1//===-- SystemZSelectionDAGInfo.cpp - SystemZ SelectionDAG Info -----------===//
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//
9// This file implements the SystemZSelectionDAGInfo class.
10//
11//===----------------------------------------------------------------------===//
12
13#include "SystemZSelectionDAGInfo.h"
14#include "SystemZTargetMachine.h"
15#include "llvm/CodeGen/SelectionDAG.h"
16
17#define GET_SDNODE_DESC
18#include "SystemZGenSDNodeInfo.inc"
19
20using namespace llvm;
21
22#define DEBUG_TYPE "systemz-selectiondag-info"
23
24SystemZSelectionDAGInfo::SystemZSelectionDAGInfo()
25 : SelectionDAGGenTargetInfo(SystemZGenSDNodeInfo) {}
26
27const char *SystemZSelectionDAGInfo::getTargetNodeName(unsigned Opcode) const {
28 switch (static_cast<SystemZISD::NodeType>(Opcode)) {
29 case SystemZISD::GET_CCMASK:
30 return "SystemZISD::GET_CCMASK";
31 }
32
33 return SelectionDAGGenTargetInfo::getTargetNodeName(Opcode);
34}
35
36static unsigned getMemMemLenAdj(unsigned Op) {
37 return Op == SystemZISD::MEMSET_MVC ? 2 : 1;
38}
39
40static SDValue createMemMemNode(SelectionDAG &DAG, const SDLoc &DL, unsigned Op,
41 SDValue Chain, SDValue Dst, SDValue Src,
42 SDValue LenAdj, SDValue Byte) {
43 SDVTList VTs = Op == SystemZISD::CLC ? DAG.getVTList(VT1: MVT::i32, VT2: MVT::Other)
44 : DAG.getVTList(VT: MVT::Other);
45 SmallVector<SDValue, 6> Ops;
46 if (Op == SystemZISD::MEMSET_MVC)
47 Ops = { Chain, Dst, LenAdj, Byte };
48 else
49 Ops = { Chain, Dst, Src, LenAdj };
50 return DAG.getNode(Opcode: Op, DL, VTList: VTs, Ops);
51}
52
53// Emit a mem-mem operation after subtracting one (or two for memset) from
54// size, which will be added back during pseudo expansion. As the Reg case
55// emitted here may be converted by DAGCombiner into having an Imm length,
56// they are both emitted the same way.
57static SDValue emitMemMemImm(SelectionDAG &DAG, const SDLoc &DL, unsigned Op,
58 SDValue Chain, SDValue Dst, SDValue Src,
59 uint64_t Size, SDValue Byte = SDValue()) {
60 unsigned Adj = getMemMemLenAdj(Op);
61 assert(Size >= Adj && "Adjusted length overflow.");
62 SDValue LenAdj = DAG.getConstant(Val: Size - Adj, DL, VT: Dst.getValueType());
63 return createMemMemNode(DAG, DL, Op, Chain, Dst, Src, LenAdj, Byte);
64}
65
66static SDValue emitMemMemReg(SelectionDAG &DAG, const SDLoc &DL, unsigned Op,
67 SDValue Chain, SDValue Dst, SDValue Src,
68 SDValue Size, SDValue Byte = SDValue()) {
69 int64_t Adj = getMemMemLenAdj(Op);
70 SDValue LenAdj = DAG.getNode(Opcode: ISD::ADD, DL, VT: MVT::i64,
71 N1: DAG.getZExtOrTrunc(Op: Size, DL, VT: MVT::i64),
72 N2: DAG.getSignedConstant(Val: 0 - Adj, DL, VT: MVT::i64));
73 return createMemMemNode(DAG, DL, Op, Chain, Dst, Src, LenAdj, Byte);
74}
75
76SDValue SystemZSelectionDAGInfo::EmitTargetCodeForMemcpy(
77 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dst, SDValue Src,
78 SDValue Size, Align Alignment, bool IsVolatile, bool AlwaysInline,
79 MachinePointerInfo DstPtrInfo, MachinePointerInfo SrcPtrInfo) const {
80 if (IsVolatile)
81 return SDValue();
82
83 if (auto *CSize = dyn_cast<ConstantSDNode>(Val&: Size))
84 return emitMemMemImm(DAG, DL, Op: SystemZISD::MVC, Chain, Dst, Src,
85 Size: CSize->getZExtValue());
86
87 return emitMemMemReg(DAG, DL, Op: SystemZISD::MVC, Chain, Dst, Src, Size);
88}
89
90// Handle a memset of 1, 2, 4 or 8 bytes with the operands given by
91// Chain, Dst, ByteVal and Size. These cases are expected to use
92// MVI, MVHHI, MVHI and MVGHI respectively.
93static SDValue memsetStore(SelectionDAG &DAG, const SDLoc &DL, SDValue Chain,
94 SDValue Dst, uint64_t ByteVal, uint64_t Size,
95 Align Alignment, MachinePointerInfo DstPtrInfo) {
96 uint64_t StoreVal = ByteVal;
97 for (unsigned I = 1; I < Size; ++I)
98 StoreVal |= ByteVal << (I * 8);
99 return DAG.getStore(
100 Chain, dl: DL, Val: DAG.getConstant(Val: StoreVal, DL, VT: MVT::getIntegerVT(BitWidth: Size * 8)),
101 Ptr: Dst, PtrInfo: DstPtrInfo, Alignment);
102}
103
104SDValue SystemZSelectionDAGInfo::EmitTargetCodeForMemset(
105 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dst,
106 SDValue Byte, SDValue Size, Align Alignment, bool IsVolatile,
107 bool AlwaysInline, MachinePointerInfo DstPtrInfo) const {
108 EVT PtrVT = Dst.getValueType();
109
110 if (IsVolatile)
111 return SDValue();
112
113 auto *CByte = dyn_cast<ConstantSDNode>(Val&: Byte);
114 if (auto *CSize = dyn_cast<ConstantSDNode>(Val&: Size)) {
115 uint64_t Bytes = CSize->getZExtValue();
116 if (Bytes == 0)
117 return SDValue();
118 if (CByte) {
119 // Handle cases that can be done using at most two of
120 // MVI, MVHI, MVHHI and MVGHI. The latter two can only be
121 // used if ByteVal is all zeros or all ones; in other cases,
122 // we can move at most 2 halfwords.
123 uint64_t ByteVal = CByte->getZExtValue();
124 if (ByteVal == 0 || ByteVal == 255
125 ? Bytes <= 16 && llvm::popcount(Value: Bytes) <= 2
126 : Bytes <= 4) {
127 unsigned Size1 = Bytes == 16 ? 8 : llvm::bit_floor(Value: Bytes);
128 unsigned Size2 = Bytes - Size1;
129 SDValue Chain1 = memsetStore(DAG, DL, Chain, Dst, ByteVal, Size: Size1,
130 Alignment, DstPtrInfo);
131 if (Size2 == 0)
132 return Chain1;
133 Dst = DAG.getNode(Opcode: ISD::ADD, DL, VT: PtrVT, N1: Dst,
134 N2: DAG.getConstant(Val: Size1, DL, VT: PtrVT));
135 DstPtrInfo = DstPtrInfo.getWithOffset(O: Size1);
136 SDValue Chain2 =
137 memsetStore(DAG, DL, Chain, Dst, ByteVal, Size: Size2,
138 Alignment: std::min(a: Alignment, b: Align(Size1)), DstPtrInfo);
139 return DAG.getNode(Opcode: ISD::TokenFactor, DL, VT: MVT::Other, N1: Chain1, N2: Chain2);
140 }
141 } else {
142 // Handle one and two bytes using STC.
143 if (Bytes <= 2) {
144 SDValue Chain1 =
145 DAG.getStore(Chain, dl: DL, Val: Byte, Ptr: Dst, PtrInfo: DstPtrInfo, Alignment);
146 if (Bytes == 1)
147 return Chain1;
148 SDValue Dst2 = DAG.getNode(Opcode: ISD::ADD, DL, VT: PtrVT, N1: Dst,
149 N2: DAG.getConstant(Val: 1, DL, VT: PtrVT));
150 SDValue Chain2 = DAG.getStore(Chain, dl: DL, Val: Byte, Ptr: Dst2,
151 PtrInfo: DstPtrInfo.getWithOffset(O: 1), Alignment: Align(1));
152 return DAG.getNode(Opcode: ISD::TokenFactor, DL, VT: MVT::Other, N1: Chain1, N2: Chain2);
153 }
154 }
155 assert(Bytes >= 2 && "Should have dealt with 0- and 1-byte cases already");
156
157 // Handle the special case of a memset of 0, which can use XC.
158 if (CByte && CByte->getZExtValue() == 0)
159 return emitMemMemImm(DAG, DL, Op: SystemZISD::XC, Chain, Dst, Src: Dst, Size: Bytes);
160
161 return emitMemMemImm(DAG, DL, Op: SystemZISD::MEMSET_MVC, Chain, Dst, Src: SDValue(),
162 Size: Bytes, Byte: DAG.getAnyExtOrTrunc(Op: Byte, DL, VT: MVT::i32));
163 }
164
165 // Variable length
166 if (CByte && CByte->getZExtValue() == 0)
167 // Handle the special case of a variable length memset of 0 with XC.
168 return emitMemMemReg(DAG, DL, Op: SystemZISD::XC, Chain, Dst, Src: Dst, Size);
169
170 return emitMemMemReg(DAG, DL, Op: SystemZISD::MEMSET_MVC, Chain, Dst, Src: SDValue(),
171 Size, Byte: DAG.getAnyExtOrTrunc(Op: Byte, DL, VT: MVT::i32));
172}
173
174// Convert the current CC value into an integer that is 0 if CC == 0,
175// greater than zero if CC == 1 and less than zero if CC >= 2.
176// The sequence starts with IPM, which puts CC into bits 29 and 28
177// of an integer and clears bits 30 and 31.
178static SDValue addIPMSequence(const SDLoc &DL, SDValue CCReg,
179 SelectionDAG &DAG) {
180 SDValue IPM = DAG.getNode(Opcode: SystemZISD::IPM, DL, VT: MVT::i32, Operand: CCReg);
181 SDValue SHL = DAG.getNode(Opcode: ISD::SHL, DL, VT: MVT::i32, N1: IPM,
182 N2: DAG.getConstant(Val: 30 - SystemZ::IPM_CC, DL, VT: MVT::i32));
183 SDValue SRA = DAG.getNode(Opcode: ISD::SRA, DL, VT: MVT::i32, N1: SHL,
184 N2: DAG.getConstant(Val: 30, DL, VT: MVT::i32));
185 return SRA;
186}
187
188std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForMemcmp(
189 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src1,
190 SDValue Src2, SDValue Size, const CallInst *CI) const {
191 SDValue CCReg;
192 // Swap operands to invert CC == 1 vs. CC == 2 cases.
193 if (auto *CSize = dyn_cast<ConstantSDNode>(Val&: Size)) {
194 uint64_t Bytes = CSize->getZExtValue();
195 assert(Bytes > 0 && "Caller should have handled 0-size case");
196 CCReg = emitMemMemImm(DAG, DL, Op: SystemZISD::CLC, Chain, Dst: Src2, Src: Src1, Size: Bytes);
197 } else
198 CCReg = emitMemMemReg(DAG, DL, Op: SystemZISD::CLC, Chain, Dst: Src2, Src: Src1, Size);
199 Chain = CCReg.getValue(R: 1);
200 return std::make_pair(x: addIPMSequence(DL, CCReg, DAG), y&: Chain);
201}
202
203std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForMemchr(
204 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src,
205 SDValue Char, SDValue Length, MachinePointerInfo SrcPtrInfo) const {
206 // Use SRST to find the character. End is its address on success.
207 EVT PtrVT = Src.getValueType();
208 SDVTList VTs = DAG.getVTList(VT1: PtrVT, VT2: MVT::i32, VT3: MVT::Other);
209 Length = DAG.getZExtOrTrunc(Op: Length, DL, VT: PtrVT);
210 Char = DAG.getZExtOrTrunc(Op: Char, DL, VT: MVT::i32);
211 Char = DAG.getNode(Opcode: ISD::AND, DL, VT: MVT::i32, N1: Char,
212 N2: DAG.getConstant(Val: 255, DL, VT: MVT::i32));
213 SDValue Limit = DAG.getNode(Opcode: ISD::ADD, DL, VT: PtrVT, N1: Src, N2: Length);
214 SDValue End = DAG.getNode(Opcode: SystemZISD::SEARCH_STRING, DL, VTList: VTs, N1: Chain,
215 N2: Limit, N3: Src, N4: Char);
216 SDValue CCReg = End.getValue(R: 1);
217 Chain = End.getValue(R: 2);
218
219 // Now select between End and null, depending on whether the character
220 // was found.
221 SDValue Ops[] = {
222 End, DAG.getConstant(Val: 0, DL, VT: PtrVT),
223 DAG.getTargetConstant(Val: SystemZ::CCMASK_SRST, DL, VT: MVT::i32),
224 DAG.getTargetConstant(Val: SystemZ::CCMASK_SRST_FOUND, DL, VT: MVT::i32), CCReg};
225 End = DAG.getNode(Opcode: SystemZISD::SELECT_CCMASK, DL, VT: PtrVT, Ops);
226 return std::make_pair(x&: End, y&: Chain);
227}
228
229std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForStrcpy(
230 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Dest,
231 SDValue Src, MachinePointerInfo DestPtrInfo, MachinePointerInfo SrcPtrInfo,
232 bool isStpcpy, const CallInst *CI) const {
233 SDVTList VTs = DAG.getVTList(VT1: Dest.getValueType(), VT2: MVT::Other);
234 SDValue EndDest = DAG.getNode(Opcode: SystemZISD::STPCPY, DL, VTList: VTs, N1: Chain, N2: Dest, N3: Src,
235 N4: DAG.getConstant(Val: 0, DL, VT: MVT::i32));
236 return std::make_pair(x&: isStpcpy ? EndDest : Dest, y: EndDest.getValue(R: 1));
237}
238
239std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForStrcmp(
240 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src1,
241 SDValue Src2, MachinePointerInfo Op1PtrInfo, MachinePointerInfo Op2PtrInfo,
242 const CallInst *CI) const {
243 SDVTList VTs = DAG.getVTList(VT1: Src1.getValueType(), VT2: MVT::i32, VT3: MVT::Other);
244 // Swap operands to invert CC == 1 vs. CC == 2 cases.
245 SDValue Unused = DAG.getNode(Opcode: SystemZISD::STRCMP, DL, VTList: VTs, N1: Chain, N2: Src2, N3: Src1,
246 N4: DAG.getConstant(Val: 0, DL, VT: MVT::i32));
247 SDValue CCReg = Unused.getValue(R: 1);
248 Chain = Unused.getValue(R: 2);
249 return std::make_pair(x: addIPMSequence(DL, CCReg, DAG), y&: Chain);
250}
251
252// Search from Src for a null character, stopping once Src reaches Limit.
253// Return a pair of values, the first being the number of nonnull characters
254// and the second being the out chain.
255//
256// This can be used for strlen by setting Limit to 0.
257static std::pair<SDValue, SDValue> getBoundedStrlen(SelectionDAG &DAG,
258 const SDLoc &DL,
259 SDValue Chain, SDValue Src,
260 SDValue Limit) {
261 EVT PtrVT = Src.getValueType();
262 SDVTList VTs = DAG.getVTList(VT1: PtrVT, VT2: MVT::i32, VT3: MVT::Other);
263 SDValue End = DAG.getNode(Opcode: SystemZISD::SEARCH_STRING, DL, VTList: VTs, N1: Chain,
264 N2: Limit, N3: Src, N4: DAG.getConstant(Val: 0, DL, VT: MVT::i32));
265 Chain = End.getValue(R: 2);
266 SDValue Len = DAG.getNode(Opcode: ISD::SUB, DL, VT: PtrVT, N1: End, N2: Src);
267 return std::make_pair(x&: Len, y&: Chain);
268}
269
270std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForStrlen(
271 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src,
272 const CallInst *CI) const {
273 EVT PtrVT = Src.getValueType();
274 return getBoundedStrlen(DAG, DL, Chain, Src, Limit: DAG.getConstant(Val: 0, DL, VT: PtrVT));
275}
276
277std::pair<SDValue, SDValue> SystemZSelectionDAGInfo::EmitTargetCodeForStrnlen(
278 SelectionDAG &DAG, const SDLoc &DL, SDValue Chain, SDValue Src,
279 SDValue MaxLength, MachinePointerInfo SrcPtrInfo) const {
280 EVT PtrVT = Src.getValueType();
281 MaxLength = DAG.getZExtOrTrunc(Op: MaxLength, DL, VT: PtrVT);
282 SDValue Limit = DAG.getNode(Opcode: ISD::ADD, DL, VT: PtrVT, N1: Src, N2: MaxLength);
283 return getBoundedStrlen(DAG, DL, Chain, Src, Limit);
284}
285