MFC r309124:

Upgrade our copies of clang, llvm, lldb, compiler-rt and libc++ to 3.9.0
release, and add lld 3.9.0.  Also completely revamp the build system for
clang, llvm, lldb and their related tools.

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

Release notes for llvm, clang and lld are available here:
<http://llvm.org/releases/3.9.0/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/clang/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.9.0/tools/lld/docs/ReleaseNotes.html>

Thanks to Ed Maste, Bryan Drewery, Andrew Turner, Antoine Brodin and Jan
Beich for their help.

Relnotes:	yes

MFC r309147:

Pull in r282174 from upstream llvm trunk (by Krzysztof Parzyszek):

  [PPC] Set SP after loading data from stack frame, if no red zone is
  present

  Follow-up to r280705: Make sure that the SP is only restored after
  all data is loaded from the stack frame, if there is no red zone.

  This completes the fix for
  https://llvm.org/bugs/show_bug.cgi?id=26519.

  Differential Revision: https://reviews.llvm.org/D24466

Reported by:    Mark Millard
PR:             214433

MFC r309149:

Pull in r283060 from upstream llvm trunk (by Hal Finkel):

  [PowerPC] Refactor soft-float support, and enable PPC64 soft float

  This change enables soft-float for PowerPC64, and also makes
  soft-float disable all vector instruction sets for both 32-bit and
  64-bit modes. This latter part is necessary because the PPC backend
  canonicalizes many Altivec vector types to floating-point types, and
  so soft-float breaks scalarization support for many operations. Both
  for embedded targets and for operating-system kernels desiring
  soft-float support, it seems reasonable that disabling hardware
  floating-point also disables vector instructions (embedded targets
  without hardware floating point support are unlikely to have Altivec,
  etc. and operating system kernels desiring not to use floating-point
  registers to lower syscall cost are unlikely to want to use vector
  registers either). If someone needs this to work, we'll need to
  change the fact that we promote many Altivec operations to act on
  v4f32. To make it possible to disable Altivec when soft-float is
  enabled, hardware floating-point support needs to be expressed as a
  positive feature, like the others, and not a negative feature,
  because target features cannot have dependencies on the disabling of
  some other feature. So +soft-float has now become -hard-float.

  Fixes PR26970.

Pull in r283061 from upstream clang trunk (by Hal Finkel):

  [PowerPC] Enable soft-float for PPC64, and +soft-float -> -hard-float

  Enable soft-float support on PPC64, as the backend now supports it.
  Also, the backend now uses -hard-float instead of +soft-float, so set
  the target features accordingly.

  Fixes PR26970.

Reported by:	Mark Millard
PR:		214433

MFC r309212:

Add a few missed clang 3.9.0 files to OptionalObsoleteFiles.

MFC r309262:

Fix packaging for clang, lldb and lld 3.9.0

During the upgrade of clang/llvm etc to 3.9.0 in r309124, the PACKAGE
directive in the usr.bin/clang/*.mk files got dropped accidentally.

Restore it, with a few minor changes and additions:
* Correct license in clang.ucl to NCSA
* Add PACKAGE=clang for clang and most of the "ll" tools
* Put lldb in its own package
* Put lld in its own package

Reviewed by:	gjb, jmallett
Differential Revision: https://reviews.freebsd.org/D8666

MFC r309656:

During the bootstrap phase, when building the minimal llvm library on
PowerPC, add lib/Support/Atomic.cpp.  This is needed because upstream
llvm revision r271821 disabled the use of std::call_once, which causes
some fallback functions from Atomic.cpp to be used instead.

Reported by:	Mark Millard
PR:		214902

MFC r309835:

Tentatively apply https://reviews.llvm.org/D18730 to work around gcc PR
70528 (bogus error: constructor required before non-static data member).
This should fix buildworld with the external gcc package.

Reported by:	https://jenkins.freebsd.org/job/FreeBSD_HEAD_amd64_gcc/

MFC r310194:

Upgrade our copies of clang, llvm, lld, lldb, compiler-rt and libc++ to
3.9.1 release.

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

Release notes for llvm, clang and lld will be available here:
<http://releases.llvm.org/3.9.1/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/clang/docs/ReleaseNotes.html>
<http://releases.llvm.org/3.9.1/tools/lld/docs/ReleaseNotes.html>

Relnotes:	yes

1 files changed, 499 insertions, 208 deletions

diff --git a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
index 961c010..3ce667f 100644
--- a/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/contrib/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -38,18 +38,19 @@ using namespace PatternMatch;
 
 #define DEBUG_TYPE "lazy-value-info"
 
-char LazyValueInfo::ID = 0;
-INITIALIZE_PASS_BEGIN(LazyValueInfo, "lazy-value-info",
+char LazyValueInfoWrapperPass::ID = 0;
+INITIALIZE_PASS_BEGIN(LazyValueInfoWrapperPass, "lazy-value-info",
                 "Lazy Value Information Analysis", false, true)
 INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
-INITIALIZE_PASS_END(LazyValueInfo, "lazy-value-info",
+INITIALIZE_PASS_END(LazyValueInfoWrapperPass, "lazy-value-info",
                 "Lazy Value Information Analysis", false, true)
 
 namespace llvm {
-  FunctionPass *createLazyValueInfoPass() { return new LazyValueInfo(); }
+  FunctionPass *createLazyValueInfoPass() { return new LazyValueInfoWrapperPass(); }
 }
 
+char LazyValueAnalysis::PassID;
 
 //===----------------------------------------------------------------------===//
 //                               LVILatticeVal
@@ -63,19 +64,24 @@ namespace llvm {
 namespace {
 class LVILatticeVal {
   enum LatticeValueTy {
-    /// This Value has no known value yet.
+    /// This Value has no known value yet.  As a result, this implies the
+    /// producing instruction is dead.  Caution: We use this as the starting
+    /// state in our local meet rules.  In this usage, it's taken to mean
+    /// "nothing known yet".
     undefined,
 
-    /// This Value has a specific constant value.
+    /// This Value has a specific constant value.  (For integers, constantrange
+    /// is used instead.)
     constant,
 
-    /// This Value is known to not have the specified value.
+    /// This Value is known to not have the specified value.  (For integers,
+    /// constantrange is used instead.)
     notconstant,
 
-    /// The Value falls within this range.
+    /// The Value falls within this range. (Used only for integer typed values.)
     constantrange,
 
-    /// This value is not known to be constant, and we know that it has a value.
+    /// We can not precisely model the dynamic values this value might take.
     overdefined
   };
 
@@ -102,7 +108,7 @@ public:
   }
   static LVILatticeVal getRange(ConstantRange CR) {
     LVILatticeVal Res;
-    Res.markConstantRange(CR);
+    Res.markConstantRange(std::move(CR));
     return Res;
   }
   static LVILatticeVal getOverdefined() {
@@ -110,7 +116,7 @@ public:
     Res.markOverdefined();
     return Res;
   }
-  
+
   bool isUndefined() const     { return Tag == undefined; }
   bool isConstant() const      { return Tag == constant; }
   bool isNotConstant() const   { return Tag == notconstant; }
@@ -176,13 +182,13 @@ public:
   }
 
   /// Return true if this is a change in status.
-  bool markConstantRange(const ConstantRange NewR) {
+  bool markConstantRange(ConstantRange NewR) {
     if (isConstantRange()) {
       if (NewR.isEmptySet())
         return markOverdefined();
 
       bool changed = Range != NewR;
-      Range = NewR;
+      Range = std::move(NewR);
       return changed;
     }
 
@@ -191,7 +197,7 @@ public:
       return markOverdefined();
 
     Tag = constantrange;
-    Range = NewR;
+    Range = std::move(NewR);
     return true;
   }
 
@@ -230,11 +236,6 @@ public:
         return markOverdefined();
       }
 
-      // RHS is a ConstantRange, LHS is a non-integer Constant.
-
-      // FIXME: consider the case where RHS is a range [1, 0) and LHS is
-      // a function. The correct result is to pick up RHS.
-
       return markOverdefined();
     }
 
@@ -287,13 +288,76 @@ raw_ostream &operator<<(raw_ostream &OS, const LVILatticeVal &Val) {
 
   if (Val.isNotConstant())
     return OS << "notconstant<" << *Val.getNotConstant() << '>';
-  else if (Val.isConstantRange())
+  if (Val.isConstantRange())
     return OS << "constantrange<" << Val.getConstantRange().getLower() << ", "
               << Val.getConstantRange().getUpper() << '>';
   return OS << "constant<" << *Val.getConstant() << '>';
 }
 }
 
+/// Returns true if this lattice value represents at most one possible value.
+/// This is as precise as any lattice value can get while still representing
+/// reachable code.
+static bool hasSingleValue(const LVILatticeVal &Val) {
+  if (Val.isConstantRange() &&
+      Val.getConstantRange().isSingleElement())
+    // Integer constants are single element ranges
+    return true;
+  if (Val.isConstant())
+    // Non integer constants
+    return true;
+  return false;
+}
+
+/// Combine two sets of facts about the same value into a single set of
+/// facts.  Note that this method is not suitable for merging facts along
+/// different paths in a CFG; that's what the mergeIn function is for.  This
+/// is for merging facts gathered about the same value at the same location
+/// through two independent means.
+/// Notes:
+/// * This method does not promise to return the most precise possible lattice
+///   value implied by A and B.  It is allowed to return any lattice element
+///   which is at least as strong as *either* A or B (unless our facts
+///   conflict, see below).
+/// * Due to unreachable code, the intersection of two lattice values could be
+///   contradictory.  If this happens, we return some valid lattice value so as
+///   not confuse the rest of LVI.  Ideally, we'd always return Undefined, but
+///   we do not make this guarantee.  TODO: This would be a useful enhancement.
+static LVILatticeVal intersect(LVILatticeVal A, LVILatticeVal B) {
+  // Undefined is the strongest state.  It means the value is known to be along
+  // an unreachable path.
+  if (A.isUndefined())
+    return A;
+  if (B.isUndefined())
+    return B;
+
+  // If we gave up for one, but got a useable fact from the other, use it.
+  if (A.isOverdefined())
+    return B;
+  if (B.isOverdefined())
+    return A;
+
+  // Can't get any more precise than constants.
+  if (hasSingleValue(A))
+    return A;
+  if (hasSingleValue(B))
+    return B;
+
+  // Could be either constant range or not constant here.
+  if (!A.isConstantRange() || !B.isConstantRange()) {
+    // TODO: Arbitrary choice, could be improved
+    return A;
+  }
+
+  // Intersect two constant ranges
+  ConstantRange Range =
+    A.getConstantRange().intersectWith(B.getConstantRange());
+  // Note: An empty range is implicitly converted to overdefined internally.
+  // TODO: We could instead use Undefined here since we've proven a conflict
+  // and thus know this path must be unreachable.
+  return LVILatticeVal::getRange(std::move(Range));
+}
+
 //===----------------------------------------------------------------------===//
 //                          LazyValueInfoCache Decl
 //===----------------------------------------------------------------------===//
@@ -354,6 +418,8 @@ namespace {
       if (!BlockValueSet.insert(BV).second)
         return false;  // It's already in the stack.
 
+      DEBUG(dbgs() << "PUSH: " << *BV.second << " in " << BV.first->getName()
+                   << "\n");
       BlockValueStack.push(BV);
       return true;
     }
@@ -375,30 +441,31 @@ namespace {
         lookup(Val)[BB] = Result;
     }
 
-    LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB);
-    bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T,
-                      LVILatticeVal &Result,
-                      Instruction *CxtI = nullptr);
-    bool hasBlockValue(Value *Val, BasicBlock *BB);
-
-    // These methods process one work item and may add more. A false value
-    // 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 solveBlockValueNonLocal(LVILatticeVal &BBLV,
-                                 Value *Val, BasicBlock *BB);
-    bool solveBlockValuePHINode(LVILatticeVal &BBLV,
-                                PHINode *PN, BasicBlock *BB);
-    bool solveBlockValueConstantRange(LVILatticeVal &BBLV,
-                                      Instruction *BBI, BasicBlock *BB);
-    void mergeAssumeBlockValueConstantRange(Value *Val, LVILatticeVal &BBLV,
-                                            Instruction *BBI);
-
-    void solve();
-
-    ValueCacheEntryTy &lookup(Value *V) {
-      return ValueCache[LVIValueHandle(V, this)];
-    }
+  LVILatticeVal getBlockValue(Value *Val, BasicBlock *BB);
+  bool getEdgeValue(Value *V, BasicBlock *F, BasicBlock *T,
+                    LVILatticeVal &Result, Instruction *CxtI = nullptr);
+  bool hasBlockValue(Value *Val, BasicBlock *BB);
+
+  // These methods process one work item and may add more. A false value
+  // 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 solveBlockValueNonLocal(LVILatticeVal &BBLV, Value *Val, BasicBlock *BB);
+  bool solveBlockValuePHINode(LVILatticeVal &BBLV, PHINode *PN, BasicBlock *BB);
+  bool solveBlockValueSelect(LVILatticeVal &BBLV, SelectInst *S,
+                             BasicBlock *BB);
+  bool solveBlockValueBinaryOp(LVILatticeVal &BBLV, Instruction *BBI,
+                               BasicBlock *BB);
+  bool solveBlockValueCast(LVILatticeVal &BBLV, Instruction *BBI,
+                           BasicBlock *BB);
+  void intersectAssumeBlockValueConstantRange(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);
@@ -427,7 +494,7 @@ namespace {
 
       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.
@@ -493,8 +560,8 @@ void LazyValueInfoCache::eraseBlock(BasicBlock *BB) {
   if (ODI != OverDefinedCache.end())
     OverDefinedCache.erase(ODI);
 
-  for (auto I = ValueCache.begin(), E = ValueCache.end(); I != E; ++I)
-    I->second.erase(BB);
+  for (auto &I : ValueCache)
+    I.second.erase(BB);
 }
 
 void LazyValueInfoCache::solve() {
@@ -508,6 +575,9 @@ void LazyValueInfoCache::solve() {
       assert(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");
+
       BlockValueStack.pop();
       BlockValueSet.erase(e);
     } else {
@@ -542,15 +612,12 @@ static LVILatticeVal getFromRangeMetadata(Instruction *BBI) {
   case Instruction::Invoke:
     if (MDNode *Ranges = BBI->getMetadata(LLVMContext::MD_range)) 
       if (isa<IntegerType>(BBI->getType())) {
-        ConstantRange Result = getConstantRangeFromMetadata(*Ranges);
-        return LVILatticeVal::getRange(Result);
+        return LVILatticeVal::getRange(getConstantRangeFromMetadata(*Ranges));
       }
     break;
   };
-  // Nothing known - Note that we do not want overdefined here.  We may know
-  // something else about the value and not having range metadata shouldn't
-  // cause us to throw away those facts.
-  return LVILatticeVal();
+  // Nothing known - will be intersected with other facts
+  return LVILatticeVal::getOverdefined();
 }
 
 bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
@@ -587,44 +654,47 @@ bool LazyValueInfoCache::solveBlockValue(Value *Val, BasicBlock *BB) {
     return true;
   }
 
-  // If this value is a nonnull pointer, record it's range and bailout.
-  PointerType *PT = dyn_cast<PointerType>(BBI->getType());
-  if (PT && isKnownNonNull(BBI)) {
-    Res = LVILatticeVal::getNot(ConstantPointerNull::get(PT));
+  if (auto *SI = dyn_cast<SelectInst>(BBI)) {
+    if (!solveBlockValueSelect(Res, SI, BB))
+      return false;
     insertResult(Val, BB, Res);
     return true;
   }
 
-  // If this is an instruction which supports range metadata, return the
-  // implied range.  TODO: This should be an intersection, not a union.
-  Res.mergeIn(getFromRangeMetadata(BBI), DL);
-
-  // We can only analyze the definitions of certain classes of instructions
-  // (integral binops and casts at the moment), so bail if this isn't one.
-  LVILatticeVal Result;
-  if ((!isa<BinaryOperator>(BBI) && !isa<CastInst>(BBI)) ||
-     !BBI->getType()->isIntegerTy()) {
-    DEBUG(dbgs() << " compute BB '" << BB->getName()
-                 << "' - overdefined because inst def found.\n");
-    Res.markOverdefined();
+  // 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
+  // definition.  We could easily extend this to look through geps, bitcasts,
+  // and the like to prove non-nullness, but it's not clear that's worth it
+  // compile time wise.  The context-insensative value walk done inside
+  // isKnownNonNull gets most of the profitable cases at much less expense.
+  // This does mean that we have a sensativity to where the defining
+  // instruction is placed, even if it could legally be hoisted much higher.
+  // That is unfortunate.
+  PointerType *PT = dyn_cast<PointerType>(BBI->getType());
+  if (PT && isKnownNonNull(BBI)) {
+    Res = LVILatticeVal::getNot(ConstantPointerNull::get(PT));
     insertResult(Val, BB, Res);
     return true;
   }
-
-  // FIXME: We're currently limited to binops with a constant RHS.  This should
-  // be improved.
-  BinaryOperator *BO = dyn_cast<BinaryOperator>(BBI);
-  if (BO && !isa<ConstantInt>(BO->getOperand(1))) { 
-    DEBUG(dbgs() << " compute BB '" << BB->getName()
-                 << "' - overdefined because inst def found.\n");
-
-    Res.markOverdefined();
-    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;
+    }
+    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 (!solveBlockValueConstantRange(Res, BBI, BB))
-    return false;
+  DEBUG(dbgs() << " compute BB '" << BB->getName()
+                 << "' - unknown inst def found.\n");
+  Res = getFromRangeMetadata(BBI);
   insertResult(Val, BB, Res);
   return true;
 }
@@ -660,37 +730,36 @@ static bool InstructionDereferencesPointer(Instruction *I, Value *Ptr) {
   return false;
 }
 
+/// Return true if the allocation associated with Val is ever dereferenced
+/// within the given basic block.  This establishes the fact Val is not null,
+/// but does not imply that the memory at Val is dereferenceable.  (Val may
+/// point off the end of the dereferenceable part of the object.)
+static bool isObjectDereferencedInBlock(Value *Val, BasicBlock *BB) {
+  assert(Val->getType()->isPointerTy());
+
+  const DataLayout &DL = BB->getModule()->getDataLayout();
+  Value *UnderlyingVal = GetUnderlyingObject(Val, DL);
+  // If 'GetUnderlyingObject' didn't converge, skip it. It won't converge
+  // inside InstructionDereferencesPointer either.
+  if (UnderlyingVal == GetUnderlyingObject(UnderlyingVal, DL, 1))
+    for (Instruction &I : *BB)
+      if (InstructionDereferencesPointer(&I, UnderlyingVal))
+        return true;
+  return false;
+}
+
 bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
                                                  Value *Val, BasicBlock *BB) {
   LVILatticeVal Result;  // Start Undefined.
 
-  // If this is a pointer, and there's a load from that pointer in this BB,
-  // then we know that the pointer can't be NULL.
-  bool NotNull = false;
-  if (Val->getType()->isPointerTy()) {
-    if (isKnownNonNull(Val)) {
-      NotNull = true;
-    } else {
-      const DataLayout &DL = BB->getModule()->getDataLayout();
-      Value *UnderlyingVal = GetUnderlyingObject(Val, DL);
-      // If 'GetUnderlyingObject' didn't converge, skip it. It won't converge
-      // inside InstructionDereferencesPointer either.
-      if (UnderlyingVal == GetUnderlyingObject(UnderlyingVal, DL, 1)) {
-        for (Instruction &I : *BB) {
-          if (InstructionDereferencesPointer(&I, UnderlyingVal)) {
-            NotNull = true;
-            break;
-          }
-        }
-      }
-    }
-  }
-
   // If this is the entry block, we must be asking about an argument.  The
   // value is overdefined.
   if (BB == &BB->getParent()->getEntryBlock()) {
     assert(isa<Argument>(Val) && "Unknown live-in to the entry block");
-    if (NotNull) {
+    // Bofore giving up, see if we can prove the pointer non-null local to
+    // this particular block.
+    if (Val->getType()->isPointerTy() &&
+        (isKnownNonNull(Val) || isObjectDereferencedInBlock(Val, BB))) {
       PointerType *PTy = cast<PointerType>(Val->getType());
       Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
     } else {
@@ -715,10 +784,11 @@ bool LazyValueInfoCache::solveBlockValueNonLocal(LVILatticeVal &BBLV,
     // to overdefined.
     if (Result.isOverdefined()) {
       DEBUG(dbgs() << " compute BB '" << BB->getName()
-            << "' - overdefined because of pred.\n");
-      // If we previously determined that this is a pointer that can't be null
-      // then return that rather than giving up entirely.
-      if (NotNull) {
+            << "' - overdefined because of pred (non local).\n");
+      // Bofore giving up, see if we can prove the pointer non-null local to
+      // this particular block.
+      if (Val->getType()->isPointerTy() &&
+          isObjectDereferencedInBlock(Val, BB)) {
         PointerType *PTy = cast<PointerType>(Val->getType());
         Result = LVILatticeVal::getNot(ConstantPointerNull::get(PTy));
       }
@@ -760,7 +830,7 @@ bool LazyValueInfoCache::solveBlockValuePHINode(LVILatticeVal &BBLV,
     // to overdefined.
     if (Result.isOverdefined()) {
       DEBUG(dbgs() << " compute BB '" << BB->getName()
-            << "' - overdefined because of pred.\n");
+            << "' - overdefined because of pred (local).\n");
 
       BBLV = Result;
       return true;
@@ -779,10 +849,9 @@ static bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
                                       LVILatticeVal &Result,
                                       bool isTrueDest = true);
 
-// If we can determine a constant range for the value Val in the context
-// provided by the instruction BBI, then merge it into BBLV. If we did find a
-// constant range, return true.
-void LazyValueInfoCache::mergeAssumeBlockValueConstantRange(Value *Val,
+// 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) {
   BBI = BBI ? BBI : dyn_cast<Instruction>(Val);
@@ -799,46 +868,264 @@ void LazyValueInfoCache::mergeAssumeBlockValueConstantRange(Value *Val,
     Value *C = I->getArgOperand(0);
     if (ICmpInst *ICI = dyn_cast<ICmpInst>(C)) {
       LVILatticeVal Result;
-      if (getValueFromFromCondition(Val, ICI, Result)) {
-        if (BBLV.isOverdefined())
-          BBLV = Result;
-        else
-          BBLV.mergeIn(Result, DL);
-      }
+      if (getValueFromFromCondition(Val, ICI, Result))
+        BBLV = intersect(BBLV, Result);
     }
   }
 }
 
-bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
-                                                      Instruction *BBI,
-                                                      BasicBlock *BB) {
-  // Figure out the range of the LHS.  If that fails, bail.
-  if (!hasBlockValue(BBI->getOperand(0), BB)) {
-    if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
+bool LazyValueInfoCache::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();
     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();
+    return true;
+  }
 
-  LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
-  mergeAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
-  if (!LHSVal.isConstantRange()) {
+  if (!hasBlockValue(SI->getFalseValue(), BB)) {
+    if (pushBlockValue(std::make_pair(BB, SI->getFalseValue())))
+      return false;
+    BBLV.markOverdefined();
+    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();
     return true;
   }
 
-  ConstantRange LHSRange = LHSVal.getConstantRange();
-  ConstantRange RHSRange(1);
-  IntegerType *ResultTy = cast<IntegerType>(BBI->getType());
-  if (isa<BinaryOperator>(BBI)) {
-    if (ConstantInt *RHS = dyn_cast<ConstantInt>(BBI->getOperand(1))) {
-      RHSRange = ConstantRange(RHS->getValue());
-    } else {
-      BBLV.markOverdefined();
-      return true;
+  if (TrueVal.isConstantRange() && FalseVal.isConstantRange()) {
+    ConstantRange TrueCR = TrueVal.getConstantRange();
+    ConstantRange FalseCR = FalseVal.getConstantRange();
+    Value *LHS = nullptr;
+    Value *RHS = nullptr;
+    SelectPatternResult SPR = matchSelectPattern(SI, LHS, RHS);
+    // Is this a min specifically of our two inputs?  (Avoid the risk of
+    // 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;
+      };
+    }
+
+    // TODO: ABS, NABS from the SelectPatternResult
+  }
+
+  // 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.
+    ICmpInst::Predicate Pred = ICI->getPredicate();
+    Value *A = ICI->getOperand(0);
+    if (ConstantInt *CIBase = dyn_cast<ConstantInt>(ICI->getOperand(1))) {
+      auto addConstants = [](ConstantInt *A, ConstantInt *B) {
+        assert(A->getType() == B->getType());
+        return ConstantInt::get(A->getType(), A->getValue() + B->getValue());
+      };
+      // See if either input is A + C2, subject to the constraint from the
+      // condition that A != C when that input is used.  We can assume that
+      // that input doesn't include C + C2.
+      ConstantInt *CIAdded;
+      switch (Pred) {
+      default: break;
+      case ICmpInst::ICMP_EQ:
+        if (match(SI->getFalseValue(), m_Add(m_Specific(A),
+                                             m_ConstantInt(CIAdded)))) {
+          auto ResNot = addConstants(CIBase, CIAdded);
+          FalseVal = intersect(FalseVal,
+                               LVILatticeVal::getNot(ResNot));
+        }
+        break;
+      case ICmpInst::ICMP_NE:
+        if (match(SI->getTrueValue(), m_Add(m_Specific(A),
+                                            m_ConstantInt(CIAdded)))) {
+          auto ResNot = addConstants(CIBase, CIAdded);
+          TrueVal = intersect(TrueVal,
+                              LVILatticeVal::getNot(ResNot));
+        }
+        break;
+      };
     }
   }
 
+  LVILatticeVal Result;  // Start Undefined.
+  Result.mergeIn(TrueVal, DL);
+  Result.mergeIn(FalseVal, DL);
+  BBLV = Result;
+  return true;
+}
+
+bool LazyValueInfoCache::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();
+    return true;
+  }
+
+  // Filter out casts we don't know how to reason about before attempting to
+  // recurse on our operand.  This can cut a long search short if we know we're
+  // not going to be able to get any useful information anways.
+  switch (BBI->getOpcode()) {
+  case Instruction::Trunc:
+  case Instruction::SExt:
+  case Instruction::ZExt:
+  case Instruction::BitCast:
+    break;
+  default:
+    // Unhandled instructions are overdefined.
+    DEBUG(dbgs() << " compute BB '" << BB->getName()
+                 << "' - overdefined (unknown cast).\n");
+    BBLV.markOverdefined();
+    return true;
+  }
+
+  // Figure out the range of the LHS.  If that fails, we still apply the
+  // transfer rule on the full set since we may be able to locally infer
+  // interesting facts.
+  if (!hasBlockValue(BBI->getOperand(0), BB))
+    if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
+      // More work to do before applying this transfer rule.
+      return false;
+
+  const unsigned OperandBitWidth =
+    DL.getTypeSizeInBits(BBI->getOperand(0)->getType());
+  ConstantRange LHSRange = ConstantRange(OperandBitWidth);
+  if (hasBlockValue(BBI->getOperand(0), BB)) {
+    LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
+    intersectAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
+    if (LHSVal.isConstantRange())
+      LHSRange = LHSVal.getConstantRange();
+  }
+
+  const unsigned ResultBitWidth =
+    cast<IntegerType>(BBI->getType())->getBitWidth();
+
+  // 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;
+  return true;
+}
+
+bool LazyValueInfoCache::solveBlockValueBinaryOp(LVILatticeVal &BBLV,
+                                                 Instruction *BBI,
+                                                 BasicBlock *BB) {
+
+  assert(BBI->getOperand(0)->getType()->isSized() &&
+         "all operands to binary operators are sized");
+
+  // Filter out operators we don't know how to reason about before attempting to
+  // recurse on our operand(s).  This can cut a long search short if we know
+  // we're not going to be able to get any useful information anways.
+  switch (BBI->getOpcode()) {
+  case Instruction::Add:
+  case Instruction::Sub:
+  case Instruction::Mul:
+  case Instruction::UDiv:
+  case Instruction::Shl:
+  case Instruction::LShr:
+  case Instruction::And:
+  case Instruction::Or:
+    // continue into the code below
+    break;
+  default:
+    // Unhandled instructions are overdefined.
+    DEBUG(dbgs() << " compute BB '" << BB->getName()
+                 << "' - overdefined (unknown binary operator).\n");
+    BBLV.markOverdefined();
+    return true;
+  };
+
+  // Figure out the range of the LHS.  If that fails, use a conservative range,
+  // but apply the transfer rule anyways.  This lets us pick up facts from
+  // expressions like "and i32 (call i32 @foo()), 32"
+  if (!hasBlockValue(BBI->getOperand(0), BB))
+    if (pushBlockValue(std::make_pair(BB, BBI->getOperand(0))))
+      // More work to do before applying this transfer rule.
+      return false;
+
+  const unsigned OperandBitWidth =
+    DL.getTypeSizeInBits(BBI->getOperand(0)->getType());
+  ConstantRange LHSRange = ConstantRange(OperandBitWidth);
+  if (hasBlockValue(BBI->getOperand(0), BB)) {
+    LVILatticeVal LHSVal = getBlockValue(BBI->getOperand(0), BB);
+    intersectAssumeBlockValueConstantRange(BBI->getOperand(0), LHSVal, BBI);
+    if (LHSVal.isConstantRange())
+      LHSRange = LHSVal.getConstantRange();
+  }
+
+  ConstantInt *RHS = cast<ConstantInt>(BBI->getOperand(1));
+  ConstantRange RHSRange = ConstantRange(RHS->getValue());
+
   // 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.
@@ -862,30 +1149,15 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
   case Instruction::LShr:
     Result.markConstantRange(LHSRange.lshr(RHSRange));
     break;
-  case Instruction::Trunc:
-    Result.markConstantRange(LHSRange.truncate(ResultTy->getBitWidth()));
-    break;
-  case Instruction::SExt:
-    Result.markConstantRange(LHSRange.signExtend(ResultTy->getBitWidth()));
-    break;
-  case Instruction::ZExt:
-    Result.markConstantRange(LHSRange.zeroExtend(ResultTy->getBitWidth()));
-    break;
-  case Instruction::BitCast:
-    Result.markConstantRange(LHSRange);
-    break;
   case Instruction::And:
     Result.markConstantRange(LHSRange.binaryAnd(RHSRange));
     break;
   case Instruction::Or:
     Result.markConstantRange(LHSRange.binaryOr(RHSRange));
     break;
-
-  // Unhandled instructions are overdefined.
   default:
-    DEBUG(dbgs() << " compute BB '" << BB->getName()
-                 << "' - overdefined because inst def found.\n");
-    Result.markOverdefined();
+    // Should be dead if the code above is correct
+    llvm_unreachable("inconsistent with above");
     break;
   }
 
@@ -895,10 +1167,11 @@ bool LazyValueInfoCache::solveBlockValueConstantRange(LVILatticeVal &BBLV,
 
 bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
                                LVILatticeVal &Result, bool isTrueDest) {
-  if (ICI && isa<Constant>(ICI->getOperand(1))) {
+  assert(ICI && "precondition");
+  if (isa<Constant>(ICI->getOperand(1))) {
     if (ICI->isEquality() && ICI->getOperand(0) == Val) {
       // We know that V has the RHS constant if this is a true SETEQ or
-      // false SETNE. 
+      // false SETNE.
       if (isTrueDest == (ICI->getPredicate() == ICmpInst::ICMP_EQ))
         Result = LVILatticeVal::get(cast<Constant>(ICI->getOperand(1)));
       else
@@ -926,7 +1199,7 @@ bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
       // If we're interested in the false dest, invert the condition.
       if (!isTrueDest) TrueValues = TrueValues.inverse();
 
-      Result = LVILatticeVal::getRange(TrueValues);
+      Result = LVILatticeVal::getRange(std::move(TrueValues));
       return true;
     }
   }
@@ -935,7 +1208,8 @@ bool getValueFromFromCondition(Value *Val, ICmpInst *ICI,
 }
 
 /// \brief Compute the value of Val on the edge BBFrom -> BBTo. Returns false if
-/// Val is not constrained on the edge.
+/// Val is not constrained on the edge.  Result is unspecified if return value
+/// is false.
 static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
                               BasicBlock *BBTo, LVILatticeVal &Result) {
   // TODO: Handle more complex conditionals. If (v == 0 || v2 < 1) is false, we
@@ -985,7 +1259,7 @@ static bool getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
       } else if (i.getCaseSuccessor() == BBTo)
         EdgesVals = EdgesVals.unionWith(EdgeVal);
     }
-    Result = LVILatticeVal::getRange(EdgesVals);
+    Result = LVILatticeVal::getRange(std::move(EdgesVals));
     return true;
   }
   return false;
@@ -1002,46 +1276,29 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
     return true;
   }
 
-  if (getEdgeValueLocal(Val, BBFrom, BBTo, Result)) {
-    if (!Result.isConstantRange() ||
-        Result.getConstantRange().getSingleElement())
-      return true;
-
-    // FIXME: this check should be moved to the beginning of the function when
-    // LVI better supports recursive values. Even for the single value case, we
-    // can intersect to detect dead code (an empty range).
-    if (!hasBlockValue(Val, BBFrom)) {
-      if (pushBlockValue(std::make_pair(BBFrom, Val)))
-        return false;
-      Result.markOverdefined();
-      return true;
-    }
-
-    // Try to intersect ranges of the BB and the constraint on the edge.
-    LVILatticeVal InBlock = getBlockValue(Val, BBFrom);
-    mergeAssumeBlockValueConstantRange(Val, InBlock, BBFrom->getTerminator());
-    // See note on the use of the CxtI with mergeAssumeBlockValueConstantRange,
-    // and caching, below.
-    mergeAssumeBlockValueConstantRange(Val, InBlock, CxtI);
-    if (!InBlock.isConstantRange())
-      return true;
+  LVILatticeVal LocalResult;
+  if (!getEdgeValueLocal(Val, BBFrom, BBTo, LocalResult))
+    // If we couldn't constrain the value on the edge, LocalResult doesn't
+    // provide any information.
+    LocalResult.markOverdefined();
 
-    ConstantRange Range =
-      Result.getConstantRange().intersectWith(InBlock.getConstantRange());
-    Result = LVILatticeVal::getRange(Range);
+  if (hasSingleValue(LocalResult)) {
+    // Can't get any more precise here
+    Result = LocalResult;
     return true;
   }
 
   if (!hasBlockValue(Val, BBFrom)) {
     if (pushBlockValue(std::make_pair(BBFrom, Val)))
       return false;
-    Result.markOverdefined();
+    // No new information.
+    Result = LocalResult;
     return true;
   }
 
-  // If we couldn't compute the value on the edge, use the value from the BB.
-  Result = getBlockValue(Val, BBFrom);
-  mergeAssumeBlockValueConstantRange(Val, Result, BBFrom->getTerminator());
+  // Try to intersect ranges of the BB and the constraint on the edge.
+  LVILatticeVal InBlock = getBlockValue(Val, BBFrom);
+  intersectAssumeBlockValueConstantRange(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
@@ -1050,7 +1307,9 @@ bool LazyValueInfoCache::getEdgeValue(Value *Val, BasicBlock *BBFrom,
   // functions, the context instruction is not provided. When called from
   // LazyValueInfoCache::getValueOnEdge, the context instruction is provided,
   // but then the result is not cached.
-  mergeAssumeBlockValueConstantRange(Val, Result, CxtI);
+  intersectAssumeBlockValueConstantRange(Val, InBlock, CxtI);
+
+  Result = intersect(LocalResult, InBlock);
   return true;
 }
 
@@ -1060,11 +1319,12 @@ LVILatticeVal LazyValueInfoCache::getValueInBlock(Value *V, BasicBlock *BB,
         << BB->getName() << "'\n");
 
   assert(BlockValueStack.empty() && BlockValueSet.empty());
-  pushBlockValue(std::make_pair(BB, V));
-
-  solve();
+  if (!hasBlockValue(V, BB)) {
+    pushBlockValue(std::make_pair(BB, V)); 
+    solve();
+  }
   LVILatticeVal Result = getBlockValue(V, BB);
-  mergeAssumeBlockValueConstantRange(V, Result, CxtI);
+  intersectAssumeBlockValueConstantRange(V, Result, CxtI);
 
   DEBUG(dbgs() << "  Result = " << Result << "\n");
   return Result;
@@ -1074,10 +1334,13 @@ LVILatticeVal LazyValueInfoCache::getValueAt(Value *V, Instruction *CxtI) {
   DEBUG(dbgs() << "LVI Getting value " << *V << " at '"
         << CxtI->getName() << "'\n");
 
-  LVILatticeVal Result;
+  if (auto *C = dyn_cast<Constant>(V))
+    return LVILatticeVal::get(C);
+
+  LVILatticeVal Result = LVILatticeVal::getOverdefined();
   if (auto *I = dyn_cast<Instruction>(V))
     Result = getFromRangeMetadata(I);
-  mergeAssumeBlockValueConstantRange(V, Result, CxtI);
+  intersectAssumeBlockValueConstantRange(V, Result, CxtI);
 
   DEBUG(dbgs() << "  Result = " << Result << "\n");
   return Result;
@@ -1172,29 +1435,32 @@ static LazyValueInfoCache &getCache(void *&PImpl, AssumptionCache *AC,
   return *static_cast<LazyValueInfoCache*>(PImpl);
 }
 
-bool LazyValueInfo::runOnFunction(Function &F) {
-  AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+bool LazyValueInfoWrapperPass::runOnFunction(Function &F) {
+  Info.AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   const DataLayout &DL = F.getParent()->getDataLayout();
 
   DominatorTreeWrapperPass *DTWP =
       getAnalysisIfAvailable<DominatorTreeWrapperPass>();
-  DT = DTWP ? &DTWP->getDomTree() : nullptr;
-
-  TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
+  Info.DT = DTWP ? &DTWP->getDomTree() : nullptr;
+  Info.TLI = &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
 
-  if (PImpl)
-    getCache(PImpl, AC, &DL, DT).clear();
+  if (Info.PImpl)
+    getCache(Info.PImpl, Info.AC, &DL, Info.DT).clear();
 
   // Fully lazy.
   return false;
 }
 
-void LazyValueInfo::getAnalysisUsage(AnalysisUsage &AU) const {
+void LazyValueInfoWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   AU.addRequired<AssumptionCacheTracker>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
 }
 
+LazyValueInfo &LazyValueInfoWrapperPass::getLVI() { return Info; }
+
+LazyValueInfo::~LazyValueInfo() { releaseMemory(); }
+
 void LazyValueInfo::releaseMemory() {
   // If the cache was allocated, free it.
   if (PImpl) {
@@ -1203,6 +1469,16 @@ void LazyValueInfo::releaseMemory() {
   }
 }
 
+void LazyValueInfoWrapperPass::releaseMemory() { Info.releaseMemory(); }
+
+LazyValueInfo LazyValueAnalysis::run(Function &F, FunctionAnalysisManager &FAM) {
+  auto &AC = FAM.getResult<AssumptionAnalysis>(F);
+  auto &TLI = FAM.getResult<TargetLibraryAnalysis>(F);
+  auto *DT = FAM.getCachedResult<DominatorTreeAnalysis>(F);
+
+  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
@@ -1238,6 +1514,21 @@ Constant *LazyValueInfo::getConstant(Value *V, BasicBlock *BB,
   return nullptr;
 }
 
+ConstantRange LazyValueInfo::getConstantRange(Value *V, BasicBlock *BB,
+                                              Instruction *CxtI) {
+  assert(V->getType()->isIntegerTy());
+  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());
+  if (Result.isUndefined())
+    return ConstantRange(Width, /*isFullSet=*/false);
+  if (Result.isConstantRange())
+    return Result.getConstantRange();
+  return ConstantRange(Width, /*isFullSet=*/true);
+}
+
 /// Determine whether the specified value is known to be a
 /// constant on the specified edge. Return null if not.
 Constant *LazyValueInfo::getConstantOnEdge(Value *V, BasicBlock *FromBB,
@@ -1379,7 +1670,7 @@ LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
   // We limit the search to one step backwards from the current BB and value.
   // We could consider extending this to search further backwards through the
   // CFG and/or value graph, but there are non-obvious compile time vs quality
-  // tradeoffs.  
+  // tradeoffs.
   if (CxtI) {
     BasicBlock *BB = CxtI->getParent();
 
@@ -1399,10 +1690,10 @@ LazyValueInfo::getPredicateAt(unsigned Pred, Value *V, Constant *C,
         for (unsigned i = 0, e = PHI->getNumIncomingValues(); i < e; i++) {
           Value *Incoming = PHI->getIncomingValue(i);
           BasicBlock *PredBB = PHI->getIncomingBlock(i);
-          // Note that PredBB may be BB itself.        
+          // Note that PredBB may be BB itself.
           Tristate Result = getPredicateOnEdge(Pred, Incoming, C, PredBB, BB,
                                                CxtI);
-          
+
           // Keep going as long as we've seen a consistent known result for
           // all inputs.
           Baseline = (i == 0) ? Result /* First iteration */