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      1 //===-- X86ShuffleDecode.cpp - X86 shuffle decode logic -------------------===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // Define several functions to decode x86 specific shuffle semantics into a
     11 // generic vector mask.
     12 //
     13 //===----------------------------------------------------------------------===//
     14 
     15 #include "X86ShuffleDecode.h"
     16 #include "llvm/ADT/ArrayRef.h"
     17 #include "llvm/CodeGen/MachineValueType.h"
     18 
     19 //===----------------------------------------------------------------------===//
     20 //  Vector Mask Decoding
     21 //===----------------------------------------------------------------------===//
     22 
     23 namespace llvm {
     24 
     25 void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
     26   // Defaults the copying the dest value.
     27   ShuffleMask.push_back(0);
     28   ShuffleMask.push_back(1);
     29   ShuffleMask.push_back(2);
     30   ShuffleMask.push_back(3);
     31 
     32   // Decode the immediate.
     33   unsigned ZMask = Imm & 15;
     34   unsigned CountD = (Imm >> 4) & 3;
     35   unsigned CountS = (Imm >> 6) & 3;
     36 
     37   // CountS selects which input element to use.
     38   unsigned InVal = 4 + CountS;
     39   // CountD specifies which element of destination to update.
     40   ShuffleMask[CountD] = InVal;
     41   // ZMask zaps values, potentially overriding the CountD elt.
     42   if (ZMask & 1) ShuffleMask[0] = SM_SentinelZero;
     43   if (ZMask & 2) ShuffleMask[1] = SM_SentinelZero;
     44   if (ZMask & 4) ShuffleMask[2] = SM_SentinelZero;
     45   if (ZMask & 8) ShuffleMask[3] = SM_SentinelZero;
     46 }
     47 
     48 void DecodeInsertElementMask(MVT VT, unsigned Idx, unsigned Len,
     49                              SmallVectorImpl<int> &ShuffleMask) {
     50   unsigned NumElts = VT.getVectorNumElements();
     51   assert((Idx + Len) <= NumElts && "Insertion out of range");
     52 
     53   for (unsigned i = 0; i != NumElts; ++i)
     54     ShuffleMask.push_back(i);
     55   for (unsigned i = 0; i != Len; ++i)
     56     ShuffleMask[Idx + i] = NumElts + i;
     57 }
     58 
     59 // <3,1> or <6,7,2,3>
     60 void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
     61   for (unsigned i = NElts / 2; i != NElts; ++i)
     62     ShuffleMask.push_back(NElts + i);
     63 
     64   for (unsigned i = NElts / 2; i != NElts; ++i)
     65     ShuffleMask.push_back(i);
     66 }
     67 
     68 // <0,2> or <0,1,4,5>
     69 void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) {
     70   for (unsigned i = 0; i != NElts / 2; ++i)
     71     ShuffleMask.push_back(i);
     72 
     73   for (unsigned i = 0; i != NElts / 2; ++i)
     74     ShuffleMask.push_back(NElts + i);
     75 }
     76 
     77 void DecodeMOVSLDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
     78   unsigned NumElts = VT.getVectorNumElements();
     79   for (int i = 0, e = NumElts / 2; i < e; ++i) {
     80     ShuffleMask.push_back(2 * i);
     81     ShuffleMask.push_back(2 * i);
     82   }
     83 }
     84 
     85 void DecodeMOVSHDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
     86   unsigned NumElts = VT.getVectorNumElements();
     87   for (int i = 0, e = NumElts / 2; i < e; ++i) {
     88     ShuffleMask.push_back(2 * i + 1);
     89     ShuffleMask.push_back(2 * i + 1);
     90   }
     91 }
     92 
     93 void DecodeMOVDDUPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
     94   unsigned VectorSizeInBits = VT.getSizeInBits();
     95   unsigned ScalarSizeInBits = VT.getScalarSizeInBits();
     96   unsigned NumElts = VT.getVectorNumElements();
     97   unsigned NumLanes = VectorSizeInBits / 128;
     98   unsigned NumLaneElts = NumElts / NumLanes;
     99   unsigned NumLaneSubElts = 64 / ScalarSizeInBits;
    100 
    101   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
    102     for (unsigned i = 0; i < NumLaneElts; i += NumLaneSubElts)
    103       for (unsigned s = 0; s != NumLaneSubElts; s++)
    104         ShuffleMask.push_back(l + s);
    105 }
    106 
    107 void DecodePSLLDQMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    108   unsigned VectorSizeInBits = VT.getSizeInBits();
    109   unsigned NumElts = VectorSizeInBits / 8;
    110   unsigned NumLanes = VectorSizeInBits / 128;
    111   unsigned NumLaneElts = NumElts / NumLanes;
    112 
    113   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
    114     for (unsigned i = 0; i < NumLaneElts; ++i) {
    115       int M = SM_SentinelZero;
    116       if (i >= Imm) M = i - Imm + l;
    117       ShuffleMask.push_back(M);
    118     }
    119 }
    120 
    121 void DecodePSRLDQMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    122   unsigned VectorSizeInBits = VT.getSizeInBits();
    123   unsigned NumElts = VectorSizeInBits / 8;
    124   unsigned NumLanes = VectorSizeInBits / 128;
    125   unsigned NumLaneElts = NumElts / NumLanes;
    126 
    127   for (unsigned l = 0; l < NumElts; l += NumLaneElts)
    128     for (unsigned i = 0; i < NumLaneElts; ++i) {
    129       unsigned Base = i + Imm;
    130       int M = Base + l;
    131       if (Base >= NumLaneElts) M = SM_SentinelZero;
    132       ShuffleMask.push_back(M);
    133     }
    134 }
    135 
    136 void DecodePALIGNRMask(MVT VT, unsigned Imm,
    137                        SmallVectorImpl<int> &ShuffleMask) {
    138   unsigned NumElts = VT.getVectorNumElements();
    139   unsigned Offset = Imm * (VT.getVectorElementType().getSizeInBits() / 8);
    140 
    141   unsigned NumLanes = VT.getSizeInBits() / 128;
    142   unsigned NumLaneElts = NumElts / NumLanes;
    143 
    144   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
    145     for (unsigned i = 0; i != NumLaneElts; ++i) {
    146       unsigned Base = i + Offset;
    147       // if i+offset is out of this lane then we actually need the other source
    148       if (Base >= NumLaneElts) Base += NumElts - NumLaneElts;
    149       ShuffleMask.push_back(Base + l);
    150     }
    151   }
    152 }
    153 
    154 /// DecodePSHUFMask - This decodes the shuffle masks for pshufw, pshufd, and vpermilp*.
    155 /// VT indicates the type of the vector allowing it to handle different
    156 /// datatypes and vector widths.
    157 void DecodePSHUFMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    158   unsigned NumElts = VT.getVectorNumElements();
    159 
    160   unsigned NumLanes = VT.getSizeInBits() / 128;
    161   if (NumLanes == 0) NumLanes = 1;  // Handle MMX
    162   unsigned NumLaneElts = NumElts / NumLanes;
    163 
    164   unsigned NewImm = Imm;
    165   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
    166     for (unsigned i = 0; i != NumLaneElts; ++i) {
    167       ShuffleMask.push_back(NewImm % NumLaneElts + l);
    168       NewImm /= NumLaneElts;
    169     }
    170     if (NumLaneElts == 4) NewImm = Imm; // reload imm
    171   }
    172 }
    173 
    174 void DecodePSHUFHWMask(MVT VT, unsigned Imm,
    175                        SmallVectorImpl<int> &ShuffleMask) {
    176   unsigned NumElts = VT.getVectorNumElements();
    177 
    178   for (unsigned l = 0; l != NumElts; l += 8) {
    179     unsigned NewImm = Imm;
    180     for (unsigned i = 0, e = 4; i != e; ++i) {
    181       ShuffleMask.push_back(l + i);
    182     }
    183     for (unsigned i = 4, e = 8; i != e; ++i) {
    184       ShuffleMask.push_back(l + 4 + (NewImm & 3));
    185       NewImm >>= 2;
    186     }
    187   }
    188 }
    189 
    190 void DecodePSHUFLWMask(MVT VT, unsigned Imm,
    191                        SmallVectorImpl<int> &ShuffleMask) {
    192   unsigned NumElts = VT.getVectorNumElements();
    193 
    194   for (unsigned l = 0; l != NumElts; l += 8) {
    195     unsigned NewImm = Imm;
    196     for (unsigned i = 0, e = 4; i != e; ++i) {
    197       ShuffleMask.push_back(l + (NewImm & 3));
    198       NewImm >>= 2;
    199     }
    200     for (unsigned i = 4, e = 8; i != e; ++i) {
    201       ShuffleMask.push_back(l + i);
    202     }
    203   }
    204 }
    205 
    206 void DecodePSWAPMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
    207   unsigned NumElts = VT.getVectorNumElements();
    208   unsigned NumHalfElts = NumElts / 2;
    209 
    210   for (unsigned l = 0; l != NumHalfElts; ++l)
    211     ShuffleMask.push_back(l + NumHalfElts);
    212   for (unsigned h = 0; h != NumHalfElts; ++h)
    213     ShuffleMask.push_back(h);
    214 }
    215 
    216 /// DecodeSHUFPMask - This decodes the shuffle masks for shufp*. VT indicates
    217 /// the type of the vector allowing it to handle different datatypes and vector
    218 /// widths.
    219 void DecodeSHUFPMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    220   unsigned NumElts = VT.getVectorNumElements();
    221 
    222   unsigned NumLanes = VT.getSizeInBits() / 128;
    223   unsigned NumLaneElts = NumElts / NumLanes;
    224 
    225   unsigned NewImm = Imm;
    226   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
    227     // each half of a lane comes from different source
    228     for (unsigned s = 0; s != NumElts * 2; s += NumElts) {
    229       for (unsigned i = 0; i != NumLaneElts / 2; ++i) {
    230         ShuffleMask.push_back(NewImm % NumLaneElts + s + l);
    231         NewImm /= NumLaneElts;
    232       }
    233     }
    234     if (NumLaneElts == 4) NewImm = Imm; // reload imm
    235   }
    236 }
    237 
    238 /// DecodeUNPCKHMask - This decodes the shuffle masks for unpckhps/unpckhpd
    239 /// and punpckh*. VT indicates the type of the vector allowing it to handle
    240 /// different datatypes and vector widths.
    241 void DecodeUNPCKHMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
    242   unsigned NumElts = VT.getVectorNumElements();
    243 
    244   // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
    245   // independently on 128-bit lanes.
    246   unsigned NumLanes = VT.getSizeInBits() / 128;
    247   if (NumLanes == 0) NumLanes = 1;  // Handle MMX
    248   unsigned NumLaneElts = NumElts / NumLanes;
    249 
    250   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
    251     for (unsigned i = l + NumLaneElts / 2, e = l + NumLaneElts; i != e; ++i) {
    252       ShuffleMask.push_back(i);           // Reads from dest/src1
    253       ShuffleMask.push_back(i + NumElts); // Reads from src/src2
    254     }
    255   }
    256 }
    257 
    258 /// DecodeUNPCKLMask - This decodes the shuffle masks for unpcklps/unpcklpd
    259 /// and punpckl*. VT indicates the type of the vector allowing it to handle
    260 /// different datatypes and vector widths.
    261 void DecodeUNPCKLMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
    262   unsigned NumElts = VT.getVectorNumElements();
    263 
    264   // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate
    265   // independently on 128-bit lanes.
    266   unsigned NumLanes = VT.getSizeInBits() / 128;
    267   if (NumLanes == 0 ) NumLanes = 1;  // Handle MMX
    268   unsigned NumLaneElts = NumElts / NumLanes;
    269 
    270   for (unsigned l = 0; l != NumElts; l += NumLaneElts) {
    271     for (unsigned i = l, e = l + NumLaneElts / 2; i != e; ++i) {
    272       ShuffleMask.push_back(i);           // Reads from dest/src1
    273       ShuffleMask.push_back(i + NumElts); // Reads from src/src2
    274     }
    275   }
    276 }
    277 
    278 /// Decodes a broadcast of a subvector to a larger vector type.
    279 void DecodeSubVectorBroadcast(MVT DstVT, MVT SrcVT,
    280                               SmallVectorImpl<int> &ShuffleMask) {
    281   assert(SrcVT.getScalarType() == DstVT.getScalarType() &&
    282          "Non matching vector element types");
    283   unsigned NumElts = SrcVT.getVectorNumElements();
    284   unsigned Scale = DstVT.getSizeInBits() / SrcVT.getSizeInBits();
    285 
    286   for (unsigned i = 0; i != Scale; ++i)
    287     for (unsigned j = 0; j != NumElts; ++j)
    288       ShuffleMask.push_back(j);
    289 }
    290 
    291 /// \brief Decode a shuffle packed values at 128-bit granularity
    292 /// (SHUFF32x4/SHUFF64x2/SHUFI32x4/SHUFI64x2)
    293 /// immediate mask into a shuffle mask.
    294 void decodeVSHUF64x2FamilyMask(MVT VT, unsigned Imm,
    295                         SmallVectorImpl<int> &ShuffleMask) {
    296   unsigned NumLanes = VT.getSizeInBits() / 128;
    297   unsigned NumElementsInLane = 128 / VT.getScalarSizeInBits();
    298   unsigned ControlBitsMask = NumLanes - 1;
    299   unsigned NumControlBits  = NumLanes / 2;
    300 
    301   for (unsigned l = 0; l != NumLanes; ++l) {
    302     unsigned LaneMask = (Imm >> (l * NumControlBits)) & ControlBitsMask;
    303     // We actually need the other source.
    304     if (l >= NumLanes / 2)
    305       LaneMask += NumLanes;
    306     for (unsigned i = 0; i != NumElementsInLane; ++i)
    307       ShuffleMask.push_back(LaneMask * NumElementsInLane + i);
    308   }
    309 }
    310 
    311 void DecodeVPERM2X128Mask(MVT VT, unsigned Imm,
    312                           SmallVectorImpl<int> &ShuffleMask) {
    313   unsigned HalfSize = VT.getVectorNumElements() / 2;
    314 
    315   for (unsigned l = 0; l != 2; ++l) {
    316     unsigned HalfMask = Imm >> (l * 4);
    317     unsigned HalfBegin = (HalfMask & 0x3) * HalfSize;
    318     for (unsigned i = HalfBegin, e = HalfBegin + HalfSize; i != e; ++i)
    319       ShuffleMask.push_back(HalfMask & 8 ? SM_SentinelZero : (int)i);
    320   }
    321 }
    322 
    323 void DecodePSHUFBMask(ArrayRef<uint64_t> RawMask,
    324                       SmallVectorImpl<int> &ShuffleMask) {
    325   for (int i = 0, e = RawMask.size(); i < e; ++i) {
    326     uint64_t M = RawMask[i];
    327     if (M == (uint64_t)SM_SentinelUndef) {
    328       ShuffleMask.push_back(M);
    329       continue;
    330     }
    331     // For 256/512-bit vectors the base of the shuffle is the 128-bit
    332     // subvector we're inside.
    333     int Base = (i / 16) * 16;
    334     // If the high bit (7) of the byte is set, the element is zeroed.
    335     if (M & (1 << 7))
    336       ShuffleMask.push_back(SM_SentinelZero);
    337     else {
    338       // Only the least significant 4 bits of the byte are used.
    339       int Index = Base + (M & 0xf);
    340       ShuffleMask.push_back(Index);
    341     }
    342   }
    343 }
    344 
    345 void DecodeBLENDMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    346   int ElementBits = VT.getScalarSizeInBits();
    347   int NumElements = VT.getVectorNumElements();
    348   for (int i = 0; i < NumElements; ++i) {
    349     // If there are more than 8 elements in the vector, then any immediate blend
    350     // mask applies to each 128-bit lane. There can never be more than
    351     // 8 elements in a 128-bit lane with an immediate blend.
    352     int Bit = NumElements > 8 ? i % (128 / ElementBits) : i;
    353     assert(Bit < 8 &&
    354            "Immediate blends only operate over 8 elements at a time!");
    355     ShuffleMask.push_back(((Imm >> Bit) & 1) ? NumElements + i : i);
    356   }
    357 }
    358 
    359 void DecodeVPPERMMask(ArrayRef<uint64_t> RawMask,
    360                       SmallVectorImpl<int> &ShuffleMask) {
    361   assert(RawMask.size() == 16 && "Illegal VPPERM shuffle mask size");
    362 
    363   // VPPERM Operation
    364   // Bits[4:0] - Byte Index (0 - 31)
    365   // Bits[7:5] - Permute Operation
    366   //
    367   // Permute Operation:
    368   // 0 - Source byte (no logical operation).
    369   // 1 - Invert source byte.
    370   // 2 - Bit reverse of source byte.
    371   // 3 - Bit reverse of inverted source byte.
    372   // 4 - 00h (zero - fill).
    373   // 5 - FFh (ones - fill).
    374   // 6 - Most significant bit of source byte replicated in all bit positions.
    375   // 7 - Invert most significant bit of source byte and replicate in all bit positions.
    376   for (int i = 0, e = RawMask.size(); i < e; ++i) {
    377     uint64_t M = RawMask[i];
    378     if (M == (uint64_t)SM_SentinelUndef) {
    379       ShuffleMask.push_back(M);
    380       continue;
    381     }
    382 
    383     uint64_t PermuteOp = (M >> 5) & 0x7;
    384     if (PermuteOp == 4) {
    385       ShuffleMask.push_back(SM_SentinelZero);
    386       continue;
    387     }
    388     if (PermuteOp != 0) {
    389       ShuffleMask.clear();
    390       return;
    391     }
    392 
    393     uint64_t Index = M & 0x1F;
    394     ShuffleMask.push_back((int)Index);
    395   }
    396 }
    397 
    398 /// DecodeVPERMMask - this decodes the shuffle masks for VPERMQ/VPERMPD.
    399 void DecodeVPERMMask(MVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) {
    400   assert((VT.is256BitVector() || VT.is512BitVector()) &&
    401          (VT.getScalarSizeInBits() == 64) && "Unexpected vector value type");
    402   unsigned NumElts = VT.getVectorNumElements();
    403   for (unsigned l = 0; l != NumElts; l += 4)
    404     for (unsigned i = 0; i != 4; ++i)
    405       ShuffleMask.push_back(l + ((Imm >> (2 * i)) & 3));
    406 }
    407 
    408 void DecodeZeroExtendMask(MVT SrcScalarVT, MVT DstVT, SmallVectorImpl<int> &Mask) {
    409   unsigned NumDstElts = DstVT.getVectorNumElements();
    410   unsigned SrcScalarBits = SrcScalarVT.getSizeInBits();
    411   unsigned DstScalarBits = DstVT.getScalarSizeInBits();
    412   unsigned Scale = DstScalarBits / SrcScalarBits;
    413   assert(SrcScalarBits < DstScalarBits &&
    414          "Expected zero extension mask to increase scalar size");
    415 
    416   for (unsigned i = 0; i != NumDstElts; i++) {
    417     Mask.push_back(i);
    418     for (unsigned j = 1; j != Scale; j++)
    419       Mask.push_back(SM_SentinelZero);
    420   }
    421 }
    422 
    423 void DecodeZeroMoveLowMask(MVT VT, SmallVectorImpl<int> &ShuffleMask) {
    424   unsigned NumElts = VT.getVectorNumElements();
    425   ShuffleMask.push_back(0);
    426   for (unsigned i = 1; i < NumElts; i++)
    427     ShuffleMask.push_back(SM_SentinelZero);
    428 }
    429 
    430 void DecodeScalarMoveMask(MVT VT, bool IsLoad, SmallVectorImpl<int> &Mask) {
    431   // First element comes from the first element of second source.
    432   // Remaining elements: Load zero extends / Move copies from first source.
    433   unsigned NumElts = VT.getVectorNumElements();
    434   Mask.push_back(NumElts);
    435   for (unsigned i = 1; i < NumElts; i++)
    436     Mask.push_back(IsLoad ? static_cast<int>(SM_SentinelZero) : i);
    437 }
    438 
    439 void DecodeEXTRQIMask(int Len, int Idx,
    440                       SmallVectorImpl<int> &ShuffleMask) {
    441   // Only the bottom 6 bits are valid for each immediate.
    442   Len &= 0x3F;
    443   Idx &= 0x3F;
    444 
    445   // We can only decode this bit extraction instruction as a shuffle if both the
    446   // length and index work with whole bytes.
    447   if (0 != (Len % 8) || 0 != (Idx % 8))
    448     return;
    449 
    450   // A length of zero is equivalent to a bit length of 64.
    451   if (Len == 0)
    452     Len = 64;
    453 
    454   // If the length + index exceeds the bottom 64 bits the result is undefined.
    455   if ((Len + Idx) > 64) {
    456     ShuffleMask.append(16, SM_SentinelUndef);
    457     return;
    458   }
    459 
    460   // Convert index and index to work with bytes.
    461   Len /= 8;
    462   Idx /= 8;
    463 
    464   // EXTRQ: Extract Len bytes starting from Idx. Zero pad the remaining bytes
    465   // of the lower 64-bits. The upper 64-bits are undefined.
    466   for (int i = 0; i != Len; ++i)
    467     ShuffleMask.push_back(i + Idx);
    468   for (int i = Len; i != 8; ++i)
    469     ShuffleMask.push_back(SM_SentinelZero);
    470   for (int i = 8; i != 16; ++i)
    471     ShuffleMask.push_back(SM_SentinelUndef);
    472 }
    473 
    474 void DecodeINSERTQIMask(int Len, int Idx,
    475                         SmallVectorImpl<int> &ShuffleMask) {
    476   // Only the bottom 6 bits are valid for each immediate.
    477   Len &= 0x3F;
    478   Idx &= 0x3F;
    479 
    480   // We can only decode this bit insertion instruction as a shuffle if both the
    481   // length and index work with whole bytes.
    482   if (0 != (Len % 8) || 0 != (Idx % 8))
    483     return;
    484 
    485   // A length of zero is equivalent to a bit length of 64.
    486   if (Len == 0)
    487     Len = 64;
    488 
    489   // If the length + index exceeds the bottom 64 bits the result is undefined.
    490   if ((Len + Idx) > 64) {
    491     ShuffleMask.append(16, SM_SentinelUndef);
    492     return;
    493   }
    494 
    495   // Convert index and index to work with bytes.
    496   Len /= 8;
    497   Idx /= 8;
    498 
    499   // INSERTQ: Extract lowest Len bytes from lower half of second source and
    500   // insert over first source starting at Idx byte. The upper 64-bits are
    501   // undefined.
    502   for (int i = 0; i != Idx; ++i)
    503     ShuffleMask.push_back(i);
    504   for (int i = 0; i != Len; ++i)
    505     ShuffleMask.push_back(i + 16);
    506   for (int i = Idx + Len; i != 8; ++i)
    507     ShuffleMask.push_back(i);
    508   for (int i = 8; i != 16; ++i)
    509     ShuffleMask.push_back(SM_SentinelUndef);
    510 }
    511 
    512 void DecodeVPERMILPMask(MVT VT, ArrayRef<uint64_t> RawMask,
    513                         SmallVectorImpl<int> &ShuffleMask) {
    514   unsigned VecSize = VT.getSizeInBits();
    515   unsigned EltSize = VT.getScalarSizeInBits();
    516   unsigned NumLanes = VecSize / 128;
    517   unsigned NumEltsPerLane = VT.getVectorNumElements() / NumLanes;
    518   assert((VecSize == 128 || VecSize == 256 || VecSize == 512) &&
    519          "Unexpected vector size");
    520   assert((EltSize == 32 || EltSize == 64) && "Unexpected element size");
    521 
    522   for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
    523     uint64_t M = RawMask[i];
    524     M = (EltSize == 64 ? ((M >> 1) & 0x1) : (M & 0x3));
    525     unsigned LaneOffset = i & ~(NumEltsPerLane - 1);
    526     ShuffleMask.push_back((int)(LaneOffset + M));
    527   }
    528 }
    529 
    530 void DecodeVPERMIL2PMask(MVT VT, unsigned M2Z, ArrayRef<uint64_t> RawMask,
    531                          SmallVectorImpl<int> &ShuffleMask) {
    532   unsigned VecSize = VT.getSizeInBits();
    533   unsigned EltSize = VT.getScalarSizeInBits();
    534   unsigned NumLanes = VecSize / 128;
    535   unsigned NumEltsPerLane = VT.getVectorNumElements() / NumLanes;
    536   assert((VecSize == 128 || VecSize == 256) &&
    537          "Unexpected vector size");
    538   assert((EltSize == 32 || EltSize == 64) && "Unexpected element size");
    539 
    540   for (unsigned i = 0, e = RawMask.size(); i < e; ++i) {
    541     // VPERMIL2 Operation.
    542     // Bits[3] - Match Bit.
    543     // Bits[2:1] - (Per Lane) PD Shuffle Mask.
    544     // Bits[2:0] - (Per Lane) PS Shuffle Mask.
    545     uint64_t Selector = RawMask[i];
    546     unsigned MatchBit = (Selector >> 3) & 0x1;
    547 
    548     // M2Z[0:1]     MatchBit
    549     //   0Xb           X        Source selected by Selector index.
    550     //   10b           0        Source selected by Selector index.
    551     //   10b           1        Zero.
    552     //   11b           0        Zero.
    553     //   11b           1        Source selected by Selector index.
    554     if ((M2Z & 0x2) != 0 && MatchBit != (M2Z & 0x1)) {
    555       ShuffleMask.push_back(SM_SentinelZero);
    556       continue;
    557     }
    558 
    559     unsigned Index = i & ~(NumEltsPerLane - 1);
    560     if (EltSize == 64)
    561       Index += (Selector >> 1) & 0x1;
    562     else
    563       Index += Selector & 0x3;
    564 
    565     unsigned SrcOffset = (Selector >> 2) & 1;
    566     ShuffleMask.push_back((int)(SrcOffset + Index));
    567   }
    568 }
    569 
    570 void DecodeVPERMVMask(ArrayRef<uint64_t> RawMask,
    571                       SmallVectorImpl<int> &ShuffleMask) {
    572   uint64_t EltMaskSize = RawMask.size() - 1;
    573   for (auto M : RawMask) {
    574     M &= EltMaskSize;
    575     ShuffleMask.push_back((int)M);
    576   }
    577 }
    578 
    579 void DecodeVPERMV3Mask(ArrayRef<uint64_t> RawMask,
    580                       SmallVectorImpl<int> &ShuffleMask) {
    581   uint64_t EltMaskSize = (RawMask.size() * 2) - 1;
    582   for (auto M : RawMask) {
    583     M &= EltMaskSize;
    584     ShuffleMask.push_back((int)M);
    585   }
    586 }
    587 
    588 } // llvm namespace
    589