MFC 261991:

Upgrade our copy of llvm/clang to 3.4 release.  This version supports
all of the features in the current working draft of the upcoming C++
standard, provisionally named C++1y.

The code generator's performance is greatly increased, and the loop
auto-vectorizer is now enabled at -Os and -O2 in addition to -O3.  The
PowerPC backend has made several major improvements to code generation
quality and compile time, and the X86, SPARC, ARM32, Aarch64 and SystemZ
backends have all seen major feature work.

Release notes for llvm and clang can be found here:
<http://llvm.org/releases/3.4/docs/ReleaseNotes.html>
<http://llvm.org/releases/3.4/tools/clang/docs/ReleaseNotes.html>

MFC 262121 (by emaste):

Update lldb for clang/llvm 3.4 import

This commit largely restores the lldb source to the upstream r196259
snapshot with the addition of threaded inferior support and a few bug
fixes.

Specific upstream lldb revisions restored include:
   SVN      git
  181387  779e6ac
  181703  7bef4e2
  182099  b31044e
  182650  f2dcf35
  182683  0d91b80
  183862  15c1774
  183929  99447a6
  184177  0b2934b
  184948  4dc3761
  184954  007e7bc
  186990  eebd175

Sponsored by:	DARPA, AFRL

MFC 262186 (by emaste):

Fix mismerge in r262121

A break statement was lost in the merge.  The error had no functional
impact, but restore it to reduce the diff against upstream.

MFC 262303:

Pull in r197521 from upstream clang trunk (by rdivacky):

  Use the integrated assembler by default on FreeBSD/ppc and ppc64.

Requested by:	jhibbits

MFC 262611:

Pull in r196874 from upstream llvm trunk:

  Fix a crash that occurs when PWD is invalid.

  MCJIT needs to be able to run in hostile environments, even when PWD
  is invalid. There's no need to crash MCJIT in this case.

  The obvious fix is to simply leave MCContext's CompilationDir empty
  when PWD can't be determined. This way, MCJIT clients,
  and other clients that link with LLVM don't need a valid working directory.

  If we do want to guarantee valid CompilationDir, that should be done
  only for clients of getCompilationDir(). This is as simple as checking
  for an empty string.

  The only current use of getCompilationDir is EmitGenDwarfInfo, which
  won't conceivably run with an invalid working dir. However, in the
  purely hypothetically and untestable case that this happens, the
  AT_comp_dir will be omitted from the compilation_unit DIE.

This should help fix assertions occurring with ports-mgmt/tinderbox,
when it is using jails, and sometimes invalidates clang's current
working directory.

Reported by:	decke

MFC 262809:

Pull in r203007 from upstream clang trunk:

  Don't produce an alias between destructors with different calling conventions.

  Fixes pr19007.

(Please note that is an LLVM PR identifier, not a FreeBSD one.)

This should fix Firefox and/or libxul crashes (due to problems with
regparm/stdcall calling conventions) on i386.

Reported by:	multiple users on freebsd-current
PR:		bin/187103

MFC 263048:

Repair recognition of "CC" as an alias for the C++ compiler, since it
was silently broken by upstream for a Windows-specific use-case.

Apparently some versions of CMake still rely on this archaic feature...

Reported by:	rakuco

MFC 263049:

Garbage collect the old way of adding the libstdc++ include directories
in clang's InitHeaderSearch.cpp.  This has been superseded by David
Chisnall's commit in r255321.

Moreover, if libc++ is used, the libstdc++ include directories should
not be in the search path at all.  These directories are now only used
if you pass -stdlib=libstdc++.

1 files changed, 249 insertions, 136 deletions

diff --git a/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index ecc9fc3..a759548 100644
--- a/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/contrib/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -95,6 +95,25 @@ static bool MultiplyOverflows(ConstantInt *C1, ConstantInt *C2, bool sign) {
   return MulExt.slt(Min) || MulExt.sgt(Max);
 }
 
+/// \brief A helper routine of InstCombiner::visitMul().
+///
+/// If C is a vector of known powers of 2, then this function returns
+/// a new vector obtained from C replacing each element with its logBase2.
+/// Return a null pointer otherwise.
+static Constant *getLogBase2Vector(ConstantDataVector *CV) {
+  const APInt *IVal;
+  SmallVector<Constant *, 4> Elts;
+
+  for (unsigned I = 0, E = CV->getNumElements(); I != E; ++I) {
+    Constant *Elt = CV->getElementAsConstant(I);
+    if (!match(Elt, m_APInt(IVal)) || !IVal->isPowerOf2())
+      return 0;
+    Elts.push_back(ConstantInt::get(Elt->getType(), IVal->logBase2()));
+  }
+
+  return ConstantVector::get(Elts);
+}
+
 Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   bool Changed = SimplifyAssociativeOrCommutative(I);
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
@@ -108,24 +127,37 @@ Instruction *InstCombiner::visitMul(BinaryOperator &I) {
   if (match(Op1, m_AllOnes()))  // X * -1 == 0 - X
     return BinaryOperator::CreateNeg(Op0, I.getName());
 
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
-
-    // ((X << C1)*C2) == (X * (C2 << C1))
-    if (BinaryOperator *SI = dyn_cast<BinaryOperator>(Op0))
-      if (SI->getOpcode() == Instruction::Shl)
-        if (Constant *ShOp = dyn_cast<Constant>(SI->getOperand(1)))
-          return BinaryOperator::CreateMul(SI->getOperand(0),
-                                           ConstantExpr::getShl(CI, ShOp));
-
-    const APInt &Val = CI->getValue();
-    if (Val.isPowerOf2()) {          // Replace X*(2^C) with X << C
-      Constant *NewCst = ConstantInt::get(Op0->getType(), Val.logBase2());
-      BinaryOperator *Shl = BinaryOperator::CreateShl(Op0, NewCst);
-      if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
-      if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
-      return Shl;
+  // Also allow combining multiply instructions on vectors.
+  {
+    Value *NewOp;
+    Constant *C1, *C2;
+    const APInt *IVal;
+    if (match(&I, m_Mul(m_Shl(m_Value(NewOp), m_Constant(C2)),
+                        m_Constant(C1))) &&
+        match(C1, m_APInt(IVal)))
+      // ((X << C1)*C2) == (X * (C2 << C1))
+      return BinaryOperator::CreateMul(NewOp, ConstantExpr::getShl(C1, C2));
+
+    if (match(&I, m_Mul(m_Value(NewOp), m_Constant(C1)))) {
+      Constant *NewCst = 0;
+      if (match(C1, m_APInt(IVal)) && IVal->isPowerOf2())
+        // Replace X*(2^C) with X << C, where C is either a scalar or a splat.
+        NewCst = ConstantInt::get(NewOp->getType(), IVal->logBase2());
+      else if (ConstantDataVector *CV = dyn_cast<ConstantDataVector>(C1))
+        // Replace X*(2^C) with X << C, where C is a vector of known
+        // constant powers of 2.
+        NewCst = getLogBase2Vector(CV);
+
+      if (NewCst) {
+        BinaryOperator *Shl = BinaryOperator::CreateShl(NewOp, NewCst);
+        if (I.hasNoSignedWrap()) Shl->setHasNoSignedWrap();
+        if (I.hasNoUnsignedWrap()) Shl->setHasNoUnsignedWrap();
+        return Shl;
+      }
     }
+  }
 
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1)) {
     // Canonicalize (X+C1)*CI -> X*CI+C1*CI.
     { Value *X; ConstantInt *C1;
       if (Op0->hasOneUse() &&
@@ -306,13 +338,13 @@ static bool isFMulOrFDivWithConstant(Value *V) {
   if (C0 && C1)
     return false;
 
-  return (C0 && C0->getValueAPF().isNormal()) ||
-         (C1 && C1->getValueAPF().isNormal());
+  return (C0 && C0->getValueAPF().isFiniteNonZero()) ||
+         (C1 && C1->getValueAPF().isFiniteNonZero());
 }
 
 static bool isNormalFp(const ConstantFP *C) {
   const APFloat &Flt = C->getValueAPF();
-  return Flt.isNormal() && !Flt.isDenormal();
+  return Flt.isNormal();
 }
 
 /// foldFMulConst() is a helper routine of InstCombiner::visitFMul().
@@ -342,9 +374,12 @@ Value *InstCombiner::foldFMulConst(Instruction *FMulOrDiv, ConstantFP *C,
   } else {
     if (C0) {
       // (C0 / X) * C => (C0 * C) / X
-      ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFMul(C0, C));
-      if (isNormalFp(F))
-        R = BinaryOperator::CreateFDiv(F, Opnd1);
+      if (FMulOrDiv->hasOneUse()) {
+        // It would otherwise introduce another div.
+        ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFMul(C0, C));
+        if (isNormalFp(F))
+          R = BinaryOperator::CreateFDiv(F, Opnd1);
+      }
     } else {
       // (X / C1) * C => X * (C/C1) if C/C1 is not a denormal
       ConstantFP *F = cast<ConstantFP>(ConstantExpr::getFDiv(C, C1));
@@ -391,7 +426,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
         return NV;
 
     ConstantFP *C = dyn_cast<ConstantFP>(Op1);
-    if (C && AllowReassociate && C->getValueAPF().isNormal()) {
+    if (C && AllowReassociate && C->getValueAPF().isFiniteNonZero()) {
       // Let MDC denote an expression in one of these forms:
       // X * C, C/X, X/C, where C is a constant.
       //
@@ -418,7 +453,7 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
           Swap = true;
         }
 
-        if (C1 && C1->getValueAPF().isNormal() &&
+        if (C1 && C1->getValueAPF().isFiniteNonZero() &&
             isFMulOrFDivWithConstant(Opnd0)) {
           Value *M1 = ConstantExpr::getFMul(C1, C);
           Value *M0 = isNormalFp(cast<ConstantFP>(M1)) ?
@@ -428,10 +463,9 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
             if (Swap && FAddSub->getOpcode() == Instruction::FSub)
               std::swap(M0, M1);
 
-            Value *R = (FAddSub->getOpcode() == Instruction::FAdd) ?
-                        BinaryOperator::CreateFAdd(M0, M1) :
-                        BinaryOperator::CreateFSub(M0, M1);
-            Instruction *RI = cast<Instruction>(R);
+            Instruction *RI = (FAddSub->getOpcode() == Instruction::FAdd)
+                                  ? BinaryOperator::CreateFAdd(M0, M1)
+                                  : BinaryOperator::CreateFSub(M0, M1);
             RI->copyFastMathFlags(&I);
             return RI;
           }
@@ -458,13 +492,13 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
     }
     // if pattern detected emit alternate sequence
     if (OpX && OpY) {
+      BuilderTy::FastMathFlagGuard Guard(*Builder);
+      Builder->SetFastMathFlags(Log2->getFastMathFlags());
       Log2->setArgOperand(0, OpY);
       Value *FMulVal = Builder->CreateFMul(OpX, Log2);
-      Instruction *FMul = cast<Instruction>(FMulVal);
-      FMul->copyFastMathFlags(Log2);
-      Instruction *FSub = BinaryOperator::CreateFSub(FMulVal, OpX);
-      FSub->copyFastMathFlags(Log2);
-      return FSub;
+      Value *FSub = Builder->CreateFSub(FMulVal, OpX);
+      FSub->takeName(&I);
+      return ReplaceInstUsesWith(I, FSub);
     }
   }
 
@@ -474,6 +508,9 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
   for (int i = 0; i < 2; i++) {
     bool IgnoreZeroSign = I.hasNoSignedZeros();
     if (BinaryOperator::isFNeg(Opnd0, IgnoreZeroSign)) {
+      BuilderTy::FastMathFlagGuard Guard(*Builder);
+      Builder->SetFastMathFlags(I.getFastMathFlags());
+
       Value *N0 = dyn_castFNegVal(Opnd0, IgnoreZeroSign);
       Value *N1 = dyn_castFNegVal(Opnd1, IgnoreZeroSign);
 
@@ -484,13 +521,9 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
       if (Opnd0->hasOneUse()) {
         // -X * Y => -(X*Y) (Promote negation as high as possible)
         Value *T = Builder->CreateFMul(N0, Opnd1);
-        cast<Instruction>(T)->setDebugLoc(I.getDebugLoc());
-        Instruction *Neg = BinaryOperator::CreateFNeg(T);
-        if (I.getFastMathFlags().any()) {
-          cast<Instruction>(T)->copyFastMathFlags(&I);
-          Neg->copyFastMathFlags(&I);
-        }
-        return Neg;
+        Value *Neg = Builder->CreateFNeg(T);
+        Neg->takeName(&I);
+        return ReplaceInstUsesWith(I, Neg);
       }
     }
 
@@ -513,13 +546,13 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
           Y = Opnd0_0;
 
         if (Y) {
-          Instruction *T = cast<Instruction>(Builder->CreateFMul(Opnd1, Opnd1));
-          T->copyFastMathFlags(&I);
-          T->setDebugLoc(I.getDebugLoc());
+          BuilderTy::FastMathFlagGuard Guard(*Builder);
+          Builder->SetFastMathFlags(I.getFastMathFlags());
+          Value *T = Builder->CreateFMul(Opnd1, Opnd1);
 
-          Instruction *R = BinaryOperator::CreateFMul(T, Y);
-          R->copyFastMathFlags(&I);
-          return R;
+          Value *R = Builder->CreateFMul(T, Y);
+          R->takeName(&I);
+          return ReplaceInstUsesWith(I, R);
         }
       }
     }
@@ -528,10 +561,10 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
     if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
       Value *LHS = Op0, *RHS = Op1;
       Value *B, *C;
-      if (!match(RHS, m_UIToFp(m_Value(C))))
+      if (!match(RHS, m_UIToFP(m_Value(C))))
         std::swap(LHS, RHS);
 
-      if (match(RHS, m_UIToFp(m_Value(C))) && C->getType()->isIntegerTy(1)) {
+      if (match(RHS, m_UIToFP(m_Value(C))) && C->getType()->isIntegerTy(1)) {
         B = LHS;
         Value *Zero = ConstantFP::getNegativeZero(B->getType());
         return SelectInst::Create(C, B, Zero);
@@ -542,10 +575,10 @@ Instruction *InstCombiner::visitFMul(BinaryOperator &I) {
     if (I.hasNoNaNs() && I.hasNoInfs() && I.hasNoSignedZeros()) {
       Value *LHS = Op0, *RHS = Op1;
       Value *A, *C;
-      if (!match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))))
+      if (!match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))))
         std::swap(LHS, RHS);
 
-      if (match(RHS, m_FSub(m_FPOne(), m_UIToFp(m_Value(C)))) &&
+      if (match(RHS, m_FSub(m_FPOne(), m_UIToFP(m_Value(C)))) &&
           C->getType()->isIntegerTy(1)) {
         A = LHS;
         Value *Zero = ConstantFP::getNegativeZero(A->getType());
@@ -613,8 +646,7 @@ bool InstCombiner::SimplifyDivRemOfSelect(BinaryOperator &I) {
         *I = SI->getOperand(NonNullOperand);
         Worklist.Add(BBI);
       } else if (*I == SelectCond) {
-        *I = NonNullOperand == 1 ? ConstantInt::getTrue(BBI->getContext()) :
-                                   ConstantInt::getFalse(BBI->getContext());
+        *I = Builder->getInt1(NonNullOperand == 1);
         Worklist.Add(BBI);
       }
     }
@@ -703,40 +735,124 @@ static Value *dyn_castZExtVal(Value *V, Type *Ty) {
   return 0;
 }
 
-Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
-  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+namespace {
+const unsigned MaxDepth = 6;
+typedef Instruction *(*FoldUDivOperandCb)(Value *Op0, Value *Op1,
+                                          const BinaryOperator &I,
+                                          InstCombiner &IC);
+
+/// \brief Used to maintain state for visitUDivOperand().
+struct UDivFoldAction {
+  FoldUDivOperandCb FoldAction; ///< Informs visitUDiv() how to fold this
+                                ///< operand.  This can be zero if this action
+                                ///< joins two actions together.
+
+  Value *OperandToFold;         ///< Which operand to fold.
+  union {
+    Instruction *FoldResult;    ///< The instruction returned when FoldAction is
+                                ///< invoked.
+
+    size_t SelectLHSIdx;        ///< Stores the LHS action index if this action
+                                ///< joins two actions together.
+  };
+
+  UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand)
+      : FoldAction(FA), OperandToFold(InputOperand), FoldResult(0) {}
+  UDivFoldAction(FoldUDivOperandCb FA, Value *InputOperand, size_t SLHS)
+      : FoldAction(FA), OperandToFold(InputOperand), SelectLHSIdx(SLHS) {}
+};
+}
 
-  if (Value *V = SimplifyUDivInst(Op0, Op1, TD))
-    return ReplaceInstUsesWith(I, V);
+// X udiv 2^C -> X >> C
+static Instruction *foldUDivPow2Cst(Value *Op0, Value *Op1,
+                                    const BinaryOperator &I, InstCombiner &IC) {
+  const APInt &C = cast<Constant>(Op1)->getUniqueInteger();
+  BinaryOperator *LShr = BinaryOperator::CreateLShr(
+      Op0, ConstantInt::get(Op0->getType(), C.logBase2()));
+  if (I.isExact()) LShr->setIsExact();
+  return LShr;
+}
 
-  // Handle the integer div common cases
-  if (Instruction *Common = commonIDivTransforms(I))
-    return Common;
+// X udiv C, where C >= signbit
+static Instruction *foldUDivNegCst(Value *Op0, Value *Op1,
+                                   const BinaryOperator &I, InstCombiner &IC) {
+  Value *ICI = IC.Builder->CreateICmpULT(Op0, cast<ConstantInt>(Op1));
 
-  {
-    // X udiv 2^C -> X >> C
-    // Check to see if this is an unsigned division with an exact power of 2,
-    // if so, convert to a right shift.
-    const APInt *C;
-    if (match(Op1, m_Power2(C))) {
-      BinaryOperator *LShr =
-      BinaryOperator::CreateLShr(Op0,
-                                 ConstantInt::get(Op0->getType(),
-                                                  C->logBase2()));
-      if (I.isExact()) LShr->setIsExact();
-      return LShr;
-    }
+  return SelectInst::Create(ICI, Constant::getNullValue(I.getType()),
+                            ConstantInt::get(I.getType(), 1));
+}
+
+// X udiv (C1 << N), where C1 is "1<<C2"  -->  X >> (N+C2)
+static Instruction *foldUDivShl(Value *Op0, Value *Op1, const BinaryOperator &I,
+                                InstCombiner &IC) {
+  Instruction *ShiftLeft = cast<Instruction>(Op1);
+  if (isa<ZExtInst>(ShiftLeft))
+    ShiftLeft = cast<Instruction>(ShiftLeft->getOperand(0));
+
+  const APInt &CI =
+      cast<Constant>(ShiftLeft->getOperand(0))->getUniqueInteger();
+  Value *N = ShiftLeft->getOperand(1);
+  if (CI != 1)
+    N = IC.Builder->CreateAdd(N, ConstantInt::get(N->getType(), CI.logBase2()));
+  if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
+    N = IC.Builder->CreateZExt(N, Z->getDestTy());
+  BinaryOperator *LShr = BinaryOperator::CreateLShr(Op0, N);
+  if (I.isExact()) LShr->setIsExact();
+  return LShr;
+}
+
+// \brief Recursively visits the possible right hand operands of a udiv
+// instruction, seeing through select instructions, to determine if we can
+// replace the udiv with something simpler.  If we find that an operand is not
+// able to simplify the udiv, we abort the entire transformation.
+static size_t visitUDivOperand(Value *Op0, Value *Op1, const BinaryOperator &I,
+                               SmallVectorImpl<UDivFoldAction> &Actions,
+                               unsigned Depth = 0) {
+  // Check to see if this is an unsigned division with an exact power of 2,
+  // if so, convert to a right shift.
+  if (match(Op1, m_Power2())) {
+    Actions.push_back(UDivFoldAction(foldUDivPow2Cst, Op1));
+    return Actions.size();
   }
 
-  if (ConstantInt *C = dyn_cast<ConstantInt>(Op1)) {
+  if (ConstantInt *C = dyn_cast<ConstantInt>(Op1))
     // X udiv C, where C >= signbit
     if (C->getValue().isNegative()) {
-      Value *IC = Builder->CreateICmpULT(Op0, C);
-      return SelectInst::Create(IC, Constant::getNullValue(I.getType()),
-                                ConstantInt::get(I.getType(), 1));
+      Actions.push_back(UDivFoldAction(foldUDivNegCst, C));
+      return Actions.size();
     }
+
+  // X udiv (C1 << N), where C1 is "1<<C2"  -->  X >> (N+C2)
+  if (match(Op1, m_Shl(m_Power2(), m_Value())) ||
+      match(Op1, m_ZExt(m_Shl(m_Power2(), m_Value())))) {
+    Actions.push_back(UDivFoldAction(foldUDivShl, Op1));
+    return Actions.size();
   }
 
+  // The remaining tests are all recursive, so bail out if we hit the limit.
+  if (Depth++ == MaxDepth)
+    return 0;
+
+  if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
+    if (size_t LHSIdx = visitUDivOperand(Op0, SI->getOperand(1), I, Actions))
+      if (visitUDivOperand(Op0, SI->getOperand(2), I, Actions)) {
+        Actions.push_back(UDivFoldAction((FoldUDivOperandCb)0, Op1, LHSIdx-1));
+        return Actions.size();
+      }
+
+  return 0;
+}
+
+Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
+  Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
+
+  if (Value *V = SimplifyUDivInst(Op0, Op1, TD))
+    return ReplaceInstUsesWith(I, V);
+
+  // Handle the integer div common cases
+  if (Instruction *Common = commonIDivTransforms(I))
+    return Common;
+
   // (x lshr C1) udiv C2 --> x udiv (C2 << C1)
   if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
     Value *X;
@@ -747,38 +863,6 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
     }
   }
 
-  // X udiv (C1 << N), where C1 is "1<<C2"  -->  X >> (N+C2)
-  { const APInt *CI; Value *N;
-    if (match(Op1, m_Shl(m_Power2(CI), m_Value(N))) ||
-        match(Op1, m_ZExt(m_Shl(m_Power2(CI), m_Value(N))))) {
-      if (*CI != 1)
-        N = Builder->CreateAdd(N,
-                               ConstantInt::get(N->getType(), CI->logBase2()));
-      if (ZExtInst *Z = dyn_cast<ZExtInst>(Op1))
-        N = Builder->CreateZExt(N, Z->getDestTy());
-      if (I.isExact())
-        return BinaryOperator::CreateExactLShr(Op0, N);
-      return BinaryOperator::CreateLShr(Op0, N);
-    }
-  }
-
-  // udiv X, (Select Cond, C1, C2) --> Select Cond, (shr X, C1), (shr X, C2)
-  // where C1&C2 are powers of two.
-  { Value *Cond; const APInt *C1, *C2;
-    if (match(Op1, m_Select(m_Value(Cond), m_Power2(C1), m_Power2(C2)))) {
-      // Construct the "on true" case of the select
-      Value *TSI = Builder->CreateLShr(Op0, C1->logBase2(), Op1->getName()+".t",
-                                       I.isExact());
-
-      // Construct the "on false" case of the select
-      Value *FSI = Builder->CreateLShr(Op0, C2->logBase2(), Op1->getName()+".f",
-                                       I.isExact());
-
-      // construct the select instruction and return it.
-      return SelectInst::Create(Cond, TSI, FSI);
-    }
-  }
-
   // (zext A) udiv (zext B) --> zext (A udiv B)
   if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
     if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
@@ -786,6 +870,37 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
                                               I.isExact()),
                           I.getType());
 
+  // (LHS udiv (select (select (...)))) -> (LHS >> (select (select (...))))
+  SmallVector<UDivFoldAction, 6> UDivActions;
+  if (visitUDivOperand(Op0, Op1, I, UDivActions))
+    for (unsigned i = 0, e = UDivActions.size(); i != e; ++i) {
+      FoldUDivOperandCb Action = UDivActions[i].FoldAction;
+      Value *ActionOp1 = UDivActions[i].OperandToFold;
+      Instruction *Inst;
+      if (Action)
+        Inst = Action(Op0, ActionOp1, I, *this);
+      else {
+        // This action joins two actions together.  The RHS of this action is
+        // simply the last action we processed, we saved the LHS action index in
+        // the joining action.
+        size_t SelectRHSIdx = i - 1;
+        Value *SelectRHS = UDivActions[SelectRHSIdx].FoldResult;
+        size_t SelectLHSIdx = UDivActions[i].SelectLHSIdx;
+        Value *SelectLHS = UDivActions[SelectLHSIdx].FoldResult;
+        Inst = SelectInst::Create(cast<SelectInst>(ActionOp1)->getCondition(),
+                                  SelectLHS, SelectRHS);
+      }
+
+      // If this is the last action to process, return it to the InstCombiner.
+      // Otherwise, we insert it before the UDiv and record it so that we may
+      // use it as part of a joining action (i.e., a SelectInst).
+      if (e - i != 1) {
+        Inst->insertBefore(&I);
+        UDivActions[i].FoldResult = Inst;
+      } else
+        return Inst;
+    }
+
   return 0;
 }
 
@@ -846,7 +961,7 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
 /// FP value and:
 ///    1) 1/C is exact, or
 ///    2) reciprocal is allowed.
-/// If the convertion was successful, the simplified expression "X * 1/C" is
+/// If the conversion was successful, the simplified expression "X * 1/C" is
 /// returned; otherwise, NULL is returned.
 ///
 static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
@@ -856,7 +971,7 @@ static Instruction *CvtFDivConstToReciprocal(Value *Dividend,
   APFloat Reciprocal(FpVal.getSemantics());
   bool Cvt = FpVal.getExactInverse(&Reciprocal);
 
-  if (!Cvt && AllowReciprocal && FpVal.isNormal()) {
+  if (!Cvt && AllowReciprocal && FpVal.isFiniteNonZero()) {
     Reciprocal = APFloat(FpVal.getSemantics(), 1.0f);
     (void)Reciprocal.divide(FpVal, APFloat::rmNearestTiesToEven);
     Cvt = !Reciprocal.isDenormal();
@@ -876,10 +991,19 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
   if (Value *V = SimplifyFDivInst(Op0, Op1, TD))
     return ReplaceInstUsesWith(I, V);
 
+  if (isa<Constant>(Op0))
+    if (SelectInst *SI = dyn_cast<SelectInst>(Op1))
+      if (Instruction *R = FoldOpIntoSelect(I, SI))
+        return R;
+
   bool AllowReassociate = I.hasUnsafeAlgebra();
   bool AllowReciprocal = I.hasAllowReciprocal();
 
   if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
+    if (SelectInst *SI = dyn_cast<SelectInst>(Op0))
+      if (Instruction *R = FoldOpIntoSelect(I, SI))
+        return R;
+
     if (AllowReassociate) {
       ConstantFP *C1 = 0;
       ConstantFP *C2 = Op1C;
@@ -891,14 +1015,14 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
         //
         Constant *C = ConstantExpr::getFDiv(C1, C2);
         const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
-        if (F.isNormal() && !F.isDenormal())
+        if (F.isNormal())
           Res = BinaryOperator::CreateFMul(X, C);
       } else if (match(Op0, m_FDiv(m_Value(X), m_ConstantFP(C1)))) {
         // (X/C1)/C2 => X /(C2*C1) [=> X * 1/(C2*C1) if reciprocal is allowed]
         //
         Constant *C = ConstantExpr::getFMul(C1, C2);
         const APFloat &F = cast<ConstantFP>(C)->getValueAPF();
-        if (F.isNormal() && !F.isDenormal()) {
+        if (F.isNormal()) {
           Res = CvtFDivConstToReciprocal(X, cast<ConstantFP>(C),
                                          AllowReciprocal);
           if (!Res)
@@ -939,7 +1063,7 @@ Instruction *InstCombiner::visitFDiv(BinaryOperator &I) {
 
     if (Fold) {
       const APFloat &FoldC = cast<ConstantFP>(Fold)->getValueAPF();
-      if (FoldC.isNormal() && !FoldC.isDenormal()) {
+      if (FoldC.isNormal()) {
         Instruction *R = CreateDiv ?
                          BinaryOperator::CreateFDiv(Fold, X) :
                          BinaryOperator::CreateFMul(X, Fold);
@@ -1027,37 +1151,26 @@ Instruction *InstCombiner::visitURem(BinaryOperator &I) {
   if (Instruction *common = commonIRemTransforms(I))
     return common;
 
-  // X urem C^2 -> X and C-1
-  { const APInt *C;
-    if (match(Op1, m_Power2(C)))
-      return BinaryOperator::CreateAnd(Op0,
-                                       ConstantInt::get(I.getType(), *C-1));
-  }
+  // (zext A) urem (zext B) --> zext (A urem B)
+  if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
+    if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
+      return new ZExtInst(Builder->CreateURem(ZOp0->getOperand(0), ZOp1),
+                          I.getType());
 
-  // Turn A % (C << N), where C is 2^k, into A & ((C << N)-1)
-  if (match(Op1, m_Shl(m_Power2(), m_Value()))) {
+  // X urem Y -> X and Y-1, where Y is a power of 2,
+  if (isKnownToBeAPowerOfTwo(Op1, /*OrZero*/true)) {
     Constant *N1 = Constant::getAllOnesValue(I.getType());
     Value *Add = Builder->CreateAdd(Op1, N1);
     return BinaryOperator::CreateAnd(Op0, Add);
   }
 
-  // urem X, (select Cond, 2^C1, 2^C2) -->
-  //    select Cond, (and X, C1-1), (and X, C2-1)
-  // when C1&C2 are powers of two.
-  { Value *Cond; const APInt *C1, *C2;
-    if (match(Op1, m_Select(m_Value(Cond), m_Power2(C1), m_Power2(C2)))) {
-      Value *TrueAnd = Builder->CreateAnd(Op0, *C1-1, Op1->getName()+".t");
-      Value *FalseAnd = Builder->CreateAnd(Op0, *C2-1, Op1->getName()+".f");
-      return SelectInst::Create(Cond, TrueAnd, FalseAnd);
-    }
+  // 1 urem X -> zext(X != 1)
+  if (match(Op0, m_One())) {
+    Value *Cmp = Builder->CreateICmpNE(Op1, Op0);
+    Value *Ext = Builder->CreateZExt(Cmp, I.getType());
+    return ReplaceInstUsesWith(I, Ext);
   }
 
-  // (zext A) urem (zext B) --> zext (A urem B)
-  if (ZExtInst *ZOp0 = dyn_cast<ZExtInst>(Op0))
-    if (Value *ZOp1 = dyn_castZExtVal(Op1, ZOp0->getSrcTy()))
-      return new ZExtInst(Builder->CreateURem(ZOp0->getOperand(0), ZOp1),
-                          I.getType());
-
   return 0;
 }