X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FAnalysis%2FInstructionSimplify.cpp;h=9d78f8bf40441fafd023f08eebb9b126931459b7;hb=491a13691d3b30b8288dfc6e01ad6a58f69a4ce6;hp=fb51fa5315b219495b9f2ef25d130d074931cacc;hpb=1cd05bb605e3c3eee9197d3f10b628c60d0cc07a;p=oota-llvm.git

diff --git a/lib/Analysis/InstructionSimplify.cpp b/lib/Analysis/InstructionSimplify.cpp
index fb51fa5315b..9d78f8bf404 100644
--- a/lib/Analysis/InstructionSimplify.cpp
+++ b/lib/Analysis/InstructionSimplify.cpp
@@ -18,17 +18,20 @@
 //===----------------------------------------------------------------------===//
 
 #define DEBUG_TYPE "instsimplify"
+#include "llvm/Operator.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/Dominators.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/Support/ConstantRange.h"
 #include "llvm/Support/PatternMatch.h"
 #include "llvm/Support/ValueHandle.h"
 #include "llvm/Target/TargetData.h"
 using namespace llvm;
 using namespace llvm::PatternMatch;
 
-#define RecursionLimit 3
+enum { RecursionLimit = 3 };
 
 STATISTIC(NumExpand,  "Number of expansions");
 STATISTIC(NumFactor , "Number of factorizations");
@@ -71,8 +74,9 @@ static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
 /// Also performs the transform "(A op' B) op C" -> "(A op C) op' (B op C)".
 /// Returns the simplified value, or null if no simplification was performed.
 static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
-                          unsigned OpcodeToExpand, const TargetData *TD,
+                          unsigned OpcToExpand, const TargetData *TD,
                           const DominatorTree *DT, unsigned MaxRecurse) {
+  Instruction::BinaryOps OpcodeToExpand = (Instruction::BinaryOps)OpcToExpand;
   // Recursion is always used, so bail out at once if we already hit the limit.
   if (!MaxRecurse--)
     return 0;
@@ -133,8 +137,9 @@ static Value *ExpandBinOp(unsigned Opcode, Value *LHS, Value *RHS,
 /// OpCodeToExtract is Mul then this tries to turn "(A*B)+(A*C)" into "A*(B+C)".
 /// Returns the simplified value, or null if no simplification was performed.
 static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
-                             unsigned OpcodeToExtract, const TargetData *TD,
+                             unsigned OpcToExtract, const TargetData *TD,
                              const DominatorTree *DT, unsigned MaxRecurse) {
+  Instruction::BinaryOps OpcodeToExtract = (Instruction::BinaryOps)OpcToExtract;
   // Recursion is always used, so bail out at once if we already hit the limit.
   if (!MaxRecurse--)
     return 0;
@@ -201,10 +206,11 @@ static Value *FactorizeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
 
 /// SimplifyAssociativeBinOp - Generic simplifications for associative binary
 /// operations.  Returns the simpler value, or null if none was found.
-static Value *SimplifyAssociativeBinOp(unsigned Opcode, Value *LHS, Value *RHS,
+static Value *SimplifyAssociativeBinOp(unsigned Opc, Value *LHS, Value *RHS,
                                        const TargetData *TD,
                                        const DominatorTree *DT,
                                        unsigned MaxRecurse) {
+  Instruction::BinaryOps Opcode = (Instruction::BinaryOps)Opc;
   assert(Instruction::isAssociative(Opcode) && "Not an associative operation!");
 
   // Recursion is always used, so bail out at once if we already hit the limit.
@@ -391,17 +397,39 @@ static Value *ThreadCmpOverSelect(CmpInst::Predicate Pred, Value *LHS,
   assert(isa<SelectInst>(LHS) && "Not comparing with a select instruction!");
   SelectInst *SI = cast<SelectInst>(LHS);
 
-  // Now that we have "cmp select(cond, TV, FV), RHS", analyse it.
+  // Now that we have "cmp select(Cond, TV, FV), RHS", analyse it.
   // Does "cmp TV, RHS" simplify?
   if (Value *TCmp = SimplifyCmpInst(Pred, SI->getTrueValue(), RHS, TD, DT,
-                                    MaxRecurse))
+                                    MaxRecurse)) {
     // It does!  Does "cmp FV, RHS" simplify?
     if (Value *FCmp = SimplifyCmpInst(Pred, SI->getFalseValue(), RHS, TD, DT,
-                                      MaxRecurse))
+                                      MaxRecurse)) {
       // It does!  If they simplified to the same value, then use it as the
       // result of the original comparison.
       if (TCmp == FCmp)
         return TCmp;
+      Value *Cond = SI->getCondition();
+      // If the false value simplified to false, then the result of the compare
+      // is equal to "Cond && TCmp".  This also catches the case when the false
+      // value simplified to false and the true value to true, returning "Cond".
+      if (match(FCmp, m_Zero()))
+        if (Value *V = SimplifyAndInst(Cond, TCmp, TD, DT, MaxRecurse))
+          return V;
+      // If the true value simplified to true, then the result of the compare
+      // is equal to "Cond || FCmp".
+      if (match(TCmp, m_One()))
+        if (Value *V = SimplifyOrInst(Cond, FCmp, TD, DT, MaxRecurse))
+          return V;
+      // Finally, if the false value simplified to true and the true value to
+      // false, then the result of the compare is equal to "!Cond".
+      if (match(FCmp, m_One()) && match(TCmp, m_Zero()))
+        if (Value *V =
+            SimplifyXorInst(Cond, Constant::getAllOnesValue(Cond->getType()),
+                            TD, DT, MaxRecurse))
+          return V;
+    }
+  }
+
   return 0;
 }
 
@@ -506,7 +534,7 @@ static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   }
 
   // X + undef -> undef
-  if (isa<UndefValue>(Op1))
+  if (match(Op1, m_Undef()))
     return Op1;
 
   // X + 0 -> X
@@ -572,7 +600,7 @@ static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
 
   // X - undef -> undef
   // undef - X -> undef
-  if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
+  if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
     return UndefValue::get(Op0->getType());
 
   // X - 0 -> X
@@ -583,23 +611,85 @@ static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   if (Op0 == Op1)
     return Constant::getNullValue(Op0->getType());
 
-  // (X + Y) - Y -> X
-  // (Y + X) - Y -> X
+  // (X*2) - X -> X
+  // (X<<1) - X -> X
   Value *X = 0;
-  if (match(Op0, m_Add(m_Value(X), m_Specific(Op1))) ||
-      match(Op0, m_Add(m_Specific(Op1), m_Value(X))))
-    return X;
+  if (match(Op0, m_Mul(m_Specific(Op1), m_ConstantInt<2>())) ||
+      match(Op0, m_Shl(m_Specific(Op1), m_One())))
+    return Op1;
 
-  /// i1 sub -> xor.
-  if (MaxRecurse && Op0->getType()->isIntegerTy(1))
-    if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1))
-      return V;
+  // (X + Y) - Z -> X + (Y - Z) or Y + (X - Z) if everything simplifies.
+  // For example, (X + Y) - Y -> X; (Y + X) - Y -> X
+  Value *Y = 0, *Z = Op1;
+  if (MaxRecurse && match(Op0, m_Add(m_Value(X), m_Value(Y)))) { // (X + Y) - Z
+    // See if "V === Y - Z" simplifies.
+    if (Value *V = SimplifyBinOp(Instruction::Sub, Y, Z, TD, DT, MaxRecurse-1))
+      // It does!  Now see if "X + V" simplifies.
+      if (Value *W = SimplifyBinOp(Instruction::Add, X, V, TD, DT,
+                                   MaxRecurse-1)) {
+        // It does, we successfully reassociated!
+        ++NumReassoc;
+        return W;
+      }
+    // See if "V === X - Z" simplifies.
+    if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1))
+      // It does!  Now see if "Y + V" simplifies.
+      if (Value *W = SimplifyBinOp(Instruction::Add, Y, V, TD, DT,
+                                   MaxRecurse-1)) {
+        // It does, we successfully reassociated!
+        ++NumReassoc;
+        return W;
+      }
+  }
+
+  // X - (Y + Z) -> (X - Y) - Z or (X - Z) - Y if everything simplifies.
+  // For example, X - (X + 1) -> -1
+  X = Op0;
+  if (MaxRecurse && match(Op1, m_Add(m_Value(Y), m_Value(Z)))) { // X - (Y + Z)
+    // See if "V === X - Y" simplifies.
+    if (Value *V = SimplifyBinOp(Instruction::Sub, X, Y, TD, DT, MaxRecurse-1))
+      // It does!  Now see if "V - Z" simplifies.
+      if (Value *W = SimplifyBinOp(Instruction::Sub, V, Z, TD, DT,
+                                   MaxRecurse-1)) {
+        // It does, we successfully reassociated!
+        ++NumReassoc;
+        return W;
+      }
+    // See if "V === X - Z" simplifies.
+    if (Value *V = SimplifyBinOp(Instruction::Sub, X, Z, TD, DT, MaxRecurse-1))
+      // It does!  Now see if "V - Y" simplifies.
+      if (Value *W = SimplifyBinOp(Instruction::Sub, V, Y, TD, DT,
+                                   MaxRecurse-1)) {
+        // It does, we successfully reassociated!
+        ++NumReassoc;
+        return W;
+      }
+  }
+
+  // Z - (X - Y) -> (Z - X) + Y if everything simplifies.
+  // For example, X - (X - Y) -> Y.
+  Z = Op0;
+  if (MaxRecurse && match(Op1, m_Sub(m_Value(X), m_Value(Y)))) // Z - (X - Y)
+    // See if "V === Z - X" simplifies.
+    if (Value *V = SimplifyBinOp(Instruction::Sub, Z, X, TD, DT, MaxRecurse-1))
+      // It does!  Now see if "V + Y" simplifies.
+      if (Value *W = SimplifyBinOp(Instruction::Add, V, Y, TD, DT,
+                                   MaxRecurse-1)) {
+        // It does, we successfully reassociated!
+        ++NumReassoc;
+        return W;
+      }
 
   // Mul distributes over Sub.  Try some generic simplifications based on this.
   if (Value *V = FactorizeBinOp(Instruction::Sub, Op0, Op1, Instruction::Mul,
                                 TD, DT, MaxRecurse))
     return V;
 
+  // i1 sub -> xor.
+  if (MaxRecurse && Op0->getType()->isIntegerTy(1))
+    if (Value *V = SimplifyXorInst(Op0, Op1, TD, DT, MaxRecurse-1))
+      return V;
+
   // Threading Sub over selects and phi nodes is pointless, so don't bother.
   // Threading over the select in "A - select(cond, B, C)" means evaluating
   // "A-B" and "A-C" and seeing if they are equal; but they are equal if and
@@ -633,7 +723,7 @@ static Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
   }
 
   // X * undef -> 0
-  if (isa<UndefValue>(Op1))
+  if (match(Op1, m_Undef()))
     return Constant::getNullValue(Op0->getType());
 
   // X * 0 -> 0
@@ -644,7 +734,16 @@ static Value *SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
   if (match(Op1, m_One()))
     return Op0;
 
-  /// i1 mul -> and.
+  // (X / Y) * Y -> X if the division is exact.
+  Value *X = 0, *Y = 0;
+  if ((match(Op0, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op1) || // (X / Y) * Y
+      (match(Op1, m_IDiv(m_Value(X), m_Value(Y))) && Y == Op0)) { // Y * (X / Y)
+    BinaryOperator *Div = cast<BinaryOperator>(Y == Op1 ? Op0 : Op1);
+    if (Div->isExact())
+      return X;
+  }
+
+  // i1 mul -> and.
   if (MaxRecurse && Op0->getType()->isIntegerTy(1))
     if (Value *V = SimplifyAndInst(Op0, Op1, TD, DT, MaxRecurse-1))
       return V;
@@ -681,6 +780,356 @@ Value *llvm::SimplifyMulInst(Value *Op0, Value *Op1, const TargetData *TD,
   return ::SimplifyMulInst(Op0, Op1, TD, DT, RecursionLimit);
 }
 
+/// SimplifyDiv - Given operands for an SDiv or UDiv, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
+                          const TargetData *TD, const DominatorTree *DT,
+                          unsigned MaxRecurse) {
+  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
+    if (Constant *C1 = dyn_cast<Constant>(Op1)) {
+      Constant *Ops[] = { C0, C1 };
+      return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD);
+    }
+  }
+
+  bool isSigned = Opcode == Instruction::SDiv;
+
+  // X / undef -> undef
+  if (match(Op1, m_Undef()))
+    return Op1;
+
+  // undef / X -> 0
+  if (match(Op0, m_Undef()))
+    return Constant::getNullValue(Op0->getType());
+
+  // 0 / X -> 0, we don't need to preserve faults!
+  if (match(Op0, m_Zero()))
+    return Op0;
+
+  // X / 1 -> X
+  if (match(Op1, m_One()))
+    return Op0;
+
+  if (Op0->getType()->isIntegerTy(1))
+    // It can't be division by zero, hence it must be division by one.
+    return Op0;
+
+  // X / X -> 1
+  if (Op0 == Op1)
+    return ConstantInt::get(Op0->getType(), 1);
+
+  // (X * Y) / Y -> X if the multiplication does not overflow.
+  Value *X = 0, *Y = 0;
+  if (match(Op0, m_Mul(m_Value(X), m_Value(Y))) && (X == Op1 || Y == Op1)) {
+    if (Y != Op1) std::swap(X, Y); // Ensure expression is (X * Y) / Y, Y = Op1
+    BinaryOperator *Mul = cast<BinaryOperator>(Op0);
+    // If the Mul knows it does not overflow, then we are good to go.
+    if ((isSigned && Mul->hasNoSignedWrap()) ||
+        (!isSigned && Mul->hasNoUnsignedWrap()))
+      return X;
+    // If X has the form X = A / Y then X * Y cannot overflow.
+    if (BinaryOperator *Div = dyn_cast<BinaryOperator>(X))
+      if (Div->getOpcode() == Opcode && Div->getOperand(1) == Y)
+        return X;
+  }
+
+  // (X rem Y) / Y -> 0
+  if ((isSigned && match(Op0, m_SRem(m_Value(), m_Specific(Op1)))) ||
+      (!isSigned && match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
+    return Constant::getNullValue(Op0->getType());
+
+  // If the operation is with the result of a select instruction, check whether
+  // operating on either branch of the select always yields the same value.
+  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
+    if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  // If the operation is with the result of a phi instruction, check whether
+  // operating on all incoming values of the phi always yields the same value.
+  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
+    if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  return 0;
+}
+
+/// SimplifySDivInst - Given operands for an SDiv, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD,
+                               const DominatorTree *DT, unsigned MaxRecurse) {
+  if (Value *V = SimplifyDiv(Instruction::SDiv, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  return 0;
+}
+
+Value *llvm::SimplifySDivInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifySDivInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+/// SimplifyUDivInst - Given operands for a UDiv, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD,
+                               const DominatorTree *DT, unsigned MaxRecurse) {
+  if (Value *V = SimplifyDiv(Instruction::UDiv, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  return 0;
+}
+
+Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifyUDivInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+static Value *SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *,
+                               const DominatorTree *, unsigned) {
+  // undef / X -> undef    (the undef could be a snan).
+  if (match(Op0, m_Undef()))
+    return Op0;
+
+  // X / undef -> undef
+  if (match(Op1, m_Undef()))
+    return Op1;
+
+  return 0;
+}
+
+Value *llvm::SimplifyFDivInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifyFDivInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+/// SimplifyRem - Given operands for an SRem or URem, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
+                          const TargetData *TD, const DominatorTree *DT,
+                          unsigned MaxRecurse) {
+  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
+    if (Constant *C1 = dyn_cast<Constant>(Op1)) {
+      Constant *Ops[] = { C0, C1 };
+      return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD);
+    }
+  }
+
+  // X % undef -> undef
+  if (match(Op1, m_Undef()))
+    return Op1;
+
+  // undef % X -> 0
+  if (match(Op0, m_Undef()))
+    return Constant::getNullValue(Op0->getType());
+
+  // 0 % X -> 0, we don't need to preserve faults!
+  if (match(Op0, m_Zero()))
+    return Op0;
+
+  // X % 0 -> undef, we don't need to preserve faults!
+  if (match(Op1, m_Zero()))
+    return UndefValue::get(Op0->getType());
+
+  // X % 1 -> 0
+  if (match(Op1, m_One()))
+    return Constant::getNullValue(Op0->getType());
+
+  if (Op0->getType()->isIntegerTy(1))
+    // It can't be remainder by zero, hence it must be remainder by one.
+    return Constant::getNullValue(Op0->getType());
+
+  // X % X -> 0
+  if (Op0 == Op1)
+    return Constant::getNullValue(Op0->getType());
+
+  // If the operation is with the result of a select instruction, check whether
+  // operating on either branch of the select always yields the same value.
+  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
+    if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  // If the operation is with the result of a phi instruction, check whether
+  // operating on all incoming values of the phi always yields the same value.
+  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
+    if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  return 0;
+}
+
+/// SimplifySRemInst - Given operands for an SRem, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD,
+                               const DominatorTree *DT, unsigned MaxRecurse) {
+  if (Value *V = SimplifyRem(Instruction::SRem, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  return 0;
+}
+
+Value *llvm::SimplifySRemInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifySRemInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+/// SimplifyURemInst - Given operands for a URem, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD,
+                               const DominatorTree *DT, unsigned MaxRecurse) {
+  if (Value *V = SimplifyRem(Instruction::URem, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  return 0;
+}
+
+Value *llvm::SimplifyURemInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifyURemInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+static Value *SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *,
+                               const DominatorTree *, unsigned) {
+  // undef % X -> undef    (the undef could be a snan).
+  if (match(Op0, m_Undef()))
+    return Op0;
+
+  // X % undef -> undef
+  if (match(Op1, m_Undef()))
+    return Op1;
+
+  return 0;
+}
+
+Value *llvm::SimplifyFRemInst(Value *Op0, Value *Op1, const TargetData *TD,
+                              const DominatorTree *DT) {
+  return ::SimplifyFRemInst(Op0, Op1, TD, DT, RecursionLimit);
+}
+
+/// SimplifyShift - Given operands for an Shl, LShr or AShr, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyShift(unsigned Opcode, Value *Op0, Value *Op1,
+                            const TargetData *TD, const DominatorTree *DT,
+                            unsigned MaxRecurse) {
+  if (Constant *C0 = dyn_cast<Constant>(Op0)) {
+    if (Constant *C1 = dyn_cast<Constant>(Op1)) {
+      Constant *Ops[] = { C0, C1 };
+      return ConstantFoldInstOperands(Opcode, C0->getType(), Ops, 2, TD);
+    }
+  }
+
+  // 0 shift by X -> 0
+  if (match(Op0, m_Zero()))
+    return Op0;
+
+  // X shift by 0 -> X
+  if (match(Op1, m_Zero()))
+    return Op0;
+
+  // X shift by undef -> undef because it may shift by the bitwidth.
+  if (match(Op1, m_Undef()))
+    return Op1;
+
+  // Shifting by the bitwidth or more is undefined.
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(Op1))
+    if (CI->getValue().getLimitedValue() >=
+        Op0->getType()->getScalarSizeInBits())
+      return UndefValue::get(Op0->getType());
+
+  // If the operation is with the result of a select instruction, check whether
+  // operating on either branch of the select always yields the same value.
+  if (isa<SelectInst>(Op0) || isa<SelectInst>(Op1))
+    if (Value *V = ThreadBinOpOverSelect(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  // If the operation is with the result of a phi instruction, check whether
+  // operating on all incoming values of the phi always yields the same value.
+  if (isa<PHINode>(Op0) || isa<PHINode>(Op1))
+    if (Value *V = ThreadBinOpOverPHI(Opcode, Op0, Op1, TD, DT, MaxRecurse))
+      return V;
+
+  return 0;
+}
+
+/// SimplifyShlInst - Given operands for an Shl, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
+                              const TargetData *TD, const DominatorTree *DT,
+                              unsigned MaxRecurse) {
+  if (Value *V = SimplifyShift(Instruction::Shl, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  // undef << X -> 0
+  if (match(Op0, m_Undef()))
+    return Constant::getNullValue(Op0->getType());
+
+  // (X >> A) << A -> X
+  Value *X;
+  if (match(Op0, m_Shr(m_Value(X), m_Specific(Op1))) &&
+      cast<PossiblyExactOperator>(Op0)->isExact())
+    return X;
+  return 0;
+}
+
+Value *llvm::SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
+                             const TargetData *TD, const DominatorTree *DT) {
+  return ::SimplifyShlInst(Op0, Op1, isNSW, isNUW, TD, DT, RecursionLimit);
+}
+
+/// SimplifyLShrInst - Given operands for an LShr, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
+                               const TargetData *TD, const DominatorTree *DT,
+                               unsigned MaxRecurse) {
+  if (Value *V = SimplifyShift(Instruction::LShr, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  // undef >>l X -> 0
+  if (match(Op0, m_Undef()))
+    return Constant::getNullValue(Op0->getType());
+
+  // (X << A) >> A -> X
+  Value *X;
+  if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
+      cast<OverflowingBinaryOperator>(Op0)->hasNoUnsignedWrap())
+    return X;
+
+  return 0;
+}
+
+Value *llvm::SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
+                              const TargetData *TD, const DominatorTree *DT) {
+  return ::SimplifyLShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit);
+}
+
+/// SimplifyAShrInst - Given operands for an AShr, see if we can
+/// fold the result.  If not, this returns null.
+static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
+                               const TargetData *TD, const DominatorTree *DT,
+                               unsigned MaxRecurse) {
+  if (Value *V = SimplifyShift(Instruction::AShr, Op0, Op1, TD, DT, MaxRecurse))
+    return V;
+
+  // all ones >>a X -> all ones
+  if (match(Op0, m_AllOnes()))
+    return Op0;
+
+  // undef >>a X -> all ones
+  if (match(Op0, m_Undef()))
+    return Constant::getAllOnesValue(Op0->getType());
+
+  // (X << A) >> A -> X
+  Value *X;
+  if (match(Op0, m_Shl(m_Value(X), m_Specific(Op1))) &&
+      cast<OverflowingBinaryOperator>(Op0)->hasNoSignedWrap())
+    return X;
+
+  return 0;
+}
+
+Value *llvm::SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
+                              const TargetData *TD, const DominatorTree *DT) {
+  return ::SimplifyAShrInst(Op0, Op1, isExact, TD, DT, RecursionLimit);
+}
+
 /// SimplifyAndInst - Given operands for an And, see if we can
 /// fold the result.  If not, this returns null.
 static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
@@ -697,7 +1146,7 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
   }
 
   // X & undef -> 0
-  if (isa<UndefValue>(Op1))
+  if (match(Op1, m_Undef()))
     return Constant::getNullValue(Op0->getType());
 
   // X & X = X
@@ -713,12 +1162,12 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Op0;
 
   // A & ~A  =  ~A & A  =  0
-  Value *A = 0, *B = 0;
-  if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
-      (match(Op1, m_Not(m_Value(A))) && A == Op0))
+  if (match(Op0, m_Not(m_Specific(Op1))) ||
+      match(Op1, m_Not(m_Specific(Op0))))
     return Constant::getNullValue(Op0->getType());
 
   // (A | ?) & A = A
+  Value *A = 0, *B = 0;
   if (match(Op0, m_Or(m_Value(A), m_Value(B))) &&
       (A == Op1 || B == Op1))
     return Op1;
@@ -786,7 +1235,7 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
   }
 
   // X | undef -> -1
-  if (isa<UndefValue>(Op1))
+  if (match(Op1, m_Undef()))
     return Constant::getAllOnesValue(Op0->getType());
 
   // X | X = X
@@ -802,12 +1251,12 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Op1;
 
   // A | ~A  =  ~A | A  =  -1
-  Value *A = 0, *B = 0;
-  if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
-      (match(Op1, m_Not(m_Value(A))) && A == Op0))
+  if (match(Op0, m_Not(m_Specific(Op1))) ||
+      match(Op1, m_Not(m_Specific(Op0))))
     return Constant::getAllOnesValue(Op0->getType());
 
   // (A & ?) | A = A
+  Value *A = 0, *B = 0;
   if (match(Op0, m_And(m_Value(A), m_Value(B))) &&
       (A == Op1 || B == Op1))
     return Op1;
@@ -817,6 +1266,16 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const TargetData *TD,
       (A == Op0 || B == Op0))
     return Op0;
 
+  // ~(A & ?) | A = -1
+  if (match(Op0, m_Not(m_And(m_Value(A), m_Value(B)))) &&
+      (A == Op1 || B == Op1))
+    return Constant::getAllOnesValue(Op1->getType());
+
+  // A | ~(A & ?) = -1
+  if (match(Op1, m_Not(m_And(m_Value(A), m_Value(B)))) &&
+      (A == Op0 || B == Op0))
+    return Constant::getAllOnesValue(Op0->getType());
+
   // Try some generic simplifications for associative operations.
   if (Value *V = SimplifyAssociativeBinOp(Instruction::Or, Op0, Op1, TD, DT,
                                           MaxRecurse))
@@ -870,7 +1329,7 @@ static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
   }
 
   // A ^ undef -> undef
-  if (isa<UndefValue>(Op1))
+  if (match(Op1, m_Undef()))
     return Op1;
 
   // A ^ 0 = A
@@ -882,9 +1341,8 @@ static Value *SimplifyXorInst(Value *Op0, Value *Op1, const TargetData *TD,
     return Constant::getNullValue(Op0->getType());
 
   // A ^ ~A  =  ~A ^ A  =  -1
-  Value *A = 0;
-  if ((match(Op0, m_Not(m_Value(A))) && A == Op1) ||
-      (match(Op1, m_Not(m_Value(A))) && A == Op0))
+  if (match(Op0, m_Not(m_Specific(Op1))) ||
+      match(Op1, m_Not(m_Specific(Op0))))
     return Constant::getAllOnesValue(Op0->getType());
 
   // Try some generic simplifications for associative operations.
@@ -918,6 +1376,26 @@ static const Type *GetCompareTy(Value *Op) {
   return CmpInst::makeCmpResultType(Op->getType());
 }
 
+/// ExtractEquivalentCondition - Rummage around inside V looking for something
+/// equivalent to the comparison "LHS Pred RHS".  Return such a value if found,
+/// otherwise return null.  Helper function for analyzing max/min idioms.
+static Value *ExtractEquivalentCondition(Value *V, CmpInst::Predicate Pred,
+                                         Value *LHS, Value *RHS) {
+  SelectInst *SI = dyn_cast<SelectInst>(V);
+  if (!SI)
+    return 0;
+  CmpInst *Cmp = dyn_cast<CmpInst>(SI->getCondition());
+  if (!Cmp)
+    return 0;
+  Value *CmpLHS = Cmp->getOperand(0), *CmpRHS = Cmp->getOperand(1);
+  if (Pred == Cmp->getPredicate() && LHS == CmpLHS && RHS == CmpRHS)
+    return Cmp;
+  if (Pred == CmpInst::getSwappedPredicate(Cmp->getPredicate()) &&
+      LHS == CmpRHS && RHS == CmpLHS)
+    return Cmp;
+  return 0;
+}
+
 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
 /// fold the result.  If not, this returns null.
 static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
@@ -935,8 +1413,8 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
     Pred = CmpInst::getSwappedPredicate(Pred);
   }
 
-  // ITy - This is the return type of the compare we're considering.
-  const Type *ITy = GetCompareTy(LHS);
+  const Type *ITy = GetCompareTy(LHS); // The return type.
+  const Type *OpTy = LHS->getType();   // The operand type.
 
   // icmp X, X -> true/false
   // X icmp undef -> true/false.  For example, icmp ugt %X, undef -> false
@@ -944,38 +1422,658 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
   if (LHS == RHS || isa<UndefValue>(RHS))
     return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
 
-  // icmp <global/alloca*/null>, <global/alloca*/null> - Global/Stack value
-  // addresses never equal each other!  We already know that Op0 != Op1.
-  if ((isa<GlobalValue>(LHS) || isa<AllocaInst>(LHS) ||
-       isa<ConstantPointerNull>(LHS)) &&
-      (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
-       isa<ConstantPointerNull>(RHS)))
+  // Special case logic when the operands have i1 type.
+  if (OpTy->isIntegerTy(1) || (OpTy->isVectorTy() &&
+       cast<VectorType>(OpTy)->getElementType()->isIntegerTy(1))) {
+    switch (Pred) {
+    default: break;
+    case ICmpInst::ICMP_EQ:
+      // X == 1 -> X
+      if (match(RHS, m_One()))
+        return LHS;
+      break;
+    case ICmpInst::ICMP_NE:
+      // X != 0 -> X
+      if (match(RHS, m_Zero()))
+        return LHS;
+      break;
+    case ICmpInst::ICMP_UGT:
+      // X >u 0 -> X
+      if (match(RHS, m_Zero()))
+        return LHS;
+      break;
+    case ICmpInst::ICMP_UGE:
+      // X >=u 1 -> X
+      if (match(RHS, m_One()))
+        return LHS;
+      break;
+    case ICmpInst::ICMP_SLT:
+      // X <s 0 -> X
+      if (match(RHS, m_Zero()))
+        return LHS;
+      break;
+    case ICmpInst::ICMP_SLE:
+      // X <=s -1 -> X
+      if (match(RHS, m_One()))
+        return LHS;
+      break;
+    }
+  }
+
+  // icmp <alloca*>, <global/alloca*/null> - Different stack variables have
+  // different addresses, and what's more the address of a stack variable is
+  // never null or equal to the address of a global.  Note that generalizing
+  // to the case where LHS is a global variable address or null is pointless,
+  // since if both LHS and RHS are constants then we already constant folded
+  // the compare, and if only one of them is then we moved it to RHS already.
+  if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
+                               isa<ConstantPointerNull>(RHS)))
+    // We already know that LHS != RHS.
     return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
 
-  // See if we are doing a comparison with a constant.
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
-    // If we have an icmp le or icmp ge instruction, turn it into the
-    // appropriate icmp lt or icmp gt instruction.  This allows us to rely on
-    // them being folded in the code below.
+  // If we are comparing with zero then try hard since this is a common case.
+  if (match(RHS, m_Zero())) {
+    bool LHSKnownNonNegative, LHSKnownNegative;
     switch (Pred) {
-    default: break;
+    default:
+      assert(false && "Unknown ICmp predicate!");
+    case ICmpInst::ICMP_ULT:
+      // getNullValue also works for vectors, unlike getFalse.
+      return Constant::getNullValue(ITy);
+    case ICmpInst::ICMP_UGE:
+      // getAllOnesValue also works for vectors, unlike getTrue.
+      return ConstantInt::getAllOnesValue(ITy);
+    case ICmpInst::ICMP_EQ:
     case ICmpInst::ICMP_ULE:
-      if (CI->isMaxValue(false))                 // A <=u MAX -> TRUE
-        return ConstantInt::getTrue(CI->getContext());
+      if (isKnownNonZero(LHS, TD))
+        return Constant::getNullValue(ITy);
+      break;
+    case ICmpInst::ICMP_NE:
+    case ICmpInst::ICMP_UGT:
+      if (isKnownNonZero(LHS, TD))
+        return ConstantInt::getAllOnesValue(ITy);
+      break;
+    case ICmpInst::ICMP_SLT:
+      ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
+      if (LHSKnownNegative)
+        return ConstantInt::getAllOnesValue(ITy);
+      if (LHSKnownNonNegative)
+        return Constant::getNullValue(ITy);
       break;
     case ICmpInst::ICMP_SLE:
-      if (CI->isMaxValue(true))                  // A <=s MAX -> TRUE
-        return ConstantInt::getTrue(CI->getContext());
+      ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
+      if (LHSKnownNegative)
+        return ConstantInt::getAllOnesValue(ITy);
+      if (LHSKnownNonNegative && isKnownNonZero(LHS, TD))
+        return Constant::getNullValue(ITy);
+      break;
+    case ICmpInst::ICMP_SGE:
+      ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
+      if (LHSKnownNegative)
+        return Constant::getNullValue(ITy);
+      if (LHSKnownNonNegative)
+        return ConstantInt::getAllOnesValue(ITy);
       break;
+    case ICmpInst::ICMP_SGT:
+      ComputeSignBit(LHS, LHSKnownNonNegative, LHSKnownNegative, TD);
+      if (LHSKnownNegative)
+        return Constant::getNullValue(ITy);
+      if (LHSKnownNonNegative && isKnownNonZero(LHS, TD))
+        return ConstantInt::getAllOnesValue(ITy);
+      break;
+    }
+  }
+
+  // See if we are doing a comparison with a constant integer.
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+    // Rule out tautological comparisons (eg., ult 0 or uge 0).
+    ConstantRange RHS_CR = ICmpInst::makeConstantRange(Pred, CI->getValue());
+    if (RHS_CR.isEmptySet())
+      return ConstantInt::getFalse(CI->getContext());
+    if (RHS_CR.isFullSet())
+      return ConstantInt::getTrue(CI->getContext());
+
+    // Many binary operators with constant RHS have easy to compute constant
+    // range.  Use them to check whether the comparison is a tautology.
+    uint32_t Width = CI->getBitWidth();
+    APInt Lower = APInt(Width, 0);
+    APInt Upper = APInt(Width, 0);
+    ConstantInt *CI2;
+    if (match(LHS, m_URem(m_Value(), m_ConstantInt(CI2)))) {
+      // 'urem x, CI2' produces [0, CI2).
+      Upper = CI2->getValue();
+    } else if (match(LHS, m_SRem(m_Value(), m_ConstantInt(CI2)))) {
+      // 'srem x, CI2' produces (-|CI2|, |CI2|).
+      Upper = CI2->getValue().abs();
+      Lower = (-Upper) + 1;
+    } else if (match(LHS, m_UDiv(m_Value(), m_ConstantInt(CI2)))) {
+      // 'udiv x, CI2' produces [0, UINT_MAX / CI2].
+      APInt NegOne = APInt::getAllOnesValue(Width);
+      if (!CI2->isZero())
+        Upper = NegOne.udiv(CI2->getValue()) + 1;
+    } else if (match(LHS, m_SDiv(m_Value(), m_ConstantInt(CI2)))) {
+      // 'sdiv x, CI2' produces [INT_MIN / CI2, INT_MAX / CI2].
+      APInt IntMin = APInt::getSignedMinValue(Width);
+      APInt IntMax = APInt::getSignedMaxValue(Width);
+      APInt Val = CI2->getValue().abs();
+      if (!Val.isMinValue()) {
+        Lower = IntMin.sdiv(Val);
+        Upper = IntMax.sdiv(Val) + 1;
+      }
+    } else if (match(LHS, m_LShr(m_Value(), m_ConstantInt(CI2)))) {
+      // 'lshr x, CI2' produces [0, UINT_MAX >> CI2].
+      APInt NegOne = APInt::getAllOnesValue(Width);
+      if (CI2->getValue().ult(Width))
+        Upper = NegOne.lshr(CI2->getValue()) + 1;
+    } else if (match(LHS, m_AShr(m_Value(), m_ConstantInt(CI2)))) {
+      // 'ashr x, CI2' produces [INT_MIN >> CI2, INT_MAX >> CI2].
+      APInt IntMin = APInt::getSignedMinValue(Width);
+      APInt IntMax = APInt::getSignedMaxValue(Width);
+      if (CI2->getValue().ult(Width)) {
+        Lower = IntMin.ashr(CI2->getValue());
+        Upper = IntMax.ashr(CI2->getValue()) + 1;
+      }
+    } else if (match(LHS, m_Or(m_Value(), m_ConstantInt(CI2)))) {
+      // 'or x, CI2' produces [CI2, UINT_MAX].
+      Lower = CI2->getValue();
+    } else if (match(LHS, m_And(m_Value(), m_ConstantInt(CI2)))) {
+      // 'and x, CI2' produces [0, CI2].
+      Upper = CI2->getValue() + 1;
+    }
+    if (Lower != Upper) {
+      ConstantRange LHS_CR = ConstantRange(Lower, Upper);
+      if (RHS_CR.contains(LHS_CR))
+        return ConstantInt::getTrue(RHS->getContext());
+      if (RHS_CR.inverse().contains(LHS_CR))
+        return ConstantInt::getFalse(RHS->getContext());
+    }
+  }
+
+  // Compare of cast, for example (zext X) != 0 -> X != 0
+  if (isa<CastInst>(LHS) && (isa<Constant>(RHS) || isa<CastInst>(RHS))) {
+    Instruction *LI = cast<CastInst>(LHS);
+    Value *SrcOp = LI->getOperand(0);
+    const Type *SrcTy = SrcOp->getType();
+    const Type *DstTy = LI->getType();
+
+    // Turn icmp (ptrtoint x), (ptrtoint/constant) into a compare of the input
+    // if the integer type is the same size as the pointer type.
+    if (MaxRecurse && TD && isa<PtrToIntInst>(LI) &&
+        TD->getPointerSizeInBits() == DstTy->getPrimitiveSizeInBits()) {
+      if (Constant *RHSC = dyn_cast<Constant>(RHS)) {
+        // Transfer the cast to the constant.
+        if (Value *V = SimplifyICmpInst(Pred, SrcOp,
+                                        ConstantExpr::getIntToPtr(RHSC, SrcTy),
+                                        TD, DT, MaxRecurse-1))
+          return V;
+      } else if (PtrToIntInst *RI = dyn_cast<PtrToIntInst>(RHS)) {
+        if (RI->getOperand(0)->getType() == SrcTy)
+          // Compare without the cast.
+          if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
+                                          TD, DT, MaxRecurse-1))
+            return V;
+      }
+    }
+
+    if (isa<ZExtInst>(LHS)) {
+      // Turn icmp (zext X), (zext Y) into a compare of X and Y if they have the
+      // same type.
+      if (ZExtInst *RI = dyn_cast<ZExtInst>(RHS)) {
+        if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
+          // Compare X and Y.  Note that signed predicates become unsigned.
+          if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
+                                          SrcOp, RI->getOperand(0), TD, DT,
+                                          MaxRecurse-1))
+            return V;
+      }
+      // Turn icmp (zext X), Cst into a compare of X and Cst if Cst is extended
+      // too.  If not, then try to deduce the result of the comparison.
+      else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+        // Compute the constant that would happen if we truncated to SrcTy then
+        // reextended to DstTy.
+        Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
+        Constant *RExt = ConstantExpr::getCast(CastInst::ZExt, Trunc, DstTy);
+
+        // If the re-extended constant didn't change then this is effectively
+        // also a case of comparing two zero-extended values.
+        if (RExt == CI && MaxRecurse)
+          if (Value *V = SimplifyICmpInst(ICmpInst::getUnsignedPredicate(Pred),
+                                          SrcOp, Trunc, TD, DT, MaxRecurse-1))
+            return V;
+
+        // Otherwise the upper bits of LHS are zero while RHS has a non-zero bit
+        // there.  Use this to work out the result of the comparison.
+        if (RExt != CI) {
+          switch (Pred) {
+          default:
+            assert(false && "Unknown ICmp predicate!");
+          // LHS <u RHS.
+          case ICmpInst::ICMP_EQ:
+          case ICmpInst::ICMP_UGT:
+          case ICmpInst::ICMP_UGE:
+            return ConstantInt::getFalse(CI->getContext());
+
+          case ICmpInst::ICMP_NE:
+          case ICmpInst::ICMP_ULT:
+          case ICmpInst::ICMP_ULE:
+            return ConstantInt::getTrue(CI->getContext());
+
+          // LHS is non-negative.  If RHS is negative then LHS >s LHS.  If RHS
+          // is non-negative then LHS <s RHS.
+          case ICmpInst::ICMP_SGT:
+          case ICmpInst::ICMP_SGE:
+            return CI->getValue().isNegative() ?
+              ConstantInt::getTrue(CI->getContext()) :
+              ConstantInt::getFalse(CI->getContext());
+
+          case ICmpInst::ICMP_SLT:
+          case ICmpInst::ICMP_SLE:
+            return CI->getValue().isNegative() ?
+              ConstantInt::getFalse(CI->getContext()) :
+              ConstantInt::getTrue(CI->getContext());
+          }
+        }
+      }
+    }
+
+    if (isa<SExtInst>(LHS)) {
+      // Turn icmp (sext X), (sext Y) into a compare of X and Y if they have the
+      // same type.
+      if (SExtInst *RI = dyn_cast<SExtInst>(RHS)) {
+        if (MaxRecurse && SrcTy == RI->getOperand(0)->getType())
+          // Compare X and Y.  Note that the predicate does not change.
+          if (Value *V = SimplifyICmpInst(Pred, SrcOp, RI->getOperand(0),
+                                          TD, DT, MaxRecurse-1))
+            return V;
+      }
+      // Turn icmp (sext X), Cst into a compare of X and Cst if Cst is extended
+      // too.  If not, then try to deduce the result of the comparison.
+      else if (ConstantInt *CI = dyn_cast<ConstantInt>(RHS)) {
+        // Compute the constant that would happen if we truncated to SrcTy then
+        // reextended to DstTy.
+        Constant *Trunc = ConstantExpr::getTrunc(CI, SrcTy);
+        Constant *RExt = ConstantExpr::getCast(CastInst::SExt, Trunc, DstTy);
+
+        // If the re-extended constant didn't change then this is effectively
+        // also a case of comparing two sign-extended values.
+        if (RExt == CI && MaxRecurse)
+          if (Value *V = SimplifyICmpInst(Pred, SrcOp, Trunc, TD, DT,
+                                          MaxRecurse-1))
+            return V;
+
+        // Otherwise the upper bits of LHS are all equal, while RHS has varying
+        // bits there.  Use this to work out the result of the comparison.
+        if (RExt != CI) {
+          switch (Pred) {
+          default:
+            assert(false && "Unknown ICmp predicate!");
+          case ICmpInst::ICMP_EQ:
+            return ConstantInt::getFalse(CI->getContext());
+          case ICmpInst::ICMP_NE:
+            return ConstantInt::getTrue(CI->getContext());
+
+          // If RHS is non-negative then LHS <s RHS.  If RHS is negative then
+          // LHS >s RHS.
+          case ICmpInst::ICMP_SGT:
+          case ICmpInst::ICMP_SGE:
+            return CI->getValue().isNegative() ?
+              ConstantInt::getTrue(CI->getContext()) :
+              ConstantInt::getFalse(CI->getContext());
+          case ICmpInst::ICMP_SLT:
+          case ICmpInst::ICMP_SLE:
+            return CI->getValue().isNegative() ?
+              ConstantInt::getFalse(CI->getContext()) :
+              ConstantInt::getTrue(CI->getContext());
+
+          // If LHS is non-negative then LHS <u RHS.  If LHS is negative then
+          // LHS >u RHS.
+          case ICmpInst::ICMP_UGT:
+          case ICmpInst::ICMP_UGE:
+            // Comparison is true iff the LHS <s 0.
+            if (MaxRecurse)
+              if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SLT, SrcOp,
+                                              Constant::getNullValue(SrcTy),
+                                              TD, DT, MaxRecurse-1))
+                return V;
+            break;
+          case ICmpInst::ICMP_ULT:
+          case ICmpInst::ICMP_ULE:
+            // Comparison is true iff the LHS >=s 0.
+            if (MaxRecurse)
+              if (Value *V = SimplifyICmpInst(ICmpInst::ICMP_SGE, SrcOp,
+                                              Constant::getNullValue(SrcTy),
+                                              TD, DT, MaxRecurse-1))
+                return V;
+            break;
+          }
+        }
+      }
+    }
+  }
+
+  // Special logic for binary operators.
+  BinaryOperator *LBO = dyn_cast<BinaryOperator>(LHS);
+  BinaryOperator *RBO = dyn_cast<BinaryOperator>(RHS);
+  if (MaxRecurse && (LBO || RBO)) {
+    // Analyze the case when either LHS or RHS is an add instruction.
+    Value *A = 0, *B = 0, *C = 0, *D = 0;
+    // LHS = A + B (or A and B are null); RHS = C + D (or C and D are null).
+    bool NoLHSWrapProblem = false, NoRHSWrapProblem = false;
+    if (LBO && LBO->getOpcode() == Instruction::Add) {
+      A = LBO->getOperand(0); B = LBO->getOperand(1);
+      NoLHSWrapProblem = ICmpInst::isEquality(Pred) ||
+        (CmpInst::isUnsigned(Pred) && LBO->hasNoUnsignedWrap()) ||
+        (CmpInst::isSigned(Pred) && LBO->hasNoSignedWrap());
+    }
+    if (RBO && RBO->getOpcode() == Instruction::Add) {
+      C = RBO->getOperand(0); D = RBO->getOperand(1);
+      NoRHSWrapProblem = ICmpInst::isEquality(Pred) ||
+        (CmpInst::isUnsigned(Pred) && RBO->hasNoUnsignedWrap()) ||
+        (CmpInst::isSigned(Pred) && RBO->hasNoSignedWrap());
+    }
+
+    // icmp (X+Y), X -> icmp Y, 0 for equalities or if there is no overflow.
+    if ((A == RHS || B == RHS) && NoLHSWrapProblem)
+      if (Value *V = SimplifyICmpInst(Pred, A == RHS ? B : A,
+                                      Constant::getNullValue(RHS->getType()),
+                                      TD, DT, MaxRecurse-1))
+        return V;
+
+    // icmp X, (X+Y) -> icmp 0, Y for equalities or if there is no overflow.
+    if ((C == LHS || D == LHS) && NoRHSWrapProblem)
+      if (Value *V = SimplifyICmpInst(Pred,
+                                      Constant::getNullValue(LHS->getType()),
+                                      C == LHS ? D : C, TD, DT, MaxRecurse-1))
+        return V;
+
+    // icmp (X+Y), (X+Z) -> icmp Y,Z for equalities or if there is no overflow.
+    if (A && C && (A == C || A == D || B == C || B == D) &&
+        NoLHSWrapProblem && NoRHSWrapProblem) {
+      // Determine Y and Z in the form icmp (X+Y), (X+Z).
+      Value *Y = (A == C || A == D) ? B : A;
+      Value *Z = (C == A || C == B) ? D : C;
+      if (Value *V = SimplifyICmpInst(Pred, Y, Z, TD, DT, MaxRecurse-1))
+        return V;
+    }
+  }
+
+  if (LBO && match(LBO, m_URem(m_Value(), m_Specific(RHS)))) {
+    bool KnownNonNegative, KnownNegative;
+    switch (Pred) {
+    default:
+      break;
+    case ICmpInst::ICMP_SGT:
+    case ICmpInst::ICMP_SGE:
+      ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD);
+      if (!KnownNonNegative)
+        break;
+      // fall-through
+    case ICmpInst::ICMP_EQ:
+    case ICmpInst::ICMP_UGT:
     case ICmpInst::ICMP_UGE:
-      if (CI->isMinValue(false))                 // A >=u MIN -> TRUE
-        return ConstantInt::getTrue(CI->getContext());
+      // getNullValue also works for vectors, unlike getFalse.
+      return Constant::getNullValue(ITy);
+    case ICmpInst::ICMP_SLT:
+    case ICmpInst::ICMP_SLE:
+      ComputeSignBit(LHS, KnownNonNegative, KnownNegative, TD);
+      if (!KnownNonNegative)
+        break;
+      // fall-through
+    case ICmpInst::ICMP_NE:
+    case ICmpInst::ICMP_ULT:
+    case ICmpInst::ICMP_ULE:
+      // getAllOnesValue also works for vectors, unlike getTrue.
+      return Constant::getAllOnesValue(ITy);
+    }
+  }
+  if (RBO && match(RBO, m_URem(m_Value(), m_Specific(LHS)))) {
+    bool KnownNonNegative, KnownNegative;
+    switch (Pred) {
+    default:
       break;
+    case ICmpInst::ICMP_SGT:
     case ICmpInst::ICMP_SGE:
-      if (CI->isMinValue(true))                  // A >=s MIN -> TRUE
-        return ConstantInt::getTrue(CI->getContext());
+      ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD);
+      if (!KnownNonNegative)
+        break;
+      // fall-through
+    case ICmpInst::ICMP_NE:
+    case ICmpInst::ICMP_UGT:
+    case ICmpInst::ICMP_UGE:
+      // getAllOnesValue also works for vectors, unlike getTrue.
+      return Constant::getAllOnesValue(ITy);
+    case ICmpInst::ICMP_SLT:
+    case ICmpInst::ICMP_SLE:
+      ComputeSignBit(RHS, KnownNonNegative, KnownNegative, TD);
+      if (!KnownNonNegative)
+        break;
+      // fall-through
+    case ICmpInst::ICMP_EQ:
+    case ICmpInst::ICMP_ULT:
+    case ICmpInst::ICMP_ULE:
+      // getNullValue also works for vectors, unlike getFalse.
+      return Constant::getNullValue(ITy);
+    }
+  }
+
+  if (MaxRecurse && LBO && RBO && LBO->getOpcode() == RBO->getOpcode() &&
+      LBO->getOperand(1) == RBO->getOperand(1)) {
+    switch (LBO->getOpcode()) {
+    default: break;
+    case Instruction::UDiv:
+    case Instruction::LShr:
+      if (ICmpInst::isSigned(Pred))
+        break;
+      // fall-through
+    case Instruction::SDiv:
+    case Instruction::AShr:
+      if (!LBO->isExact() || !RBO->isExact())
+        break;
+      if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+                                      RBO->getOperand(0), TD, DT, MaxRecurse-1))
+        return V;
+      break;
+    case Instruction::Shl: {
+      bool NUW = LBO->hasNoUnsignedWrap() && LBO->hasNoUnsignedWrap();
+      bool NSW = LBO->hasNoSignedWrap() && RBO->hasNoSignedWrap();
+      if (!NUW && !NSW)
+        break;
+      if (!NSW && ICmpInst::isSigned(Pred))
+        break;
+      if (Value *V = SimplifyICmpInst(Pred, LBO->getOperand(0),
+                                      RBO->getOperand(0), TD, DT, MaxRecurse-1))
+        return V;
+      break;
+    }
+    }
+  }
+
+  // Simplify comparisons involving max/min.
+  Value *A, *B;
+  CmpInst::Predicate P = CmpInst::BAD_ICMP_PREDICATE;
+  CmpInst::Predicate EqP; // Chosen so that "A == max/min(A,B)" iff "A EqP B".
+
+  // Signed variants on "max(a,b)>=a -> true".
+  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
+    if (A != RHS) std::swap(A, B); // smax(A, B) pred A.
+    EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
+    // We analyze this as smax(A, B) pred A.
+    P = Pred;
+  } else if (match(RHS, m_SMax(m_Value(A), m_Value(B))) &&
+             (A == LHS || B == LHS)) {
+    if (A != LHS) std::swap(A, B); // A pred smax(A, B).
+    EqP = CmpInst::ICMP_SGE; // "A == smax(A, B)" iff "A sge B".
+    // We analyze this as smax(A, B) swapped-pred A.
+    P = CmpInst::getSwappedPredicate(Pred);
+  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
+             (A == RHS || B == RHS)) {
+    if (A != RHS) std::swap(A, B); // smin(A, B) pred A.
+    EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
+    // We analyze this as smax(-A, -B) swapped-pred -A.
+    // Note that we do not need to actually form -A or -B thanks to EqP.
+    P = CmpInst::getSwappedPredicate(Pred);
+  } else if (match(RHS, m_SMin(m_Value(A), m_Value(B))) &&
+             (A == LHS || B == LHS)) {
+    if (A != LHS) std::swap(A, B); // A pred smin(A, B).
+    EqP = CmpInst::ICMP_SLE; // "A == smin(A, B)" iff "A sle B".
+    // We analyze this as smax(-A, -B) pred -A.
+    // Note that we do not need to actually form -A or -B thanks to EqP.
+    P = Pred;
+  }
+  if (P != CmpInst::BAD_ICMP_PREDICATE) {
+    // Cases correspond to "max(A, B) p A".
+    switch (P) {
+    default:
+      break;
+    case CmpInst::ICMP_EQ:
+    case CmpInst::ICMP_SLE:
+      // Equivalent to "A EqP B".  This may be the same as the condition tested
+      // in the max/min; if so, we can just return that.
+      if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
+        return V;
+      if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
+        return V;
+      // Otherwise, see if "A EqP B" simplifies.
+      if (MaxRecurse)
+        if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1))
+          return V;
+      break;
+    case CmpInst::ICMP_NE:
+    case CmpInst::ICMP_SGT: {
+      CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
+      // Equivalent to "A InvEqP B".  This may be the same as the condition
+      // tested in the max/min; if so, we can just return that.
+      if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
+        return V;
+      if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
+        return V;
+      // Otherwise, see if "A InvEqP B" simplifies.
+      if (MaxRecurse)
+        if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1))
+          return V;
+      break;
+    }
+    case CmpInst::ICMP_SGE:
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    case CmpInst::ICMP_SLT:
+      // Always false.
+      return Constant::getNullValue(ITy);
+    }
+  }
+
+  // Unsigned variants on "max(a,b)>=a -> true".
+  P = CmpInst::BAD_ICMP_PREDICATE;
+  if (match(LHS, m_UMax(m_Value(A), m_Value(B))) && (A == RHS || B == RHS)) {
+    if (A != RHS) std::swap(A, B); // umax(A, B) pred A.
+    EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
+    // We analyze this as umax(A, B) pred A.
+    P = Pred;
+  } else if (match(RHS, m_UMax(m_Value(A), m_Value(B))) &&
+             (A == LHS || B == LHS)) {
+    if (A != LHS) std::swap(A, B); // A pred umax(A, B).
+    EqP = CmpInst::ICMP_UGE; // "A == umax(A, B)" iff "A uge B".
+    // We analyze this as umax(A, B) swapped-pred A.
+    P = CmpInst::getSwappedPredicate(Pred);
+  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
+             (A == RHS || B == RHS)) {
+    if (A != RHS) std::swap(A, B); // umin(A, B) pred A.
+    EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
+    // We analyze this as umax(-A, -B) swapped-pred -A.
+    // Note that we do not need to actually form -A or -B thanks to EqP.
+    P = CmpInst::getSwappedPredicate(Pred);
+  } else if (match(RHS, m_UMin(m_Value(A), m_Value(B))) &&
+             (A == LHS || B == LHS)) {
+    if (A != LHS) std::swap(A, B); // A pred umin(A, B).
+    EqP = CmpInst::ICMP_ULE; // "A == umin(A, B)" iff "A ule B".
+    // We analyze this as umax(-A, -B) pred -A.
+    // Note that we do not need to actually form -A or -B thanks to EqP.
+    P = Pred;
+  }
+  if (P != CmpInst::BAD_ICMP_PREDICATE) {
+    // Cases correspond to "max(A, B) p A".
+    switch (P) {
+    default:
+      break;
+    case CmpInst::ICMP_EQ:
+    case CmpInst::ICMP_ULE:
+      // Equivalent to "A EqP B".  This may be the same as the condition tested
+      // in the max/min; if so, we can just return that.
+      if (Value *V = ExtractEquivalentCondition(LHS, EqP, A, B))
+        return V;
+      if (Value *V = ExtractEquivalentCondition(RHS, EqP, A, B))
+        return V;
+      // Otherwise, see if "A EqP B" simplifies.
+      if (MaxRecurse)
+        if (Value *V = SimplifyICmpInst(EqP, A, B, TD, DT, MaxRecurse-1))
+          return V;
+      break;
+    case CmpInst::ICMP_NE:
+    case CmpInst::ICMP_UGT: {
+      CmpInst::Predicate InvEqP = CmpInst::getInversePredicate(EqP);
+      // Equivalent to "A InvEqP B".  This may be the same as the condition
+      // tested in the max/min; if so, we can just return that.
+      if (Value *V = ExtractEquivalentCondition(LHS, InvEqP, A, B))
+        return V;
+      if (Value *V = ExtractEquivalentCondition(RHS, InvEqP, A, B))
+        return V;
+      // Otherwise, see if "A InvEqP B" simplifies.
+      if (MaxRecurse)
+        if (Value *V = SimplifyICmpInst(InvEqP, A, B, TD, DT, MaxRecurse-1))
+          return V;
       break;
     }
+    case CmpInst::ICMP_UGE:
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    case CmpInst::ICMP_ULT:
+      // Always false.
+      return Constant::getNullValue(ITy);
+    }
+  }
+
+  // Variants on "max(x,y) >= min(x,z)".
+  Value *C, *D;
+  if (match(LHS, m_SMax(m_Value(A), m_Value(B))) &&
+      match(RHS, m_SMin(m_Value(C), m_Value(D))) &&
+      (A == C || A == D || B == C || B == D)) {
+    // max(x, ?) pred min(x, ?).
+    if (Pred == CmpInst::ICMP_SGE)
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    if (Pred == CmpInst::ICMP_SLT)
+      // Always false.
+      return Constant::getNullValue(ITy);
+  } else if (match(LHS, m_SMin(m_Value(A), m_Value(B))) &&
+             match(RHS, m_SMax(m_Value(C), m_Value(D))) &&
+             (A == C || A == D || B == C || B == D)) {
+    // min(x, ?) pred max(x, ?).
+    if (Pred == CmpInst::ICMP_SLE)
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    if (Pred == CmpInst::ICMP_SGT)
+      // Always false.
+      return Constant::getNullValue(ITy);
+  } else if (match(LHS, m_UMax(m_Value(A), m_Value(B))) &&
+             match(RHS, m_UMin(m_Value(C), m_Value(D))) &&
+             (A == C || A == D || B == C || B == D)) {
+    // max(x, ?) pred min(x, ?).
+    if (Pred == CmpInst::ICMP_UGE)
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    if (Pred == CmpInst::ICMP_ULT)
+      // Always false.
+      return Constant::getNullValue(ITy);
+  } else if (match(LHS, m_UMin(m_Value(A), m_Value(B))) &&
+             match(RHS, m_UMax(m_Value(C), m_Value(D))) &&
+             (A == C || A == D || B == C || B == D)) {
+    // min(x, ?) pred max(x, ?).
+    if (Pred == CmpInst::ICMP_ULE)
+      // Always true.
+      return Constant::getAllOnesValue(ITy);
+    if (Pred == CmpInst::ICMP_UGT)
+      // Always false.
+      return Constant::getNullValue(ITy);
   }
 
   // If the comparison is with the result of a select instruction, check whether
@@ -1203,15 +2301,28 @@ static Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
                             const TargetData *TD, const DominatorTree *DT,
                             unsigned MaxRecurse) {
   switch (Opcode) {
-  case Instruction::Add: return SimplifyAddInst(LHS, RHS, /* isNSW */ false,
-                                                /* isNUW */ false, TD, DT,
-                                                MaxRecurse);
-  case Instruction::Sub: return SimplifySubInst(LHS, RHS, /* isNSW */ false,
-                                                /* isNUW */ false, TD, DT,
-                                                MaxRecurse);
-  case Instruction::Mul: return SimplifyMulInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::Add:
+    return SimplifyAddInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
+                           TD, DT, MaxRecurse);
+  case Instruction::Sub:
+    return SimplifySubInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
+                           TD, DT, MaxRecurse);
+  case Instruction::Mul:  return SimplifyMulInst (LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::SDiv: return SimplifySDivInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::UDiv: return SimplifyUDivInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::FDiv: return SimplifyFDivInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::SRem: return SimplifySRemInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::URem: return SimplifyURemInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::FRem: return SimplifyFRemInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::Shl:
+    return SimplifyShlInst(LHS, RHS, /*isNSW*/false, /*isNUW*/false,
+                           TD, DT, MaxRecurse);
+  case Instruction::LShr:
+    return SimplifyLShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse);
+  case Instruction::AShr:
+    return SimplifyAShrInst(LHS, RHS, /*isExact*/false, TD, DT, MaxRecurse);
   case Instruction::And: return SimplifyAndInst(LHS, RHS, TD, DT, MaxRecurse);
-  case Instruction::Or:  return SimplifyOrInst(LHS, RHS, TD, DT, MaxRecurse);
+  case Instruction::Or:  return SimplifyOrInst (LHS, RHS, TD, DT, MaxRecurse);
   case Instruction::Xor: return SimplifyXorInst(LHS, RHS, TD, DT, MaxRecurse);
   default:
     if (Constant *CLHS = dyn_cast<Constant>(LHS))
@@ -1288,6 +2399,40 @@ Value *llvm::SimplifyInstruction(Instruction *I, const TargetData *TD,
   case Instruction::Mul:
     Result = SimplifyMulInst(I->getOperand(0), I->getOperand(1), TD, DT);
     break;
+  case Instruction::SDiv:
+    Result = SimplifySDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::UDiv:
+    Result = SimplifyUDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::FDiv:
+    Result = SimplifyFDivInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::SRem:
+    Result = SimplifySRemInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::URem:
+    Result = SimplifyURemInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::FRem:
+    Result = SimplifyFRemInst(I->getOperand(0), I->getOperand(1), TD, DT);
+    break;
+  case Instruction::Shl:
+    Result = SimplifyShlInst(I->getOperand(0), I->getOperand(1),
+                             cast<BinaryOperator>(I)->hasNoSignedWrap(),
+                             cast<BinaryOperator>(I)->hasNoUnsignedWrap(),
+                             TD, DT);
+    break;
+  case Instruction::LShr:
+    Result = SimplifyLShrInst(I->getOperand(0), I->getOperand(1),
+                              cast<BinaryOperator>(I)->isExact(),
+                              TD, DT);
+    break;
+  case Instruction::AShr:
+    Result = SimplifyAShrInst(I->getOperand(0), I->getOperand(1),
+                              cast<BinaryOperator>(I)->isExact(),
+                              TD, DT);
+    break;
   case Instruction::And:
     Result = SimplifyAndInst(I->getOperand(0), I->getOperand(1), TD, DT);
     break;