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 17 //===----------------------------------------------------------------------===// 18 // Vector Mask Decoding 19 //===----------------------------------------------------------------------===// 20 21 namespace llvm { 22 23 void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) { 24 // Defaults the copying the dest value. 25 ShuffleMask.push_back(0); 26 ShuffleMask.push_back(1); 27 ShuffleMask.push_back(2); 28 ShuffleMask.push_back(3); 29 30 // Decode the immediate. 31 unsigned ZMask = Imm & 15; 32 unsigned CountD = (Imm >> 4) & 3; 33 unsigned CountS = (Imm >> 6) & 3; 34 35 // CountS selects which input element to use. 36 unsigned InVal = 4+CountS; 37 // CountD specifies which element of destination to update. 38 ShuffleMask[CountD] = InVal; 39 // ZMask zaps values, potentially overriding the CountD elt. 40 if (ZMask & 1) ShuffleMask[0] = SM_SentinelZero; 41 if (ZMask & 2) ShuffleMask[1] = SM_SentinelZero; 42 if (ZMask & 4) ShuffleMask[2] = SM_SentinelZero; 43 if (ZMask & 8) ShuffleMask[3] = SM_SentinelZero; 44 } 45 46 // <3,1> or <6,7,2,3> 47 void DecodeMOVHLPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) { 48 for (unsigned i = NElts/2; i != NElts; ++i) 49 ShuffleMask.push_back(NElts+i); 50 51 for (unsigned i = NElts/2; i != NElts; ++i) 52 ShuffleMask.push_back(i); 53 } 54 55 // <0,2> or <0,1,4,5> 56 void DecodeMOVLHPSMask(unsigned NElts, SmallVectorImpl<int> &ShuffleMask) { 57 for (unsigned i = 0; i != NElts/2; ++i) 58 ShuffleMask.push_back(i); 59 60 for (unsigned i = 0; i != NElts/2; ++i) 61 ShuffleMask.push_back(NElts+i); 62 } 63 64 /// DecodePSHUFMask - This decodes the shuffle masks for pshufd, and vpermilp*. 65 /// VT indicates the type of the vector allowing it to handle different 66 /// datatypes and vector widths. 67 void DecodePSHUFMask(EVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) { 68 unsigned NumElts = VT.getVectorNumElements(); 69 70 unsigned NumLanes = VT.getSizeInBits() / 128; 71 unsigned NumLaneElts = NumElts / NumLanes; 72 73 int NewImm = Imm; 74 for (unsigned l = 0; l != NumElts; l += NumLaneElts) { 75 for (unsigned i = 0; i != NumLaneElts; ++i) { 76 ShuffleMask.push_back(NewImm % NumLaneElts + l); 77 NewImm /= NumLaneElts; 78 } 79 if (NumLaneElts == 4) NewImm = Imm; // reload imm 80 } 81 } 82 83 void DecodePSHUFHWMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) { 84 ShuffleMask.push_back(0); 85 ShuffleMask.push_back(1); 86 ShuffleMask.push_back(2); 87 ShuffleMask.push_back(3); 88 for (unsigned i = 0; i != 4; ++i) { 89 ShuffleMask.push_back(4+(Imm & 3)); 90 Imm >>= 2; 91 } 92 } 93 94 void DecodePSHUFLWMask(unsigned Imm, SmallVectorImpl<int> &ShuffleMask) { 95 for (unsigned i = 0; i != 4; ++i) { 96 ShuffleMask.push_back((Imm & 3)); 97 Imm >>= 2; 98 } 99 ShuffleMask.push_back(4); 100 ShuffleMask.push_back(5); 101 ShuffleMask.push_back(6); 102 ShuffleMask.push_back(7); 103 } 104 105 /// DecodeSHUFPMask - This decodes the shuffle masks for shufp*. VT indicates 106 /// the type of the vector allowing it to handle different datatypes and vector 107 /// widths. 108 void DecodeSHUFPMask(EVT VT, unsigned Imm, SmallVectorImpl<int> &ShuffleMask) { 109 unsigned NumElts = VT.getVectorNumElements(); 110 111 unsigned NumLanes = VT.getSizeInBits() / 128; 112 unsigned NumLaneElts = NumElts / NumLanes; 113 114 int NewImm = Imm; 115 for (unsigned l = 0; l != NumElts; l += NumLaneElts) { 116 // Part that reads from dest. 117 for (unsigned i = 0; i != NumLaneElts/2; ++i) { 118 ShuffleMask.push_back(NewImm % NumLaneElts + l); 119 NewImm /= NumLaneElts; 120 } 121 // Part that reads from src. 122 for (unsigned i = 0; i != NumLaneElts/2; ++i) { 123 ShuffleMask.push_back(NewImm % NumLaneElts + NumElts + l); 124 NewImm /= NumLaneElts; 125 } 126 if (NumLaneElts == 4) NewImm = Imm; // reload imm 127 } 128 } 129 130 /// DecodeUNPCKHMask - This decodes the shuffle masks for unpckhps/unpckhpd 131 /// and punpckh*. VT indicates the type of the vector allowing it to handle 132 /// different datatypes and vector widths. 133 void DecodeUNPCKHMask(EVT VT, SmallVectorImpl<int> &ShuffleMask) { 134 unsigned NumElts = VT.getVectorNumElements(); 135 136 // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate 137 // independently on 128-bit lanes. 138 unsigned NumLanes = VT.getSizeInBits() / 128; 139 if (NumLanes == 0 ) NumLanes = 1; // Handle MMX 140 unsigned NumLaneElts = NumElts / NumLanes; 141 142 for (unsigned l = 0; l != NumElts; l += NumLaneElts) { 143 for (unsigned i = l + NumLaneElts/2, e = l + NumLaneElts; i != e; ++i) { 144 ShuffleMask.push_back(i); // Reads from dest/src1 145 ShuffleMask.push_back(i+NumElts); // Reads from src/src2 146 } 147 } 148 } 149 150 /// DecodeUNPCKLMask - This decodes the shuffle masks for unpcklps/unpcklpd 151 /// and punpckl*. VT indicates the type of the vector allowing it to handle 152 /// different datatypes and vector widths. 153 void DecodeUNPCKLMask(EVT VT, SmallVectorImpl<int> &ShuffleMask) { 154 unsigned NumElts = VT.getVectorNumElements(); 155 156 // Handle 128 and 256-bit vector lengths. AVX defines UNPCK* to operate 157 // independently on 128-bit lanes. 158 unsigned NumLanes = VT.getSizeInBits() / 128; 159 if (NumLanes == 0 ) NumLanes = 1; // Handle MMX 160 unsigned NumLaneElts = NumElts / NumLanes; 161 162 for (unsigned l = 0; l != NumElts; l += NumLaneElts) { 163 for (unsigned i = l, e = l + NumLaneElts/2; i != e; ++i) { 164 ShuffleMask.push_back(i); // Reads from dest/src1 165 ShuffleMask.push_back(i+NumElts); // Reads from src/src2 166 } 167 } 168 } 169 170 void DecodeVPERM2X128Mask(EVT VT, unsigned Imm, 171 SmallVectorImpl<int> &ShuffleMask) { 172 if (Imm & 0x88) 173 return; // Not a shuffle 174 175 unsigned HalfSize = VT.getVectorNumElements()/2; 176 unsigned FstHalfBegin = (Imm & 0x3) * HalfSize; 177 unsigned SndHalfBegin = ((Imm >> 4) & 0x3) * HalfSize; 178 179 for (int i = FstHalfBegin, e = FstHalfBegin+HalfSize; i != e; ++i) 180 ShuffleMask.push_back(i); 181 for (int i = SndHalfBegin, e = SndHalfBegin+HalfSize; i != e; ++i) 182 ShuffleMask.push_back(i); 183 } 184 185 } // llvm namespace 186