X86ShuffleDecode.cpp revision 221345 
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
21namespace llvm {
22
23void DecodeINSERTPSMask(unsigned Imm, SmallVectorImpl<unsigned> &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>
47void DecodeMOVHLPSMask(unsigned NElts,
48                       SmallVectorImpl<unsigned> &ShuffleMask) {
49  for (unsigned i = NElts/2; i != NElts; ++i)
50    ShuffleMask.push_back(NElts+i);
51
52  for (unsigned i = NElts/2; i != NElts; ++i)
53    ShuffleMask.push_back(i);
54}
55
56// <0,2> or <0,1,4,5>
57void DecodeMOVLHPSMask(unsigned NElts,
58                       SmallVectorImpl<unsigned> &ShuffleMask) {
59  for (unsigned i = 0; i != NElts/2; ++i)
60    ShuffleMask.push_back(i);
61
62  for (unsigned i = 0; i != NElts/2; ++i)
63    ShuffleMask.push_back(NElts+i);
64}
65
66void DecodePSHUFMask(unsigned NElts, unsigned Imm,
67                     SmallVectorImpl<unsigned> &ShuffleMask) {
68  for (unsigned i = 0; i != NElts; ++i) {
69    ShuffleMask.push_back(Imm % NElts);
70    Imm /= NElts;
71  }
72}
73
74void DecodePSHUFHWMask(unsigned Imm,
75                       SmallVectorImpl<unsigned> &ShuffleMask) {
76  ShuffleMask.push_back(0);
77  ShuffleMask.push_back(1);
78  ShuffleMask.push_back(2);
79  ShuffleMask.push_back(3);
80  for (unsigned i = 0; i != 4; ++i) {
81    ShuffleMask.push_back(4+(Imm & 3));
82    Imm >>= 2;
83  }
84}
85
86void DecodePSHUFLWMask(unsigned Imm,
87                       SmallVectorImpl<unsigned> &ShuffleMask) {
88  for (unsigned i = 0; i != 4; ++i) {
89    ShuffleMask.push_back((Imm & 3));
90    Imm >>= 2;
91  }
92  ShuffleMask.push_back(4);
93  ShuffleMask.push_back(5);
94  ShuffleMask.push_back(6);
95  ShuffleMask.push_back(7);
96}
97
98void DecodePUNPCKLBWMask(unsigned NElts,
99                         SmallVectorImpl<unsigned> &ShuffleMask) {
100  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i8, NElts), ShuffleMask);
101}
102
103void DecodePUNPCKLWDMask(unsigned NElts,
104                         SmallVectorImpl<unsigned> &ShuffleMask) {
105  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i16, NElts), ShuffleMask);
106}
107
108void DecodePUNPCKLDQMask(unsigned NElts,
109                         SmallVectorImpl<unsigned> &ShuffleMask) {
110  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i32, NElts), ShuffleMask);
111}
112
113void DecodePUNPCKLQDQMask(unsigned NElts,
114                          SmallVectorImpl<unsigned> &ShuffleMask) {
115  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i64, NElts), ShuffleMask);
116}
117
118void DecodePUNPCKLMask(EVT VT,
119                       SmallVectorImpl<unsigned> &ShuffleMask) {
120  DecodeUNPCKLPMask(VT, ShuffleMask);
121}
122
123void DecodePUNPCKHMask(unsigned NElts,
124                       SmallVectorImpl<unsigned> &ShuffleMask) {
125  for (unsigned i = 0; i != NElts/2; ++i) {
126    ShuffleMask.push_back(i+NElts/2);
127    ShuffleMask.push_back(i+NElts+NElts/2);
128  }
129}
130
131void DecodeSHUFPSMask(unsigned NElts, unsigned Imm,
132                      SmallVectorImpl<unsigned> &ShuffleMask) {
133  // Part that reads from dest.
134  for (unsigned i = 0; i != NElts/2; ++i) {
135    ShuffleMask.push_back(Imm % NElts);
136    Imm /= NElts;
137  }
138  // Part that reads from src.
139  for (unsigned i = 0; i != NElts/2; ++i) {
140    ShuffleMask.push_back(Imm % NElts + NElts);
141    Imm /= NElts;
142  }
143}
144
145void DecodeUNPCKHPMask(unsigned NElts,
146                       SmallVectorImpl<unsigned> &ShuffleMask) {
147  for (unsigned i = 0; i != NElts/2; ++i) {
148    ShuffleMask.push_back(i+NElts/2);        // Reads from dest
149    ShuffleMask.push_back(i+NElts+NElts/2);  // Reads from src
150  }
151}
152
153void DecodeUNPCKLPSMask(unsigned NElts,
154                        SmallVectorImpl<unsigned> &ShuffleMask) {
155  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i32, NElts), ShuffleMask);
156}
157
158void DecodeUNPCKLPDMask(unsigned NElts,
159                        SmallVectorImpl<unsigned> &ShuffleMask) {
160  DecodeUNPCKLPMask(MVT::getVectorVT(MVT::i64, NElts), ShuffleMask);
161}
162
163/// DecodeUNPCKLPMask - This decodes the shuffle masks for unpcklps/unpcklpd
164/// etc.  VT indicates the type of the vector allowing it to handle different
165/// datatypes and vector widths.
166void DecodeUNPCKLPMask(EVT VT,
167                       SmallVectorImpl<unsigned> &ShuffleMask) {
168  unsigned NumElts = VT.getVectorNumElements();
169
170  // Handle vector lengths > 128 bits.  Define a "section" as a set of
171  // 128 bits.  AVX defines UNPCK* to operate independently on 128-bit
172  // sections.
173  unsigned NumSections = VT.getSizeInBits() / 128;
174  if (NumSections == 0 ) NumSections = 1;  // Handle MMX
175  unsigned NumSectionElts = NumElts / NumSections;
176
177  unsigned Start = 0;
178  unsigned End = NumSectionElts / 2;
179  for (unsigned s = 0; s < NumSections; ++s) {
180    for (unsigned i = Start; i != End; ++i) {
181      ShuffleMask.push_back(i);                 // Reads from dest/src1
182      ShuffleMask.push_back(i+NumSectionElts);  // Reads from src/src2
183    }
184    // Process the next 128 bits.
185    Start += NumSectionElts;
186    End += NumSectionElts;
187  }
188}
189
190} // llvm namespace
191