Vendor import of llvm-project main 8e464dd76bef, the last commit beforevendor/llvm-project/llvmorg-12-init-17869-g8e464dd76bef

the upstream release/12.x branch was created.

1 files changed, 2017 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp b/llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp
new file mode 100644
index 000000000000..c4150ed52854
--- /dev/null
+++ b/llvm/lib/Target/X86/X86InstCombineIntrinsic.cpp
@@ -0,0 +1,2017 @@
+//===-- X86InstCombineIntrinsic.cpp - X86 specific InstCombine pass -------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This file implements a TargetTransformInfo analysis pass specific to the
+/// X86 target machine. It uses the target's detailed information to provide
+/// more precise answers to certain TTI queries, while letting the target
+/// independent and default TTI implementations handle the rest.
+///
+//===----------------------------------------------------------------------===//
+
+#include "X86TargetTransformInfo.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/IntrinsicsX86.h"
+#include "llvm/Support/KnownBits.h"
+#include "llvm/Transforms/InstCombine/InstCombiner.h"
+
+using namespace llvm;
+
+#define DEBUG_TYPE "x86tti"
+
+/// Return a constant boolean vector that has true elements in all positions
+/// where the input constant data vector has an element with the sign bit set.
+static Constant *getNegativeIsTrueBoolVec(Constant *V) {
+  VectorType *IntTy = VectorType::getInteger(cast<VectorType>(V->getType()));
+  V = ConstantExpr::getBitCast(V, IntTy);
+  V = ConstantExpr::getICmp(CmpInst::ICMP_SGT, Constant::getNullValue(IntTy),
+                            V);
+  return V;
+}
+
+/// Convert the x86 XMM integer vector mask to a vector of bools based on
+/// each element's most significant bit (the sign bit).
+static Value *getBoolVecFromMask(Value *Mask) {
+  // Fold Constant Mask.
+  if (auto *ConstantMask = dyn_cast<ConstantDataVector>(Mask))
+    return getNegativeIsTrueBoolVec(ConstantMask);
+
+  // Mask was extended from a boolean vector.
+  Value *ExtMask;
+  if (PatternMatch::match(
+          Mask, PatternMatch::m_SExt(PatternMatch::m_Value(ExtMask))) &&
+      ExtMask->getType()->isIntOrIntVectorTy(1))
+    return ExtMask;
+
+  return nullptr;
+}
+
+// TODO: If the x86 backend knew how to convert a bool vector mask back to an
+// XMM register mask efficiently, we could transform all x86 masked intrinsics
+// to LLVM masked intrinsics and remove the x86 masked intrinsic defs.
+static Instruction *simplifyX86MaskedLoad(IntrinsicInst &II, InstCombiner &IC) {
+  Value *Ptr = II.getOperand(0);
+  Value *Mask = II.getOperand(1);
+  Constant *ZeroVec = Constant::getNullValue(II.getType());
+
+  // Zero Mask - masked load instruction creates a zero vector.
+  if (isa<ConstantAggregateZero>(Mask))
+    return IC.replaceInstUsesWith(II, ZeroVec);
+
+  // The mask is constant or extended from a bool vector. Convert this x86
+  // intrinsic to the LLVM intrinsic to allow target-independent optimizations.
+  if (Value *BoolMask = getBoolVecFromMask(Mask)) {
+    // First, cast the x86 intrinsic scalar pointer to a vector pointer to match
+    // the LLVM intrinsic definition for the pointer argument.
+    unsigned AddrSpace = cast<PointerType>(Ptr->getType())->getAddressSpace();
+    PointerType *VecPtrTy = PointerType::get(II.getType(), AddrSpace);
+    Value *PtrCast = IC.Builder.CreateBitCast(Ptr, VecPtrTy, "castvec");
+
+    // The pass-through vector for an x86 masked load is a zero vector.
+    CallInst *NewMaskedLoad =
+        IC.Builder.CreateMaskedLoad(PtrCast, Align(1), BoolMask, ZeroVec);
+    return IC.replaceInstUsesWith(II, NewMaskedLoad);
+  }
+
+  return nullptr;
+}
+
+// TODO: If the x86 backend knew how to convert a bool vector mask back to an
+// XMM register mask efficiently, we could transform all x86 masked intrinsics
+// to LLVM masked intrinsics and remove the x86 masked intrinsic defs.
+static bool simplifyX86MaskedStore(IntrinsicInst &II, InstCombiner &IC) {
+  Value *Ptr = II.getOperand(0);
+  Value *Mask = II.getOperand(1);
+  Value *Vec = II.getOperand(2);
+
+  // Zero Mask - this masked store instruction does nothing.
+  if (isa<ConstantAggregateZero>(Mask)) {
+    IC.eraseInstFromFunction(II);
+    return true;
+  }
+
+  // The SSE2 version is too weird (eg, unaligned but non-temporal) to do
+  // anything else at this level.
+  if (II.getIntrinsicID() == Intrinsic::x86_sse2_maskmov_dqu)
+    return false;
+
+  // The mask is constant or extended from a bool vector. Convert this x86
+  // intrinsic to the LLVM intrinsic to allow target-independent optimizations.
+  if (Value *BoolMask = getBoolVecFromMask(Mask)) {
+    unsigned AddrSpace = cast<PointerType>(Ptr->getType())->getAddressSpace();
+    PointerType *VecPtrTy = PointerType::get(Vec->getType(), AddrSpace);
+    Value *PtrCast = IC.Builder.CreateBitCast(Ptr, VecPtrTy, "castvec");
+
+    IC.Builder.CreateMaskedStore(Vec, PtrCast, Align(1), BoolMask);
+
+    // 'Replace uses' doesn't work for stores. Erase the original masked store.
+    IC.eraseInstFromFunction(II);
+    return true;
+  }
+
+  return false;
+}
+
+static Value *simplifyX86immShift(const IntrinsicInst &II,
+                                  InstCombiner::BuilderTy &Builder) {
+  bool LogicalShift = false;
+  bool ShiftLeft = false;
+  bool IsImm = false;
+
+  switch (II.getIntrinsicID()) {
+  default:
+    llvm_unreachable("Unexpected intrinsic!");
+  case Intrinsic::x86_sse2_psrai_d:
+  case Intrinsic::x86_sse2_psrai_w:
+  case Intrinsic::x86_avx2_psrai_d:
+  case Intrinsic::x86_avx2_psrai_w:
+  case Intrinsic::x86_avx512_psrai_q_128:
+  case Intrinsic::x86_avx512_psrai_q_256:
+  case Intrinsic::x86_avx512_psrai_d_512:
+  case Intrinsic::x86_avx512_psrai_q_512:
+  case Intrinsic::x86_avx512_psrai_w_512:
+    IsImm = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::x86_sse2_psra_d:
+  case Intrinsic::x86_sse2_psra_w:
+  case Intrinsic::x86_avx2_psra_d:
+  case Intrinsic::x86_avx2_psra_w:
+  case Intrinsic::x86_avx512_psra_q_128:
+  case Intrinsic::x86_avx512_psra_q_256:
+  case Intrinsic::x86_avx512_psra_d_512:
+  case Intrinsic::x86_avx512_psra_q_512:
+  case Intrinsic::x86_avx512_psra_w_512:
+    LogicalShift = false;
+    ShiftLeft = false;
+    break;
+  case Intrinsic::x86_sse2_psrli_d:
+  case Intrinsic::x86_sse2_psrli_q:
+  case Intrinsic::x86_sse2_psrli_w:
+  case Intrinsic::x86_avx2_psrli_d:
+  case Intrinsic::x86_avx2_psrli_q:
+  case Intrinsic::x86_avx2_psrli_w:
+  case Intrinsic::x86_avx512_psrli_d_512:
+  case Intrinsic::x86_avx512_psrli_q_512:
+  case Intrinsic::x86_avx512_psrli_w_512:
+    IsImm = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::x86_sse2_psrl_d:
+  case Intrinsic::x86_sse2_psrl_q:
+  case Intrinsic::x86_sse2_psrl_w:
+  case Intrinsic::x86_avx2_psrl_d:
+  case Intrinsic::x86_avx2_psrl_q:
+  case Intrinsic::x86_avx2_psrl_w:
+  case Intrinsic::x86_avx512_psrl_d_512:
+  case Intrinsic::x86_avx512_psrl_q_512:
+  case Intrinsic::x86_avx512_psrl_w_512:
+    LogicalShift = true;
+    ShiftLeft = false;
+    break;
+  case Intrinsic::x86_sse2_pslli_d:
+  case Intrinsic::x86_sse2_pslli_q:
+  case Intrinsic::x86_sse2_pslli_w:
+  case Intrinsic::x86_avx2_pslli_d:
+  case Intrinsic::x86_avx2_pslli_q:
+  case Intrinsic::x86_avx2_pslli_w:
+  case Intrinsic::x86_avx512_pslli_d_512:
+  case Intrinsic::x86_avx512_pslli_q_512:
+  case Intrinsic::x86_avx512_pslli_w_512:
+    IsImm = true;
+    LLVM_FALLTHROUGH;
+  case Intrinsic::x86_sse2_psll_d:
+  case Intrinsic::x86_sse2_psll_q:
+  case Intrinsic::x86_sse2_psll_w:
+  case Intrinsic::x86_avx2_psll_d:
+  case Intrinsic::x86_avx2_psll_q:
+  case Intrinsic::x86_avx2_psll_w:
+  case Intrinsic::x86_avx512_psll_d_512:
+  case Intrinsic::x86_avx512_psll_q_512:
+  case Intrinsic::x86_avx512_psll_w_512:
+    LogicalShift = true;
+    ShiftLeft = true;
+    break;
+  }
+  assert((LogicalShift || !ShiftLeft) && "Only logical shifts can shift left");
+
+  auto Vec = II.getArgOperand(0);
+  auto Amt = II.getArgOperand(1);
+  auto VT = cast<FixedVectorType>(Vec->getType());
+  auto SVT = VT->getElementType();
+  auto AmtVT = Amt->getType();
+  unsigned VWidth = VT->getNumElements();
+  unsigned BitWidth = SVT->getPrimitiveSizeInBits();
+
+  // If the shift amount is guaranteed to be in-range we can replace it with a
+  // generic shift. If its guaranteed to be out of range, logical shifts combine
+  // to zero and arithmetic shifts are clamped to (BitWidth - 1).
+  if (IsImm) {
+    assert(AmtVT->isIntegerTy(32) && "Unexpected shift-by-immediate type");
+    KnownBits KnownAmtBits =
+        llvm::computeKnownBits(Amt, II.getModule()->getDataLayout());
+    if (KnownAmtBits.getMaxValue().ult(BitWidth)) {
+      Amt = Builder.CreateZExtOrTrunc(Amt, SVT);
+      Amt = Builder.CreateVectorSplat(VWidth, Amt);
+      return (LogicalShift ? (ShiftLeft ? Builder.CreateShl(Vec, Amt)
+                                        : Builder.CreateLShr(Vec, Amt))
+                           : Builder.CreateAShr(Vec, Amt));
+    }
+    if (KnownAmtBits.getMinValue().uge(BitWidth)) {
+      if (LogicalShift)
+        return ConstantAggregateZero::get(VT);
+      Amt = ConstantInt::get(SVT, BitWidth - 1);
+      return Builder.CreateAShr(Vec, Builder.CreateVectorSplat(VWidth, Amt));
+    }
+  } else {
+    // Ensure the first element has an in-range value and the rest of the
+    // elements in the bottom 64 bits are zero.
+    assert(AmtVT->isVectorTy() && AmtVT->getPrimitiveSizeInBits() == 128 &&
+           cast<VectorType>(AmtVT)->getElementType() == SVT &&
+           "Unexpected shift-by-scalar type");
+    unsigned NumAmtElts = cast<FixedVectorType>(AmtVT)->getNumElements();
+    APInt DemandedLower = APInt::getOneBitSet(NumAmtElts, 0);
+    APInt DemandedUpper = APInt::getBitsSet(NumAmtElts, 1, NumAmtElts / 2);
+    KnownBits KnownLowerBits = llvm::computeKnownBits(
+        Amt, DemandedLower, II.getModule()->getDataLayout());
+    KnownBits KnownUpperBits = llvm::computeKnownBits(
+        Amt, DemandedUpper, II.getModule()->getDataLayout());
+    if (KnownLowerBits.getMaxValue().ult(BitWidth) &&
+        (DemandedUpper.isNullValue() || KnownUpperBits.isZero())) {
+      SmallVector<int, 16> ZeroSplat(VWidth, 0);
+      Amt = Builder.CreateShuffleVector(Amt, ZeroSplat);
+      return (LogicalShift ? (ShiftLeft ? Builder.CreateShl(Vec, Amt)
+                                        : Builder.CreateLShr(Vec, Amt))
+                           : Builder.CreateAShr(Vec, Amt));
+    }
+  }
+
+  // Simplify if count is constant vector.
+  auto CDV = dyn_cast<ConstantDataVector>(Amt);
+  if (!CDV)
+    return nullptr;
+
+  // SSE2/AVX2 uses all the first 64-bits of the 128-bit vector
+  // operand to compute the shift amount.
+  assert(AmtVT->isVectorTy() && AmtVT->getPrimitiveSizeInBits() == 128 &&
+         cast<VectorType>(AmtVT)->getElementType() == SVT &&
+         "Unexpected shift-by-scalar type");
+
+  // Concatenate the sub-elements to create the 64-bit value.
+  APInt Count(64, 0);
+  for (unsigned i = 0, NumSubElts = 64 / BitWidth; i != NumSubElts; ++i) {
+    unsigned SubEltIdx = (NumSubElts - 1) - i;
+    auto SubElt = cast<ConstantInt>(CDV->getElementAsConstant(SubEltIdx));
+    Count <<= BitWidth;
+    Count |= SubElt->getValue().zextOrTrunc(64);
+  }
+
+  // If shift-by-zero then just return the original value.
+  if (Count.isNullValue())
+    return Vec;
+
+  // Handle cases when Shift >= BitWidth.
+  if (Count.uge(BitWidth)) {
+    // If LogicalShift - just return zero.
+    if (LogicalShift)
+      return ConstantAggregateZero::get(VT);
+
+    // If ArithmeticShift - clamp Shift to (BitWidth - 1).
+    Count = APInt(64, BitWidth - 1);
+  }
+
+  // Get a constant vector of the same type as the first operand.
+  auto ShiftAmt = ConstantInt::get(SVT, Count.zextOrTrunc(BitWidth));
+  auto ShiftVec = Builder.CreateVectorSplat(VWidth, ShiftAmt);
+
+  if (ShiftLeft)
+    return Builder.CreateShl(Vec, ShiftVec);
+
+  if (LogicalShift)
+    return Builder.CreateLShr(Vec, ShiftVec);
+
+  return Builder.CreateAShr(Vec, ShiftVec);
+}
+
+// Attempt to simplify AVX2 per-element shift intrinsics to a generic IR shift.
+// Unlike the generic IR shifts, the intrinsics have defined behaviour for out
+// of range shift amounts (logical - set to zero, arithmetic - splat sign bit).
+static Value *simplifyX86varShift(const IntrinsicInst &II,
+                                  InstCombiner::BuilderTy &Builder) {
+  bool LogicalShift = false;
+  bool ShiftLeft = false;
+
+  switch (II.getIntrinsicID()) {
+  default:
+    llvm_unreachable("Unexpected intrinsic!");
+  case Intrinsic::x86_avx2_psrav_d:
+  case Intrinsic::x86_avx2_psrav_d_256:
+  case Intrinsic::x86_avx512_psrav_q_128:
+  case Intrinsic::x86_avx512_psrav_q_256:
+  case Intrinsic::x86_avx512_psrav_d_512:
+  case Intrinsic::x86_avx512_psrav_q_512:
+  case Intrinsic::x86_avx512_psrav_w_128:
+  case Intrinsic::x86_avx512_psrav_w_256:
+  case Intrinsic::x86_avx512_psrav_w_512:
+    LogicalShift = false;
+    ShiftLeft = false;
+    break;
+  case Intrinsic::x86_avx2_psrlv_d:
+  case Intrinsic::x86_avx2_psrlv_d_256:
+  case Intrinsic::x86_avx2_psrlv_q:
+  case Intrinsic::x86_avx2_psrlv_q_256:
+  case Intrinsic::x86_avx512_psrlv_d_512:
+  case Intrinsic::x86_avx512_psrlv_q_512:
+  case Intrinsic::x86_avx512_psrlv_w_128:
+  case Intrinsic::x86_avx512_psrlv_w_256:
+  case Intrinsic::x86_avx512_psrlv_w_512:
+    LogicalShift = true;
+    ShiftLeft = false;
+    break;
+  case Intrinsic::x86_avx2_psllv_d:
+  case Intrinsic::x86_avx2_psllv_d_256:
+  case Intrinsic::x86_avx2_psllv_q:
+  case Intrinsic::x86_avx2_psllv_q_256:
+  case Intrinsic::x86_avx512_psllv_d_512:
+  case Intrinsic::x86_avx512_psllv_q_512:
+  case Intrinsic::x86_avx512_psllv_w_128:
+  case Intrinsic::x86_avx512_psllv_w_256:
+  case Intrinsic::x86_avx512_psllv_w_512:
+    LogicalShift = true;
+    ShiftLeft = true;
+    break;
+  }
+  assert((LogicalShift || !ShiftLeft) && "Only logical shifts can shift left");
+
+  auto Vec = II.getArgOperand(0);
+  auto Amt = II.getArgOperand(1);
+  auto VT = cast<FixedVectorType>(II.getType());
+  auto SVT = VT->getElementType();
+  int NumElts = VT->getNumElements();
+  int BitWidth = SVT->getIntegerBitWidth();
+
+  // If the shift amount is guaranteed to be in-range we can replace it with a
+  // generic shift.
+  APInt UpperBits =
+      APInt::getHighBitsSet(BitWidth, BitWidth - Log2_32(BitWidth));
+  if (llvm::MaskedValueIsZero(Amt, UpperBits,
+                              II.getModule()->getDataLayout())) {
+    return (LogicalShift ? (ShiftLeft ? Builder.CreateShl(Vec, Amt)
+                                      : Builder.CreateLShr(Vec, Amt))
+                         : Builder.CreateAShr(Vec, Amt));
+  }
+
+  // Simplify if all shift amounts are constant/undef.
+  auto *CShift = dyn_cast<Constant>(Amt);
+  if (!CShift)
+    return nullptr;
+
+  // Collect each element's shift amount.
+  // We also collect special cases: UNDEF = -1, OUT-OF-RANGE = BitWidth.
+  bool AnyOutOfRange = false;
+  SmallVector<int, 8> ShiftAmts;
+  for (int I = 0; I < NumElts; ++I) {
+    auto *CElt = CShift->getAggregateElement(I);
+    if (isa_and_nonnull<UndefValue>(CElt)) {
+      ShiftAmts.push_back(-1);
+      continue;
+    }
+
+    auto *COp = dyn_cast_or_null<ConstantInt>(CElt);
+    if (!COp)
+      return nullptr;
+
+    // Handle out of range shifts.
+    // If LogicalShift - set to BitWidth (special case).
+    // If ArithmeticShift - set to (BitWidth - 1) (sign splat).
+    APInt ShiftVal = COp->getValue();
+    if (ShiftVal.uge(BitWidth)) {
+      AnyOutOfRange = LogicalShift;
+      ShiftAmts.push_back(LogicalShift ? BitWidth : BitWidth - 1);
+      continue;
+    }
+
+    ShiftAmts.push_back((int)ShiftVal.getZExtValue());
+  }
+
+  // If all elements out of range or UNDEF, return vector of zeros/undefs.
+  // ArithmeticShift should only hit this if they are all UNDEF.
+  auto OutOfRange = [&](int Idx) { return (Idx < 0) || (BitWidth <= Idx); };
+  if (llvm::all_of(ShiftAmts, OutOfRange)) {
+    SmallVector<Constant *, 8> ConstantVec;
+    for (int Idx : ShiftAmts) {
+      if (Idx < 0) {
+        ConstantVec.push_back(UndefValue::get(SVT));
+      } else {
+        assert(LogicalShift && "Logical shift expected");
+        ConstantVec.push_back(ConstantInt::getNullValue(SVT));
+      }
+    }
+    return ConstantVector::get(ConstantVec);
+  }
+
+  // We can't handle only some out of range values with generic logical shifts.
+  if (AnyOutOfRange)
+    return nullptr;
+
+  // Build the shift amount constant vector.
+  SmallVector<Constant *, 8> ShiftVecAmts;
+  for (int Idx : ShiftAmts) {
+    if (Idx < 0)
+      ShiftVecAmts.push_back(UndefValue::get(SVT));
+    else
+      ShiftVecAmts.push_back(ConstantInt::get(SVT, Idx));
+  }
+  auto ShiftVec = ConstantVector::get(ShiftVecAmts);
+
+  if (ShiftLeft)
+    return Builder.CreateShl(Vec, ShiftVec);
+
+  if (LogicalShift)
+    return Builder.CreateLShr(Vec, ShiftVec);
+
+  return Builder.CreateAShr(Vec, ShiftVec);
+}
+
+static Value *simplifyX86pack(IntrinsicInst &II,
+                              InstCombiner::BuilderTy &Builder, bool IsSigned) {
+  Value *Arg0 = II.getArgOperand(0);
+  Value *Arg1 = II.getArgOperand(1);
+  Type *ResTy = II.getType();
+
+  // Fast all undef handling.
+  if (isa<UndefValue>(Arg0) && isa<UndefValue>(Arg1))
+    return UndefValue::get(ResTy);
+
+  auto *ArgTy = cast<FixedVectorType>(Arg0->getType());
+  unsigned NumLanes = ResTy->getPrimitiveSizeInBits() / 128;
+  unsigned NumSrcElts = ArgTy->getNumElements();
+  assert(cast<FixedVectorType>(ResTy)->getNumElements() == (2 * NumSrcElts) &&
+         "Unexpected packing types");
+
+  unsigned NumSrcEltsPerLane = NumSrcElts / NumLanes;
+  unsigned DstScalarSizeInBits = ResTy->getScalarSizeInBits();
+  unsigned SrcScalarSizeInBits = ArgTy->getScalarSizeInBits();
+  assert(SrcScalarSizeInBits == (2 * DstScalarSizeInBits) &&
+         "Unexpected packing types");
+
+  // Constant folding.
+  if (!isa<Constant>(Arg0) || !isa<Constant>(Arg1))
+    return nullptr;
+
+  // Clamp Values - signed/unsigned both use signed clamp values, but they
+  // differ on the min/max values.
+  APInt MinValue, MaxValue;
+  if (IsSigned) {
+    // PACKSS: Truncate signed value with signed saturation.
+    // Source values less than dst minint are saturated to minint.
+    // Source values greater than dst maxint are saturated to maxint.
+    MinValue =
+        APInt::getSignedMinValue(DstScalarSizeInBits).sext(SrcScalarSizeInBits);
+    MaxValue =
+        APInt::getSignedMaxValue(DstScalarSizeInBits).sext(SrcScalarSizeInBits);
+  } else {
+    // PACKUS: Truncate signed value with unsigned saturation.
+    // Source values less than zero are saturated to zero.
+    // Source values greater than dst maxuint are saturated to maxuint.
+    MinValue = APInt::getNullValue(SrcScalarSizeInBits);
+    MaxValue = APInt::getLowBitsSet(SrcScalarSizeInBits, DstScalarSizeInBits);
+  }
+
+  auto *MinC = Constant::getIntegerValue(ArgTy, MinValue);
+  auto *MaxC = Constant::getIntegerValue(ArgTy, MaxValue);
+  Arg0 = Builder.CreateSelect(Builder.CreateICmpSLT(Arg0, MinC), MinC, Arg0);
+  Arg1 = Builder.CreateSelect(Builder.CreateICmpSLT(Arg1, MinC), MinC, Arg1);
+  Arg0 = Builder.CreateSelect(Builder.CreateICmpSGT(Arg0, MaxC), MaxC, Arg0);
+  Arg1 = Builder.CreateSelect(Builder.CreateICmpSGT(Arg1, MaxC), MaxC, Arg1);
+
+  // Shuffle clamped args together at the lane level.
+  SmallVector<int, 32> PackMask;
+  for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
+    for (unsigned Elt = 0; Elt != NumSrcEltsPerLane; ++Elt)
+      PackMask.push_back(Elt + (Lane * NumSrcEltsPerLane));
+    for (unsigned Elt = 0; Elt != NumSrcEltsPerLane; ++Elt)
+      PackMask.push_back(Elt + (Lane * NumSrcEltsPerLane) + NumSrcElts);
+  }
+  auto *Shuffle = Builder.CreateShuffleVector(Arg0, Arg1, PackMask);
+
+  // Truncate to dst size.
+  return Builder.CreateTrunc(Shuffle, ResTy);
+}
+
+static Value *simplifyX86movmsk(const IntrinsicInst &II,
+                                InstCombiner::BuilderTy &Builder) {
+  Value *Arg = II.getArgOperand(0);
+  Type *ResTy = II.getType();
+
+  // movmsk(undef) -> zero as we must ensure the upper bits are zero.
+  if (isa<UndefValue>(Arg))
+    return Constant::getNullValue(ResTy);
+
+  auto *ArgTy = dyn_cast<FixedVectorType>(Arg->getType());
+  // We can't easily peek through x86_mmx types.
+  if (!ArgTy)
+    return nullptr;
+
+  // Expand MOVMSK to compare/bitcast/zext:
+  // e.g. PMOVMSKB(v16i8 x):
+  // %cmp = icmp slt <16 x i8> %x, zeroinitializer
+  // %int = bitcast <16 x i1> %cmp to i16
+  // %res = zext i16 %int to i32
+  unsigned NumElts = ArgTy->getNumElements();
+  Type *IntegerVecTy = VectorType::getInteger(ArgTy);
+  Type *IntegerTy = Builder.getIntNTy(NumElts);
+
+  Value *Res = Builder.CreateBitCast(Arg, IntegerVecTy);
+  Res = Builder.CreateICmpSLT(Res, Constant::getNullValue(IntegerVecTy));
+  Res = Builder.CreateBitCast(Res, IntegerTy);
+  Res = Builder.CreateZExtOrTrunc(Res, ResTy);
+  return Res;
+}
+
+static Value *simplifyX86addcarry(const IntrinsicInst &II,
+                                  InstCombiner::BuilderTy &Builder) {
+  Value *CarryIn = II.getArgOperand(0);
+  Value *Op1 = II.getArgOperand(1);
+  Value *Op2 = II.getArgOperand(2);
+  Type *RetTy = II.getType();
+  Type *OpTy = Op1->getType();
+  assert(RetTy->getStructElementType(0)->isIntegerTy(8) &&
+         RetTy->getStructElementType(1) == OpTy && OpTy == Op2->getType() &&
+         "Unexpected types for x86 addcarry");
+
+  // If carry-in is zero, this is just an unsigned add with overflow.
+  if (match(CarryIn, PatternMatch::m_ZeroInt())) {
+    Value *UAdd = Builder.CreateIntrinsic(Intrinsic::uadd_with_overflow, OpTy,
+                                          {Op1, Op2});
+    // The types have to be adjusted to match the x86 call types.
+    Value *UAddResult = Builder.CreateExtractValue(UAdd, 0);
+    Value *UAddOV = Builder.CreateZExt(Builder.CreateExtractValue(UAdd, 1),
+                                       Builder.getInt8Ty());
+    Value *Res = UndefValue::get(RetTy);
+    Res = Builder.CreateInsertValue(Res, UAddOV, 0);
+    return Builder.CreateInsertValue(Res, UAddResult, 1);
+  }
+
+  return nullptr;
+}
+
+static Value *simplifyX86insertps(const IntrinsicInst &II,
+                                  InstCombiner::BuilderTy &Builder) {
+  auto *CInt = dyn_cast<ConstantInt>(II.getArgOperand(2));
+  if (!CInt)
+    return nullptr;
+
+  auto *VecTy = cast<FixedVectorType>(II.getType());
+  assert(VecTy->getNumElements() == 4 && "insertps with wrong vector type");
+
+  // The immediate permute control byte looks like this:
+  //    [3:0] - zero mask for each 32-bit lane
+  //    [5:4] - select one 32-bit destination lane
+  //    [7:6] - select one 32-bit source lane
+
+  uint8_t Imm = CInt->getZExtValue();
+  uint8_t ZMask = Imm & 0xf;
+  uint8_t DestLane = (Imm >> 4) & 0x3;
+  uint8_t SourceLane = (Imm >> 6) & 0x3;
+
+  ConstantAggregateZero *ZeroVector = ConstantAggregateZero::get(VecTy);
+
+  // If all zero mask bits are set, this was just a weird way to
+  // generate a zero vector.
+  if (ZMask == 0xf)
+    return ZeroVector;
+
+  // Initialize by passing all of the first source bits through.
+  int ShuffleMask[4] = {0, 1, 2, 3};
+
+  // We may replace the second operand with the zero vector.
+  Value *V1 = II.getArgOperand(1);
+
+  if (ZMask) {
+    // If the zero mask is being used with a single input or the zero mask
+    // overrides the destination lane, this is a shuffle with the zero vector.
+    if ((II.getArgOperand(0) == II.getArgOperand(1)) ||
+        (ZMask & (1 << DestLane))) {
+      V1 = ZeroVector;
+      // We may still move 32-bits of the first source vector from one lane
+      // to another.
+      ShuffleMask[DestLane] = SourceLane;
+      // The zero mask may override the previous insert operation.
+      for (unsigned i = 0; i < 4; ++i)
+        if ((ZMask >> i) & 0x1)
+          ShuffleMask[i] = i + 4;
+    } else {
+      // TODO: Model this case as 2 shuffles or a 'logical and' plus shuffle?
+      return nullptr;
+    }
+  } else {
+    // Replace the selected destination lane with the selected source lane.
+    ShuffleMask[DestLane] = SourceLane + 4;
+  }
+
+  return Builder.CreateShuffleVector(II.getArgOperand(0), V1, ShuffleMask);
+}
+
+/// Attempt to simplify SSE4A EXTRQ/EXTRQI instructions using constant folding
+/// or conversion to a shuffle vector.
+static Value *simplifyX86extrq(IntrinsicInst &II, Value *Op0,
+                               ConstantInt *CILength, ConstantInt *CIIndex,
+                               InstCombiner::BuilderTy &Builder) {
+  auto LowConstantHighUndef = [&](uint64_t Val) {
+    Type *IntTy64 = Type::getInt64Ty(II.getContext());
+    Constant *Args[] = {ConstantInt::get(IntTy64, Val),
+                        UndefValue::get(IntTy64)};
+    return ConstantVector::get(Args);
+  };
+
+  // See if we're dealing with constant values.
+  Constant *C0 = dyn_cast<Constant>(Op0);
+  ConstantInt *CI0 =
+      C0 ? dyn_cast_or_null<ConstantInt>(C0->getAggregateElement((unsigned)0))
+         : nullptr;
+
+  // Attempt to constant fold.
+  if (CILength && CIIndex) {
+    // From AMD documentation: "The bit index and field length are each six
+    // bits in length other bits of the field are ignored."
+    APInt APIndex = CIIndex->getValue().zextOrTrunc(6);
+    APInt APLength = CILength->getValue().zextOrTrunc(6);
+
+    unsigned Index = APIndex.getZExtValue();
+
+    // From AMD documentation: "a value of zero in the field length is
+    // defined as length of 64".
+    unsigned Length = APLength == 0 ? 64 : APLength.getZExtValue();
+
+    // From AMD documentation: "If the sum of the bit index + length field
+    // is greater than 64, the results are undefined".
+    unsigned End = Index + Length;
+
+    // Note that both field index and field length are 8-bit quantities.
+    // Since variables 'Index' and 'Length' are unsigned values
+    // obtained from zero-extending field index and field length
+    // respectively, their sum should never wrap around.
+    if (End > 64)
+      return UndefValue::get(II.getType());
+
+    // If we are inserting whole bytes, we can convert this to a shuffle.
+    // Lowering can recognize EXTRQI shuffle masks.
+    if ((Length % 8) == 0 && (Index % 8) == 0) {
+      // Convert bit indices to byte indices.
+      Length /= 8;
+      Index /= 8;
+
+      Type *IntTy8 = Type::getInt8Ty(II.getContext());
+      auto *ShufTy = FixedVectorType::get(IntTy8, 16);
+
+      SmallVector<int, 16> ShuffleMask;
+      for (int i = 0; i != (int)Length; ++i)
+        ShuffleMask.push_back(i + Index);
+      for (int i = Length; i != 8; ++i)
+        ShuffleMask.push_back(i + 16);
+      for (int i = 8; i != 16; ++i)
+        ShuffleMask.push_back(-1);
+
+      Value *SV = Builder.CreateShuffleVector(
+          Builder.CreateBitCast(Op0, ShufTy),
+          ConstantAggregateZero::get(ShufTy), ShuffleMask);
+      return Builder.CreateBitCast(SV, II.getType());
+    }
+
+    // Constant Fold - shift Index'th bit to lowest position and mask off
+    // Length bits.
+    if (CI0) {
+      APInt Elt = CI0->getValue();
+      Elt.lshrInPlace(Index);
+      Elt = Elt.zextOrTrunc(Length);
+      return LowConstantHighUndef(Elt.getZExtValue());
+    }
+
+    // If we were an EXTRQ call, we'll save registers if we convert to EXTRQI.
+    if (II.getIntrinsicID() == Intrinsic::x86_sse4a_extrq) {
+      Value *Args[] = {Op0, CILength, CIIndex};
+      Module *M = II.getModule();
+      Function *F = Intrinsic::getDeclaration(M, Intrinsic::x86_sse4a_extrqi);
+      return Builder.CreateCall(F, Args);
+    }
+  }
+
+  // Constant Fold - extraction from zero is always {zero, undef}.
+  if (CI0 && CI0->isZero())
+    return LowConstantHighUndef(0);
+
+  return nullptr;
+}
+
+/// Attempt to simplify SSE4A INSERTQ/INSERTQI instructions using constant
+/// folding or conversion to a shuffle vector.
+static Value *simplifyX86insertq(IntrinsicInst &II, Value *Op0, Value *Op1,
+                                 APInt APLength, APInt APIndex,
+                                 InstCombiner::BuilderTy &Builder) {
+  // From AMD documentation: "The bit index and field length are each six bits
+  // in length other bits of the field are ignored."
+  APIndex = APIndex.zextOrTrunc(6);
+  APLength = APLength.zextOrTrunc(6);
+
+  // Attempt to constant fold.
+  unsigned Index = APIndex.getZExtValue();
+
+  // From AMD documentation: "a value of zero in the field length is
+  // defined as length of 64".
+  unsigned Length = APLength == 0 ? 64 : APLength.getZExtValue();
+
+  // From AMD documentation: "If the sum of the bit index + length field
+  // is greater than 64, the results are undefined".
+  unsigned End = Index + Length;
+
+  // Note that both field index and field length are 8-bit quantities.
+  // Since variables 'Index' and 'Length' are unsigned values
+  // obtained from zero-extending field index and field length
+  // respectively, their sum should never wrap around.
+  if (End > 64)
+    return UndefValue::get(II.getType());
+
+  // If we are inserting whole bytes, we can convert this to a shuffle.
+  // Lowering can recognize INSERTQI shuffle masks.
+  if ((Length % 8) == 0 && (Index % 8) == 0) {
+    // Convert bit indices to byte indices.
+    Length /= 8;
+    Index /= 8;
+
+    Type *IntTy8 = Type::getInt8Ty(II.getContext());
+    auto *ShufTy = FixedVectorType::get(IntTy8, 16);
+
+    SmallVector<int, 16> ShuffleMask;
+    for (int i = 0; i != (int)Index; ++i)
+      ShuffleMask.push_back(i);
+    for (int i = 0; i != (int)Length; ++i)
+      ShuffleMask.push_back(i + 16);
+    for (int i = Index + Length; i != 8; ++i)
+      ShuffleMask.push_back(i);
+    for (int i = 8; i != 16; ++i)
+      ShuffleMask.push_back(-1);
+
+    Value *SV = Builder.CreateShuffleVector(Builder.CreateBitCast(Op0, ShufTy),
+                                            Builder.CreateBitCast(Op1, ShufTy),
+                                            ShuffleMask);
+    return Builder.CreateBitCast(SV, II.getType());
+  }
+
+  // See if we're dealing with constant values.
+  Constant *C0 = dyn_cast<Constant>(Op0);
+  Constant *C1 = dyn_cast<Constant>(Op1);
+  ConstantInt *CI00 =
+      C0 ? dyn_cast_or_null<ConstantInt>(C0->getAggregateElement((unsigned)0))
+         : nullptr;
+  ConstantInt *CI10 =
+      C1 ? dyn_cast_or_null<ConstantInt>(C1->getAggregateElement((unsigned)0))
+         : nullptr;
+
+  // Constant Fold - insert bottom Length bits starting at the Index'th bit.
+  if (CI00 && CI10) {
+    APInt V00 = CI00->getValue();
+    APInt V10 = CI10->getValue();
+    APInt Mask = APInt::getLowBitsSet(64, Length).shl(Index);
+    V00 = V00 & ~Mask;
+    V10 = V10.zextOrTrunc(Length).zextOrTrunc(64).shl(Index);
+    APInt Val = V00 | V10;
+    Type *IntTy64 = Type::getInt64Ty(II.getContext());
+    Constant *Args[] = {ConstantInt::get(IntTy64, Val.getZExtValue()),
+                        UndefValue::get(IntTy64)};
+    return ConstantVector::get(Args);
+  }
+
+  // If we were an INSERTQ call, we'll save demanded elements if we convert to
+  // INSERTQI.
+  if (II.getIntrinsicID() == Intrinsic::x86_sse4a_insertq) {
+    Type *IntTy8 = Type::getInt8Ty(II.getContext());
+    Constant *CILength = ConstantInt::get(IntTy8, Length, false);
+    Constant *CIIndex = ConstantInt::get(IntTy8, Index, false);
+
+    Value *Args[] = {Op0, Op1, CILength, CIIndex};
+    Module *M = II.getModule();
+    Function *F = Intrinsic::getDeclaration(M, Intrinsic::x86_sse4a_insertqi);
+    return Builder.CreateCall(F, Args);
+  }
+
+  return nullptr;
+}
+
+/// Attempt to convert pshufb* to shufflevector if the mask is constant.
+static Value *simplifyX86pshufb(const IntrinsicInst &II,
+                                InstCombiner::BuilderTy &Builder) {
+  Constant *V = dyn_cast<Constant>(II.getArgOperand(1));
+  if (!V)
+    return nullptr;
+
+  auto *VecTy = cast<FixedVectorType>(II.getType());
+  unsigned NumElts = VecTy->getNumElements();
+  assert((NumElts == 16 || NumElts == 32 || NumElts == 64) &&
+         "Unexpected number of elements in shuffle mask!");
+
+  // Construct a shuffle mask from constant integers or UNDEFs.
+  int Indexes[64];
+
+  // Each byte in the shuffle control mask forms an index to permute the
+  // corresponding byte in the destination operand.
+  for (unsigned I = 0; I < NumElts; ++I) {
+    Constant *COp = V->getAggregateElement(I);
+    if (!COp || (!isa<UndefValue>(COp) && !isa<ConstantInt>(COp)))
+      return nullptr;
+
+    if (isa<UndefValue>(COp)) {
+      Indexes[I] = -1;
+      continue;
+    }
+
+    int8_t Index = cast<ConstantInt>(COp)->getValue().getZExtValue();
+
+    // If the most significant bit (bit[7]) of each byte of the shuffle
+    // control mask is set, then zero is written in the result byte.
+    // The zero vector is in the right-hand side of the resulting
+    // shufflevector.
+
+    // The value of each index for the high 128-bit lane is the least
+    // significant 4 bits of the respective shuffle control byte.
+    Index = ((Index < 0) ? NumElts : Index & 0x0F) + (I & 0xF0);
+    Indexes[I] = Index;
+  }
+
+  auto V1 = II.getArgOperand(0);
+  auto V2 = Constant::getNullValue(VecTy);
+  return Builder.CreateShuffleVector(V1, V2, makeArrayRef(Indexes, NumElts));
+}
+
+/// Attempt to convert vpermilvar* to shufflevector if the mask is constant.
+static Value *simplifyX86vpermilvar(const IntrinsicInst &II,
+                                    InstCombiner::BuilderTy &Builder) {
+  Constant *V = dyn_cast<Constant>(II.getArgOperand(1));
+  if (!V)
+    return nullptr;
+
+  auto *VecTy = cast<FixedVectorType>(II.getType());
+  unsigned NumElts = VecTy->getNumElements();
+  bool IsPD = VecTy->getScalarType()->isDoubleTy();
+  unsigned NumLaneElts = IsPD ? 2 : 4;
+  assert(NumElts == 16 || NumElts == 8 || NumElts == 4 || NumElts == 2);
+
+  // Construct a shuffle mask from constant integers or UNDEFs.
+  int Indexes[16];
+
+  // The intrinsics only read one or two bits, clear the rest.
+  for (unsigned I = 0; I < NumElts; ++I) {
+    Constant *COp = V->getAggregateElement(I);
+    if (!COp || (!isa<UndefValue>(COp) && !isa<ConstantInt>(COp)))
+      return nullptr;
+
+    if (isa<UndefValue>(COp)) {
+      Indexes[I] = -1;
+      continue;
+    }
+
+    APInt Index = cast<ConstantInt>(COp)->getValue();
+    Index = Index.zextOrTrunc(32).getLoBits(2);
+
+    // The PD variants uses bit 1 to select per-lane element index, so
+    // shift down to convert to generic shuffle mask index.
+    if (IsPD)
+      Index.lshrInPlace(1);
+
+    // The _256 variants are a bit trickier since the mask bits always index
+    // into the corresponding 128 half. In order to convert to a generic
+    // shuffle, we have to make that explicit.
+    Index += APInt(32, (I / NumLaneElts) * NumLaneElts);
+
+    Indexes[I] = Index.getZExtValue();
+  }
+
+  auto V1 = II.getArgOperand(0);
+  return Builder.CreateShuffleVector(V1, makeArrayRef(Indexes, NumElts));
+}
+
+/// Attempt to convert vpermd/vpermps to shufflevector if the mask is constant.
+static Value *simplifyX86vpermv(const IntrinsicInst &II,
+                                InstCombiner::BuilderTy &Builder) {
+  auto *V = dyn_cast<Constant>(II.getArgOperand(1));
+  if (!V)
+    return nullptr;
+
+  auto *VecTy = cast<FixedVectorType>(II.getType());
+  unsigned Size = VecTy->getNumElements();
+  assert((Size == 4 || Size == 8 || Size == 16 || Size == 32 || Size == 64) &&
+         "Unexpected shuffle mask size");
+
+  // Construct a shuffle mask from constant integers or UNDEFs.
+  int Indexes[64];
+
+  for (unsigned I = 0; I < Size; ++I) {
+    Constant *COp = V->getAggregateElement(I);
+    if (!COp || (!isa<UndefValue>(COp) && !isa<ConstantInt>(COp)))
+      return nullptr;
+
+    if (isa<UndefValue>(COp)) {
+      Indexes[I] = -1;
+      continue;
+    }
+
+    uint32_t Index = cast<ConstantInt>(COp)->getZExtValue();
+    Index &= Size - 1;
+    Indexes[I] = Index;
+  }
+
+  auto V1 = II.getArgOperand(0);
+  return Builder.CreateShuffleVector(V1, makeArrayRef(Indexes, Size));
+}
+
+Optional<Instruction *>
+X86TTIImpl::instCombineIntrinsic(InstCombiner &IC, IntrinsicInst &II) const {
+  auto SimplifyDemandedVectorEltsLow = [&IC](Value *Op, unsigned Width,
+                                             unsigned DemandedWidth) {
+    APInt UndefElts(Width, 0);
+    APInt DemandedElts = APInt::getLowBitsSet(Width, DemandedWidth);
+    return IC.SimplifyDemandedVectorElts(Op, DemandedElts, UndefElts);
+  };
+
+  Intrinsic::ID IID = II.getIntrinsicID();
+  switch (IID) {
+  case Intrinsic::x86_bmi_bextr_32:
+  case Intrinsic::x86_bmi_bextr_64:
+  case Intrinsic::x86_tbm_bextri_u32:
+  case Intrinsic::x86_tbm_bextri_u64:
+    // If the RHS is a constant we can try some simplifications.
+    if (auto *C = dyn_cast<ConstantInt>(II.getArgOperand(1))) {
+      uint64_t Shift = C->getZExtValue();
+      uint64_t Length = (Shift >> 8) & 0xff;
+      Shift &= 0xff;
+      unsigned BitWidth = II.getType()->getIntegerBitWidth();
+      // If the length is 0 or the shift is out of range, replace with zero.
+      if (Length == 0 || Shift >= BitWidth) {
+        return IC.replaceInstUsesWith(II, ConstantInt::get(II.getType(), 0));
+      }
+      // If the LHS is also a constant, we can completely constant fold this.
+      if (auto *InC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
+        uint64_t Result = InC->getZExtValue() >> Shift;
+        if (Length > BitWidth)
+          Length = BitWidth;
+        Result &= maskTrailingOnes<uint64_t>(Length);
+        return IC.replaceInstUsesWith(II,
+                                      ConstantInt::get(II.getType(), Result));
+      }
+      // TODO should we turn this into 'and' if shift is 0? Or 'shl' if we
+      // are only masking bits that a shift already cleared?
+    }
+    break;
+
+  case Intrinsic::x86_bmi_bzhi_32:
+  case Intrinsic::x86_bmi_bzhi_64:
+    // If the RHS is a constant we can try some simplifications.
+    if (auto *C = dyn_cast<ConstantInt>(II.getArgOperand(1))) {
+      uint64_t Index = C->getZExtValue() & 0xff;
+      unsigned BitWidth = II.getType()->getIntegerBitWidth();
+      if (Index >= BitWidth) {
+        return IC.replaceInstUsesWith(II, II.getArgOperand(0));
+      }
+      if (Index == 0) {
+        return IC.replaceInstUsesWith(II, ConstantInt::get(II.getType(), 0));
+      }
+      // If the LHS is also a constant, we can completely constant fold this.
+      if (auto *InC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
+        uint64_t Result = InC->getZExtValue();
+        Result &= maskTrailingOnes<uint64_t>(Index);
+        return IC.replaceInstUsesWith(II,
+                                      ConstantInt::get(II.getType(), Result));
+      }
+      // TODO should we convert this to an AND if the RHS is constant?
+    }
+    break;
+  case Intrinsic::x86_bmi_pext_32:
+  case Intrinsic::x86_bmi_pext_64:
+    if (auto *MaskC = dyn_cast<ConstantInt>(II.getArgOperand(1))) {
+      if (MaskC->isNullValue()) {
+        return IC.replaceInstUsesWith(II, ConstantInt::get(II.getType(), 0));
+      }
+      if (MaskC->isAllOnesValue()) {
+        return IC.replaceInstUsesWith(II, II.getArgOperand(0));
+      }
+
+      if (MaskC->getValue().isShiftedMask()) {
+        // any single contingous sequence of 1s anywhere in the mask simply
+        // describes a subset of the input bits shifted to the appropriate
+        // position.  Replace with the straight forward IR.
+        unsigned ShiftAmount = MaskC->getValue().countTrailingZeros();
+        Value *Input = II.getArgOperand(0);
+        Value *Masked = IC.Builder.CreateAnd(Input, II.getArgOperand(1));
+        Value *Shifted = IC.Builder.CreateLShr(Masked,
+                                               ConstantInt::get(II.getType(),
+                                                                ShiftAmount));
+        return IC.replaceInstUsesWith(II, Shifted);
+      }
+
+
+      if (auto *SrcC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
+        uint64_t Src = SrcC->getZExtValue();
+        uint64_t Mask = MaskC->getZExtValue();
+        uint64_t Result = 0;
+        uint64_t BitToSet = 1;
+
+        while (Mask) {
+          // Isolate lowest set bit.
+          uint64_t BitToTest = Mask & -Mask;
+          if (BitToTest & Src)
+            Result |= BitToSet;
+
+          BitToSet <<= 1;
+          // Clear lowest set bit.
+          Mask &= Mask - 1;
+        }
+
+        return IC.replaceInstUsesWith(II,
+                                      ConstantInt::get(II.getType(), Result));
+      }
+    }
+    break;
+  case Intrinsic::x86_bmi_pdep_32:
+  case Intrinsic::x86_bmi_pdep_64:
+    if (auto *MaskC = dyn_cast<ConstantInt>(II.getArgOperand(1))) {
+      if (MaskC->isNullValue()) {
+        return IC.replaceInstUsesWith(II, ConstantInt::get(II.getType(), 0));
+      }
+      if (MaskC->isAllOnesValue()) {
+        return IC.replaceInstUsesWith(II, II.getArgOperand(0));
+      }
+      if (MaskC->getValue().isShiftedMask()) {
+        // any single contingous sequence of 1s anywhere in the mask simply
+        // describes a subset of the input bits shifted to the appropriate
+        // position.  Replace with the straight forward IR.
+        unsigned ShiftAmount = MaskC->getValue().countTrailingZeros();
+        Value *Input = II.getArgOperand(0);
+        Value *Shifted = IC.Builder.CreateShl(Input,
+                                              ConstantInt::get(II.getType(),
+                                                               ShiftAmount));
+        Value *Masked = IC.Builder.CreateAnd(Shifted, II.getArgOperand(1));
+        return IC.replaceInstUsesWith(II, Masked);
+      }
+
+      if (auto *SrcC = dyn_cast<ConstantInt>(II.getArgOperand(0))) {
+        uint64_t Src = SrcC->getZExtValue();
+        uint64_t Mask = MaskC->getZExtValue();
+        uint64_t Result = 0;
+        uint64_t BitToTest = 1;
+
+        while (Mask) {
+          // Isolate lowest set bit.
+          uint64_t BitToSet = Mask & -Mask;
+          if (BitToTest & Src)
+            Result |= BitToSet;
+
+          BitToTest <<= 1;
+          // Clear lowest set bit;
+          Mask &= Mask - 1;
+        }
+
+        return IC.replaceInstUsesWith(II,
+                                      ConstantInt::get(II.getType(), Result));
+      }
+    }
+    break;
+
+  case Intrinsic::x86_sse_cvtss2si:
+  case Intrinsic::x86_sse_cvtss2si64:
+  case Intrinsic::x86_sse_cvttss2si:
+  case Intrinsic::x86_sse_cvttss2si64:
+  case Intrinsic::x86_sse2_cvtsd2si:
+  case Intrinsic::x86_sse2_cvtsd2si64:
+  case Intrinsic::x86_sse2_cvttsd2si:
+  case Intrinsic::x86_sse2_cvttsd2si64:
+  case Intrinsic::x86_avx512_vcvtss2si32:
+  case Intrinsic::x86_avx512_vcvtss2si64:
+  case Intrinsic::x86_avx512_vcvtss2usi32:
+  case Intrinsic::x86_avx512_vcvtss2usi64:
+  case Intrinsic::x86_avx512_vcvtsd2si32:
+  case Intrinsic::x86_avx512_vcvtsd2si64:
+  case Intrinsic::x86_avx512_vcvtsd2usi32:
+  case Intrinsic::x86_avx512_vcvtsd2usi64:
+  case Intrinsic::x86_avx512_cvttss2si:
+  case Intrinsic::x86_avx512_cvttss2si64:
+  case Intrinsic::x86_avx512_cvttss2usi:
+  case Intrinsic::x86_avx512_cvttss2usi64:
+  case Intrinsic::x86_avx512_cvttsd2si:
+  case Intrinsic::x86_avx512_cvttsd2si64:
+  case Intrinsic::x86_avx512_cvttsd2usi:
+  case Intrinsic::x86_avx512_cvttsd2usi64: {
+    // These intrinsics only demand the 0th element of their input vectors. If
+    // we can simplify the input based on that, do so now.
+    Value *Arg = II.getArgOperand(0);
+    unsigned VWidth = cast<FixedVectorType>(Arg->getType())->getNumElements();
+    if (Value *V = SimplifyDemandedVectorEltsLow(Arg, VWidth, 1)) {
+      return IC.replaceOperand(II, 0, V);
+    }
+    break;
+  }
+
+  case Intrinsic::x86_mmx_pmovmskb:
+  case Intrinsic::x86_sse_movmsk_ps:
+  case Intrinsic::x86_sse2_movmsk_pd:
+  case Intrinsic::x86_sse2_pmovmskb_128:
+  case Intrinsic::x86_avx_movmsk_pd_256:
+  case Intrinsic::x86_avx_movmsk_ps_256:
+  case Intrinsic::x86_avx2_pmovmskb:
+    if (Value *V = simplifyX86movmsk(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_sse_comieq_ss:
+  case Intrinsic::x86_sse_comige_ss:
+  case Intrinsic::x86_sse_comigt_ss:
+  case Intrinsic::x86_sse_comile_ss:
+  case Intrinsic::x86_sse_comilt_ss:
+  case Intrinsic::x86_sse_comineq_ss:
+  case Intrinsic::x86_sse_ucomieq_ss:
+  case Intrinsic::x86_sse_ucomige_ss:
+  case Intrinsic::x86_sse_ucomigt_ss:
+  case Intrinsic::x86_sse_ucomile_ss:
+  case Intrinsic::x86_sse_ucomilt_ss:
+  case Intrinsic::x86_sse_ucomineq_ss:
+  case Intrinsic::x86_sse2_comieq_sd:
+  case Intrinsic::x86_sse2_comige_sd:
+  case Intrinsic::x86_sse2_comigt_sd:
+  case Intrinsic::x86_sse2_comile_sd:
+  case Intrinsic::x86_sse2_comilt_sd:
+  case Intrinsic::x86_sse2_comineq_sd:
+  case Intrinsic::x86_sse2_ucomieq_sd:
+  case Intrinsic::x86_sse2_ucomige_sd:
+  case Intrinsic::x86_sse2_ucomigt_sd:
+  case Intrinsic::x86_sse2_ucomile_sd:
+  case Intrinsic::x86_sse2_ucomilt_sd:
+  case Intrinsic::x86_sse2_ucomineq_sd:
+  case Intrinsic::x86_avx512_vcomi_ss:
+  case Intrinsic::x86_avx512_vcomi_sd:
+  case Intrinsic::x86_avx512_mask_cmp_ss:
+  case Intrinsic::x86_avx512_mask_cmp_sd: {
+    // These intrinsics only demand the 0th element of their input vectors. If
+    // we can simplify the input based on that, do so now.
+    bool MadeChange = false;
+    Value *Arg0 = II.getArgOperand(0);
+    Value *Arg1 = II.getArgOperand(1);
+    unsigned VWidth = cast<FixedVectorType>(Arg0->getType())->getNumElements();
+    if (Value *V = SimplifyDemandedVectorEltsLow(Arg0, VWidth, 1)) {
+      IC.replaceOperand(II, 0, V);
+      MadeChange = true;
+    }
+    if (Value *V = SimplifyDemandedVectorEltsLow(Arg1, VWidth, 1)) {
+      IC.replaceOperand(II, 1, V);
+      MadeChange = true;
+    }
+    if (MadeChange) {
+      return &II;
+    }
+    break;
+  }
+
+  case Intrinsic::x86_avx512_add_ps_512:
+  case Intrinsic::x86_avx512_div_ps_512:
+  case Intrinsic::x86_avx512_mul_ps_512:
+  case Intrinsic::x86_avx512_sub_ps_512:
+  case Intrinsic::x86_avx512_add_pd_512:
+  case Intrinsic::x86_avx512_div_pd_512:
+  case Intrinsic::x86_avx512_mul_pd_512:
+  case Intrinsic::x86_avx512_sub_pd_512:
+    // If the rounding mode is CUR_DIRECTION(4) we can turn these into regular
+    // IR operations.
+    if (auto *R = dyn_cast<ConstantInt>(II.getArgOperand(2))) {
+      if (R->getValue() == 4) {
+        Value *Arg0 = II.getArgOperand(0);
+        Value *Arg1 = II.getArgOperand(1);
+
+        Value *V;
+        switch (IID) {
+        default:
+          llvm_unreachable("Case stmts out of sync!");
+        case Intrinsic::x86_avx512_add_ps_512:
+        case Intrinsic::x86_avx512_add_pd_512:
+          V = IC.Builder.CreateFAdd(Arg0, Arg1);
+          break;
+        case Intrinsic::x86_avx512_sub_ps_512:
+        case Intrinsic::x86_avx512_sub_pd_512:
+          V = IC.Builder.CreateFSub(Arg0, Arg1);
+          break;
+        case Intrinsic::x86_avx512_mul_ps_512:
+        case Intrinsic::x86_avx512_mul_pd_512:
+          V = IC.Builder.CreateFMul(Arg0, Arg1);
+          break;
+        case Intrinsic::x86_avx512_div_ps_512:
+        case Intrinsic::x86_avx512_div_pd_512:
+          V = IC.Builder.CreateFDiv(Arg0, Arg1);
+          break;
+        }
+
+        return IC.replaceInstUsesWith(II, V);
+      }
+    }
+    break;
+
+  case Intrinsic::x86_avx512_mask_add_ss_round:
+  case Intrinsic::x86_avx512_mask_div_ss_round:
+  case Intrinsic::x86_avx512_mask_mul_ss_round:
+  case Intrinsic::x86_avx512_mask_sub_ss_round:
+  case Intrinsic::x86_avx512_mask_add_sd_round:
+  case Intrinsic::x86_avx512_mask_div_sd_round:
+  case Intrinsic::x86_avx512_mask_mul_sd_round:
+  case Intrinsic::x86_avx512_mask_sub_sd_round:
+    // If the rounding mode is CUR_DIRECTION(4) we can turn these into regular
+    // IR operations.
+    if (auto *R = dyn_cast<ConstantInt>(II.getArgOperand(4))) {
+      if (R->getValue() == 4) {
+        // Extract the element as scalars.
+        Value *Arg0 = II.getArgOperand(0);
+        Value *Arg1 = II.getArgOperand(1);
+        Value *LHS = IC.Builder.CreateExtractElement(Arg0, (uint64_t)0);
+        Value *RHS = IC.Builder.CreateExtractElement(Arg1, (uint64_t)0);
+
+        Value *V;
+        switch (IID) {
+        default:
+          llvm_unreachable("Case stmts out of sync!");
+        case Intrinsic::x86_avx512_mask_add_ss_round:
+        case Intrinsic::x86_avx512_mask_add_sd_round:
+          V = IC.Builder.CreateFAdd(LHS, RHS);
+          break;
+        case Intrinsic::x86_avx512_mask_sub_ss_round:
+        case Intrinsic::x86_avx512_mask_sub_sd_round:
+          V = IC.Builder.CreateFSub(LHS, RHS);
+          break;
+        case Intrinsic::x86_avx512_mask_mul_ss_round:
+        case Intrinsic::x86_avx512_mask_mul_sd_round:
+          V = IC.Builder.CreateFMul(LHS, RHS);
+          break;
+        case Intrinsic::x86_avx512_mask_div_ss_round:
+        case Intrinsic::x86_avx512_mask_div_sd_round:
+          V = IC.Builder.CreateFDiv(LHS, RHS);
+          break;
+        }
+
+        // Handle the masking aspect of the intrinsic.
+        Value *Mask = II.getArgOperand(3);
+        auto *C = dyn_cast<ConstantInt>(Mask);
+        // We don't need a select if we know the mask bit is a 1.
+        if (!C || !C->getValue()[0]) {
+          // Cast the mask to an i1 vector and then extract the lowest element.
+          auto *MaskTy = FixedVectorType::get(
+              IC.Builder.getInt1Ty(),
+              cast<IntegerType>(Mask->getType())->getBitWidth());
+          Mask = IC.Builder.CreateBitCast(Mask, MaskTy);
+          Mask = IC.Builder.CreateExtractElement(Mask, (uint64_t)0);
+          // Extract the lowest element from the passthru operand.
+          Value *Passthru =
+              IC.Builder.CreateExtractElement(II.getArgOperand(2), (uint64_t)0);
+          V = IC.Builder.CreateSelect(Mask, V, Passthru);
+        }
+
+        // Insert the result back into the original argument 0.
+        V = IC.Builder.CreateInsertElement(Arg0, V, (uint64_t)0);
+
+        return IC.replaceInstUsesWith(II, V);
+      }
+    }
+    break;
+
+  // Constant fold ashr( <A x Bi>, Ci ).
+  // Constant fold lshr( <A x Bi>, Ci ).
+  // Constant fold shl( <A x Bi>, Ci ).
+  case Intrinsic::x86_sse2_psrai_d:
+  case Intrinsic::x86_sse2_psrai_w:
+  case Intrinsic::x86_avx2_psrai_d:
+  case Intrinsic::x86_avx2_psrai_w:
+  case Intrinsic::x86_avx512_psrai_q_128:
+  case Intrinsic::x86_avx512_psrai_q_256:
+  case Intrinsic::x86_avx512_psrai_d_512:
+  case Intrinsic::x86_avx512_psrai_q_512:
+  case Intrinsic::x86_avx512_psrai_w_512:
+  case Intrinsic::x86_sse2_psrli_d:
+  case Intrinsic::x86_sse2_psrli_q:
+  case Intrinsic::x86_sse2_psrli_w:
+  case Intrinsic::x86_avx2_psrli_d:
+  case Intrinsic::x86_avx2_psrli_q:
+  case Intrinsic::x86_avx2_psrli_w:
+  case Intrinsic::x86_avx512_psrli_d_512:
+  case Intrinsic::x86_avx512_psrli_q_512:
+  case Intrinsic::x86_avx512_psrli_w_512:
+  case Intrinsic::x86_sse2_pslli_d:
+  case Intrinsic::x86_sse2_pslli_q:
+  case Intrinsic::x86_sse2_pslli_w:
+  case Intrinsic::x86_avx2_pslli_d:
+  case Intrinsic::x86_avx2_pslli_q:
+  case Intrinsic::x86_avx2_pslli_w:
+  case Intrinsic::x86_avx512_pslli_d_512:
+  case Intrinsic::x86_avx512_pslli_q_512:
+  case Intrinsic::x86_avx512_pslli_w_512:
+    if (Value *V = simplifyX86immShift(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_sse2_psra_d:
+  case Intrinsic::x86_sse2_psra_w:
+  case Intrinsic::x86_avx2_psra_d:
+  case Intrinsic::x86_avx2_psra_w:
+  case Intrinsic::x86_avx512_psra_q_128:
+  case Intrinsic::x86_avx512_psra_q_256:
+  case Intrinsic::x86_avx512_psra_d_512:
+  case Intrinsic::x86_avx512_psra_q_512:
+  case Intrinsic::x86_avx512_psra_w_512:
+  case Intrinsic::x86_sse2_psrl_d:
+  case Intrinsic::x86_sse2_psrl_q:
+  case Intrinsic::x86_sse2_psrl_w:
+  case Intrinsic::x86_avx2_psrl_d:
+  case Intrinsic::x86_avx2_psrl_q:
+  case Intrinsic::x86_avx2_psrl_w:
+  case Intrinsic::x86_avx512_psrl_d_512:
+  case Intrinsic::x86_avx512_psrl_q_512:
+  case Intrinsic::x86_avx512_psrl_w_512:
+  case Intrinsic::x86_sse2_psll_d:
+  case Intrinsic::x86_sse2_psll_q:
+  case Intrinsic::x86_sse2_psll_w:
+  case Intrinsic::x86_avx2_psll_d:
+  case Intrinsic::x86_avx2_psll_q:
+  case Intrinsic::x86_avx2_psll_w:
+  case Intrinsic::x86_avx512_psll_d_512:
+  case Intrinsic::x86_avx512_psll_q_512:
+  case Intrinsic::x86_avx512_psll_w_512: {
+    if (Value *V = simplifyX86immShift(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+
+    // SSE2/AVX2 uses only the first 64-bits of the 128-bit vector
+    // operand to compute the shift amount.
+    Value *Arg1 = II.getArgOperand(1);
+    assert(Arg1->getType()->getPrimitiveSizeInBits() == 128 &&
+           "Unexpected packed shift size");
+    unsigned VWidth = cast<FixedVectorType>(Arg1->getType())->getNumElements();
+
+    if (Value *V = SimplifyDemandedVectorEltsLow(Arg1, VWidth, VWidth / 2)) {
+      return IC.replaceOperand(II, 1, V);
+    }
+    break;
+  }
+
+  case Intrinsic::x86_avx2_psllv_d:
+  case Intrinsic::x86_avx2_psllv_d_256:
+  case Intrinsic::x86_avx2_psllv_q:
+  case Intrinsic::x86_avx2_psllv_q_256:
+  case Intrinsic::x86_avx512_psllv_d_512:
+  case Intrinsic::x86_avx512_psllv_q_512:
+  case Intrinsic::x86_avx512_psllv_w_128:
+  case Intrinsic::x86_avx512_psllv_w_256:
+  case Intrinsic::x86_avx512_psllv_w_512:
+  case Intrinsic::x86_avx2_psrav_d:
+  case Intrinsic::x86_avx2_psrav_d_256:
+  case Intrinsic::x86_avx512_psrav_q_128:
+  case Intrinsic::x86_avx512_psrav_q_256:
+  case Intrinsic::x86_avx512_psrav_d_512:
+  case Intrinsic::x86_avx512_psrav_q_512:
+  case Intrinsic::x86_avx512_psrav_w_128:
+  case Intrinsic::x86_avx512_psrav_w_256:
+  case Intrinsic::x86_avx512_psrav_w_512:
+  case Intrinsic::x86_avx2_psrlv_d:
+  case Intrinsic::x86_avx2_psrlv_d_256:
+  case Intrinsic::x86_avx2_psrlv_q:
+  case Intrinsic::x86_avx2_psrlv_q_256:
+  case Intrinsic::x86_avx512_psrlv_d_512:
+  case Intrinsic::x86_avx512_psrlv_q_512:
+  case Intrinsic::x86_avx512_psrlv_w_128:
+  case Intrinsic::x86_avx512_psrlv_w_256:
+  case Intrinsic::x86_avx512_psrlv_w_512:
+    if (Value *V = simplifyX86varShift(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_sse2_packssdw_128:
+  case Intrinsic::x86_sse2_packsswb_128:
+  case Intrinsic::x86_avx2_packssdw:
+  case Intrinsic::x86_avx2_packsswb:
+  case Intrinsic::x86_avx512_packssdw_512:
+  case Intrinsic::x86_avx512_packsswb_512:
+    if (Value *V = simplifyX86pack(II, IC.Builder, true)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_sse2_packuswb_128:
+  case Intrinsic::x86_sse41_packusdw:
+  case Intrinsic::x86_avx2_packusdw:
+  case Intrinsic::x86_avx2_packuswb:
+  case Intrinsic::x86_avx512_packusdw_512:
+  case Intrinsic::x86_avx512_packuswb_512:
+    if (Value *V = simplifyX86pack(II, IC.Builder, false)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_pclmulqdq:
+  case Intrinsic::x86_pclmulqdq_256:
+  case Intrinsic::x86_pclmulqdq_512: {
+    if (auto *C = dyn_cast<ConstantInt>(II.getArgOperand(2))) {
+      unsigned Imm = C->getZExtValue();
+
+      bool MadeChange = false;
+      Value *Arg0 = II.getArgOperand(0);
+      Value *Arg1 = II.getArgOperand(1);
+      unsigned VWidth =
+          cast<FixedVectorType>(Arg0->getType())->getNumElements();
+
+      APInt UndefElts1(VWidth, 0);
+      APInt DemandedElts1 =
+          APInt::getSplat(VWidth, APInt(2, (Imm & 0x01) ? 2 : 1));
+      if (Value *V =
+              IC.SimplifyDemandedVectorElts(Arg0, DemandedElts1, UndefElts1)) {
+        IC.replaceOperand(II, 0, V);
+        MadeChange = true;
+      }
+
+      APInt UndefElts2(VWidth, 0);
+      APInt DemandedElts2 =
+          APInt::getSplat(VWidth, APInt(2, (Imm & 0x10) ? 2 : 1));
+      if (Value *V =
+              IC.SimplifyDemandedVectorElts(Arg1, DemandedElts2, UndefElts2)) {
+        IC.replaceOperand(II, 1, V);
+        MadeChange = true;
+      }
+
+      // If either input elements are undef, the result is zero.
+      if (DemandedElts1.isSubsetOf(UndefElts1) ||
+          DemandedElts2.isSubsetOf(UndefElts2)) {
+        return IC.replaceInstUsesWith(II,
+                                      ConstantAggregateZero::get(II.getType()));
+      }
+
+      if (MadeChange) {
+        return &II;
+      }
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse41_insertps:
+    if (Value *V = simplifyX86insertps(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_sse4a_extrq: {
+    Value *Op0 = II.getArgOperand(0);
+    Value *Op1 = II.getArgOperand(1);
+    unsigned VWidth0 = cast<FixedVectorType>(Op0->getType())->getNumElements();
+    unsigned VWidth1 = cast<FixedVectorType>(Op1->getType())->getNumElements();
+    assert(Op0->getType()->getPrimitiveSizeInBits() == 128 &&
+           Op1->getType()->getPrimitiveSizeInBits() == 128 && VWidth0 == 2 &&
+           VWidth1 == 16 && "Unexpected operand sizes");
+
+    // See if we're dealing with constant values.
+    Constant *C1 = dyn_cast<Constant>(Op1);
+    ConstantInt *CILength =
+        C1 ? dyn_cast_or_null<ConstantInt>(C1->getAggregateElement((unsigned)0))
+           : nullptr;
+    ConstantInt *CIIndex =
+        C1 ? dyn_cast_or_null<ConstantInt>(C1->getAggregateElement((unsigned)1))
+           : nullptr;
+
+    // Attempt to simplify to a constant, shuffle vector or EXTRQI call.
+    if (Value *V = simplifyX86extrq(II, Op0, CILength, CIIndex, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+
+    // EXTRQ only uses the lowest 64-bits of the first 128-bit vector
+    // operands and the lowest 16-bits of the second.
+    bool MadeChange = false;
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth0, 1)) {
+      IC.replaceOperand(II, 0, V);
+      MadeChange = true;
+    }
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op1, VWidth1, 2)) {
+      IC.replaceOperand(II, 1, V);
+      MadeChange = true;
+    }
+    if (MadeChange) {
+      return &II;
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse4a_extrqi: {
+    // EXTRQI: Extract Length bits starting from Index. Zero pad the remaining
+    // bits of the lower 64-bits. The upper 64-bits are undefined.
+    Value *Op0 = II.getArgOperand(0);
+    unsigned VWidth = cast<FixedVectorType>(Op0->getType())->getNumElements();
+    assert(Op0->getType()->getPrimitiveSizeInBits() == 128 && VWidth == 2 &&
+           "Unexpected operand size");
+
+    // See if we're dealing with constant values.
+    ConstantInt *CILength = dyn_cast<ConstantInt>(II.getArgOperand(1));
+    ConstantInt *CIIndex = dyn_cast<ConstantInt>(II.getArgOperand(2));
+
+    // Attempt to simplify to a constant or shuffle vector.
+    if (Value *V = simplifyX86extrq(II, Op0, CILength, CIIndex, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+
+    // EXTRQI only uses the lowest 64-bits of the first 128-bit vector
+    // operand.
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth, 1)) {
+      return IC.replaceOperand(II, 0, V);
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse4a_insertq: {
+    Value *Op0 = II.getArgOperand(0);
+    Value *Op1 = II.getArgOperand(1);
+    unsigned VWidth = cast<FixedVectorType>(Op0->getType())->getNumElements();
+    assert(Op0->getType()->getPrimitiveSizeInBits() == 128 &&
+           Op1->getType()->getPrimitiveSizeInBits() == 128 && VWidth == 2 &&
+           cast<FixedVectorType>(Op1->getType())->getNumElements() == 2 &&
+           "Unexpected operand size");
+
+    // See if we're dealing with constant values.
+    Constant *C1 = dyn_cast<Constant>(Op1);
+    ConstantInt *CI11 =
+        C1 ? dyn_cast_or_null<ConstantInt>(C1->getAggregateElement((unsigned)1))
+           : nullptr;
+
+    // Attempt to simplify to a constant, shuffle vector or INSERTQI call.
+    if (CI11) {
+      const APInt &V11 = CI11->getValue();
+      APInt Len = V11.zextOrTrunc(6);
+      APInt Idx = V11.lshr(8).zextOrTrunc(6);
+      if (Value *V = simplifyX86insertq(II, Op0, Op1, Len, Idx, IC.Builder)) {
+        return IC.replaceInstUsesWith(II, V);
+      }
+    }
+
+    // INSERTQ only uses the lowest 64-bits of the first 128-bit vector
+    // operand.
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth, 1)) {
+      return IC.replaceOperand(II, 0, V);
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse4a_insertqi: {
+    // INSERTQI: Extract lowest Length bits from lower half of second source and
+    // insert over first source starting at Index bit. The upper 64-bits are
+    // undefined.
+    Value *Op0 = II.getArgOperand(0);
+    Value *Op1 = II.getArgOperand(1);
+    unsigned VWidth0 = cast<FixedVectorType>(Op0->getType())->getNumElements();
+    unsigned VWidth1 = cast<FixedVectorType>(Op1->getType())->getNumElements();
+    assert(Op0->getType()->getPrimitiveSizeInBits() == 128 &&
+           Op1->getType()->getPrimitiveSizeInBits() == 128 && VWidth0 == 2 &&
+           VWidth1 == 2 && "Unexpected operand sizes");
+
+    // See if we're dealing with constant values.
+    ConstantInt *CILength = dyn_cast<ConstantInt>(II.getArgOperand(2));
+    ConstantInt *CIIndex = dyn_cast<ConstantInt>(II.getArgOperand(3));
+
+    // Attempt to simplify to a constant or shuffle vector.
+    if (CILength && CIIndex) {
+      APInt Len = CILength->getValue().zextOrTrunc(6);
+      APInt Idx = CIIndex->getValue().zextOrTrunc(6);
+      if (Value *V = simplifyX86insertq(II, Op0, Op1, Len, Idx, IC.Builder)) {
+        return IC.replaceInstUsesWith(II, V);
+      }
+    }
+
+    // INSERTQI only uses the lowest 64-bits of the first two 128-bit vector
+    // operands.
+    bool MadeChange = false;
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op0, VWidth0, 1)) {
+      IC.replaceOperand(II, 0, V);
+      MadeChange = true;
+    }
+    if (Value *V = SimplifyDemandedVectorEltsLow(Op1, VWidth1, 1)) {
+      IC.replaceOperand(II, 1, V);
+      MadeChange = true;
+    }
+    if (MadeChange) {
+      return &II;
+    }
+    break;
+  }
+
+  case Intrinsic::x86_sse41_pblendvb:
+  case Intrinsic::x86_sse41_blendvps:
+  case Intrinsic::x86_sse41_blendvpd:
+  case Intrinsic::x86_avx_blendv_ps_256:
+  case Intrinsic::x86_avx_blendv_pd_256:
+  case Intrinsic::x86_avx2_pblendvb: {
+    // fold (blend A, A, Mask) -> A
+    Value *Op0 = II.getArgOperand(0);
+    Value *Op1 = II.getArgOperand(1);
+    Value *Mask = II.getArgOperand(2);
+    if (Op0 == Op1) {
+      return IC.replaceInstUsesWith(II, Op0);
+    }
+
+    // Zero Mask - select 1st argument.
+    if (isa<ConstantAggregateZero>(Mask)) {
+      return IC.replaceInstUsesWith(II, Op0);
+    }
+
+    // Constant Mask - select 1st/2nd argument lane based on top bit of mask.
+    if (auto *ConstantMask = dyn_cast<ConstantDataVector>(Mask)) {
+      Constant *NewSelector = getNegativeIsTrueBoolVec(ConstantMask);
+      return SelectInst::Create(NewSelector, Op1, Op0, "blendv");
+    }
+
+    // Convert to a vector select if we can bypass casts and find a boolean
+    // vector condition value.
+    Value *BoolVec;
+    Mask = InstCombiner::peekThroughBitcast(Mask);
+    if (match(Mask, PatternMatch::m_SExt(PatternMatch::m_Value(BoolVec))) &&
+        BoolVec->getType()->isVectorTy() &&
+        BoolVec->getType()->getScalarSizeInBits() == 1) {
+      assert(Mask->getType()->getPrimitiveSizeInBits() ==
+                 II.getType()->getPrimitiveSizeInBits() &&
+             "Not expecting mask and operands with different sizes");
+
+      unsigned NumMaskElts =
+          cast<FixedVectorType>(Mask->getType())->getNumElements();
+      unsigned NumOperandElts =
+          cast<FixedVectorType>(II.getType())->getNumElements();
+      if (NumMaskElts == NumOperandElts) {
+        return SelectInst::Create(BoolVec, Op1, Op0);
+      }
+
+      // If the mask has less elements than the operands, each mask bit maps to
+      // multiple elements of the operands. Bitcast back and forth.
+      if (NumMaskElts < NumOperandElts) {
+        Value *CastOp0 = IC.Builder.CreateBitCast(Op0, Mask->getType());
+        Value *CastOp1 = IC.Builder.CreateBitCast(Op1, Mask->getType());
+        Value *Sel = IC.Builder.CreateSelect(BoolVec, CastOp1, CastOp0);
+        return new BitCastInst(Sel, II.getType());
+      }
+    }
+
+    break;
+  }
+
+  case Intrinsic::x86_ssse3_pshuf_b_128:
+  case Intrinsic::x86_avx2_pshuf_b:
+  case Intrinsic::x86_avx512_pshuf_b_512:
+    if (Value *V = simplifyX86pshufb(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_avx_vpermilvar_ps:
+  case Intrinsic::x86_avx_vpermilvar_ps_256:
+  case Intrinsic::x86_avx512_vpermilvar_ps_512:
+  case Intrinsic::x86_avx_vpermilvar_pd:
+  case Intrinsic::x86_avx_vpermilvar_pd_256:
+  case Intrinsic::x86_avx512_vpermilvar_pd_512:
+    if (Value *V = simplifyX86vpermilvar(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_avx2_permd:
+  case Intrinsic::x86_avx2_permps:
+  case Intrinsic::x86_avx512_permvar_df_256:
+  case Intrinsic::x86_avx512_permvar_df_512:
+  case Intrinsic::x86_avx512_permvar_di_256:
+  case Intrinsic::x86_avx512_permvar_di_512:
+  case Intrinsic::x86_avx512_permvar_hi_128:
+  case Intrinsic::x86_avx512_permvar_hi_256:
+  case Intrinsic::x86_avx512_permvar_hi_512:
+  case Intrinsic::x86_avx512_permvar_qi_128:
+  case Intrinsic::x86_avx512_permvar_qi_256:
+  case Intrinsic::x86_avx512_permvar_qi_512:
+  case Intrinsic::x86_avx512_permvar_sf_512:
+  case Intrinsic::x86_avx512_permvar_si_512:
+    if (Value *V = simplifyX86vpermv(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  case Intrinsic::x86_avx_maskload_ps:
+  case Intrinsic::x86_avx_maskload_pd:
+  case Intrinsic::x86_avx_maskload_ps_256:
+  case Intrinsic::x86_avx_maskload_pd_256:
+  case Intrinsic::x86_avx2_maskload_d:
+  case Intrinsic::x86_avx2_maskload_q:
+  case Intrinsic::x86_avx2_maskload_d_256:
+  case Intrinsic::x86_avx2_maskload_q_256:
+    if (Instruction *I = simplifyX86MaskedLoad(II, IC)) {
+      return I;
+    }
+    break;
+
+  case Intrinsic::x86_sse2_maskmov_dqu:
+  case Intrinsic::x86_avx_maskstore_ps:
+  case Intrinsic::x86_avx_maskstore_pd:
+  case Intrinsic::x86_avx_maskstore_ps_256:
+  case Intrinsic::x86_avx_maskstore_pd_256:
+  case Intrinsic::x86_avx2_maskstore_d:
+  case Intrinsic::x86_avx2_maskstore_q:
+  case Intrinsic::x86_avx2_maskstore_d_256:
+  case Intrinsic::x86_avx2_maskstore_q_256:
+    if (simplifyX86MaskedStore(II, IC)) {
+      return nullptr;
+    }
+    break;
+
+  case Intrinsic::x86_addcarry_32:
+  case Intrinsic::x86_addcarry_64:
+    if (Value *V = simplifyX86addcarry(II, IC.Builder)) {
+      return IC.replaceInstUsesWith(II, V);
+    }
+    break;
+
+  default:
+    break;
+  }
+  return None;
+}
+
+Optional<Value *> X86TTIImpl::simplifyDemandedUseBitsIntrinsic(
+    InstCombiner &IC, IntrinsicInst &II, APInt DemandedMask, KnownBits &Known,
+    bool &KnownBitsComputed) const {
+  switch (II.getIntrinsicID()) {
+  default:
+    break;
+  case Intrinsic::x86_mmx_pmovmskb:
+  case Intrinsic::x86_sse_movmsk_ps:
+  case Intrinsic::x86_sse2_movmsk_pd:
+  case Intrinsic::x86_sse2_pmovmskb_128:
+  case Intrinsic::x86_avx_movmsk_ps_256:
+  case Intrinsic::x86_avx_movmsk_pd_256:
+  case Intrinsic::x86_avx2_pmovmskb: {
+    // MOVMSK copies the vector elements' sign bits to the low bits
+    // and zeros the high bits.
+    unsigned ArgWidth;
+    if (II.getIntrinsicID() == Intrinsic::x86_mmx_pmovmskb) {
+      ArgWidth = 8; // Arg is x86_mmx, but treated as <8 x i8>.
+    } else {
+      auto Arg = II.getArgOperand(0);
+      auto ArgType = cast<FixedVectorType>(Arg->getType());
+      ArgWidth = ArgType->getNumElements();
+    }
+
+    // If we don't need any of low bits then return zero,
+    // we know that DemandedMask is non-zero already.
+    APInt DemandedElts = DemandedMask.zextOrTrunc(ArgWidth);
+    Type *VTy = II.getType();
+    if (DemandedElts.isNullValue()) {
+      return ConstantInt::getNullValue(VTy);
+    }
+
+    // We know that the upper bits are set to zero.
+    Known.Zero.setBitsFrom(ArgWidth);
+    KnownBitsComputed = true;
+    break;
+  }
+  }
+  return None;
+}
+
+Optional<Value *> X86TTIImpl::simplifyDemandedVectorEltsIntrinsic(
+    InstCombiner &IC, IntrinsicInst &II, APInt DemandedElts, APInt &UndefElts,
+    APInt &UndefElts2, APInt &UndefElts3,
+    std::function<void(Instruction *, unsigned, APInt, APInt &)>
+        simplifyAndSetOp) const {
+  unsigned VWidth = cast<FixedVectorType>(II.getType())->getNumElements();
+  switch (II.getIntrinsicID()) {
+  default:
+    break;
+  case Intrinsic::x86_xop_vfrcz_ss:
+  case Intrinsic::x86_xop_vfrcz_sd:
+    // The instructions for these intrinsics are speced to zero upper bits not
+    // pass them through like other scalar intrinsics. So we shouldn't just
+    // use Arg0 if DemandedElts[0] is clear like we do for other intrinsics.
+    // Instead we should return a zero vector.
+    if (!DemandedElts[0]) {
+      IC.addToWorklist(&II);
+      return ConstantAggregateZero::get(II.getType());
+    }
+
+    // Only the lower element is used.
+    DemandedElts = 1;
+    simplifyAndSetOp(&II, 0, DemandedElts, UndefElts);
+
+    // Only the lower element is undefined. The high elements are zero.
+    UndefElts = UndefElts[0];
+    break;
+
+  // Unary scalar-as-vector operations that work column-wise.
+  case Intrinsic::x86_sse_rcp_ss:
+  case Intrinsic::x86_sse_rsqrt_ss:
+    simplifyAndSetOp(&II, 0, DemandedElts, UndefElts);
+
+    // If lowest element of a scalar op isn't used then use Arg0.
+    if (!DemandedElts[0]) {
+      IC.addToWorklist(&II);
+      return II.getArgOperand(0);
+    }
+    // TODO: If only low elt lower SQRT to FSQRT (with rounding/exceptions
+    // checks).
+    break;
+
+  // Binary scalar-as-vector operations that work column-wise. The high
+  // elements come from operand 0. The low element is a function of both
+  // operands.
+  case Intrinsic::x86_sse_min_ss:
+  case Intrinsic::x86_sse_max_ss:
+  case Intrinsic::x86_sse_cmp_ss:
+  case Intrinsic::x86_sse2_min_sd:
+  case Intrinsic::x86_sse2_max_sd:
+  case Intrinsic::x86_sse2_cmp_sd: {
+    simplifyAndSetOp(&II, 0, DemandedElts, UndefElts);
+
+    // If lowest element of a scalar op isn't used then use Arg0.
+    if (!DemandedElts[0]) {
+      IC.addToWorklist(&II);
+      return II.getArgOperand(0);
+    }
+
+    // Only lower element is used for operand 1.
+    DemandedElts = 1;
+    simplifyAndSetOp(&II, 1, DemandedElts, UndefElts2);
+
+    // Lower element is undefined if both lower elements are undefined.
+    // Consider things like undef&0.  The result is known zero, not undef.
+    if (!UndefElts2[0])
+      UndefElts.clearBit(0);
+
+    break;
+  }
+
+  // Binary scalar-as-vector operations that work column-wise. The high
+  // elements come from operand 0 and the low element comes from operand 1.
+  case Intrinsic::x86_sse41_round_ss:
+  case Intrinsic::x86_sse41_round_sd: {
+    // Don't use the low element of operand 0.
+    APInt DemandedElts2 = DemandedElts;
+    DemandedElts2.clearBit(0);
+    simplifyAndSetOp(&II, 0, DemandedElts2, UndefElts);
+
+    // If lowest element of a scalar op isn't used then use Arg0.
+    if (!DemandedElts[0]) {
+      IC.addToWorklist(&II);
+      return II.getArgOperand(0);
+    }
+
+    // Only lower element is used for operand 1.
+    DemandedElts = 1;
+    simplifyAndSetOp(&II, 1, DemandedElts, UndefElts2);
+
+    // Take the high undef elements from operand 0 and take the lower element
+    // from operand 1.
+    UndefElts.clearBit(0);
+    UndefElts |= UndefElts2[0];
+    break;
+  }
+
+  // Three input scalar-as-vector operations that work column-wise. The high
+  // elements come from operand 0 and the low element is a function of all
+  // three inputs.
+  case Intrinsic::x86_avx512_mask_add_ss_round:
+  case Intrinsic::x86_avx512_mask_div_ss_round:
+  case Intrinsic::x86_avx512_mask_mul_ss_round:
+  case Intrinsic::x86_avx512_mask_sub_ss_round:
+  case Intrinsic::x86_avx512_mask_max_ss_round:
+  case Intrinsic::x86_avx512_mask_min_ss_round:
+  case Intrinsic::x86_avx512_mask_add_sd_round:
+  case Intrinsic::x86_avx512_mask_div_sd_round:
+  case Intrinsic::x86_avx512_mask_mul_sd_round:
+  case Intrinsic::x86_avx512_mask_sub_sd_round:
+  case Intrinsic::x86_avx512_mask_max_sd_round:
+  case Intrinsic::x86_avx512_mask_min_sd_round:
+    simplifyAndSetOp(&II, 0, DemandedElts, UndefElts);
+
+    // If lowest element of a scalar op isn't used then use Arg0.
+    if (!DemandedElts[0]) {
+      IC.addToWorklist(&II);
+      return II.getArgOperand(0);
+    }
+
+    // Only lower element is used for operand 1 and 2.
+    DemandedElts = 1;
+    simplifyAndSetOp(&II, 1, DemandedElts, UndefElts2);
+    simplifyAndSetOp(&II, 2, DemandedElts, UndefElts3);
+
+    // Lower element is undefined if all three lower elements are undefined.
+    // Consider things like undef&0.  The result is known zero, not undef.
+    if (!UndefElts2[0] || !UndefElts3[0])
+      UndefElts.clearBit(0);
+    break;
+
+  // TODO: Add fmaddsub support?
+  case Intrinsic::x86_sse3_addsub_pd:
+  case Intrinsic::x86_sse3_addsub_ps:
+  case Intrinsic::x86_avx_addsub_pd_256:
+  case Intrinsic::x86_avx_addsub_ps_256: {
+    // If none of the even or none of the odd lanes are required, turn this
+    // into a generic FP math instruction.
+    APInt SubMask = APInt::getSplat(VWidth, APInt(2, 0x1));
+    APInt AddMask = APInt::getSplat(VWidth, APInt(2, 0x2));
+    bool IsSubOnly = DemandedElts.isSubsetOf(SubMask);
+    bool IsAddOnly = DemandedElts.isSubsetOf(AddMask);
+    if (IsSubOnly || IsAddOnly) {
+      assert((IsSubOnly ^ IsAddOnly) && "Can't be both add-only and sub-only");
+      IRBuilderBase::InsertPointGuard Guard(IC.Builder);
+      IC.Builder.SetInsertPoint(&II);
+      Value *Arg0 = II.getArgOperand(0), *Arg1 = II.getArgOperand(1);
+      return IC.Builder.CreateBinOp(
+          IsSubOnly ? Instruction::FSub : Instruction::FAdd, Arg0, Arg1);
+    }
+
+    simplifyAndSetOp(&II, 0, DemandedElts, UndefElts);
+    simplifyAndSetOp(&II, 1, DemandedElts, UndefElts2);
+    UndefElts &= UndefElts2;
+    break;
+  }
+
+  case Intrinsic::x86_sse2_packssdw_128:
+  case Intrinsic::x86_sse2_packsswb_128:
+  case Intrinsic::x86_sse2_packuswb_128:
+  case Intrinsic::x86_sse41_packusdw:
+  case Intrinsic::x86_avx2_packssdw:
+  case Intrinsic::x86_avx2_packsswb:
+  case Intrinsic::x86_avx2_packusdw:
+  case Intrinsic::x86_avx2_packuswb:
+  case Intrinsic::x86_avx512_packssdw_512:
+  case Intrinsic::x86_avx512_packsswb_512:
+  case Intrinsic::x86_avx512_packusdw_512:
+  case Intrinsic::x86_avx512_packuswb_512: {
+    auto *Ty0 = II.getArgOperand(0)->getType();
+    unsigned InnerVWidth = cast<FixedVectorType>(Ty0)->getNumElements();
+    assert(VWidth == (InnerVWidth * 2) && "Unexpected input size");
+
+    unsigned NumLanes = Ty0->getPrimitiveSizeInBits() / 128;
+    unsigned VWidthPerLane = VWidth / NumLanes;
+    unsigned InnerVWidthPerLane = InnerVWidth / NumLanes;
+
+    // Per lane, pack the elements of the first input and then the second.
+    // e.g.
+    // v8i16 PACK(v4i32 X, v4i32 Y) - (X[0..3],Y[0..3])
+    // v32i8 PACK(v16i16 X, v16i16 Y) - (X[0..7],Y[0..7]),(X[8..15],Y[8..15])
+    for (int OpNum = 0; OpNum != 2; ++OpNum) {
+      APInt OpDemandedElts(InnerVWidth, 0);
+      for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
+        unsigned LaneIdx = Lane * VWidthPerLane;
+        for (unsigned Elt = 0; Elt != InnerVWidthPerLane; ++Elt) {
+          unsigned Idx = LaneIdx + Elt + InnerVWidthPerLane * OpNum;
+          if (DemandedElts[Idx])
+            OpDemandedElts.setBit((Lane * InnerVWidthPerLane) + Elt);
+        }
+      }
+
+      // Demand elements from the operand.
+      APInt OpUndefElts(InnerVWidth, 0);
+      simplifyAndSetOp(&II, OpNum, OpDemandedElts, OpUndefElts);
+
+      // Pack the operand's UNDEF elements, one lane at a time.
+      OpUndefElts = OpUndefElts.zext(VWidth);
+      for (unsigned Lane = 0; Lane != NumLanes; ++Lane) {
+        APInt LaneElts = OpUndefElts.lshr(InnerVWidthPerLane * Lane);
+        LaneElts = LaneElts.getLoBits(InnerVWidthPerLane);
+        LaneElts <<= InnerVWidthPerLane * (2 * Lane + OpNum);
+        UndefElts |= LaneElts;
+      }
+    }
+    break;
+  }
+
+  // PSHUFB
+  case Intrinsic::x86_ssse3_pshuf_b_128:
+  case Intrinsic::x86_avx2_pshuf_b:
+  case Intrinsic::x86_avx512_pshuf_b_512:
+  // PERMILVAR
+  case Intrinsic::x86_avx_vpermilvar_ps:
+  case Intrinsic::x86_avx_vpermilvar_ps_256:
+  case Intrinsic::x86_avx512_vpermilvar_ps_512:
+  case Intrinsic::x86_avx_vpermilvar_pd:
+  case Intrinsic::x86_avx_vpermilvar_pd_256:
+  case Intrinsic::x86_avx512_vpermilvar_pd_512:
+  // PERMV
+  case Intrinsic::x86_avx2_permd:
+  case Intrinsic::x86_avx2_permps: {
+    simplifyAndSetOp(&II, 1, DemandedElts, UndefElts);
+    break;
+  }
+
+  // SSE4A instructions leave the upper 64-bits of the 128-bit result
+  // in an undefined state.
+  case Intrinsic::x86_sse4a_extrq:
+  case Intrinsic::x86_sse4a_extrqi:
+  case Intrinsic::x86_sse4a_insertq:
+  case Intrinsic::x86_sse4a_insertqi:
+    UndefElts.setHighBits(VWidth / 2);
+    break;
+  }
+  return None;
+}