Import LLVM 7.0.1 release including clang, lld and lldb.

1 files changed, 509 insertions, 283 deletions

diff --git a/gnu/llvm/lib/Analysis/InstructionSimplify.cpp b/gnu/llvm/lib/Analysis/InstructionSimplify.cpp
index f382a1f5018..5e72798d459 100644
--- a/gnu/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/gnu/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -62,6 +62,50 @@ static Value *SimplifyOrInst(Value *, Value *, const SimplifyQuery &, unsigned);
 static Value *SimplifyXorInst(Value *, Value *, const SimplifyQuery &, unsigned);
 static Value *SimplifyCastInst(unsigned, Value *, Type *,
                                const SimplifyQuery &, unsigned);
+static Value *SimplifyGEPInst(Type *, ArrayRef<Value *>, const SimplifyQuery &,
+                              unsigned);
+
+static Value *foldSelectWithBinaryOp(Value *Cond, Value *TrueVal,
+                                     Value *FalseVal) {
+  BinaryOperator::BinaryOps BinOpCode;
+  if (auto *BO = dyn_cast<BinaryOperator>(Cond))
+    BinOpCode = BO->getOpcode();
+  else
+    return nullptr;
+
+  CmpInst::Predicate ExpectedPred, Pred1, Pred2;
+  if (BinOpCode == BinaryOperator::Or) {
+    ExpectedPred = ICmpInst::ICMP_NE;
+  } else if (BinOpCode == BinaryOperator::And) {
+    ExpectedPred = ICmpInst::ICMP_EQ;
+  } else
+    return nullptr;
+
+  // %A = icmp eq %TV, %FV
+  // %B = icmp eq %X, %Y (and one of these is a select operand)
+  // %C = and %A, %B
+  // %D = select %C, %TV, %FV
+  // -->
+  // %FV
+
+  // %A = icmp ne %TV, %FV
+  // %B = icmp ne %X, %Y (and one of these is a select operand)
+  // %C = or %A, %B
+  // %D = select %C, %TV, %FV
+  // -->
+  // %TV
+  Value *X, *Y;
+  if (!match(Cond, m_c_BinOp(m_c_ICmp(Pred1, m_Specific(TrueVal),
+                                      m_Specific(FalseVal)),
+                             m_ICmp(Pred2, m_Value(X), m_Value(Y)))) ||
+      Pred1 != Pred2 || Pred1 != ExpectedPred)
+    return nullptr;
+
+  if (X == TrueVal || X == FalseVal || Y == TrueVal || Y == FalseVal)
+    return BinOpCode == BinaryOperator::Or ? TrueVal : FalseVal;
+
+  return nullptr;
+}
 
 /// For a boolean type or a vector of boolean type, return false or a vector
 /// with every element false.
@@ -90,7 +134,7 @@ static bool isSameCompare(Value *V, CmpInst::Predicate Pred, Value *LHS,
 }
 
 /// Does the given value dominate the specified phi node?
-static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
+static bool valueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
   Instruction *I = dyn_cast<Instruction>(V);
   if (!I)
     // Arguments and constants dominate all instructions.
@@ -99,7 +143,7 @@ static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
   // If we are processing instructions (and/or basic blocks) that have not been
   // fully added to a function, the parent nodes may still be null. Simply
   // return the conservative answer in these cases.
-  if (!I->getParent() || !P->getParent() || !I->getParent()->getParent())
+  if (!I->getParent() || !P->getParent() || !I->getFunction())
     return false;
 
   // If we have a DominatorTree then do a precise test.
@@ -108,7 +152,7 @@ static bool ValueDominatesPHI(Value *V, PHINode *P, const DominatorTree *DT) {
 
   // Otherwise, if the instruction is in the entry block and is not an invoke,
   // then it obviously dominates all phi nodes.
-  if (I->getParent() == &I->getParent()->getParent()->getEntryBlock() &&
+  if (I->getParent() == &I->getFunction()->getEntryBlock() &&
       !isa<InvokeInst>(I))
     return true;
 
@@ -443,13 +487,13 @@ static Value *ThreadBinOpOverPHI(Instruction::BinaryOps Opcode, Value *LHS,
   if (isa<PHINode>(LHS)) {
     PI = cast<PHINode>(LHS);
     // Bail out if RHS and the phi may be mutually interdependent due to a loop.
-    if (!ValueDominatesPHI(RHS, PI, Q.DT))
+    if (!valueDominatesPHI(RHS, PI, Q.DT))
       return nullptr;
   } else {
     assert(isa<PHINode>(RHS) && "No PHI instruction operand!");
     PI = cast<PHINode>(RHS);
     // Bail out if LHS and the phi may be mutually interdependent due to a loop.
-    if (!ValueDominatesPHI(LHS, PI, Q.DT))
+    if (!valueDominatesPHI(LHS, PI, Q.DT))
       return nullptr;
   }
 
@@ -490,7 +534,7 @@ static Value *ThreadCmpOverPHI(CmpInst::Predicate Pred, Value *LHS, Value *RHS,
   PHINode *PI = cast<PHINode>(LHS);
 
   // Bail out if RHS and the phi may be mutually interdependent due to a loop.
-  if (!ValueDominatesPHI(RHS, PI, Q.DT))
+  if (!valueDominatesPHI(RHS, PI, Q.DT))
     return nullptr;
 
   // Evaluate the BinOp on the incoming phi values.
@@ -525,7 +569,7 @@ static Constant *foldOrCommuteConstant(Instruction::BinaryOps Opcode,
 
 /// Given operands for an Add, see if we can fold the result.
 /// If not, this returns null.
-static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
+static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
                               const SimplifyQuery &Q, unsigned MaxRecurse) {
   if (Constant *C = foldOrCommuteConstant(Instruction::Add, Op0, Op1, Q))
     return C;
@@ -538,6 +582,10 @@ static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   if (match(Op1, m_Zero()))
     return Op0;
 
+  // If two operands are negative, return 0.
+  if (isKnownNegation(Op0, Op1))
+    return Constant::getNullValue(Op0->getType());
+
   // X + (Y - X) -> Y
   // (Y - X) + X -> Y
   // Eg: X + -X -> 0
@@ -555,10 +603,14 @@ static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   // add nsw/nuw (xor Y, signmask), signmask --> Y
   // The no-wrapping add guarantees that the top bit will be set by the add.
   // Therefore, the xor must be clearing the already set sign bit of Y.
-  if ((isNSW || isNUW) && match(Op1, m_SignMask()) &&
+  if ((IsNSW || IsNUW) && match(Op1, m_SignMask()) &&
       match(Op0, m_Xor(m_Value(Y), m_SignMask())))
     return Y;
 
+  // add nuw %x, -1  ->  -1, because %x can only be 0.
+  if (IsNUW && match(Op1, m_AllOnes()))
+    return Op1; // Which is -1.
+
   /// i1 add -> xor.
   if (MaxRecurse && Op0->getType()->isIntOrIntVectorTy(1))
     if (Value *V = SimplifyXorInst(Op0, Op1, Q, MaxRecurse-1))
@@ -581,12 +633,12 @@ static Value *SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   return nullptr;
 }
 
-Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
+Value *llvm::SimplifyAddInst(Value *Op0, Value *Op1, bool IsNSW, bool IsNUW,
                              const SimplifyQuery &Query) {
-  return ::SimplifyAddInst(Op0, Op1, isNSW, isNUW, Query, RecursionLimit);
+  return ::SimplifyAddInst(Op0, Op1, IsNSW, IsNUW, Query, RecursionLimit);
 }
 
-/// \brief Compute the base pointer and cumulative constant offsets for V.
+/// Compute the base pointer and cumulative constant offsets for V.
 ///
 /// This strips all constant offsets off of V, leaving it the base pointer, and
 /// accumulates the total constant offset applied in the returned constant. It
@@ -637,7 +689,7 @@ static Constant *stripAndComputeConstantOffsets(const DataLayout &DL, Value *&V,
   return OffsetIntPtr;
 }
 
-/// \brief Compute the constant difference between two pointer values.
+/// Compute the constant difference between two pointer values.
 /// If the difference is not a constant, returns zero.
 static Constant *computePointerDifference(const DataLayout &DL, Value *LHS,
                                           Value *RHS) {
@@ -680,14 +732,14 @@ static Value *SimplifySubInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   if (match(Op0, m_Zero())) {
     // 0 - X -> 0 if the sub is NUW.
     if (isNUW)
-      return Op0;
+      return Constant::getNullValue(Op0->getType());
 
     KnownBits Known = computeKnownBits(Op1, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
     if (Known.Zero.isMaxSignedValue()) {
       // Op1 is either 0 or the minimum signed value. If the sub is NSW, then
       // Op1 must be 0 because negating the minimum signed value is undefined.
       if (isNSW)
-        return Op0;
+        return Constant::getNullValue(Op0->getType());
 
       // 0 - X -> X if X is 0 or the minimum signed value.
       return Op1;
@@ -799,12 +851,9 @@ static Value *SimplifyMulInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
     return C;
 
   // X * undef -> 0
-  if (match(Op1, m_Undef()))
-    return Constant::getNullValue(Op0->getType());
-
   // X * 0 -> 0
-  if (match(Op1, m_Zero()))
-    return Op1;
+  if (match(Op1, m_CombineOr(m_Undef(), m_Zero())))
+    return Constant::getNullValue(Op0->getType());
 
   // X * 1 -> X
   if (match(Op1, m_One()))
@@ -868,13 +917,14 @@ static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
   if (match(Op1, m_Zero()))
     return UndefValue::get(Ty);
 
-  // If any element of a constant divisor vector is zero, the whole op is undef.
+  // If any element of a constant divisor vector is zero or undef, the whole op
+  // is undef.
   auto *Op1C = dyn_cast<Constant>(Op1);
   if (Op1C && Ty->isVectorTy()) {
     unsigned NumElts = Ty->getVectorNumElements();
     for (unsigned i = 0; i != NumElts; ++i) {
       Constant *Elt = Op1C->getAggregateElement(i);
-      if (Elt && Elt->isNullValue())
+      if (Elt && (Elt->isNullValue() || isa<UndefValue>(Elt)))
         return UndefValue::get(Ty);
     }
   }
@@ -887,7 +937,7 @@ static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
   // 0 / X -> 0
   // 0 % X -> 0
   if (match(Op0, m_Zero()))
-    return Op0;
+    return Constant::getNullValue(Op0->getType());
 
   // X / X -> 1
   // X % X -> 0
@@ -898,7 +948,10 @@ static Value *simplifyDivRem(Value *Op0, Value *Op1, bool IsDiv) {
   // X % 1 -> 0
   // If this is a boolean op (single-bit element type), we can't have
   // division-by-zero or remainder-by-zero, so assume the divisor is 1.
-  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1))
+  // Similarly, if we're zero-extending a boolean divisor, then assume it's a 1.
+  Value *X;
+  if (match(Op1, m_One()) || Ty->isIntOrIntVectorTy(1) ||
+      (match(Op1, m_ZExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
     return IsDiv ? Op0 : Constant::getNullValue(Ty);
 
   return nullptr;
@@ -978,18 +1031,17 @@ static Value *simplifyDiv(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
   bool IsSigned = Opcode == Instruction::SDiv;
 
   // (X * Y) / Y -> X if the multiplication does not overflow.
-  Value *X = nullptr, *Y = nullptr;
-  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
-    OverflowingBinaryOperator *Mul = cast<OverflowingBinaryOperator>(Op0);
-    // If the Mul knows it does not overflow, then we are good to go.
+  Value *X;
+  if (match(Op0, m_c_Mul(m_Value(X), m_Specific(Op1)))) {
+    auto *Mul = cast<OverflowingBinaryOperator>(Op0);
+    // If the Mul 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;
+    // If X has the form X = A / Y, then X * Y cannot overflow.
+    if ((IsSigned && match(X, m_SDiv(m_Value(), m_Specific(Op1)))) ||
+        (!IsSigned && match(X, m_UDiv(m_Value(), m_Specific(Op1)))))
+      return X;
   }
 
   // (X rem Y) / Y -> 0
@@ -1041,6 +1093,13 @@ static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
        match(Op0, m_URem(m_Value(), m_Specific(Op1)))))
     return Op0;
 
+  // (X << Y) % X -> 0
+  if ((Opcode == Instruction::SRem &&
+       match(Op0, m_NSWShl(m_Specific(Op1), m_Value()))) ||
+      (Opcode == Instruction::URem &&
+       match(Op0, m_NUWShl(m_Specific(Op1), m_Value()))))
+    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))
@@ -1064,6 +1123,10 @@ static Value *simplifyRem(Instruction::BinaryOps Opcode, Value *Op0, Value *Op1,
 /// If not, this returns null.
 static Value *SimplifySDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                                unsigned MaxRecurse) {
+  // If two operands are negated and no signed overflow, return -1.
+  if (isKnownNegation(Op0, Op1, /*NeedNSW=*/true))
+    return Constant::getAllOnesValue(Op0->getType());
+
   return simplifyDiv(Instruction::SDiv, Op0, Op1, Q, MaxRecurse);
 }
 
@@ -1086,6 +1149,16 @@ Value *llvm::SimplifyUDivInst(Value *Op0, Value *Op1, const SimplifyQuery &Q) {
 /// If not, this returns null.
 static Value *SimplifySRemInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                                unsigned MaxRecurse) {
+  // If the divisor is 0, the result is undefined, so assume the divisor is -1.
+  // srem Op0, (sext i1 X) --> srem Op0, -1 --> 0
+  Value *X;
+  if (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1))
+    return ConstantInt::getNullValue(Op0->getType());
+
+  // If the two operands are negated, return 0.
+  if (isKnownNegation(Op0, Op1))
+    return ConstantInt::getNullValue(Op0->getType());
+
   return simplifyRem(Instruction::SRem, Op0, Op1, Q, MaxRecurse);
 }
 
@@ -1140,10 +1213,14 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
 
   // 0 shift by X -> 0
   if (match(Op0, m_Zero()))
-    return Op0;
+    return Constant::getNullValue(Op0->getType());
 
   // X shift by 0 -> X
-  if (match(Op1, m_Zero()))
+  // Shift-by-sign-extended bool must be shift-by-0 because shift-by-all-ones
+  // would be poison.
+  Value *X;
+  if (match(Op1, m_Zero()) ||
+      (match(Op1, m_SExt(m_Value(X))) && X->getType()->isIntOrIntVectorTy(1)))
     return Op0;
 
   // Fold undefined shifts.
@@ -1177,7 +1254,7 @@ static Value *SimplifyShift(Instruction::BinaryOps Opcode, Value *Op0,
   return nullptr;
 }
 
-/// \brief Given operands for an Shl, LShr or AShr, see if we can
+/// Given operands for an Shl, LShr or AShr, see if we can
 /// fold the result.  If not, this returns null.
 static Value *SimplifyRightShift(Instruction::BinaryOps Opcode, Value *Op0,
                                  Value *Op1, bool isExact, const SimplifyQuery &Q,
@@ -1220,6 +1297,13 @@ static Value *SimplifyShlInst(Value *Op0, Value *Op1, bool isNSW, bool isNUW,
   Value *X;
   if (match(Op0, m_Exact(m_Shr(m_Value(X), m_Specific(Op1)))))
     return X;
+
+  // shl nuw i8 C, %x  ->  C  iff C has sign bit set.
+  if (isNUW && match(Op0, m_Negative()))
+    return Op0;
+  // NOTE: could use computeKnownBits() / LazyValueInfo,
+  // but the cost-benefit analysis suggests it isn't worth it.
+
   return nullptr;
 }
 
@@ -1241,6 +1325,23 @@ static Value *SimplifyLShrInst(Value *Op0, Value *Op1, bool isExact,
   if (match(Op0, m_NUWShl(m_Value(X), m_Specific(Op1))))
     return X;
 
+  // ((X << A) | Y) >> A -> X  if effective width of Y is not larger than A.
+  // We can return X as we do in the above case since OR alters no bits in X.
+  // SimplifyDemandedBits in InstCombine can do more general optimization for
+  // bit manipulation. This pattern aims to provide opportunities for other
+  // optimizers by supporting a simple but common case in InstSimplify.
+  Value *Y;
+  const APInt *ShRAmt, *ShLAmt;
+  if (match(Op1, m_APInt(ShRAmt)) &&
+      match(Op0, m_c_Or(m_NUWShl(m_Value(X), m_APInt(ShLAmt)), m_Value(Y))) &&
+      *ShRAmt == *ShLAmt) {
+    const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
+    const unsigned Width = Op0->getType()->getScalarSizeInBits();
+    const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
+    if (ShRAmt->uge(EffWidthY))
+      return X;
+  }
+
   return nullptr;
 }
 
@@ -1257,9 +1358,10 @@ static Value *SimplifyAShrInst(Value *Op0, Value *Op1, bool isExact,
                                     MaxRecurse))
     return V;
 
-  // all ones >>a X -> all ones
+  // all ones >>a X -> -1
+  // Do not return Op0 because it may contain undef elements if it's a vector.
   if (match(Op0, m_AllOnes()))
-    return Op0;
+    return Constant::getAllOnesValue(Op0->getType());
 
   // (X << A) >> A -> X
   Value *X;
@@ -1295,7 +1397,7 @@ static Value *simplifyUnsignedRangeCheck(ICmpInst *ZeroICmp,
       ICmpInst::isUnsigned(UnsignedPred))
     ;
   else if (match(UnsignedICmp,
-                 m_ICmp(UnsignedPred, m_Value(Y), m_Specific(X))) &&
+                 m_ICmp(UnsignedPred, m_Specific(Y), m_Value(X))) &&
            ICmpInst::isUnsigned(UnsignedPred))
     UnsignedPred = ICmpInst::getSwappedPredicate(UnsignedPred);
   else
@@ -1413,6 +1515,43 @@ static Value *simplifyAndOrOfICmpsWithConstants(ICmpInst *Cmp0, ICmpInst *Cmp1,
   return nullptr;
 }
 
+static Value *simplifyAndOrOfICmpsWithZero(ICmpInst *Cmp0, ICmpInst *Cmp1,
+                                           bool IsAnd) {
+  ICmpInst::Predicate P0 = Cmp0->getPredicate(), P1 = Cmp1->getPredicate();
+  if (!match(Cmp0->getOperand(1), m_Zero()) ||
+      !match(Cmp1->getOperand(1), m_Zero()) || P0 != P1)
+    return nullptr;
+
+  if ((IsAnd && P0 != ICmpInst::ICMP_NE) || (!IsAnd && P1 != ICmpInst::ICMP_EQ))
+    return nullptr;
+
+  // We have either "(X == 0 || Y == 0)" or "(X != 0 && Y != 0)".
+  Value *X = Cmp0->getOperand(0);
+  Value *Y = Cmp1->getOperand(0);
+
+  // If one of the compares is a masked version of a (not) null check, then
+  // that compare implies the other, so we eliminate the other. Optionally, look
+  // through a pointer-to-int cast to match a null check of a pointer type.
+
+  // (X == 0) || (([ptrtoint] X & ?) == 0) --> ([ptrtoint] X & ?) == 0
+  // (X == 0) || ((? & [ptrtoint] X) == 0) --> (? & [ptrtoint] X) == 0
+  // (X != 0) && (([ptrtoint] X & ?) != 0) --> ([ptrtoint] X & ?) != 0
+  // (X != 0) && ((? & [ptrtoint] X) != 0) --> (? & [ptrtoint] X) != 0
+  if (match(Y, m_c_And(m_Specific(X), m_Value())) ||
+      match(Y, m_c_And(m_PtrToInt(m_Specific(X)), m_Value())))
+    return Cmp1;
+
+  // (([ptrtoint] Y & ?) == 0) || (Y == 0) --> ([ptrtoint] Y & ?) == 0
+  // ((? & [ptrtoint] Y) == 0) || (Y == 0) --> (? & [ptrtoint] Y) == 0
+  // (([ptrtoint] Y & ?) != 0) && (Y != 0) --> ([ptrtoint] Y & ?) != 0
+  // ((? & [ptrtoint] Y) != 0) && (Y != 0) --> (? & [ptrtoint] Y) != 0
+  if (match(X, m_c_And(m_Specific(Y), m_Value())) ||
+      match(X, m_c_And(m_PtrToInt(m_Specific(Y)), m_Value())))
+    return Cmp0;
+
+  return nullptr;
+}
+
 static Value *simplifyAndOfICmpsWithAdd(ICmpInst *Op0, ICmpInst *Op1) {
   // (icmp (add V, C0), C1) & (icmp V, C0)
   ICmpInst::Predicate Pred0, Pred1;
@@ -1473,6 +1612,9 @@ static Value *simplifyAndOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
   if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, true))
     return X;
 
+  if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, true))
+    return X;
+
   if (Value *X = simplifyAndOfICmpsWithAdd(Op0, Op1))
     return X;
   if (Value *X = simplifyAndOfICmpsWithAdd(Op1, Op0))
@@ -1541,6 +1683,9 @@ static Value *simplifyOrOfICmps(ICmpInst *Op0, ICmpInst *Op1) {
   if (Value *X = simplifyAndOrOfICmpsWithConstants(Op0, Op1, false))
     return X;
 
+  if (Value *X = simplifyAndOrOfICmpsWithZero(Op0, Op1, false))
+    return X;
+
   if (Value *X = simplifyOrOfICmpsWithAdd(Op0, Op1))
     return X;
   if (Value *X = simplifyOrOfICmpsWithAdd(Op1, Op0))
@@ -1638,7 +1783,7 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
 
   // X & 0 = 0
   if (match(Op1, m_Zero()))
-    return Op1;
+    return Constant::getNullValue(Op0->getType());
 
   // X & -1 = X
   if (match(Op1, m_AllOnes()))
@@ -1718,6 +1863,40 @@ static Value *SimplifyAndInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
                                       MaxRecurse))
       return V;
 
+  // Assuming the effective width of Y is not larger than A, i.e. all bits
+  // from X and Y are disjoint in (X << A) | Y,
+  // if the mask of this AND op covers all bits of X or Y, while it covers
+  // no bits from the other, we can bypass this AND op. E.g.,
+  // ((X << A) | Y) & Mask -> Y,
+  //     if Mask = ((1 << effective_width_of(Y)) - 1)
+  // ((X << A) | Y) & Mask -> X << A,
+  //     if Mask = ((1 << effective_width_of(X)) - 1) << A
+  // SimplifyDemandedBits in InstCombine can optimize the general case.
+  // This pattern aims to help other passes for a common case.
+  Value *Y, *XShifted;
+  if (match(Op1, m_APInt(Mask)) &&
+      match(Op0, m_c_Or(m_CombineAnd(m_NUWShl(m_Value(X), m_APInt(ShAmt)),
+                                     m_Value(XShifted)),
+                        m_Value(Y)))) {
+    const unsigned Width = Op0->getType()->getScalarSizeInBits();
+    const unsigned ShftCnt = ShAmt->getLimitedValue(Width);
+    const KnownBits YKnown = computeKnownBits(Y, Q.DL, 0, Q.AC, Q.CxtI, Q.DT);
+    const unsigned EffWidthY = Width - YKnown.countMinLeadingZeros();
+    if (EffWidthY <= ShftCnt) {
+      const KnownBits XKnown = computeKnownBits(X, Q.DL, 0, Q.AC, Q.CxtI,
+                                                Q.DT);
+      const unsigned EffWidthX = Width - XKnown.countMinLeadingZeros();
+      const APInt EffBitsY = APInt::getLowBitsSet(Width, EffWidthY);
+      const APInt EffBitsX = APInt::getLowBitsSet(Width, EffWidthX) << ShftCnt;
+      // If the mask is extracting all bits from X or Y as is, we can skip
+      // this AND op.
+      if (EffBitsY.isSubsetOf(*Mask) && !EffBitsX.intersects(*Mask))
+        return Y;
+      if (EffBitsX.isSubsetOf(*Mask) && !EffBitsY.intersects(*Mask))
+        return XShifted;
+    }
+  }
+
   return nullptr;
 }
 
@@ -1733,21 +1912,16 @@ static Value *SimplifyOrInst(Value *Op0, Value *Op1, const SimplifyQuery &Q,
     return C;
 
   // X | undef -> -1
-  if (match(Op1, m_Undef()))
+  // X | -1 = -1
+  // Do not return Op1 because it may contain undef elements if it's a vector.
+  if (match(Op1, m_Undef()) || match(Op1, m_AllOnes()))
     return Constant::getAllOnesValue(Op0->getType());
 
   // X | X = X
-  if (Op0 == Op1)
-    return Op0;
-
   // X | 0 = X
-  if (match(Op1, m_Zero()))
+  if (Op0 == Op1 || match(Op1, m_Zero()))
     return Op0;
 
-  // X | -1 = -1
-  if (match(Op1, m_AllOnes()))
-    return Op1;
-
   // A | ~A  =  ~A | A  =  -1
   if (match(Op0, m_Not(m_Specific(Op1))) ||
       match(Op1, m_Not(m_Specific(Op0))))
@@ -2051,9 +2225,12 @@ computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
       ConstantInt *LHSOffsetCI = dyn_cast<ConstantInt>(LHSOffset);
       ConstantInt *RHSOffsetCI = dyn_cast<ConstantInt>(RHSOffset);
       uint64_t LHSSize, RHSSize;
+      ObjectSizeOpts Opts;
+      Opts.NullIsUnknownSize =
+          NullPointerIsDefined(cast<AllocaInst>(LHS)->getFunction());
       if (LHSOffsetCI && RHSOffsetCI &&
-          getObjectSize(LHS, LHSSize, DL, TLI) &&
-          getObjectSize(RHS, RHSSize, DL, TLI)) {
+          getObjectSize(LHS, LHSSize, DL, TLI, Opts) &&
+          getObjectSize(RHS, RHSSize, DL, TLI, Opts)) {
         const APInt &LHSOffsetValue = LHSOffsetCI->getValue();
         const APInt &RHSOffsetValue = RHSOffsetCI->getValue();
         if (!LHSOffsetValue.isNegative() &&
@@ -2442,6 +2619,20 @@ static void setLimitsForBinOp(BinaryOperator &BO, APInt &Lower, APInt &Upper) {
 
 static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
                                        Value *RHS) {
+  Type *ITy = GetCompareTy(RHS); // The return type.
+
+  Value *X;
+  // Sign-bit checks can be optimized to true/false after unsigned
+  // floating-point casts:
+  // icmp slt (bitcast (uitofp X)),  0 --> false
+  // icmp sgt (bitcast (uitofp X)), -1 --> true
+  if (match(LHS, m_BitCast(m_UIToFP(m_Value(X))))) {
+    if (Pred == ICmpInst::ICMP_SLT && match(RHS, m_Zero()))
+      return ConstantInt::getFalse(ITy);
+    if (Pred == ICmpInst::ICMP_SGT && match(RHS, m_AllOnes()))
+      return ConstantInt::getTrue(ITy);
+  }
+
   const APInt *C;
   if (!match(RHS, m_APInt(C)))
     return nullptr;
@@ -2449,9 +2640,9 @@ static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
   // Rule out tautological comparisons (eg., ult 0 or uge 0).
   ConstantRange RHS_CR = ConstantRange::makeExactICmpRegion(Pred, *C);
   if (RHS_CR.isEmptySet())
-    return ConstantInt::getFalse(GetCompareTy(RHS));
+    return ConstantInt::getFalse(ITy);
   if (RHS_CR.isFullSet())
-    return ConstantInt::getTrue(GetCompareTy(RHS));
+    return ConstantInt::getTrue(ITy);
 
   // Find the range of possible values for binary operators.
   unsigned Width = C->getBitWidth();
@@ -2469,9 +2660,9 @@ static Value *simplifyICmpWithConstant(CmpInst::Predicate Pred, Value *LHS,
 
   if (!LHS_CR.isFullSet()) {
     if (RHS_CR.contains(LHS_CR))
-      return ConstantInt::getTrue(GetCompareTy(RHS));
+      return ConstantInt::getTrue(ITy);
     if (RHS_CR.inverse().contains(LHS_CR))
-      return ConstantInt::getFalse(GetCompareTy(RHS));
+      return ConstantInt::getFalse(ITy);
   }
 
   return nullptr;
@@ -3008,8 +3199,7 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
   Type *ITy = GetCompareTy(LHS); // The return type.
 
   // icmp X, X -> true/false
-  // X icmp undef -> true/false.  For example, icmp ugt %X, undef -> false
-  // because X could be 0.
+  // icmp X, undef -> true/false because undef could be X.
   if (LHS == RHS || isa<UndefValue>(RHS))
     return ConstantInt::get(ITy, CmpInst::isTrueWhenEqual(Pred));
 
@@ -3309,6 +3499,12 @@ static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
       return getTrue(RetTy);
   }
 
+  // NaN is unordered; NaN is not ordered.
+  assert((FCmpInst::isOrdered(Pred) || FCmpInst::isUnordered(Pred)) &&
+         "Comparison must be either ordered or unordered");
+  if (match(RHS, m_NaN()))
+    return ConstantInt::get(RetTy, CmpInst::isUnordered(Pred));
+
   // fcmp pred x, undef  and  fcmp pred undef, x
   // fold to true if unordered, false if ordered
   if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS)) {
@@ -3328,15 +3524,6 @@ static Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
   // Handle fcmp with constant RHS.
   const APFloat *C;
   if (match(RHS, m_APFloat(C))) {
-    // If the constant is a nan, see if we can fold the comparison based on it.
-    if (C->isNaN()) {
-      if (FCmpInst::isOrdered(Pred)) // True "if ordered and foo"
-        return getFalse(RetTy);
-      assert(FCmpInst::isUnordered(Pred) &&
-             "Comparison must be either ordered or unordered!");
-      // True if unordered.
-      return getTrue(RetTy);
-    }
     // Check whether the constant is an infinity.
     if (C->isInfinity()) {
       if (C->isNegative()) {
@@ -3475,6 +3662,17 @@ static const Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
     }
   }
 
+  // Same for GEPs.
+  if (auto *GEP = dyn_cast<GetElementPtrInst>(I)) {
+    if (MaxRecurse) {
+      SmallVector<Value *, 8> NewOps(GEP->getNumOperands());
+      transform(GEP->operands(), NewOps.begin(),
+                [&](Value *V) { return V == Op ? RepOp : V; });
+      return SimplifyGEPInst(GEP->getSourceElementType(), NewOps, Q,
+                             MaxRecurse - 1);
+    }
+  }
+
   // TODO: We could hand off more cases to instsimplify here.
 
   // If all operands are constant after substituting Op for RepOp then we can
@@ -3581,24 +3779,6 @@ static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
                                               TrueVal, FalseVal))
     return V;
 
-  if (CondVal->hasOneUse()) {
-    const APInt *C;
-    if (match(CmpRHS, m_APInt(C))) {
-      // X < MIN ? T : F  -->  F
-      if (Pred == ICmpInst::ICMP_SLT && C->isMinSignedValue())
-        return FalseVal;
-      // X < MIN ? T : F  -->  F
-      if (Pred == ICmpInst::ICMP_ULT && C->isMinValue())
-        return FalseVal;
-      // X > MAX ? T : F  -->  F
-      if (Pred == ICmpInst::ICMP_SGT && C->isMaxSignedValue())
-        return FalseVal;
-      // X > MAX ? T : F  -->  F
-      if (Pred == ICmpInst::ICMP_UGT && C->isMaxValue())
-        return FalseVal;
-    }
-  }
-
   // If we have an equality comparison, then we know the value in one of the
   // arms of the select. See if substituting this value into the arm and
   // simplifying the result yields the same value as the other arm.
@@ -3631,37 +3811,41 @@ static Value *simplifySelectWithICmpCond(Value *CondVal, Value *TrueVal,
 
 /// Given operands for a SelectInst, see if we can fold the result.
 /// If not, this returns null.
-static Value *SimplifySelectInst(Value *CondVal, Value *TrueVal,
-                                 Value *FalseVal, const SimplifyQuery &Q,
-                                 unsigned MaxRecurse) {
-  // select true, X, Y  -> X
-  // select false, X, Y -> Y
-  if (Constant *CB = dyn_cast<Constant>(CondVal)) {
-    if (Constant *CT = dyn_cast<Constant>(TrueVal))
-      if (Constant *CF = dyn_cast<Constant>(FalseVal))
-        return ConstantFoldSelectInstruction(CB, CT, CF);
-    if (CB->isAllOnesValue())
+static Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
+                                 const SimplifyQuery &Q, unsigned MaxRecurse) {
+  if (auto *CondC = dyn_cast<Constant>(Cond)) {
+    if (auto *TrueC = dyn_cast<Constant>(TrueVal))
+      if (auto *FalseC = dyn_cast<Constant>(FalseVal))
+        return ConstantFoldSelectInstruction(CondC, TrueC, FalseC);
+
+    // select undef, X, Y -> X or Y
+    if (isa<UndefValue>(CondC))
+      return isa<Constant>(FalseVal) ? FalseVal : TrueVal;
+
+    // TODO: Vector constants with undef elements don't simplify.
+
+    // select true, X, Y  -> X
+    if (CondC->isAllOnesValue())
       return TrueVal;
-    if (CB->isNullValue())
+    // select false, X, Y -> Y
+    if (CondC->isNullValue())
       return FalseVal;
   }
 
-  // select C, X, X -> X
+  // select ?, X, X -> X
   if (TrueVal == FalseVal)
     return TrueVal;
 
-  if (isa<UndefValue>(CondVal)) {  // select undef, X, Y -> X or Y
-    if (isa<Constant>(FalseVal))
-      return FalseVal;
-    return TrueVal;
-  }
-  if (isa<UndefValue>(TrueVal))   // select C, undef, X -> X
+  if (isa<UndefValue>(TrueVal))   // select ?, undef, X -> X
     return FalseVal;
-  if (isa<UndefValue>(FalseVal))   // select C, X, undef -> X
+  if (isa<UndefValue>(FalseVal))   // select ?, X, undef -> X
     return TrueVal;
 
   if (Value *V =
-          simplifySelectWithICmpCond(CondVal, TrueVal, FalseVal, Q, MaxRecurse))
+          simplifySelectWithICmpCond(Cond, TrueVal, FalseVal, Q, MaxRecurse))
+    return V;
+
+  if (Value *V = foldSelectWithBinaryOp(Cond, TrueVal, FalseVal))
     return V;
 
   return nullptr;
@@ -3697,7 +3881,7 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
 
   if (Ops.size() == 2) {
     // getelementptr P, 0 -> P.
-    if (match(Ops[1], m_Zero()))
+    if (match(Ops[1], m_Zero()) && Ops[0]->getType() == GEPTy)
       return Ops[0];
 
     Type *Ty = SrcTy;
@@ -3706,13 +3890,13 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
       uint64_t C;
       uint64_t TyAllocSize = Q.DL.getTypeAllocSize(Ty);
       // getelementptr P, N -> P if P points to a type of zero size.
-      if (TyAllocSize == 0)
+      if (TyAllocSize == 0 && Ops[0]->getType() == GEPTy)
         return Ops[0];
 
       // The following transforms are only safe if the ptrtoint cast
       // doesn't truncate the pointers.
       if (Ops[1]->getType()->getScalarSizeInBits() ==
-          Q.DL.getPointerSizeInBits(AS)) {
+          Q.DL.getIndexSizeInBits(AS)) {
         auto PtrToIntOrZero = [GEPTy](Value *P) -> Value * {
           if (match(P, m_Zero()))
             return Constant::getNullValue(GEPTy);
@@ -3752,10 +3936,10 @@ static Value *SimplifyGEPInst(Type *SrcTy, ArrayRef<Value *> Ops,
   if (Q.DL.getTypeAllocSize(LastType) == 1 &&
       all_of(Ops.slice(1).drop_back(1),
              [](Value *Idx) { return match(Idx, m_Zero()); })) {
-    unsigned PtrWidth =
-        Q.DL.getPointerSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
-    if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == PtrWidth) {
-      APInt BasePtrOffset(PtrWidth, 0);
+    unsigned IdxWidth =
+        Q.DL.getIndexSizeInBits(Ops[0]->getType()->getPointerAddressSpace());
+    if (Q.DL.getTypeSizeInBits(Ops.back()->getType()) == IdxWidth) {
+      APInt BasePtrOffset(IdxWidth, 0);
       Value *StrippedBasePtr =
           Ops[0]->stripAndAccumulateInBoundsConstantOffsets(Q.DL,
                                                             BasePtrOffset);
@@ -3946,7 +4130,7 @@ static Value *SimplifyPHINode(PHINode *PN, const SimplifyQuery &Q) {
   // instruction, we cannot return X as the result of the PHI node unless it
   // dominates the PHI block.
   if (HasUndefInput)
-    return ValueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
+    return valueDominatesPHI(CommonValue, PN, Q.DT) ? CommonValue : nullptr;
 
   return CommonValue;
 }
@@ -4123,6 +4307,28 @@ Value *llvm::SimplifyShuffleVectorInst(Value *Op0, Value *Op1, Constant *Mask,
   return ::SimplifyShuffleVectorInst(Op0, Op1, Mask, RetTy, Q, RecursionLimit);
 }
 
+static Constant *propagateNaN(Constant *In) {
+  // If the input is a vector with undef elements, just return a default NaN.
+  if (!In->isNaN())
+    return ConstantFP::getNaN(In->getType());
+
+  // Propagate the existing NaN constant when possible.
+  // TODO: Should we quiet a signaling NaN?
+  return In;
+}
+
+static Constant *simplifyFPBinop(Value *Op0, Value *Op1) {
+  if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
+    return ConstantFP::getNaN(Op0->getType());
+
+  if (match(Op0, m_NaN()))
+    return propagateNaN(cast<Constant>(Op0));
+  if (match(Op1, m_NaN()))
+    return propagateNaN(cast<Constant>(Op1));
+
+  return nullptr;
+}
+
 /// Given operands for an FAdd, see if we can fold the result.  If not, this
 /// returns null.
 static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
@@ -4130,29 +4336,28 @@ static Value *SimplifyFAddInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FAdd, Op0, Op1, Q))
     return C;
 
+  if (Constant *C = simplifyFPBinop(Op0, Op1))
+    return C;
+
   // fadd X, -0 ==> X
-  if (match(Op1, m_NegZero()))
+  if (match(Op1, m_NegZeroFP()))
     return Op0;
 
   // fadd X, 0 ==> X, when we know X is not -0
-  if (match(Op1, m_Zero()) &&
+  if (match(Op1, m_PosZeroFP()) &&
       (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
     return Op0;
 
-  // fadd [nnan ninf] X, (fsub [nnan ninf] 0, X) ==> 0
-  //   where nnan and ninf have to occur at least once somewhere in this
-  //   expression
-  Value *SubOp = nullptr;
-  if (match(Op1, m_FSub(m_AnyZero(), m_Specific(Op0))))
-    SubOp = Op1;
-  else if (match(Op0, m_FSub(m_AnyZero(), m_Specific(Op1))))
-    SubOp = Op0;
-  if (SubOp) {
-    Instruction *FSub = cast<Instruction>(SubOp);
-    if ((FMF.noNaNs() || FSub->hasNoNaNs()) &&
-        (FMF.noInfs() || FSub->hasNoInfs()))
-      return Constant::getNullValue(Op0->getType());
-  }
+  // With nnan: (+/-0.0 - X) + X --> 0.0 (and commuted variant)
+  // We don't have to explicitly exclude infinities (ninf): INF + -INF == NaN.
+  // Negative zeros are allowed because we always end up with positive zero:
+  // X = -0.0: (-0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
+  // X = -0.0: ( 0.0 - (-0.0)) + (-0.0) == ( 0.0) + (-0.0) == 0.0
+  // X =  0.0: (-0.0 - ( 0.0)) + ( 0.0) == (-0.0) + ( 0.0) == 0.0
+  // X =  0.0: ( 0.0 - ( 0.0)) + ( 0.0) == ( 0.0) + ( 0.0) == 0.0
+  if (FMF.noNaNs() && (match(Op0, m_FSub(m_AnyZeroFP(), m_Specific(Op1))) ||
+                       match(Op1, m_FSub(m_AnyZeroFP(), m_Specific(Op0)))))
+    return ConstantFP::getNullValue(Op0->getType());
 
   return nullptr;
 }
@@ -4164,23 +4369,27 @@ static Value *SimplifyFSubInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FSub, Op0, Op1, Q))
     return C;
 
-  // fsub X, 0 ==> X
-  if (match(Op1, m_Zero()))
+  if (Constant *C = simplifyFPBinop(Op0, Op1))
+    return C;
+
+  // fsub X, +0 ==> X
+  if (match(Op1, m_PosZeroFP()))
     return Op0;
 
   // fsub X, -0 ==> X, when we know X is not -0
-  if (match(Op1, m_NegZero()) &&
+  if (match(Op1, m_NegZeroFP()) &&
       (FMF.noSignedZeros() || CannotBeNegativeZero(Op0, Q.TLI)))
     return Op0;
 
   // fsub -0.0, (fsub -0.0, X) ==> X
   Value *X;
-  if (match(Op0, m_NegZero()) && match(Op1, m_FSub(m_NegZero(), m_Value(X))))
+  if (match(Op0, m_NegZeroFP()) &&
+      match(Op1, m_FSub(m_NegZeroFP(), m_Value(X))))
     return X;
 
   // fsub 0.0, (fsub 0.0, X) ==> X if signed zeros are ignored.
-  if (FMF.noSignedZeros() && match(Op0, m_AnyZero()) &&
-      match(Op1, m_FSub(m_AnyZero(), m_Value(X))))
+  if (FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()) &&
+      match(Op1, m_FSub(m_AnyZeroFP(), m_Value(X))))
     return X;
 
   // fsub nnan x, x ==> 0.0
@@ -4196,13 +4405,25 @@ static Value *SimplifyFMulInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FMul, Op0, Op1, Q))
     return C;
 
+  if (Constant *C = simplifyFPBinop(Op0, Op1))
+    return C;
+
   // fmul X, 1.0 ==> X
   if (match(Op1, m_FPOne()))
     return Op0;
 
   // fmul nnan nsz X, 0 ==> 0
-  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZero()))
-    return Op1;
+  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op1, m_AnyZeroFP()))
+    return ConstantFP::getNullValue(Op0->getType());
+
+  // sqrt(X) * sqrt(X) --> X, if we can:
+  // 1. Remove the intermediate rounding (reassociate).
+  // 2. Ignore non-zero negative numbers because sqrt would produce NAN.
+  // 3. Ignore -0.0 because sqrt(-0.0) == -0.0, but -0.0 * -0.0 == 0.0.
+  Value *X;
+  if (Op0 == Op1 && match(Op0, m_Intrinsic<Intrinsic::sqrt>(m_Value(X))) &&
+      FMF.allowReassoc() && FMF.noNaNs() && FMF.noSignedZeros())
+    return X;
 
   return nullptr;
 }
@@ -4228,13 +4449,8 @@ static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FDiv, Op0, Op1, Q))
     return C;
 
-  // 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;
+  if (Constant *C = simplifyFPBinop(Op0, Op1))
+    return C;
 
   // X / 1.0 -> X
   if (match(Op1, m_FPOne()))
@@ -4243,14 +4459,20 @@ static Value *SimplifyFDivInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   // 0 / X -> 0
   // Requires that NaNs are off (X could be zero) and signed zeroes are
   // ignored (X could be positive or negative, so the output sign is unknown).
-  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
-    return Op0;
+  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZeroFP()))
+    return ConstantFP::getNullValue(Op0->getType());
 
   if (FMF.noNaNs()) {
     // X / X -> 1.0 is legal when NaNs are ignored.
+    // We can ignore infinities because INF/INF is NaN.
     if (Op0 == Op1)
       return ConstantFP::get(Op0->getType(), 1.0);
 
+    // (X * Y) / Y --> X if we can reassociate to the above form.
+    Value *X;
+    if (FMF.allowReassoc() && match(Op0, m_c_FMul(m_Value(X), m_Specific(Op1))))
+      return X;
+
     // -X /  X -> -1.0 and
     //  X / -X -> -1.0 are legal when NaNs are ignored.
     // We can ignore signed zeros because +-0.0/+-0.0 is NaN and ignored.
@@ -4274,19 +4496,20 @@ static Value *SimplifyFRemInst(Value *Op0, Value *Op1, FastMathFlags FMF,
   if (Constant *C = foldOrCommuteConstant(Instruction::FRem, Op0, Op1, Q))
     return C;
 
-  // 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;
+  if (Constant *C = simplifyFPBinop(Op0, Op1))
+    return C;
 
-  // 0 % X -> 0
-  // Requires that NaNs are off (X could be zero) and signed zeroes are
-  // ignored (X could be positive or negative, so the output sign is unknown).
-  if (FMF.noNaNs() && FMF.noSignedZeros() && match(Op0, m_AnyZero()))
-    return Op0;
+  // Unlike fdiv, the result of frem always matches the sign of the dividend.
+  // The constant match may include undef elements in a vector, so return a full
+  // zero constant as the result.
+  if (FMF.noNaNs()) {
+    // +0 % X -> 0
+    if (match(Op0, m_PosZeroFP()))
+      return ConstantFP::getNullValue(Op0->getType());
+    // -0 % X -> -0
+    if (match(Op0, m_NegZeroFP()))
+      return ConstantFP::getNegativeZero(Op0->getType());
+  }
 
   return nullptr;
 }
@@ -4477,141 +4700,131 @@ static bool maskIsAllZeroOrUndef(Value *Mask) {
   return true;
 }
 
-template <typename IterTy>
-static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
-                                const SimplifyQuery &Q, unsigned MaxRecurse) {
+static Value *simplifyUnaryIntrinsic(Function *F, Value *Op0,
+                                     const SimplifyQuery &Q) {
+  // Idempotent functions return the same result when called repeatedly.
   Intrinsic::ID IID = F->getIntrinsicID();
-  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
-
-  // Unary Ops
-  if (NumOperands == 1) {
-    // Perform idempotent optimizations
-    if (IsIdempotent(IID)) {
-      if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(*ArgBegin)) {
-        if (II->getIntrinsicID() == IID)
-          return II;
-      }
-    }
+  if (IsIdempotent(IID))
+    if (auto *II = dyn_cast<IntrinsicInst>(Op0))
+      if (II->getIntrinsicID() == IID)
+        return II;
 
-    Value *IIOperand = *ArgBegin;
-    Value *X;
-    switch (IID) {
-    case Intrinsic::fabs: {
-      if (SignBitMustBeZero(IIOperand, Q.TLI))
-        return IIOperand;
-      return nullptr;
-    }
-    case Intrinsic::bswap: {
-      // bswap(bswap(x)) -> x
-      if (match(IIOperand, m_BSwap(m_Value(X))))
-        return X;
-      return nullptr;
-    }
-    case Intrinsic::bitreverse: {
-      // bitreverse(bitreverse(x)) -> x
-      if (match(IIOperand, m_BitReverse(m_Value(X))))
-        return X;
-      return nullptr;
-    }
-    case Intrinsic::exp: {
-      // exp(log(x)) -> x
-      if (Q.CxtI->isFast() &&
-          match(IIOperand, m_Intrinsic<Intrinsic::log>(m_Value(X))))
-        return X;
-      return nullptr;
-    }
-    case Intrinsic::exp2: {
-      // exp2(log2(x)) -> x
-      if (Q.CxtI->isFast() &&
-          match(IIOperand, m_Intrinsic<Intrinsic::log2>(m_Value(X))))
-        return X;
-      return nullptr;
-    }
-    case Intrinsic::log: {
-      // log(exp(x)) -> x
-      if (Q.CxtI->isFast() &&
-          match(IIOperand, m_Intrinsic<Intrinsic::exp>(m_Value(X))))
-        return X;
-      return nullptr;
-    }
-    case Intrinsic::log2: {
-      // log2(exp2(x)) -> x
-      if (Q.CxtI->isFast() &&
-          match(IIOperand, m_Intrinsic<Intrinsic::exp2>(m_Value(X)))) {
-        return X;
-      }
-      return nullptr;
-    }
-    default:
-      return nullptr;
-    }
+  Value *X;
+  switch (IID) {
+  case Intrinsic::fabs:
+    if (SignBitMustBeZero(Op0, Q.TLI)) return Op0;
+    break;
+  case Intrinsic::bswap:
+    // bswap(bswap(x)) -> x
+    if (match(Op0, m_BSwap(m_Value(X)))) return X;
+    break;
+  case Intrinsic::bitreverse:
+    // bitreverse(bitreverse(x)) -> x
+    if (match(Op0, m_BitReverse(m_Value(X)))) return X;
+    break;
+  case Intrinsic::exp:
+    // exp(log(x)) -> x
+    if (Q.CxtI->hasAllowReassoc() &&
+        match(Op0, m_Intrinsic<Intrinsic::log>(m_Value(X)))) return X;
+    break;
+  case Intrinsic::exp2:
+    // exp2(log2(x)) -> x
+    if (Q.CxtI->hasAllowReassoc() &&
+        match(Op0, m_Intrinsic<Intrinsic::log2>(m_Value(X)))) return X;
+    break;
+  case Intrinsic::log:
+    // log(exp(x)) -> x
+    if (Q.CxtI->hasAllowReassoc() &&
+        match(Op0, m_Intrinsic<Intrinsic::exp>(m_Value(X)))) return X;
+    break;
+  case Intrinsic::log2:
+    // log2(exp2(x)) -> x
+    if (Q.CxtI->hasAllowReassoc() &&
+        match(Op0, m_Intrinsic<Intrinsic::exp2>(m_Value(X)))) return X;
+    break;
+  default:
+    break;
   }
 
-  // Binary Ops
-  if (NumOperands == 2) {
-    Value *LHS = *ArgBegin;
-    Value *RHS = *(ArgBegin + 1);
-    Type *ReturnType = F->getReturnType();
+  return nullptr;
+}
 
-    switch (IID) {
-    case Intrinsic::usub_with_overflow:
-    case Intrinsic::ssub_with_overflow: {
-      // X - X -> { 0, false }
-      if (LHS == RHS)
-        return Constant::getNullValue(ReturnType);
+static Value *simplifyBinaryIntrinsic(Function *F, Value *Op0, Value *Op1,
+                                      const SimplifyQuery &Q) {
+  Intrinsic::ID IID = F->getIntrinsicID();
+  Type *ReturnType = F->getReturnType();
+  switch (IID) {
+  case Intrinsic::usub_with_overflow:
+  case Intrinsic::ssub_with_overflow:
+    // X - X -> { 0, false }
+    if (Op0 == Op1)
+      return Constant::getNullValue(ReturnType);
+    // X - undef -> undef
+    // undef - X -> undef
+    if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
+      return UndefValue::get(ReturnType);
+    break;
+  case Intrinsic::uadd_with_overflow:
+  case Intrinsic::sadd_with_overflow:
+    // X + undef -> undef
+    if (isa<UndefValue>(Op0) || isa<UndefValue>(Op1))
+      return UndefValue::get(ReturnType);
+    break;
+  case Intrinsic::umul_with_overflow:
+  case Intrinsic::smul_with_overflow:
+    // 0 * X -> { 0, false }
+    // X * 0 -> { 0, false }
+    if (match(Op0, m_Zero()) || match(Op1, m_Zero()))
+      return Constant::getNullValue(ReturnType);
+    // undef * X -> { 0, false }
+    // X * undef -> { 0, false }
+    if (match(Op0, m_Undef()) || match(Op1, m_Undef()))
+      return Constant::getNullValue(ReturnType);
+    break;
+  case Intrinsic::load_relative:
+    if (auto *C0 = dyn_cast<Constant>(Op0))
+      if (auto *C1 = dyn_cast<Constant>(Op1))
+        return SimplifyRelativeLoad(C0, C1, Q.DL);
+    break;
+  case Intrinsic::powi:
+    if (auto *Power = dyn_cast<ConstantInt>(Op1)) {
+      // powi(x, 0) -> 1.0
+      if (Power->isZero())
+        return ConstantFP::get(Op0->getType(), 1.0);
+      // powi(x, 1) -> x
+      if (Power->isOne())
+        return Op0;
+    }
+    break;
+  case Intrinsic::maxnum:
+  case Intrinsic::minnum:
+    // If one argument is NaN, return the other argument.
+    if (match(Op0, m_NaN())) return Op1;
+    if (match(Op1, m_NaN())) return Op0;
+    break;
+  default:
+    break;
+  }
 
-      // X - undef -> undef
-      // undef - X -> undef
-      if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
-        return UndefValue::get(ReturnType);
+  return nullptr;
+}
 
-      return nullptr;
-    }
-    case Intrinsic::uadd_with_overflow:
-    case Intrinsic::sadd_with_overflow: {
-      // X + undef -> undef
-      if (isa<UndefValue>(LHS) || isa<UndefValue>(RHS))
-        return UndefValue::get(ReturnType);
+template <typename IterTy>
+static Value *simplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
+                                const SimplifyQuery &Q) {
+  // Intrinsics with no operands have some kind of side effect. Don't simplify.
+  unsigned NumOperands = std::distance(ArgBegin, ArgEnd);
+  if (NumOperands == 0)
+    return nullptr;
 
-      return nullptr;
-    }
-    case Intrinsic::umul_with_overflow:
-    case Intrinsic::smul_with_overflow: {
-      // 0 * X -> { 0, false }
-      // X * 0 -> { 0, false }
-      if (match(LHS, m_Zero()) || match(RHS, m_Zero()))
-        return Constant::getNullValue(ReturnType);
-
-      // undef * X -> { 0, false }
-      // X * undef -> { 0, false }
-      if (match(LHS, m_Undef()) || match(RHS, m_Undef()))
-        return Constant::getNullValue(ReturnType);
+  Intrinsic::ID IID = F->getIntrinsicID();
+  if (NumOperands == 1)
+    return simplifyUnaryIntrinsic(F, ArgBegin[0], Q);
 
-      return nullptr;
-    }
-    case Intrinsic::load_relative: {
-      Constant *C0 = dyn_cast<Constant>(LHS);
-      Constant *C1 = dyn_cast<Constant>(RHS);
-      if (C0 && C1)
-        return SimplifyRelativeLoad(C0, C1, Q.DL);
-      return nullptr;
-    }
-    case Intrinsic::powi:
-      if (ConstantInt *Power = dyn_cast<ConstantInt>(RHS)) {
-        // powi(x, 0) -> 1.0
-        if (Power->isZero())
-          return ConstantFP::get(LHS->getType(), 1.0);
-        // powi(x, 1) -> x
-        if (Power->isOne())
-          return LHS;
-      }
-      return nullptr;
-    default:
-      return nullptr;
-    }
-  }
+  if (NumOperands == 2)
+    return simplifyBinaryIntrinsic(F, ArgBegin[0], ArgBegin[1], Q);
 
-  // Simplify calls to llvm.masked.load.*
+  // Handle intrinsics with 3 or more arguments.
   switch (IID) {
   case Intrinsic::masked_load: {
     Value *MaskArg = ArgBegin[2];
@@ -4621,6 +4834,19 @@ static Value *SimplifyIntrinsic(Function *F, IterTy ArgBegin, IterTy ArgEnd,
       return PassthruArg;
     return nullptr;
   }
+  case Intrinsic::fshl:
+  case Intrinsic::fshr: {
+    Value *ShAmtArg = ArgBegin[2];
+    const APInt *ShAmtC;
+    if (match(ShAmtArg, m_APInt(ShAmtC))) {
+      // If there's effectively no shift, return the 1st arg or 2nd arg.
+      // TODO: For vectors, we could check each element of a non-splat constant.
+      APInt BitWidth = APInt(ShAmtC->getBitWidth(), ShAmtC->getBitWidth());
+      if (ShAmtC->urem(BitWidth).isNullValue())
+        return ArgBegin[IID == Intrinsic::fshl ? 0 : 1];
+    }
+    return nullptr;
+  }
   default:
     return nullptr;
   }
@@ -4645,7 +4871,7 @@ static Value *SimplifyCall(ImmutableCallSite CS, Value *V, IterTy ArgBegin,
     return nullptr;
 
   if (F->isIntrinsic())
-    if (Value *Ret = SimplifyIntrinsic(F, ArgBegin, ArgEnd, Q, MaxRecurse))
+    if (Value *Ret = simplifyIntrinsic(F, ArgBegin, ArgEnd, Q))
       return Ret;
 
   if (!canConstantFoldCallTo(CS, F))
@@ -4843,7 +5069,7 @@ Value *llvm::SimplifyInstruction(Instruction *I, const SimplifyQuery &SQ,
   return Result == I ? UndefValue::get(I->getType()) : Result;
 }
 
-/// \brief Implementation of recursive simplification through an instruction's
+/// Implementation of recursive simplification through an instruction's
 /// uses.
 ///
 /// This is the common implementation of the recursive simplification routines.