lib/Target/X86/Utils/X86ShuffleDecode.cpp - llvm - Git at Google

 //===-- X86ShuffleDecode.cpp - X86 shuffle decode logic -------------------===//
 //
 // 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
 //
 //===----------------------------------------------------------------------===//
 //
 // Define several functions to decode x86 specific shuffle semantics into a
 // generic vector mask.
 //
 //===----------------------------------------------------------------------===//

 #include "X86ShuffleDecode.h"
 #include "llvm/ADT/ArrayRef.h"

 //===----------------------------------------------------------------------===//
 //  Vector Mask Decoding
 //===----------------------------------------------------------------------===//

 namespace llvm {

 void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
   // Defaults the copying the dest value.
   ShuffleMask.push_back(0);
   ShuffleMask.push_back(1);
   ShuffleMask.push_back(2);
   ShuffleMask.push_back(3);

   // Decode the immediate.
   unsigned ZMask = Imm & 15;
   unsigned CountD = (Imm >> 4) & 3;
   unsigned CountS = (Imm >> 6) & 3;

   // CountS selects which input element to use.
   unsigned InVal = 4 + CountS;
   // CountD specifies which element of destination to update.
   ShuffleMask[CountD] = InVal;
   // ZMask zaps values, potentially overriding the CountD elt.
   if (ZMask & 1) ShuffleMask[0] = SM_SentinelZero;
   if (ZMask & 2) ShuffleMask[1] = SM_SentinelZero;
   if (ZMask & 4) ShuffleMask[2] = SM_SentinelZero;
   if (ZMask & 8) ShuffleMask[3] = SM_SentinelZero;
 }

 void DecodeInsertElementMask(unsigned NumElts, unsigned Idx, unsigned Len,
                              SmallVectorImpl<int> &ShuffleMask) {
   assert((Idx + Len) <= NumElts && "Insertion out of range");

   for (unsigned i = 0; i != NumElts; ++i)
     ShuffleMask.push_back(i);
   for (unsigned i = 0; i != Len; ++i)
     ShuffleMask[Idx + i] = NumElts + i;
 }

 // <3,1> or <6,7,2,3>
 void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned i = NElts / 2; i != NElts; ++i)
     ShuffleMask.push_back(NElts + i);

   for (unsigned i = NElts / 2; i != NElts; ++i)
     ShuffleMask.push_back(i);
 }

 // <0,2> or <0,1,4,5>
 void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned i = 0; i != NElts / 2; ++i)
     ShuffleMask.push_back(i);

   for (unsigned i = 0; i != NElts / 2; ++i)
     ShuffleMask.push_back(NElts + i);
 }

 void DecodeMOVSLDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
   for (int i = 0, e = NumElts / 2; i < e; ++i) {
     ShuffleMask.push_back(2 * i);
     ShuffleMask.push_back(2 * i);
   }
 }

 void DecodeMOVSHDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
   for (int i = 0, e = NumElts / 2; i < e; ++i) {
     ShuffleMask.push_back(2 * i + 1);
     ShuffleMask.push_back(2 * i + 1);
   }
 }

 void DecodeMOVDDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
   const unsigned NumLaneElts = 2;

   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
     for (unsigned i = 0; i < NumLaneElts; ++i)
       ShuffleMask.push_back(l);
 }

 void DecodePSLLDQMask(unsigned NumElts, unsigned Imm,
                       SmallVectorImpl<int> &ShuffleMask) {
   const unsigned NumLaneElts = 16;

   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
     for (unsigned i = 0; i < NumLaneElts; ++i) {
       int M = SM_SentinelZero;
       if (i >= Imm) M = i - Imm + l;
       ShuffleMask.push_back(M);
     }
 }

 void DecodePSRLDQMask(unsigned NumElts, unsigned Imm,
                       SmallVectorImpl<int> &ShuffleMask) {
   const unsigned NumLaneElts = 16;

   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
     for (unsigned i = 0; i < NumLaneElts; ++i) {
       unsigned Base = i + Imm;
       int M = Base + l;
       if (Base >= NumLaneElts) M = SM_SentinelZero;
       ShuffleMask.push_back(M);
     }
 }

 void DecodePALIGNRMask(unsigned NumElts, unsigned Imm,
                        SmallVectorImpl<int> &ShuffleMask) {
   const unsigned NumLaneElts = 16;

   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
     for (unsigned i = 0; i != NumLaneElts; ++i) {
       unsigned Base = i + Imm;
       // if i+imm is out of this lane then we actually need the other source
       if (Base >= NumLaneElts) Base += NumElts - NumLaneElts;
       ShuffleMask.push_back(Base + l);
     }
   }
 }

 void DecodeVALIGNMask(unsigned NumElts, unsigned Imm,
                       SmallVectorImpl<int> &ShuffleMask) {
   // Not all bits of the immediate are used so mask it.
   assert(isPowerOf2_32(NumElts) && "NumElts should be power of 2");
   Imm = Imm & (NumElts - 1);
   for (unsigned i = 0; i != NumElts; ++i)
     ShuffleMask.push_back(i + Imm);
 }

 /// DecodePSHUFMask - This decodes the shuffle masks for pshufw, pshufd, and vpermilp*.
 /// VT indicates the type of the vector allowing it to handle different
 /// datatypes and vector widths.
 void DecodePSHUFMask(unsigned NumElts, unsigned ScalarBits, unsigned Imm,
                      SmallVectorImpl<int> &ShuffleMask) {
   unsigned Size = NumElts * ScalarBits;
   unsigned NumLanes = Size / 128;
   if (NumLanes == 0) NumLanes = 1;  // Handle MMX
   unsigned NumLaneElts = NumElts / NumLanes;

   uint32_t SplatImm = (Imm & 0xff) * 0x01010101;
   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
     for (unsigned i = 0; i != NumLaneElts; ++i) {
       ShuffleMask.push_back(SplatImm % NumLaneElts + l);
       SplatImm /= NumLaneElts;
     }
   }
 }

 void DecodePSHUFHWMask(unsigned NumElts, unsigned Imm,
                        SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned l = 0; l != NumElts; l += 8) {
     unsigned NewImm = Imm;
     for (unsigned i = 0, e = 4; i != e; ++i) {
       ShuffleMask.push_back(l + i);
     }
     for (unsigned i = 4, e = 8; i != e; ++i) {
       ShuffleMask.push_back(l + 4 + (NewImm & 3));
       NewImm >>= 2;
     }
   }
 }

 void DecodePSHUFLWMask(unsigned NumElts, unsigned Imm,
                        SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned l = 0; l != NumElts; l += 8) {
     unsigned NewImm = Imm;
     for (unsigned i = 0, e = 4; i != e; ++i) {
       ShuffleMask.push_back(l + (NewImm & 3));
       NewImm >>= 2;
     }
     for (unsigned i = 4, e = 8; i != e; ++i) {
       ShuffleMask.push_back(l + i);
     }
   }
 }

 void DecodePSWAPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
   unsigned NumHalfElts = NumElts / 2;

   for (unsigned l = 0; l != NumHalfElts; ++l)
     ShuffleMask.push_back(l + NumHalfElts);
   for (unsigned h = 0; h != NumHalfElts; ++h)
     ShuffleMask.push_back(h);
 }

 /// DecodeSHUFPMask - This decodes the shuffle masks for shufp*. VT indicates
 /// the type of the vector allowing it to handle different datatypes and vector
 /// widths.
 void DecodeSHUFPMask(unsigned NumElts, unsigned ScalarBits,
                      unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
   unsigned NumLaneElts = 128 / ScalarBits;

   unsigned NewImm = Imm;
   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
     // each half of a lane comes from different source
     for (unsigned s = 0; s != NumElts * 2; s += NumElts) {
       for (unsigned i = 0; i != NumLaneElts / 2; ++i) {
         ShuffleMask.push_back(NewImm % NumLaneElts + s + l);
         NewImm /= NumLaneElts;
       }
     }
     if (NumLaneElts == 4) NewImm = Imm; // reload imm
   }
 }

 /// DecodeUNPCKHMask - This decodes the shuffle masks for unpckhps/unpckhpd
 /// and punpckh*. VT indicates the type of the vector allowing it to handle
 /// different datatypes and vector widths.
 void DecodeUNPCKHMask(unsigned NumElts, unsigned ScalarBits,
                       SmallVectorImpl<int> &ShuffleMask) {
   // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
   // independently on 128-bit lanes.
   unsigned NumLanes = (NumElts * ScalarBits) / 128;
   if (NumLanes == 0) NumLanes = 1;  // Handle MMX
   unsigned NumLaneElts = NumElts / NumLanes;

   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
     for (unsigned i = l + NumLaneElts / 2, e = l + NumLaneElts; i != e; ++i) {
       ShuffleMask.push_back(i);           // Reads from dest/src1
       ShuffleMask.push_back(i + NumElts); // Reads from src/src2
     }
   }
 }

 /// DecodeUNPCKLMask - This decodes the shuffle masks for unpcklps/unpcklpd
 /// and punpckl*. VT indicates the type of the vector allowing it to handle
 /// different datatypes and vector widths.
 void DecodeUNPCKLMask(unsigned NumElts, unsigned ScalarBits,
                       SmallVectorImpl<int> &ShuffleMask) {
   // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
   // independently on 128-bit lanes.
   unsigned NumLanes = (NumElts * ScalarBits) / 128;
   if (NumLanes == 0 ) NumLanes = 1;  // Handle MMX
   unsigned NumLaneElts = NumElts / NumLanes;

   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
     for (unsigned i = l, e = l + NumLaneElts / 2; i != e; ++i) {
       ShuffleMask.push_back(i);           // Reads from dest/src1
       ShuffleMask.push_back(i + NumElts); // Reads from src/src2
     }
   }
 }

 /// Decodes a broadcast of the first element of a vector.
 void DecodeVectorBroadcast(unsigned NumElts,
                            SmallVectorImpl<int> &ShuffleMask) {
   ShuffleMask.append(NumElts, 0);
 }

 /// Decodes a broadcast of a subvector to a larger vector type.
 void DecodeSubVectorBroadcast(unsigned DstNumElts, unsigned SrcNumElts,
                               SmallVectorImpl<int> &ShuffleMask) {
   unsigned Scale = DstNumElts / SrcNumElts;

   for (unsigned i = 0; i != Scale; ++i)
     for (unsigned j = 0; j != SrcNumElts; ++j)
       ShuffleMask.push_back(j);
 }

 /// Decode a shuffle packed values at 128-bit granularity
 /// (SHUFF32x4/SHUFF64x2/SHUFI32x4/SHUFI64x2)
 /// immediate mask into a shuffle mask.
 void decodeVSHUF64x2FamilyMask(unsigned NumElts, unsigned ScalarSize,
                                unsigned Imm,
                                SmallVectorImpl<int> &ShuffleMask) {
   unsigned NumElementsInLane = 128 / ScalarSize;
   unsigned NumLanes = NumElts / NumElementsInLane;

   for (unsigned l = 0; l != NumElts; l += NumElementsInLane) {
     unsigned Index = (Imm % NumLanes) * NumElementsInLane;
     Imm /= NumLanes; // Discard the bits we just used.
     // We actually need the other source.
     if (l >= (NumElts / 2))
       Index += NumElts;
     for (unsigned i = 0; i != NumElementsInLane; ++i)
       ShuffleMask.push_back(Index + i);
   }
 }

 void DecodeVPERM2X128Mask(unsigned NumElts, unsigned Imm,
                           SmallVectorImpl<int> &ShuffleMask) {
   unsigned HalfSize = NumElts / 2;

   for (unsigned l = 0; l != 2; ++l) {
     unsigned HalfMask = Imm >> (l * 4);
     unsigned HalfBegin = (HalfMask & 0x3) * HalfSize;
     for (unsigned i = HalfBegin, e = HalfBegin + HalfSize; i != e; ++i)
       ShuffleMask.push_back(HalfMask & 8 ? SM_SentinelZero : (int)i);
   }
 }

 void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                       SmallVectorImpl<int> &ShuffleMask) {
   for (int i = 0, e = RawMask.size(); i < e; ++i) {
     uint64_t M = RawMask[i];
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }
     // For 256/512-bit vectors the base of the shuffle is the 128-bit
     // subvector we're inside.
     int Base = (i / 16) * 16;
     // If the high bit (7) of the byte is set, the element is zeroed.
     if (M & (1 << 7))
       ShuffleMask.push_back(SM_SentinelZero);
     else {
       // Only the least significant 4 bits of the byte are used.
       int Index = Base + (M & 0xf);
       ShuffleMask.push_back(Index);
     }
   }
 }

 void DecodeBLENDMask(unsigned NumElts, unsigned Imm,
                      SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned i = 0; i < NumElts; ++i) {
     // If there are more than 8 elements in the vector, then any immediate blend
     // mask wraps around.
     unsigned Bit = i % 8;
     ShuffleMask.push_back(((Imm >> Bit) & 1) ? NumElts + i : i);
   }
 }

 void DecodeVPPERMMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                       SmallVectorImpl<int> &ShuffleMask) {
   assert(RawMask.size() == 16 && "Illegal VPPERM shuffle mask size");

   // VPPERM Operation
   // Bits[4:0] - Byte Index (0 - 31)
   // Bits[7:5] - Permute Operation
   //
   // Permute Operation:
   // 0 - Source byte (no logical operation).
   // 1 - Invert source byte.
   // 2 - Bit reverse of source byte.
   // 3 - Bit reverse of inverted source byte.
   // 4 - 00h (zero - fill).
   // 5 - FFh (ones - fill).
   // 6 - Most significant bit of source byte replicated in all bit positions.
   // 7 - Invert most significant bit of source byte and replicate in all bit positions.
   for (int i = 0, e = RawMask.size(); i < e; ++i) {
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }

     uint64_t M = RawMask[i];
     uint64_t PermuteOp = (M >> 5) & 0x7;
     if (PermuteOp == 4) {
       ShuffleMask.push_back(SM_SentinelZero);
       continue;
     }
     if (PermuteOp != 0) {
       ShuffleMask.clear();
       return;
     }

     uint64_t Index = M & 0x1F;
     ShuffleMask.push_back((int)Index);
   }
 }

 /// DecodeVPERMMask - this decodes the shuffle masks for VPERMQ/VPERMPD.
 void DecodeVPERMMask(unsigned NumElts, unsigned Imm,
                      SmallVectorImpl<int> &ShuffleMask) {
   for (unsigned l = 0; l != NumElts; l += 4)
     for (unsigned i = 0; i != 4; ++i)
       ShuffleMask.push_back(l + ((Imm >> (2 * i)) & 3));
 }

 void DecodeZeroExtendMask(unsigned SrcScalarBits, unsigned DstScalarBits,
                           unsigned NumDstElts, SmallVectorImpl<int> &Mask) {
   unsigned Scale = DstScalarBits / SrcScalarBits;
   assert(SrcScalarBits < DstScalarBits &&
          "Expected zero extension mask to increase scalar size");

   for (unsigned i = 0; i != NumDstElts; i++) {
     Mask.push_back(i);
     for (unsigned j = 1; j != Scale; j++)
       Mask.push_back(SM_SentinelZero);
   }
 }

 void DecodeZeroMoveLowMask(unsigned NumElts,
                            SmallVectorImpl<int> &ShuffleMask) {
   ShuffleMask.push_back(0);
   for (unsigned i = 1; i < NumElts; i++)
     ShuffleMask.push_back(SM_SentinelZero);
 }

 void DecodeScalarMoveMask(unsigned NumElts, bool IsLoad,
                           SmallVectorImpl<int> &Mask) {
   // First element comes from the first element of second source.
   // Remaining elements: Load zero extends / Move copies from first source.
   Mask.push_back(NumElts);
   for (unsigned i = 1; i < NumElts; i++)
     Mask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
 }

 void DecodeEXTRQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
                       SmallVectorImpl<int> &ShuffleMask) {
   unsigned HalfElts = NumElts / 2;

   // Only the bottom 6 bits are valid for each immediate.
   Len &= 0x3F;
   Idx &= 0x3F;

   // We can only decode this bit extraction instruction as a shuffle if both the
   // length and index work with whole elements.
   if (0 != (Len % EltSize) || 0 != (Idx % EltSize))
     return;

   // A length of zero is equivalent to a bit length of 64.
   if (Len == 0)
     Len = 64;

   // If the length + index exceeds the bottom 64 bits the result is undefined.
   if ((Len + Idx) > 64) {
     ShuffleMask.append(NumElts, SM_SentinelUndef);
     return;
   }

   // Convert index and index to work with elements.
   Len /= EltSize;
   Idx /= EltSize;

   // EXTRQ: Extract Len elements starting from Idx. Zero pad the remaining
   // elements of the lower 64-bits. The upper 64-bits are undefined.
   for (int i = 0; i != Len; ++i)
     ShuffleMask.push_back(i + Idx);
   for (int i = Len; i != (int)HalfElts; ++i)
     ShuffleMask.push_back(SM_SentinelZero);
   for (int i = HalfElts; i != (int)NumElts; ++i)
     ShuffleMask.push_back(SM_SentinelUndef);
 }

 void DecodeINSERTQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
                         SmallVectorImpl<int> &ShuffleMask) {
   unsigned HalfElts = NumElts / 2;

   // Only the bottom 6 bits are valid for each immediate.
   Len &= 0x3F;
   Idx &= 0x3F;

   // We can only decode this bit insertion instruction as a shuffle if both the
   // length and index work with whole elements.
   if (0 != (Len % EltSize) || 0 != (Idx % EltSize))
     return;

   // A length of zero is equivalent to a bit length of 64.
   if (Len == 0)
     Len = 64;

   // If the length + index exceeds the bottom 64 bits the result is undefined.
   if ((Len + Idx) > 64) {
     ShuffleMask.append(NumElts, SM_SentinelUndef);
     return;
   }

   // Convert index and index to work with elements.
   Len /= EltSize;
   Idx /= EltSize;

   // INSERTQ: Extract lowest Len elements from lower half of second source and
   // insert over first source starting at Idx element. The upper 64-bits are
   // undefined.
   for (int i = 0; i != Idx; ++i)
     ShuffleMask.push_back(i);
   for (int i = 0; i != Len; ++i)
     ShuffleMask.push_back(i + NumElts);
   for (int i = Idx + Len; i != (int)HalfElts; ++i)
     ShuffleMask.push_back(i);
   for (int i = HalfElts; i != (int)NumElts; ++i)
     ShuffleMask.push_back(SM_SentinelUndef);
 }

 void DecodeVPERMILPMask(unsigned NumElts, unsigned ScalarBits,
                         ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                         SmallVectorImpl<int> &ShuffleMask) {
   unsigned VecSize = NumElts * ScalarBits;
   unsigned NumLanes = VecSize / 128;
   unsigned NumEltsPerLane = NumElts / NumLanes;
   assert((VecSize == 128 || VecSize == 256 || VecSize == 512) &&
          "Unexpected vector size");
   assert((ScalarBits == 32 || ScalarBits == 64) && "Unexpected element size");

   for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }
     uint64_t M = RawMask[i];
     M = (ScalarBits == 64 ? ((M >> 1) & 0x1) : (M & 0x3));
     unsigned LaneOffset = i & ~(NumEltsPerLane - 1);
     ShuffleMask.push_back((int)(LaneOffset + M));
   }
 }

 void DecodeVPERMIL2PMask(unsigned NumElts, unsigned ScalarBits, unsigned M2Z,
                          ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                          SmallVectorImpl<int> &ShuffleMask) {
   unsigned VecSize = NumElts * ScalarBits;
   unsigned NumLanes = VecSize / 128;
   unsigned NumEltsPerLane = NumElts / NumLanes;
   assert((VecSize == 128 || VecSize == 256) && "Unexpected vector size");
   assert((ScalarBits == 32 || ScalarBits == 64) && "Unexpected element size");
   assert((NumElts == RawMask.size()) && "Unexpected mask size");

   for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }

     // VPERMIL2 Operation.
     // Bits[3] - Match Bit.
     // Bits[2:1] - (Per Lane) PD Shuffle Mask.
     // Bits[2:0] - (Per Lane) PS Shuffle Mask.
     uint64_t Selector = RawMask[i];
     unsigned MatchBit = (Selector >> 3) & 0x1;

     // M2Z[0:1]     MatchBit
     //   0Xb           X        Source selected by Selector index.
     //   10b           0        Source selected by Selector index.
     //   10b           1        Zero.
     //   11b           0        Zero.
     //   11b           1        Source selected by Selector index.
     if ((M2Z & 0x2) != 0 && MatchBit != (M2Z & 0x1)) {
       ShuffleMask.push_back(SM_SentinelZero);
       continue;
     }

     int Index = i & ~(NumEltsPerLane - 1);
     if (ScalarBits == 64)
       Index += (Selector >> 1) & 0x1;
     else
       Index += Selector & 0x3;

     int Src = (Selector >> 2) & 0x1;
     Index += Src * NumElts;
     ShuffleMask.push_back(Index);
   }
 }

 void DecodeVPERMVMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                       SmallVectorImpl<int> &ShuffleMask) {
   uint64_t EltMaskSize = RawMask.size() - 1;
   for (int i = 0, e = RawMask.size(); i != e; ++i) {
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }
     uint64_t M = RawMask[i];
     M &= EltMaskSize;
     ShuffleMask.push_back((int)M);
   }
 }

 void DecodeVPERMV3Mask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
                       SmallVectorImpl<int> &ShuffleMask) {
   uint64_t EltMaskSize = (RawMask.size() * 2) - 1;
   for (int i = 0, e = RawMask.size(); i != e; ++i) {
     if (UndefElts[i]) {
       ShuffleMask.push_back(SM_SentinelUndef);
       continue;
     }
     uint64_t M = RawMask[i];
     M &= EltMaskSize;
     ShuffleMask.push_back((int)M);
   }
 }

 } // llvm namespace
	//===-- X86ShuffleDecode.cpp - X86 shuffle decode logic -------------------===//
	//
	// 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
	//
	//===----------------------------------------------------------------------===//
	//
	// Define several functions to decode x86 specific shuffle semantics into a
	// generic vector mask.
	//
	//===----------------------------------------------------------------------===//

	#include "X86ShuffleDecode.h"
	#include "llvm/ADT/ArrayRef.h"

	//===----------------------------------------------------------------------===//
	// Vector Mask Decoding
	//===----------------------------------------------------------------------===//

	namespace llvm {

	void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
	// Defaults the copying the dest value.
	ShuffleMask.push_back(0);
	ShuffleMask.push_back(1);
	ShuffleMask.push_back(2);
	ShuffleMask.push_back(3);

	// Decode the immediate.
	unsigned ZMask = Imm & 15;
	unsigned CountD = (Imm >> 4) & 3;
	unsigned CountS = (Imm >> 6) & 3;

	// CountS selects which input element to use.
	unsigned InVal = 4 + CountS;
	// CountD specifies which element of destination to update.
	ShuffleMask[CountD] = InVal;
	// ZMask zaps values, potentially overriding the CountD elt.
	if (ZMask & 1) ShuffleMask[0] = SM_SentinelZero;
	if (ZMask & 2) ShuffleMask[1] = SM_SentinelZero;
	if (ZMask & 4) ShuffleMask[2] = SM_SentinelZero;
	if (ZMask & 8) ShuffleMask[3] = SM_SentinelZero;
	}

	void DecodeInsertElementMask(unsigned NumElts, unsigned Idx, unsigned Len,
	SmallVectorImpl<int> &ShuffleMask) {
	assert((Idx + Len) <= NumElts && "Insertion out of range");

	for (unsigned i = 0; i != NumElts; ++i)
	ShuffleMask.push_back(i);
	for (unsigned i = 0; i != Len; ++i)
	ShuffleMask[Idx + i] = NumElts + i;
	}

	// <3,1> or <6,7,2,3>
	void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned i = NElts / 2; i != NElts; ++i)
	ShuffleMask.push_back(NElts + i);

	for (unsigned i = NElts / 2; i != NElts; ++i)
	ShuffleMask.push_back(i);
	}

	// <0,2> or <0,1,4,5>
	void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned i = 0; i != NElts / 2; ++i)
	ShuffleMask.push_back(i);

	for (unsigned i = 0; i != NElts / 2; ++i)
	ShuffleMask.push_back(NElts + i);
	}

	void DecodeMOVSLDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
	for (int i = 0, e = NumElts / 2; i < e; ++i) {
	ShuffleMask.push_back(2 * i);
	ShuffleMask.push_back(2 * i);
	}
	}

	void DecodeMOVSHDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
	for (int i = 0, e = NumElts / 2; i < e; ++i) {
	ShuffleMask.push_back(2 * i + 1);
	ShuffleMask.push_back(2 * i + 1);
	}
	}

	void DecodeMOVDDUPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
	const unsigned NumLaneElts = 2;

	for (unsigned l = 0; l < NumElts; l += NumLaneElts)
	for (unsigned i = 0; i < NumLaneElts; ++i)
	ShuffleMask.push_back(l);
	}

	void DecodePSLLDQMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	const unsigned NumLaneElts = 16;

	for (unsigned l = 0; l < NumElts; l += NumLaneElts)
	for (unsigned i = 0; i < NumLaneElts; ++i) {
	int M = SM_SentinelZero;
	if (i >= Imm) M = i - Imm + l;
	ShuffleMask.push_back(M);
	}
	}

	void DecodePSRLDQMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	const unsigned NumLaneElts = 16;

	for (unsigned l = 0; l < NumElts; l += NumLaneElts)
	for (unsigned i = 0; i < NumLaneElts; ++i) {
	unsigned Base = i + Imm;
	int M = Base + l;
	if (Base >= NumLaneElts) M = SM_SentinelZero;
	ShuffleMask.push_back(M);
	}
	}

	void DecodePALIGNRMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	const unsigned NumLaneElts = 16;

	for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
	for (unsigned i = 0; i != NumLaneElts; ++i) {
	unsigned Base = i + Imm;
	// if i+imm is out of this lane then we actually need the other source
	if (Base >= NumLaneElts) Base += NumElts - NumLaneElts;
	ShuffleMask.push_back(Base + l);
	}
	}
	}

	void DecodeVALIGNMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	// Not all bits of the immediate are used so mask it.
	assert(isPowerOf2_32(NumElts) && "NumElts should be power of 2");
	Imm = Imm & (NumElts - 1);
	for (unsigned i = 0; i != NumElts; ++i)
	ShuffleMask.push_back(i + Imm);
	}

	/// DecodePSHUFMask - This decodes the shuffle masks for pshufw, pshufd, and vpermilp*.
	/// VT indicates the type of the vector allowing it to handle different
	/// datatypes and vector widths.
	void DecodePSHUFMask(unsigned NumElts, unsigned ScalarBits, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned Size = NumElts * ScalarBits;
	unsigned NumLanes = Size / 128;
	if (NumLanes == 0) NumLanes = 1; // Handle MMX
	unsigned NumLaneElts = NumElts / NumLanes;

	uint32_t SplatImm = (Imm & 0xff) * 0x01010101;
	for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
	for (unsigned i = 0; i != NumLaneElts; ++i) {
	ShuffleMask.push_back(SplatImm % NumLaneElts + l);
	SplatImm /= NumLaneElts;
	}
	}
	}

	void DecodePSHUFHWMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned l = 0; l != NumElts; l += 8) {
	unsigned NewImm = Imm;
	for (unsigned i = 0, e = 4; i != e; ++i) {
	ShuffleMask.push_back(l + i);
	}
	for (unsigned i = 4, e = 8; i != e; ++i) {
	ShuffleMask.push_back(l + 4 + (NewImm & 3));
	NewImm >>= 2;
	}
	}
	}

	void DecodePSHUFLWMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned l = 0; l != NumElts; l += 8) {
	unsigned NewImm = Imm;
	for (unsigned i = 0, e = 4; i != e; ++i) {
	ShuffleMask.push_back(l + (NewImm & 3));
	NewImm >>= 2;
	}
	for (unsigned i = 4, e = 8; i != e; ++i) {
	ShuffleMask.push_back(l + i);
	}
	}
	}

	void DecodePSWAPMask(unsigned NumElts, SmallVectorImpl<int> &ShuffleMask) {
	unsigned NumHalfElts = NumElts / 2;

	for (unsigned l = 0; l != NumHalfElts; ++l)
	ShuffleMask.push_back(l + NumHalfElts);
	for (unsigned h = 0; h != NumHalfElts; ++h)
	ShuffleMask.push_back(h);
	}

	/// DecodeSHUFPMask - This decodes the shuffle masks for shufp*. VT indicates
	/// the type of the vector allowing it to handle different datatypes and vector
	/// widths.
	void DecodeSHUFPMask(unsigned NumElts, unsigned ScalarBits,
	unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
	unsigned NumLaneElts = 128 / ScalarBits;

	unsigned NewImm = Imm;
	for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
	// each half of a lane comes from different source
	for (unsigned s = 0; s != NumElts * 2; s += NumElts) {
	for (unsigned i = 0; i != NumLaneElts / 2; ++i) {
	ShuffleMask.push_back(NewImm % NumLaneElts + s + l);
	NewImm /= NumLaneElts;
	}
	}
	if (NumLaneElts == 4) NewImm = Imm; // reload imm
	}
	}

	/// DecodeUNPCKHMask - This decodes the shuffle masks for unpckhps/unpckhpd
	/// and punpckh*. VT indicates the type of the vector allowing it to handle
	/// different datatypes and vector widths.
	void DecodeUNPCKHMask(unsigned NumElts, unsigned ScalarBits,
	SmallVectorImpl<int> &ShuffleMask) {
	// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
	// independently on 128-bit lanes.
	unsigned NumLanes = (NumElts * ScalarBits) / 128;
	if (NumLanes == 0) NumLanes = 1; // Handle MMX
	unsigned NumLaneElts = NumElts / NumLanes;

	for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
	for (unsigned i = l + NumLaneElts / 2, e = l + NumLaneElts; i != e; ++i) {
	ShuffleMask.push_back(i); // Reads from dest/src1
	ShuffleMask.push_back(i + NumElts); // Reads from src/src2
	}
	}
	}

	/// DecodeUNPCKLMask - This decodes the shuffle masks for unpcklps/unpcklpd
	/// and punpckl*. VT indicates the type of the vector allowing it to handle
	/// different datatypes and vector widths.
	void DecodeUNPCKLMask(unsigned NumElts, unsigned ScalarBits,
	SmallVectorImpl<int> &ShuffleMask) {
	// Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
	// independently on 128-bit lanes.
	unsigned NumLanes = (NumElts * ScalarBits) / 128;
	if (NumLanes == 0 ) NumLanes = 1; // Handle MMX
	unsigned NumLaneElts = NumElts / NumLanes;

	for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
	for (unsigned i = l, e = l + NumLaneElts / 2; i != e; ++i) {
	ShuffleMask.push_back(i); // Reads from dest/src1
	ShuffleMask.push_back(i + NumElts); // Reads from src/src2
	}
	}
	}

	/// Decodes a broadcast of the first element of a vector.
	void DecodeVectorBroadcast(unsigned NumElts,
	SmallVectorImpl<int> &ShuffleMask) {
	ShuffleMask.append(NumElts, 0);
	}

	/// Decodes a broadcast of a subvector to a larger vector type.
	void DecodeSubVectorBroadcast(unsigned DstNumElts, unsigned SrcNumElts,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned Scale = DstNumElts / SrcNumElts;

	for (unsigned i = 0; i != Scale; ++i)
	for (unsigned j = 0; j != SrcNumElts; ++j)
	ShuffleMask.push_back(j);
	}

	/// Decode a shuffle packed values at 128-bit granularity
	/// (SHUFF32x4/SHUFF64x2/SHUFI32x4/SHUFI64x2)
	/// immediate mask into a shuffle mask.
	void decodeVSHUF64x2FamilyMask(unsigned NumElts, unsigned ScalarSize,
	unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned NumElementsInLane = 128 / ScalarSize;
	unsigned NumLanes = NumElts / NumElementsInLane;

	for (unsigned l = 0; l != NumElts; l += NumElementsInLane) {
	unsigned Index = (Imm % NumLanes) * NumElementsInLane;
	Imm /= NumLanes; // Discard the bits we just used.
	// We actually need the other source.
	if (l >= (NumElts / 2))
	Index += NumElts;
	for (unsigned i = 0; i != NumElementsInLane; ++i)
	ShuffleMask.push_back(Index + i);
	}
	}

	void DecodeVPERM2X128Mask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned HalfSize = NumElts / 2;

	for (unsigned l = 0; l != 2; ++l) {
	unsigned HalfMask = Imm >> (l * 4);
	unsigned HalfBegin = (HalfMask & 0x3) * HalfSize;
	for (unsigned i = HalfBegin, e = HalfBegin + HalfSize; i != e; ++i)
	ShuffleMask.push_back(HalfMask & 8 ? SM_SentinelZero : (int)i);
	}
	}

	void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	for (int i = 0, e = RawMask.size(); i < e; ++i) {
	uint64_t M = RawMask[i];
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}
	// For 256/512-bit vectors the base of the shuffle is the 128-bit
	// subvector we're inside.
	int Base = (i / 16) * 16;
	// If the high bit (7) of the byte is set, the element is zeroed.
	if (M & (1 << 7))
	ShuffleMask.push_back(SM_SentinelZero);
	else {
	// Only the least significant 4 bits of the byte are used.
	int Index = Base + (M & 0xf);
	ShuffleMask.push_back(Index);
	}
	}
	}

	void DecodeBLENDMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned i = 0; i < NumElts; ++i) {
	// If there are more than 8 elements in the vector, then any immediate blend
	// mask wraps around.
	unsigned Bit = i % 8;
	ShuffleMask.push_back(((Imm >> Bit) & 1) ? NumElts + i : i);
	}
	}

	void DecodeVPPERMMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	assert(RawMask.size() == 16 && "Illegal VPPERM shuffle mask size");

	// VPPERM Operation
	// Bits[4:0] - Byte Index (0 - 31)
	// Bits[7:5] - Permute Operation
	//
	// Permute Operation:
	// 0 - Source byte (no logical operation).
	// 1 - Invert source byte.
	// 2 - Bit reverse of source byte.
	// 3 - Bit reverse of inverted source byte.
	// 4 - 00h (zero - fill).
	// 5 - FFh (ones - fill).
	// 6 - Most significant bit of source byte replicated in all bit positions.
	// 7 - Invert most significant bit of source byte and replicate in all bit positions.
	for (int i = 0, e = RawMask.size(); i < e; ++i) {
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}

	uint64_t M = RawMask[i];
	uint64_t PermuteOp = (M >> 5) & 0x7;
	if (PermuteOp == 4) {
	ShuffleMask.push_back(SM_SentinelZero);
	continue;
	}
	if (PermuteOp != 0) {
	ShuffleMask.clear();
	return;
	}

	uint64_t Index = M & 0x1F;
	ShuffleMask.push_back((int)Index);
	}
	}

	/// DecodeVPERMMask - this decodes the shuffle masks for VPERMQ/VPERMPD.
	void DecodeVPERMMask(unsigned NumElts, unsigned Imm,
	SmallVectorImpl<int> &ShuffleMask) {
	for (unsigned l = 0; l != NumElts; l += 4)
	for (unsigned i = 0; i != 4; ++i)
	ShuffleMask.push_back(l + ((Imm >> (2 * i)) & 3));
	}

	void DecodeZeroExtendMask(unsigned SrcScalarBits, unsigned DstScalarBits,
	unsigned NumDstElts, SmallVectorImpl<int> &Mask) {
	unsigned Scale = DstScalarBits / SrcScalarBits;
	assert(SrcScalarBits < DstScalarBits &&
	"Expected zero extension mask to increase scalar size");

	for (unsigned i = 0; i != NumDstElts; i++) {
	Mask.push_back(i);
	for (unsigned j = 1; j != Scale; j++)
	Mask.push_back(SM_SentinelZero);
	}
	}

	void DecodeZeroMoveLowMask(unsigned NumElts,
	SmallVectorImpl<int> &ShuffleMask) {
	ShuffleMask.push_back(0);
	for (unsigned i = 1; i < NumElts; i++)
	ShuffleMask.push_back(SM_SentinelZero);
	}

	void DecodeScalarMoveMask(unsigned NumElts, bool IsLoad,
	SmallVectorImpl<int> &Mask) {
	// First element comes from the first element of second source.
	// Remaining elements: Load zero extends / Move copies from first source.
	Mask.push_back(NumElts);
	for (unsigned i = 1; i < NumElts; i++)
	Mask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
	}

	void DecodeEXTRQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned HalfElts = NumElts / 2;

	// Only the bottom 6 bits are valid for each immediate.
	Len &= 0x3F;
	Idx &= 0x3F;

	// We can only decode this bit extraction instruction as a shuffle if both the
	// length and index work with whole elements.
	if (0 != (Len % EltSize) \|\| 0 != (Idx % EltSize))
	return;

	// A length of zero is equivalent to a bit length of 64.
	if (Len == 0)
	Len = 64;

	// If the length + index exceeds the bottom 64 bits the result is undefined.
	if ((Len + Idx) > 64) {
	ShuffleMask.append(NumElts, SM_SentinelUndef);
	return;
	}

	// Convert index and index to work with elements.
	Len /= EltSize;
	Idx /= EltSize;

	// EXTRQ: Extract Len elements starting from Idx. Zero pad the remaining
	// elements of the lower 64-bits. The upper 64-bits are undefined.
	for (int i = 0; i != Len; ++i)
	ShuffleMask.push_back(i + Idx);
	for (int i = Len; i != (int)HalfElts; ++i)
	ShuffleMask.push_back(SM_SentinelZero);
	for (int i = HalfElts; i != (int)NumElts; ++i)
	ShuffleMask.push_back(SM_SentinelUndef);
	}

	void DecodeINSERTQIMask(unsigned NumElts, unsigned EltSize, int Len, int Idx,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned HalfElts = NumElts / 2;

	// Only the bottom 6 bits are valid for each immediate.
	Len &= 0x3F;
	Idx &= 0x3F;

	// We can only decode this bit insertion instruction as a shuffle if both the
	// length and index work with whole elements.
	if (0 != (Len % EltSize) \|\| 0 != (Idx % EltSize))
	return;

	// A length of zero is equivalent to a bit length of 64.
	if (Len == 0)
	Len = 64;

	// If the length + index exceeds the bottom 64 bits the result is undefined.
	if ((Len + Idx) > 64) {
	ShuffleMask.append(NumElts, SM_SentinelUndef);
	return;
	}

	// Convert index and index to work with elements.
	Len /= EltSize;
	Idx /= EltSize;

	// INSERTQ: Extract lowest Len elements from lower half of second source and
	// insert over first source starting at Idx element. The upper 64-bits are
	// undefined.
	for (int i = 0; i != Idx; ++i)
	ShuffleMask.push_back(i);
	for (int i = 0; i != Len; ++i)
	ShuffleMask.push_back(i + NumElts);
	for (int i = Idx + Len; i != (int)HalfElts; ++i)
	ShuffleMask.push_back(i);
	for (int i = HalfElts; i != (int)NumElts; ++i)
	ShuffleMask.push_back(SM_SentinelUndef);
	}

	void DecodeVPERMILPMask(unsigned NumElts, unsigned ScalarBits,
	ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned VecSize = NumElts * ScalarBits;
	unsigned NumLanes = VecSize / 128;
	unsigned NumEltsPerLane = NumElts / NumLanes;
	assert((VecSize == 128 \|\| VecSize == 256 \|\| VecSize == 512) &&
	"Unexpected vector size");
	assert((ScalarBits == 32 \|\| ScalarBits == 64) && "Unexpected element size");

	for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}
	uint64_t M = RawMask[i];
	M = (ScalarBits == 64 ? ((M >> 1) & 0x1) : (M & 0x3));
	unsigned LaneOffset = i & ~(NumEltsPerLane - 1);
	ShuffleMask.push_back((int)(LaneOffset + M));
	}
	}

	void DecodeVPERMIL2PMask(unsigned NumElts, unsigned ScalarBits, unsigned M2Z,
	ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	unsigned VecSize = NumElts * ScalarBits;
	unsigned NumLanes = VecSize / 128;
	unsigned NumEltsPerLane = NumElts / NumLanes;
	assert((VecSize == 128 \|\| VecSize == 256) && "Unexpected vector size");
	assert((ScalarBits == 32 \|\| ScalarBits == 64) && "Unexpected element size");
	assert((NumElts == RawMask.size()) && "Unexpected mask size");

	for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}

	// VPERMIL2 Operation.
	// Bits[3] - Match Bit.
	// Bits[2:1] - (Per Lane) PD Shuffle Mask.
	// Bits[2:0] - (Per Lane) PS Shuffle Mask.
	uint64_t Selector = RawMask[i];
	unsigned MatchBit = (Selector >> 3) & 0x1;

	// M2Z[0:1] MatchBit
	// 0Xb X Source selected by Selector index.
	// 10b 0 Source selected by Selector index.
	// 10b 1 Zero.
	// 11b 0 Zero.
	// 11b 1 Source selected by Selector index.
	if ((M2Z & 0x2) != 0 && MatchBit != (M2Z & 0x1)) {
	ShuffleMask.push_back(SM_SentinelZero);
	continue;
	}

	int Index = i & ~(NumEltsPerLane - 1);
	if (ScalarBits == 64)
	Index += (Selector >> 1) & 0x1;
	else
	Index += Selector & 0x3;

	int Src = (Selector >> 2) & 0x1;
	Index += Src * NumElts;
	ShuffleMask.push_back(Index);
	}
	}

	void DecodeVPERMVMask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	uint64_t EltMaskSize = RawMask.size() - 1;
	for (int i = 0, e = RawMask.size(); i != e; ++i) {
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}
	uint64_t M = RawMask[i];
	M &= EltMaskSize;
	ShuffleMask.push_back((int)M);
	}
	}

	void DecodeVPERMV3Mask(ArrayRef<uint64_t> RawMask, const APInt &UndefElts,
	SmallVectorImpl<int> &ShuffleMask) {
	uint64_t EltMaskSize = (RawMask.size() * 2) - 1;
	for (int i = 0, e = RawMask.size(); i != e; ++i) {
	if (UndefElts[i]) {
	ShuffleMask.push_back(SM_SentinelUndef);
	continue;
	}
	uint64_t M = RawMask[i];
	M &= EltMaskSize;
	ShuffleMask.push_back((int)M);
	}
	}

	} // llvm namespace