Constant>(RHS));
       else
-        Result = LVILatticeVal::getNot(cast<Constant>(ICI->getOperand(1)));
-      return true;
+        return LVILatticeVal::getNot(cast<Constant>(RHS));
     }
+  }
 
-    // Recognize the range checking idiom that InstCombine produces.
-    // (X-C1) u< C2 --> [C1, C1+C2)
-    ConstantInt *NegOffset = nullptr;
-    if (ICI->getPredicate() == ICmpInst::ICMP_ULT)
-      match(ICI->getOperand(0), m_Add(m_Specific(Val),
-                                      m_ConstantInt(NegOffset)));
-
-    ConstantInt *CI = dyn_cast<ConstantInt>(ICI->getOperand(1));
-    if (CI && (ICI->getOperand(0) == Val || NegOffset)) {
-      // Calculate the range of values that are allowed by the comparison
-      ConstantRange CmpRange(CI->getValue());
-      ConstantRange TrueValues =
-          ConstantRange::makeAllowedICmpRegion(ICI->getPredicate(), CmpRange);
+  if (!Val->getType()->isIntegerTy())
+    return LVILatticeVal::getOverdefined();
+
+  // Use ConstantRange::makeAllowedICmpRegion in order to determine the possible
+  // range of Val guaranteed by the condition. Recognize comparisons in the from
+  // of:
+  //  icmp <pred> Val, ...
+  //  icmp <pred> (add Val, Offset), ...
+  // The latter is the range checking idiom that InstCombine produces. Subtract
+  // the offset from the allowed range for RHS in this case.
+
+  // Val or (add Val, Offset) can be on either hand of the comparison
+  if (LHS != Val && !match(LHS, m_Add(m_Specific(Val), m_ConstantInt()))) {
+    std::swap(LHS, RHS);
+    Predicate = CmpInst::getSwappedPredicate(Predicate);
+  }
 
-      if (NegOffset) // Apply the offset from above.
-        TrueValues = TrueValues.subtract(NegOffset->getValue());
+  ConstantInt *Offset = nullptr;
+  if (LHS != Val)
+    match(LHS, m_Add(m_Specific(Val), m_ConstantInt(Offset)));
+
+  if (LHS == Val || Offset) {
+    // Calculate the range of values that are allowed by the comparison
+    ConstantRange RHSRange(RHS->getType()->getIntegerBitWidth(),
+                           /*isFullSet=*/true);
+    if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS))
+      RHSRange = ConstantRange(CI->getValue());
+    else if (Instruction *I = dyn_cast<Instruction>(RHS))
+      if (auto *Ranges = I->getMetadata(LLVMContext::MD_range))
+        RHSRange = getConstantRangeFromMetadata(*Ranges);
+
+    // If we're interested in the false dest, invert the condition
+    CmpInst::Predicate Pred =
+            isTrueDest ? Predicate : CmpInst::getInversePredicate(Predicate);
+    ConstantRange TrueValues =
+            ConstantRange::makeAllowedICmpRegion(Pred, RHSRange);
 
-      // If we're interested in the false dest, invert the condition.
-      if (!isTrueDest) TrueValues = TrueValues.inverse();
+    if (Offset) // Apply the offset from above.
+      TrueValues = TrueValues.subtract(Offset->getValue());
 
-      Result = LVILatticeVal::getRange(std::move(TrueValues));
-      return true;
-    }
+    return LVILatticeVal::getRange(std::move(TrueValues));
   }
 
-  return false;
+  return LVILatticeVal::getOverdefined();
+}
+
+static LVILatticeVal
+getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest,
+                      DenseMap<Value*, LVILatticeVal> &Visited);
+
+static LVILatticeVal
+getValueFromConditionImpl(Value *Val, Value *Cond, bool isTrueDest,
+                          DenseMap<Value*, LVILatticeVal> &Visited) {
+  if (ICmpInst *ICI = dyn_cast<ICmpInst>(Cond))
+    return getValueFromICmpCondition(Val, ICI, isTrueDest);
+
+  // Handle conditions in the form of (cond1 && cond2), we know that on the
+  // true dest path both of the conditions hold.
+  if (!isTrueDest)
+    return LVILatticeVal::getOverdefined();
+
+  BinaryOperator *BO = dyn_cast<BinaryOperator>(Cond);
+  if (!BO || BO->getOpcode() != BinaryOperator::And)
+    return LVILatticeVal::getOverdefined();
+
+  auto RHS = getValueFromCondition(Val, BO->getOperand(0), isTrueDest, Visited);
+  auto LHS = getValueFromCondition(Val, BO->getOperand(1), isTrueDest, Visited);
+  return intersect(RHS, LHS);
+}
+
+static LVILatticeVal
+getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest,
+                      DenseMap<Value*, LVILatticeVal> &Visited) {
+  auto I = Visited.find(Cond);
+  if (I != Visited.end())
+    return I->second;
+
+  auto Result = getValueFromConditionImpl(Val, Cond, isTrueDest, Visited);
+  Visited[Cond] = Result;
+  return Result;
+}
+
+LVILatticeVal getValueFromCondition(Value *Val, Value *Cond, bool isTrueDest) {
+  assert(Cond && "precondition");
+  DenseMap<Value*, LVILatticeVal> Visited;
+  return getValueFromCondition(Val, Cond, isTrueDest, Visited);
 }
 
 /// \brief Compute the value of Val on the edge BBFrom -> BBTo. Returns false if
@@ -1233,9 +1317,9 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
 
       // If the condition of the branch is an equality comparison, we may be
       // able to infer the value.
-      if (ICmpInst *ICI = dyn_cast<ICmpInst>(BI->getCondition()))
-        if (getValueFromFromCondition(Val, ICI, Result, isTrueDest))
-          return true;
+      Result = getValueFromCondition(Val, BI->getCondition(), isTrueDest);
+      if (!Result.isOverdefined())
+        return true;
     }
   }
 
@@ -1267,7 +1351,7 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
 
 /// \brief Compute the value of Val on the edge BBFrom -> BBTo or the value at
 /// the basic block if the edge does not constrain Val.
-bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
+bool LazyValueInfoImpl::getEdgeValue(Value *Val, BasicBlock *BBFrom,
                                       BasicBlock *BBTo, LVILatticeVal &Result,
                                       Instruction *CxtI) {
   // If already a constant, there is nothing to compute.
@@ -1280,7 +1364,7 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
   if (!getEdgeValueLocal(Val, BBFrom, BBTo, LocalResult))
     // If we couldn't constrain the value on the edge, LocalResult doesn't
     // provide any information.
-    LocalResult.markOverdefined();
+    LocalResult = LVILatticeVal::getOverdefined();
 
   if (hasSingleValue(LocalResult)) {
     // Can't get any more precise here
@@ -1298,39 +1382,40 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
 
   // Try to intersect ranges of the BB and the constraint on the edge.
   LVILatticeVal InBlock = getBlockValue(Val, BBFrom);
-  intersectAssumeBlockValueConstantRange(Val, InBlock, BBFrom->getTerminator());
+  intersectAssumeOrGuardBlockValueConstantRange(Val, InBlock,
+                                                BBFrom->getTerminator());
   // We can use the context instruction (generically the ultimate instruction
   // the calling pass is trying to simplify) here, even though the result of
   // this function is generally cached when called from the solve* functions
   // (and that cached result might be used with queries using a different
   // context instruction), because when this function is called from the solve*
   // functions, the context instruction is not provided. When called from
-  // LazyValueInfoCache::getValueOnEdge, the context instruction is provided,
+  // LazyValueInfoImpl::getValueOnEdge, the context instruction is provided,
   // but then the result is not cached.
-  intersectAssumeBlockValueConstantRange(Val, InBlock, CxtI);
+  intersectAssumeOrGuardBlockValueConstantRange(Val, InBlock, CxtI);
 
   Result = intersect(LocalResult, InBlock);
   return true;
 }
 
-LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB,
+LVILatticeVal LazyValueInfoImpl::getValueInBlock(Value *V, BasicBlock *BB,
                                                   Instruction *CxtI) {
   DEBUG(dbgs() << "LVI Getting block end value " << *V << " at '"
         << BB->getName() << "'\n");
 
   assert(BlockValueStack.empty() && BlockValueSet.empty());
   if (!hasBlockValue(V, BB)) {
-    pushBlockValue(std::make_pair(BB, V)); 
+    pushBlockValue(std::make_pair(BB, V));
     solve();
   }
   LVILatticeVal Result = getBlockValue(V, BB);
-  intersectAssumeBlockValueConstantRange(V, Result, CxtI);
+  intersectAssumeOrGuardBlockValueConstantRange(V, Result, CxtI);
 
   DEBUG(dbgs() << "  Result = " << Result << "\n");
   return Result;
 }
 
-LVILatticeVal LazyValueInfoCache::getValueAt(Value *V, Instruction *CxtI) {
+LVILatticeVal LazyValueInfoImpl::getValueAt(Value *V, Instruction *CxtI) {
   DEBUG(dbgs() << "LVI Getting value " << *V << " at '"
         << CxtI->getName() << "'\n");
 
@@ -1340,13 +1425,13 @@ LVILatticeVal LazyValueInfoCache::getValueAt(Value *V, Instruction *CxtI) {
   LVILatticeVal Result = LVILatticeVal::getOverdefined();
   if (auto *I = dyn_cast<Instruction>(V))
     Result = getFromRangeMetadata(I);
-  intersectAssumeBlockValueConstantRange(V, Result, CxtI);
+  intersectAssumeOrGuardBlockValueConstantRange(V, Result, CxtI);
 
   DEBUG(dbgs() << "  Result = " << Result << "\n");
   return Result;
 }
 
-LVILatticeVal LazyValueInfoCache::
+LVILatticeVal LazyValueInfoImpl::
 getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
                Instruction *CxtI) {
   DEBUG(dbgs() << "LVI Getting edge value " << *V << " from '"
@@ -1364,75 +1449,24 @@ getValueOnEdge(Value *V, BasicBlock *FromBB, BasicBlock *ToBB,
   return Result;
 }
 
-void LazyValueInfoCache::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc,
-                                    BasicBlock *NewSucc) {
-  // When an edge in the graph has been threaded, values that we could not
-  // determine a value for before (i.e. were marked overdefined) may be
-  // possible to solve now. We do NOT try to proactively update these values.
-  // Instead, we clear their entries from the cache, and allow lazy updating to
-  // recompute them when needed.
-
-  // The updating process is fairly simple: we need to drop cached info
-  // for all values that were marked overdefined in OldSucc, and for those same
-  // values in any successor of OldSucc (except NewSucc) in which they were
-  // also marked overdefined.
-  std::vector<BasicBlock*> worklist;
-  worklist.push_back(OldSucc);
-
-  auto I = OverDefinedCache.find(OldSucc);
-  if (I == OverDefinedCache.end())
-    return; // Nothing to process here.
-  SmallVector<Value *, 4> ValsToClear(I->second.begin(), I->second.end());
-
-  // Use a worklist to perform a depth-first search of OldSucc's successors.
-  // NOTE: We do not need a visited list since any blocks we have already
-  // visited will have had their overdefined markers cleared already, and we
-  // thus won't loop to their successors.
-  while (!worklist.empty()) {
-    BasicBlock *ToUpdate = worklist.back();
-    worklist.pop_back();
-
-    // Skip blocks only accessible through NewSucc.
-    if (ToUpdate == NewSucc) continue;
-
-    bool changed = false;
-    for (Value *V : ValsToClear) {
-      // If a value was marked overdefined in OldSucc, and is here too...
-      auto OI = OverDefinedCache.find(ToUpdate);
-      if (OI == OverDefinedCache.end())
-        continue;
-      SmallPtrSetImpl<Value *> &ValueSet = OI->second;
-      if (!ValueSet.count(V))
-        continue;
-
-      ValueSet.erase(V);
-      if (ValueSet.empty())
-        OverDefinedCache.erase(OI);
-
-      // If we removed anything, then we potentially need to update
-      // blocks successors too.
-      changed = true;
-    }
-
-    if (!changed) continue;
-
-    worklist.insert(worklist.end(), succ_begin(ToUpdate), succ_end(ToUpdate));
-  }
+void LazyValueInfoImpl::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc,
+                                   BasicBlock *NewSucc) {
+  TheCache.threadEdgeImpl(OldSucc, NewSucc);
 }
 
 //===----------------------------------------------------------------------===//
 //                            LazyValueInfo Impl
 //===----------------------------------------------------------------------===//
 
-/// This lazily constructs the LazyValueInfoCache.
-static LazyValueInfoCache &getCache(void *&PImpl, AssumptionCache *AC,
-                                    const DataLayout *DL,
-                                    DominatorTree *DT = nullptr) {
+/// This lazily constructs the LazyValueInfoImpl.
+static LazyValueInfoImpl &getImpl(void *&PImpl, AssumptionCache *AC,
+                                  const DataLayout *DL,
+                                  DominatorTree *DT = nullptr) {
   if (!PImpl) {
     assert(DL && "getCache() called with a null DataLayout");
-    PImpl = new LazyValueInfoCache(AC, *DL, DT);
+    PImpl = new LazyValueInfoImpl(AC, *DL, DT);
   }
-  return *static_cast<LazyValueInfoCache*>(PImpl);
+  return *static_cast<LazyValueInfoImpl*>(PImpl);
 }
 
 bool LazyValueInfoWrapperPass::runOnFunction(Function &F) {
@@ -1445,7 +1479,7 @@ bool LazyValueInfoWrapperPass::runOnFunction(Function &F) {
   Info.TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
 
   if (Info.PImpl)
-    getCache(Info.PImpl, Info.AC, &DL, Info.DT).clear();
+    getImpl(Info.PImpl, Info.AC, &DL, Info.DT).clear();
 
   // Fully lazy.
   return false;
@@ -1464,7 +1498,7 @@ LazyValueInfo::~LazyValueInfo() { releaseMemory(); }
 void LazyValueInfo::releaseMemory() {
   // If the cache was allocated, free it.
   if (PImpl) {
-    delete &getCache(PImpl, AC, nullptr);
+    delete &getImpl(PImpl, AC, nullptr);
     PImpl = nullptr;
   }
 }
@@ -1479,7 +1513,6 @@ LazyValueInfo LazyValueAnalysis::run(Function &F, FunctionAnalysisManager &FAM)
   return LazyValueInfo(&AC, &TLI, DT);
 }
 
- 
 /// Returns true if we can statically tell that this value will never be a
 /// "useful" constant.  In practice, this means we've got something like an
 /// alloca or a malloc call for which a comparison against a constant can
@@ -1502,7 +1535,7 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB,
 
   const DataLayout &DL = BB->getModule()->getDataLayout();
   LVILatticeVal Result =
-      getCache(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
+      getImpl(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
 
   if (Result.isConstant())
     return Result.getConstant();
@@ -1520,12 +1553,15 @@ ConstantRange LazyValueInfo::getConstantRange(Value *V, BasicBlock *BB,
   unsigned Width = V->getType()->getIntegerBitWidth();
   const DataLayout &DL = BB->getModule()->getDataLayout();
   LVILatticeVal Result =
-      getCache(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
-  assert(!Result.isConstant());
+      getImpl(PImpl, AC, &DL, DT).getValueInBlock(V, BB, CxtI);
   if (Result.isUndefined())
     return ConstantRange(Width, /*isFullSet=*/false);
   if (Result.isConstantRange())
     return Result.getConstantRange();
+  // We represent ConstantInt constants as constant ranges but other kinds
+  // of integer constants, i.e. ConstantExpr will be tagged as constants
+  assert(!(Result.isConstant() && isa<ConstantInt>(Result.getConstant())) &&
+         "ConstantInt value must be represented as constantrange");
   return ConstantRange(Width, /*isFullSet=*/true);
 }
 
@@ -1536,7 +1572,7 @@ Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,
                                            Instruction *CxtI) {
   const DataLayout &DL = FromBB->getModule()->getDataLayout();
   LVILatticeVal Result =
-      getCache(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
+      getImpl(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
 
   if (Result.isConstant())
     return Result.getConstant();
@@ -1583,8 +1619,8 @@ static LazyValueInfo::Tristate getPredicateResult(unsigned Pred, Constant *C,
     }
 
     // Handle more complex predicates.
-    ConstantRange TrueValues =
-        ICmpInst::makeConstantRange((ICmpInst::Predicate)Pred, CI->getValue());
+    ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(
+        (ICmpInst::Predicate)Pred, CI->getValue());
     if (TrueValues.contains(CR))
       return LazyValueInfo::True;
     if (TrueValues.inverse().contains(CR))
@@ -1624,7 +1660,7 @@ LazyValueInfo::getPredicateOnEdge(unsigned Pred, Value *V, Constant *C,
                                   Instruction *CxtI) {
   const DataLayout &DL = FromBB->getModule()->getDataLayout();
   LVILatticeVal Result =
-      getCache(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
+      getImpl(PImpl, AC, &DL, DT).getValueOnEdge(V, FromBB, ToBB, CxtI);
 
   return getPredicateResult(Pred, C, Result, DL, TLI);
 }
@@ -1644,7 +1680,7 @@ LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
       return LazyValueInfo::True;
   }
   const DataLayout &DL = CxtI->getModule()->getDataLayout();
-  LVILatticeVal Result = getCache(PImpl, AC, &DL, DT).getValueAt(V, CxtI);
+  LVILatticeVal Result = getImpl(PImpl, AC, &DL, DT).getValueAt(V, CxtI);
   Tristate Ret = getPredicateResult(Pred, C, Result, DL, TLI);
   if (Ret != Unknown)
     return Ret;
@@ -1703,7 +1739,7 @@ LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
         }
         if (Baseline != Unknown)
           return Baseline;
-      }    
+      }
 
     // For a comparison where the V is outside this block, it's possible
     // that we've branched on it before. Look to see if the value is known
@@ -1734,13 +1770,13 @@ void LazyValueInfo::threadEdge(BasicBlock *PredBB, BasicBlock *OldSucc,
                                BasicBlock *NewSucc) {
   if (PImpl) {
     const DataLayout &DL = PredBB->getModule()->getDataLayout();
-    getCache(PImpl, AC, &DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
+    getImpl(PImpl, AC, &DL, DT).threadEdge(PredBB, OldSucc, NewSucc);
   }
 }
 
 void LazyValueInfo::eraseBlock(BasicBlock *BB) {
   if (PImpl) {
     const DataLayout &DL = BB->getModule()->getDataLayout();
-    getCache(PImpl, AC, &DL, DT).eraseBlock(BB);
+    getImpl(PImpl, AC, &DL, DT).eraseBlock(BB);
   }
 }