1//===- PPCGenRegisterBankInfo.def -------------------------------*- C++ -*-==//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8/// \file
9/// This file defines all the static objects used by PPCRegisterBankInfo.
10/// \todo This should be generated by TableGen, because the logic here can be
11///  derived from register bank definition. Not yet implemented.
12//===----------------------------------------------------------------------===//
13
14namespace llvm {
15RegisterBankInfo::PartialMapping PPCGenRegisterBankInfo::PartMappings[]{
16    /* StartIdx, Length, RegBank */
17    // 0: GPR 32-bit value.
18    {0, 32, PPC::GPRRegBank},
19    // 1: GPR 64-bit value.
20    {0, 64, PPC::GPRRegBank},
21    // 2: FPR 32-bit value
22    {0, 32, PPC::FPRRegBank},
23    // 3: FPR 64-bit value
24    {0, 64, PPC::FPRRegBank},
25    // 4: 128-bit vector (VSX, Altivec)
26    {0, 128, PPC::VECRegBank},
27    // 5: CR 4-bit value
28    {0, 4, PPC::CRRegBank},
29};
30
31// ValueMappings.
32// Pointers to the entries in this array are returned by getValueMapping() and
33// getCopyMapping().
34//
35// The array has the following structure:
36// - At index 0 is the invalid entry.
37// - After that, the mappings for the register types from PartialMappingIdx
38//   follow. Each mapping consists of 3 entries, which is needed to cover
39//   3-operands instructions.
40// - Last, mappings for cross-register bank moves follow. Since COPY has only
41//   2 operands, a mapping consists of 2 entries.
42RegisterBankInfo::ValueMapping PPCGenRegisterBankInfo::ValMappings[]{
43    /* BreakDown, NumBreakDowns */
44    // 0: invalid
45    {nullptr, 0},
46    // 1: GPR 32-bit value.
47    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR32 - PMI_Min], 1},
48    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR32 - PMI_Min], 1},
49    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR32 - PMI_Min], 1},
50    // 4: GPR 64-bit value.
51    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR64 - PMI_Min], 1},
52    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR64 - PMI_Min], 1},
53    {&PPCGenRegisterBankInfo::PartMappings[PMI_GPR64 - PMI_Min], 1},
54    // 7: FPR 32-bit value.
55    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR32 - PMI_Min], 1},
56    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR32 - PMI_Min], 1},
57    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR32 - PMI_Min], 1},
58    // 10: FPR 64-bit value.
59    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR64 - PMI_Min], 1},
60    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR64 - PMI_Min], 1},
61    {&PPCGenRegisterBankInfo::PartMappings[PMI_FPR64 - PMI_Min], 1},
62    // 13: 128-bit vector.
63    {&PPCGenRegisterBankInfo::PartMappings[PMI_VEC128 - PMI_Min], 1},
64    {&PPCGenRegisterBankInfo::PartMappings[PMI_VEC128 - PMI_Min], 1},
65    {&PPCGenRegisterBankInfo::PartMappings[PMI_VEC128 - PMI_Min], 1},
66    // 16: CR 4-bit value.
67    {&PPCGenRegisterBankInfo::PartMappings[PMI_CR - PMI_Min], 1},
68};
69
70// TODO Too simple!
71const RegisterBankInfo::ValueMapping *
72PPCGenRegisterBankInfo::getValueMapping(PartialMappingIdx RBIdx) {
73  assert(RBIdx != PartialMappingIdx::PMI_None && "No mapping needed for that");
74
75  unsigned ValMappingIdx = RBIdx - PMI_Min;
76
77  return &ValMappings[1 + 3 * ValMappingIdx];
78}
79
80PPCGenRegisterBankInfo::PartialMappingIdx
81  PPCGenRegisterBankInfo::BankIDToCopyMapIdx[]{
82    PMI_None,
83    PMI_FPR64,  // FPR
84    PMI_GPR64,  // GPR
85    PMI_VEC128, // VEC
86};
87
88// TODO Too simple!
89const RegisterBankInfo::ValueMapping *
90PPCGenRegisterBankInfo::getCopyMapping(unsigned DstBankID, unsigned SrcBankID,
91                                       unsigned Size) {
92  assert(DstBankID < PPC::NumRegisterBanks && "Invalid bank ID");
93  assert(SrcBankID < PPC::NumRegisterBanks && "Invalid bank ID");
94  PartialMappingIdx DstRBIdx = BankIDToCopyMapIdx[DstBankID];
95  PartialMappingIdx SrcRBIdx = BankIDToCopyMapIdx[SrcBankID];
96  assert(DstRBIdx != PMI_None && "No such mapping");
97  assert(SrcRBIdx != PMI_None && "No such mapping");
98
99  if (DstRBIdx == SrcRBIdx)
100    return getValueMapping(DstRBIdx);
101
102  assert(Size <= 128 && "Can currently handle types up to 128 bits (vectors)!");
103  // TODO: This function needs to be updated to handle all cases for
104  //       GPRs, FPRs and vectors. It currently only handles bitcasting to
105  //       the same type and has only mainly been tested for bitcasting
106  //       between different vector types.
107  unsigned ValMappingIdx = DstRBIdx - PMI_Min;
108
109  return &ValMappings[1 + 3 * ValMappingIdx];
110}
111
112} // namespace llvm
113