File: | llvm/lib/Target/AMDGPU/SIModeRegister.cpp |
Warning: | line 190, column 55 The result of the left shift is undefined due to shifting by '32', which is greater or equal to the width of type 'int' |
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1 | //===-- SIModeRegister.cpp - Mode Register --------------------------------===// | |||
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 pass inserts changes to the Mode register settings as required. | |||
10 | /// Note that currently it only deals with the Double Precision Floating Point | |||
11 | /// rounding mode setting, but is intended to be generic enough to be easily | |||
12 | /// expanded. | |||
13 | /// | |||
14 | //===----------------------------------------------------------------------===// | |||
15 | // | |||
16 | #include "AMDGPU.h" | |||
17 | #include "GCNSubtarget.h" | |||
18 | #include "MCTargetDesc/AMDGPUMCTargetDesc.h" | |||
19 | #include "llvm/ADT/Statistic.h" | |||
20 | #include <queue> | |||
21 | ||||
22 | #define DEBUG_TYPE"si-mode-register" "si-mode-register" | |||
23 | ||||
24 | STATISTIC(NumSetregInserted, "Number of setreg of mode register inserted.")static llvm::Statistic NumSetregInserted = {"si-mode-register" , "NumSetregInserted", "Number of setreg of mode register inserted." }; | |||
25 | ||||
26 | using namespace llvm; | |||
27 | ||||
28 | struct Status { | |||
29 | // Mask is a bitmask where a '1' indicates the corresponding Mode bit has a | |||
30 | // known value | |||
31 | unsigned Mask; | |||
32 | unsigned Mode; | |||
33 | ||||
34 | Status() : Mask(0), Mode(0){}; | |||
35 | ||||
36 | Status(unsigned NewMask, unsigned NewMode) : Mask(NewMask), Mode(NewMode) { | |||
37 | Mode &= Mask; | |||
38 | }; | |||
39 | ||||
40 | // merge two status values such that only values that don't conflict are | |||
41 | // preserved | |||
42 | Status merge(const Status &S) const { | |||
43 | return Status((Mask | S.Mask), ((Mode & ~S.Mask) | (S.Mode & S.Mask))); | |||
44 | } | |||
45 | ||||
46 | // merge an unknown value by using the unknown value's mask to remove bits | |||
47 | // from the result | |||
48 | Status mergeUnknown(unsigned newMask) { | |||
49 | return Status(Mask & ~newMask, Mode & ~newMask); | |||
50 | } | |||
51 | ||||
52 | // intersect two Status values to produce a mode and mask that is a subset | |||
53 | // of both values | |||
54 | Status intersect(const Status &S) const { | |||
55 | unsigned NewMask = (Mask & S.Mask) & (Mode ^ ~S.Mode); | |||
56 | unsigned NewMode = (Mode & NewMask); | |||
57 | return Status(NewMask, NewMode); | |||
58 | } | |||
59 | ||||
60 | // produce the delta required to change the Mode to the required Mode | |||
61 | Status delta(const Status &S) const { | |||
62 | return Status((S.Mask & (Mode ^ S.Mode)) | (~Mask & S.Mask), S.Mode); | |||
63 | } | |||
64 | ||||
65 | bool operator==(const Status &S) const { | |||
66 | return (Mask == S.Mask) && (Mode == S.Mode); | |||
67 | } | |||
68 | ||||
69 | bool operator!=(const Status &S) const { return !(*this == S); } | |||
70 | ||||
71 | bool isCompatible(Status &S) { | |||
72 | return ((Mask & S.Mask) == S.Mask) && ((Mode & S.Mask) == S.Mode); | |||
73 | } | |||
74 | ||||
75 | bool isCombinable(Status &S) { return !(Mask & S.Mask) || isCompatible(S); } | |||
76 | }; | |||
77 | ||||
78 | class BlockData { | |||
79 | public: | |||
80 | // The Status that represents the mode register settings required by the | |||
81 | // FirstInsertionPoint (if any) in this block. Calculated in Phase 1. | |||
82 | Status Require; | |||
83 | ||||
84 | // The Status that represents the net changes to the Mode register made by | |||
85 | // this block, Calculated in Phase 1. | |||
86 | Status Change; | |||
87 | ||||
88 | // The Status that represents the mode register settings on exit from this | |||
89 | // block. Calculated in Phase 2. | |||
90 | Status Exit; | |||
91 | ||||
92 | // The Status that represents the intersection of exit Mode register settings | |||
93 | // from all predecessor blocks. Calculated in Phase 2, and used by Phase 3. | |||
94 | Status Pred; | |||
95 | ||||
96 | // In Phase 1 we record the first instruction that has a mode requirement, | |||
97 | // which is used in Phase 3 if we need to insert a mode change. | |||
98 | MachineInstr *FirstInsertionPoint; | |||
99 | ||||
100 | // A flag to indicate whether an Exit value has been set (we can't tell by | |||
101 | // examining the Exit value itself as all values may be valid results). | |||
102 | bool ExitSet; | |||
103 | ||||
104 | BlockData() : FirstInsertionPoint(nullptr), ExitSet(false){}; | |||
105 | }; | |||
106 | ||||
107 | namespace { | |||
108 | ||||
109 | class SIModeRegister : public MachineFunctionPass { | |||
110 | public: | |||
111 | static char ID; | |||
112 | ||||
113 | std::vector<std::unique_ptr<BlockData>> BlockInfo; | |||
114 | std::queue<MachineBasicBlock *> Phase2List; | |||
115 | ||||
116 | // The default mode register setting currently only caters for the floating | |||
117 | // point double precision rounding mode. | |||
118 | // We currently assume the default rounding mode is Round to Nearest | |||
119 | // NOTE: this should come from a per function rounding mode setting once such | |||
120 | // a setting exists. | |||
121 | unsigned DefaultMode = FP_ROUND_ROUND_TO_NEAREST0; | |||
122 | Status DefaultStatus = | |||
123 | Status(FP_ROUND_MODE_DP(0x3)(((0x3) & 0x3) << 2), FP_ROUND_MODE_DP(DefaultMode)(((DefaultMode) & 0x3) << 2)); | |||
124 | ||||
125 | bool Changed = false; | |||
126 | ||||
127 | public: | |||
128 | SIModeRegister() : MachineFunctionPass(ID) {} | |||
129 | ||||
130 | bool runOnMachineFunction(MachineFunction &MF) override; | |||
131 | ||||
132 | void getAnalysisUsage(AnalysisUsage &AU) const override { | |||
133 | AU.setPreservesCFG(); | |||
134 | MachineFunctionPass::getAnalysisUsage(AU); | |||
135 | } | |||
136 | ||||
137 | void processBlockPhase1(MachineBasicBlock &MBB, const SIInstrInfo *TII); | |||
138 | ||||
139 | void processBlockPhase2(MachineBasicBlock &MBB, const SIInstrInfo *TII); | |||
140 | ||||
141 | void processBlockPhase3(MachineBasicBlock &MBB, const SIInstrInfo *TII); | |||
142 | ||||
143 | Status getInstructionMode(MachineInstr &MI, const SIInstrInfo *TII); | |||
144 | ||||
145 | void insertSetreg(MachineBasicBlock &MBB, MachineInstr *I, | |||
146 | const SIInstrInfo *TII, Status InstrMode); | |||
147 | }; | |||
148 | } // End anonymous namespace. | |||
149 | ||||
150 | INITIALIZE_PASS(SIModeRegister, DEBUG_TYPE,static void *initializeSIModeRegisterPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Insert required mode register values" , "si-mode-register", &SIModeRegister::ID, PassInfo::NormalCtor_t (callDefaultCtor<SIModeRegister>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeSIModeRegisterPassFlag; void llvm::initializeSIModeRegisterPass (PassRegistry &Registry) { llvm::call_once(InitializeSIModeRegisterPassFlag , initializeSIModeRegisterPassOnce, std::ref(Registry)); } | |||
151 | "Insert required mode register values", false, false)static void *initializeSIModeRegisterPassOnce(PassRegistry & Registry) { PassInfo *PI = new PassInfo( "Insert required mode register values" , "si-mode-register", &SIModeRegister::ID, PassInfo::NormalCtor_t (callDefaultCtor<SIModeRegister>), false, false); Registry .registerPass(*PI, true); return PI; } static llvm::once_flag InitializeSIModeRegisterPassFlag; void llvm::initializeSIModeRegisterPass (PassRegistry &Registry) { llvm::call_once(InitializeSIModeRegisterPassFlag , initializeSIModeRegisterPassOnce, std::ref(Registry)); } | |||
152 | ||||
153 | char SIModeRegister::ID = 0; | |||
154 | ||||
155 | char &llvm::SIModeRegisterID = SIModeRegister::ID; | |||
156 | ||||
157 | FunctionPass *llvm::createSIModeRegisterPass() { return new SIModeRegister(); } | |||
158 | ||||
159 | // Determine the Mode register setting required for this instruction. | |||
160 | // Instructions which don't use the Mode register return a null Status. | |||
161 | // Note this currently only deals with instructions that use the floating point | |||
162 | // double precision setting. | |||
163 | Status SIModeRegister::getInstructionMode(MachineInstr &MI, | |||
164 | const SIInstrInfo *TII) { | |||
165 | if (TII->usesFPDPRounding(MI)) { | |||
166 | switch (MI.getOpcode()) { | |||
167 | case AMDGPU::V_INTERP_P1LL_F16: | |||
168 | case AMDGPU::V_INTERP_P1LV_F16: | |||
169 | case AMDGPU::V_INTERP_P2_F16: | |||
170 | // f16 interpolation instructions need double precision round to zero | |||
171 | return Status(FP_ROUND_MODE_DP(3)(((3) & 0x3) << 2), | |||
172 | FP_ROUND_MODE_DP(FP_ROUND_ROUND_TO_ZERO)(((3) & 0x3) << 2)); | |||
173 | default: | |||
174 | return DefaultStatus; | |||
175 | } | |||
176 | } | |||
177 | return Status(); | |||
178 | } | |||
179 | ||||
180 | // Insert a setreg instruction to update the Mode register. | |||
181 | // It is possible (though unlikely) for an instruction to require a change to | |||
182 | // the value of disjoint parts of the Mode register when we don't know the | |||
183 | // value of the intervening bits. In that case we need to use more than one | |||
184 | // setreg instruction. | |||
185 | void SIModeRegister::insertSetreg(MachineBasicBlock &MBB, MachineInstr *MI, | |||
186 | const SIInstrInfo *TII, Status InstrMode) { | |||
187 | while (InstrMode.Mask) { | |||
188 | unsigned Offset = countTrailingZeros<unsigned>(InstrMode.Mask); | |||
189 | unsigned Width = countTrailingOnes<unsigned>(InstrMode.Mask >> Offset); | |||
190 | unsigned Value = (InstrMode.Mode >> Offset) & ((1 << Width) - 1); | |||
| ||||
191 | BuildMI(MBB, MI, 0, TII->get(AMDGPU::S_SETREG_IMM32_B32)) | |||
192 | .addImm(Value) | |||
193 | .addImm(((Width - 1) << AMDGPU::Hwreg::WIDTH_M1_SHIFT_) | | |||
194 | (Offset << AMDGPU::Hwreg::OFFSET_SHIFT_) | | |||
195 | (AMDGPU::Hwreg::ID_MODE << AMDGPU::Hwreg::ID_SHIFT_)); | |||
196 | ++NumSetregInserted; | |||
197 | Changed = true; | |||
198 | InstrMode.Mask &= ~(((1 << Width) - 1) << Offset); | |||
199 | } | |||
200 | } | |||
201 | ||||
202 | // In Phase 1 we iterate through the instructions of the block and for each | |||
203 | // instruction we get its mode usage. If the instruction uses the Mode register | |||
204 | // we: | |||
205 | // - update the Change status, which tracks the changes to the Mode register | |||
206 | // made by this block | |||
207 | // - if this instruction's requirements are compatible with the current setting | |||
208 | // of the Mode register we merge the modes | |||
209 | // - if it isn't compatible and an InsertionPoint isn't set, then we set the | |||
210 | // InsertionPoint to the current instruction, and we remember the current | |||
211 | // mode | |||
212 | // - if it isn't compatible and InsertionPoint is set we insert a seteg before | |||
213 | // that instruction (unless this instruction forms part of the block's | |||
214 | // entry requirements in which case the insertion is deferred until Phase 3 | |||
215 | // when predecessor exit values are known), and move the insertion point to | |||
216 | // this instruction | |||
217 | // - if this is a setreg instruction we treat it as an incompatible instruction. | |||
218 | // This is sub-optimal but avoids some nasty corner cases, and is expected to | |||
219 | // occur very rarely. | |||
220 | // - on exit we have set the Require, Change, and initial Exit modes. | |||
221 | void SIModeRegister::processBlockPhase1(MachineBasicBlock &MBB, | |||
222 | const SIInstrInfo *TII) { | |||
223 | auto NewInfo = std::make_unique<BlockData>(); | |||
224 | MachineInstr *InsertionPoint = nullptr; | |||
225 | // RequirePending is used to indicate whether we are collecting the initial | |||
226 | // requirements for the block, and need to defer the first InsertionPoint to | |||
227 | // Phase 3. It is set to false once we have set FirstInsertionPoint, or when | |||
228 | // we discover an explict setreg that means this block doesn't have any | |||
229 | // initial requirements. | |||
230 | bool RequirePending = true; | |||
231 | Status IPChange; | |||
232 | for (MachineInstr &MI : MBB) { | |||
233 | Status InstrMode = getInstructionMode(MI, TII); | |||
234 | if (MI.getOpcode() == AMDGPU::S_SETREG_B32 || | |||
235 | MI.getOpcode() == AMDGPU::S_SETREG_B32_mode || | |||
236 | MI.getOpcode() == AMDGPU::S_SETREG_IMM32_B32 || | |||
237 | MI.getOpcode() == AMDGPU::S_SETREG_IMM32_B32_mode) { | |||
238 | // We preserve any explicit mode register setreg instruction we encounter, | |||
239 | // as we assume it has been inserted by a higher authority (this is | |||
240 | // likely to be a very rare occurrence). | |||
241 | unsigned Dst = TII->getNamedOperand(MI, AMDGPU::OpName::simm16)->getImm(); | |||
242 | if (((Dst & AMDGPU::Hwreg::ID_MASK_) >> AMDGPU::Hwreg::ID_SHIFT_) != | |||
243 | AMDGPU::Hwreg::ID_MODE) | |||
244 | continue; | |||
245 | ||||
246 | unsigned Width = ((Dst & AMDGPU::Hwreg::WIDTH_M1_MASK_) >> | |||
247 | AMDGPU::Hwreg::WIDTH_M1_SHIFT_) + | |||
248 | 1; | |||
249 | unsigned Offset = | |||
250 | (Dst & AMDGPU::Hwreg::OFFSET_MASK_) >> AMDGPU::Hwreg::OFFSET_SHIFT_; | |||
251 | unsigned Mask = ((1 << Width) - 1) << Offset; | |||
252 | ||||
253 | // If an InsertionPoint is set we will insert a setreg there. | |||
254 | if (InsertionPoint) { | |||
255 | insertSetreg(MBB, InsertionPoint, TII, IPChange.delta(NewInfo->Change)); | |||
256 | InsertionPoint = nullptr; | |||
257 | } | |||
258 | // If this is an immediate then we know the value being set, but if it is | |||
259 | // not an immediate then we treat the modified bits of the mode register | |||
260 | // as unknown. | |||
261 | if (MI.getOpcode() == AMDGPU::S_SETREG_IMM32_B32 || | |||
262 | MI.getOpcode() == AMDGPU::S_SETREG_IMM32_B32_mode) { | |||
263 | unsigned Val = TII->getNamedOperand(MI, AMDGPU::OpName::imm)->getImm(); | |||
264 | unsigned Mode = (Val << Offset) & Mask; | |||
265 | Status Setreg = Status(Mask, Mode); | |||
266 | // If we haven't already set the initial requirements for the block we | |||
267 | // don't need to as the requirements start from this explicit setreg. | |||
268 | RequirePending = false; | |||
269 | NewInfo->Change = NewInfo->Change.merge(Setreg); | |||
270 | } else { | |||
271 | NewInfo->Change = NewInfo->Change.mergeUnknown(Mask); | |||
272 | } | |||
273 | } else if (!NewInfo->Change.isCompatible(InstrMode)) { | |||
274 | // This instruction uses the Mode register and its requirements aren't | |||
275 | // compatible with the current mode. | |||
276 | if (InsertionPoint) { | |||
277 | // If the required mode change cannot be included in the current | |||
278 | // InsertionPoint changes, we need a setreg and start a new | |||
279 | // InsertionPoint. | |||
280 | if (!IPChange.delta(NewInfo->Change).isCombinable(InstrMode)) { | |||
281 | if (RequirePending) { | |||
282 | // This is the first insertionPoint in the block so we will defer | |||
283 | // the insertion of the setreg to Phase 3 where we know whether or | |||
284 | // not it is actually needed. | |||
285 | NewInfo->FirstInsertionPoint = InsertionPoint; | |||
286 | NewInfo->Require = NewInfo->Change; | |||
287 | RequirePending = false; | |||
288 | } else { | |||
289 | insertSetreg(MBB, InsertionPoint, TII, | |||
290 | IPChange.delta(NewInfo->Change)); | |||
291 | IPChange = NewInfo->Change; | |||
292 | } | |||
293 | // Set the new InsertionPoint | |||
294 | InsertionPoint = &MI; | |||
295 | } | |||
296 | NewInfo->Change = NewInfo->Change.merge(InstrMode); | |||
297 | } else { | |||
298 | // No InsertionPoint is currently set - this is either the first in | |||
299 | // the block or we have previously seen an explicit setreg. | |||
300 | InsertionPoint = &MI; | |||
301 | IPChange = NewInfo->Change; | |||
302 | NewInfo->Change = NewInfo->Change.merge(InstrMode); | |||
303 | } | |||
304 | } | |||
305 | } | |||
306 | if (RequirePending) { | |||
307 | // If we haven't yet set the initial requirements for the block we set them | |||
308 | // now. | |||
309 | NewInfo->FirstInsertionPoint = InsertionPoint; | |||
310 | NewInfo->Require = NewInfo->Change; | |||
311 | } else if (InsertionPoint) { | |||
312 | // We need to insert a setreg at the InsertionPoint | |||
313 | insertSetreg(MBB, InsertionPoint, TII, IPChange.delta(NewInfo->Change)); | |||
314 | } | |||
315 | NewInfo->Exit = NewInfo->Change; | |||
316 | BlockInfo[MBB.getNumber()] = std::move(NewInfo); | |||
317 | } | |||
318 | ||||
319 | // In Phase 2 we revisit each block and calculate the common Mode register | |||
320 | // value provided by all predecessor blocks. If the Exit value for the block | |||
321 | // is changed, then we add the successor blocks to the worklist so that the | |||
322 | // exit value is propagated. | |||
323 | void SIModeRegister::processBlockPhase2(MachineBasicBlock &MBB, | |||
324 | const SIInstrInfo *TII) { | |||
325 | bool RevisitRequired = false; | |||
326 | bool ExitSet = false; | |||
327 | unsigned ThisBlock = MBB.getNumber(); | |||
328 | if (MBB.pred_empty()) { | |||
329 | // There are no predecessors, so use the default starting status. | |||
330 | BlockInfo[ThisBlock]->Pred = DefaultStatus; | |||
331 | ExitSet = true; | |||
332 | } else { | |||
333 | // Build a status that is common to all the predecessors by intersecting | |||
334 | // all the predecessor exit status values. | |||
335 | // Mask bits (which represent the Mode bits with a known value) can only be | |||
336 | // added by explicit SETREG instructions or the initial default value - | |||
337 | // the intersection process may remove Mask bits. | |||
338 | // If we find a predecessor that has not yet had an exit value determined | |||
339 | // (this can happen for example if a block is its own predecessor) we defer | |||
340 | // use of that value as the Mask will be all zero, and we will revisit this | |||
341 | // block again later (unless the only predecessor without an exit value is | |||
342 | // this block). | |||
343 | MachineBasicBlock::pred_iterator P = MBB.pred_begin(), E = MBB.pred_end(); | |||
344 | MachineBasicBlock &PB = *(*P); | |||
345 | unsigned PredBlock = PB.getNumber(); | |||
346 | if ((ThisBlock == PredBlock) && (std::next(P) == E)) { | |||
347 | BlockInfo[ThisBlock]->Pred = DefaultStatus; | |||
348 | ExitSet = true; | |||
349 | } else if (BlockInfo[PredBlock]->ExitSet) { | |||
350 | BlockInfo[ThisBlock]->Pred = BlockInfo[PredBlock]->Exit; | |||
351 | ExitSet = true; | |||
352 | } else if (PredBlock != ThisBlock) | |||
353 | RevisitRequired = true; | |||
354 | ||||
355 | for (P = std::next(P); P != E; P = std::next(P)) { | |||
356 | MachineBasicBlock *Pred = *P; | |||
357 | unsigned PredBlock = Pred->getNumber(); | |||
358 | if (BlockInfo[PredBlock]->ExitSet) { | |||
359 | if (BlockInfo[ThisBlock]->ExitSet) { | |||
360 | BlockInfo[ThisBlock]->Pred = | |||
361 | BlockInfo[ThisBlock]->Pred.intersect(BlockInfo[PredBlock]->Exit); | |||
362 | } else { | |||
363 | BlockInfo[ThisBlock]->Pred = BlockInfo[PredBlock]->Exit; | |||
364 | } | |||
365 | ExitSet = true; | |||
366 | } else if (PredBlock != ThisBlock) | |||
367 | RevisitRequired = true; | |||
368 | } | |||
369 | } | |||
370 | Status TmpStatus = | |||
371 | BlockInfo[ThisBlock]->Pred.merge(BlockInfo[ThisBlock]->Change); | |||
372 | if (BlockInfo[ThisBlock]->Exit != TmpStatus) { | |||
373 | BlockInfo[ThisBlock]->Exit = TmpStatus; | |||
374 | // Add the successors to the work list so we can propagate the changed exit | |||
375 | // status. | |||
376 | for (MachineBasicBlock::succ_iterator S = MBB.succ_begin(), | |||
377 | E = MBB.succ_end(); | |||
378 | S != E; S = std::next(S)) { | |||
379 | MachineBasicBlock &B = *(*S); | |||
380 | Phase2List.push(&B); | |||
381 | } | |||
382 | } | |||
383 | BlockInfo[ThisBlock]->ExitSet = ExitSet; | |||
384 | if (RevisitRequired) | |||
385 | Phase2List.push(&MBB); | |||
386 | } | |||
387 | ||||
388 | // In Phase 3 we revisit each block and if it has an insertion point defined we | |||
389 | // check whether the predecessor mode meets the block's entry requirements. If | |||
390 | // not we insert an appropriate setreg instruction to modify the Mode register. | |||
391 | void SIModeRegister::processBlockPhase3(MachineBasicBlock &MBB, | |||
392 | const SIInstrInfo *TII) { | |||
393 | unsigned ThisBlock = MBB.getNumber(); | |||
394 | if (!BlockInfo[ThisBlock]->Pred.isCompatible(BlockInfo[ThisBlock]->Require)) { | |||
395 | Status Delta = | |||
396 | BlockInfo[ThisBlock]->Pred.delta(BlockInfo[ThisBlock]->Require); | |||
397 | if (BlockInfo[ThisBlock]->FirstInsertionPoint) | |||
398 | insertSetreg(MBB, BlockInfo[ThisBlock]->FirstInsertionPoint, TII, Delta); | |||
399 | else | |||
400 | insertSetreg(MBB, &MBB.instr_front(), TII, Delta); | |||
401 | } | |||
402 | } | |||
403 | ||||
404 | bool SIModeRegister::runOnMachineFunction(MachineFunction &MF) { | |||
405 | BlockInfo.resize(MF.getNumBlockIDs()); | |||
406 | const GCNSubtarget &ST = MF.getSubtarget<GCNSubtarget>(); | |||
407 | const SIInstrInfo *TII = ST.getInstrInfo(); | |||
408 | ||||
409 | // Processing is performed in a number of phases | |||
410 | ||||
411 | // Phase 1 - determine the initial mode required by each block, and add setreg | |||
412 | // instructions for intra block requirements. | |||
413 | for (MachineBasicBlock &BB : MF) | |||
414 | processBlockPhase1(BB, TII); | |||
415 | ||||
416 | // Phase 2 - determine the exit mode from each block. We add all blocks to the | |||
417 | // list here, but will also add any that need to be revisited during Phase 2 | |||
418 | // processing. | |||
419 | for (MachineBasicBlock &BB : MF) | |||
420 | Phase2List.push(&BB); | |||
421 | while (!Phase2List.empty()) { | |||
| ||||
422 | processBlockPhase2(*Phase2List.front(), TII); | |||
423 | Phase2List.pop(); | |||
424 | } | |||
425 | ||||
426 | // Phase 3 - add an initial setreg to each block where the required entry mode | |||
427 | // is not satisfied by the exit mode of all its predecessors. | |||
428 | for (MachineBasicBlock &BB : MF) | |||
429 | processBlockPhase3(BB, TII); | |||
430 | ||||
431 | BlockInfo.clear(); | |||
432 | ||||
433 | return Changed; | |||
434 | } |
1 | //===-- llvm/Support/MathExtras.h - Useful math functions -------*- 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 | // | ||||
9 | // This file contains some functions that are useful for math stuff. | ||||
10 | // | ||||
11 | //===----------------------------------------------------------------------===// | ||||
12 | |||||
13 | #ifndef LLVM_SUPPORT_MATHEXTRAS_H | ||||
14 | #define LLVM_SUPPORT_MATHEXTRAS_H | ||||
15 | |||||
16 | #include "llvm/Support/Compiler.h" | ||||
17 | #include <cassert> | ||||
18 | #include <climits> | ||||
19 | #include <cmath> | ||||
20 | #include <cstdint> | ||||
21 | #include <cstring> | ||||
22 | #include <limits> | ||||
23 | #include <type_traits> | ||||
24 | |||||
25 | #ifdef __ANDROID_NDK__ | ||||
26 | #include <android/api-level.h> | ||||
27 | #endif | ||||
28 | |||||
29 | #ifdef _MSC_VER | ||||
30 | // Declare these intrinsics manually rather including intrin.h. It's very | ||||
31 | // expensive, and MathExtras.h is popular. | ||||
32 | // #include <intrin.h> | ||||
33 | extern "C" { | ||||
34 | unsigned char _BitScanForward(unsigned long *_Index, unsigned long _Mask); | ||||
35 | unsigned char _BitScanForward64(unsigned long *_Index, unsigned __int64 _Mask); | ||||
36 | unsigned char _BitScanReverse(unsigned long *_Index, unsigned long _Mask); | ||||
37 | unsigned char _BitScanReverse64(unsigned long *_Index, unsigned __int64 _Mask); | ||||
38 | } | ||||
39 | #endif | ||||
40 | |||||
41 | namespace llvm { | ||||
42 | |||||
43 | /// The behavior an operation has on an input of 0. | ||||
44 | enum ZeroBehavior { | ||||
45 | /// The returned value is undefined. | ||||
46 | ZB_Undefined, | ||||
47 | /// The returned value is numeric_limits<T>::max() | ||||
48 | ZB_Max, | ||||
49 | /// The returned value is numeric_limits<T>::digits | ||||
50 | ZB_Width | ||||
51 | }; | ||||
52 | |||||
53 | /// Mathematical constants. | ||||
54 | namespace numbers { | ||||
55 | // TODO: Track C++20 std::numbers. | ||||
56 | // TODO: Favor using the hexadecimal FP constants (requires C++17). | ||||
57 | constexpr double e = 2.7182818284590452354, // (0x1.5bf0a8b145749P+1) https://oeis.org/A001113 | ||||
58 | egamma = .57721566490153286061, // (0x1.2788cfc6fb619P-1) https://oeis.org/A001620 | ||||
59 | ln2 = .69314718055994530942, // (0x1.62e42fefa39efP-1) https://oeis.org/A002162 | ||||
60 | ln10 = 2.3025850929940456840, // (0x1.24bb1bbb55516P+1) https://oeis.org/A002392 | ||||
61 | log2e = 1.4426950408889634074, // (0x1.71547652b82feP+0) | ||||
62 | log10e = .43429448190325182765, // (0x1.bcb7b1526e50eP-2) | ||||
63 | pi = 3.1415926535897932385, // (0x1.921fb54442d18P+1) https://oeis.org/A000796 | ||||
64 | inv_pi = .31830988618379067154, // (0x1.45f306bc9c883P-2) https://oeis.org/A049541 | ||||
65 | sqrtpi = 1.7724538509055160273, // (0x1.c5bf891b4ef6bP+0) https://oeis.org/A002161 | ||||
66 | inv_sqrtpi = .56418958354775628695, // (0x1.20dd750429b6dP-1) https://oeis.org/A087197 | ||||
67 | sqrt2 = 1.4142135623730950488, // (0x1.6a09e667f3bcdP+0) https://oeis.org/A00219 | ||||
68 | inv_sqrt2 = .70710678118654752440, // (0x1.6a09e667f3bcdP-1) | ||||
69 | sqrt3 = 1.7320508075688772935, // (0x1.bb67ae8584caaP+0) https://oeis.org/A002194 | ||||
70 | inv_sqrt3 = .57735026918962576451, // (0x1.279a74590331cP-1) | ||||
71 | phi = 1.6180339887498948482; // (0x1.9e3779b97f4a8P+0) https://oeis.org/A001622 | ||||
72 | constexpr float ef = 2.71828183F, // (0x1.5bf0a8P+1) https://oeis.org/A001113 | ||||
73 | egammaf = .577215665F, // (0x1.2788d0P-1) https://oeis.org/A001620 | ||||
74 | ln2f = .693147181F, // (0x1.62e430P-1) https://oeis.org/A002162 | ||||
75 | ln10f = 2.30258509F, // (0x1.26bb1cP+1) https://oeis.org/A002392 | ||||
76 | log2ef = 1.44269504F, // (0x1.715476P+0) | ||||
77 | log10ef = .434294482F, // (0x1.bcb7b2P-2) | ||||
78 | pif = 3.14159265F, // (0x1.921fb6P+1) https://oeis.org/A000796 | ||||
79 | inv_pif = .318309886F, // (0x1.45f306P-2) https://oeis.org/A049541 | ||||
80 | sqrtpif = 1.77245385F, // (0x1.c5bf8aP+0) https://oeis.org/A002161 | ||||
81 | inv_sqrtpif = .564189584F, // (0x1.20dd76P-1) https://oeis.org/A087197 | ||||
82 | sqrt2f = 1.41421356F, // (0x1.6a09e6P+0) https://oeis.org/A002193 | ||||
83 | inv_sqrt2f = .707106781F, // (0x1.6a09e6P-1) | ||||
84 | sqrt3f = 1.73205081F, // (0x1.bb67aeP+0) https://oeis.org/A002194 | ||||
85 | inv_sqrt3f = .577350269F, // (0x1.279a74P-1) | ||||
86 | phif = 1.61803399F; // (0x1.9e377aP+0) https://oeis.org/A001622 | ||||
87 | } // namespace numbers | ||||
88 | |||||
89 | namespace detail { | ||||
90 | template <typename T, std::size_t SizeOfT> struct TrailingZerosCounter { | ||||
91 | static unsigned count(T Val, ZeroBehavior) { | ||||
92 | if (!Val) | ||||
93 | return std::numeric_limits<T>::digits; | ||||
94 | if (Val & 0x1) | ||||
95 | return 0; | ||||
96 | |||||
97 | // Bisection method. | ||||
98 | unsigned ZeroBits = 0; | ||||
99 | T Shift = std::numeric_limits<T>::digits >> 1; | ||||
100 | T Mask = std::numeric_limits<T>::max() >> Shift; | ||||
101 | while (Shift) { | ||||
102 | if ((Val & Mask) == 0) { | ||||
103 | Val >>= Shift; | ||||
104 | ZeroBits |= Shift; | ||||
105 | } | ||||
106 | Shift >>= 1; | ||||
107 | Mask >>= Shift; | ||||
108 | } | ||||
109 | return ZeroBits; | ||||
110 | } | ||||
111 | }; | ||||
112 | |||||
113 | #if defined(__GNUC__4) || defined(_MSC_VER) | ||||
114 | template <typename T> struct TrailingZerosCounter<T, 4> { | ||||
115 | static unsigned count(T Val, ZeroBehavior ZB) { | ||||
116 | if (ZB
| ||||
117 | return 32; | ||||
118 | |||||
119 | #if __has_builtin(__builtin_ctz)1 || defined(__GNUC__4) | ||||
120 | return __builtin_ctz(Val); | ||||
121 | #elif defined(_MSC_VER) | ||||
122 | unsigned long Index; | ||||
123 | _BitScanForward(&Index, Val); | ||||
124 | return Index; | ||||
125 | #endif | ||||
126 | } | ||||
127 | }; | ||||
128 | |||||
129 | #if !defined(_MSC_VER) || defined(_M_X64) | ||||
130 | template <typename T> struct TrailingZerosCounter<T, 8> { | ||||
131 | static unsigned count(T Val, ZeroBehavior ZB) { | ||||
132 | if (ZB != ZB_Undefined && Val == 0) | ||||
133 | return 64; | ||||
134 | |||||
135 | #if __has_builtin(__builtin_ctzll)1 || defined(__GNUC__4) | ||||
136 | return __builtin_ctzll(Val); | ||||
137 | #elif defined(_MSC_VER) | ||||
138 | unsigned long Index; | ||||
139 | _BitScanForward64(&Index, Val); | ||||
140 | return Index; | ||||
141 | #endif | ||||
142 | } | ||||
143 | }; | ||||
144 | #endif | ||||
145 | #endif | ||||
146 | } // namespace detail | ||||
147 | |||||
148 | /// Count number of 0's from the least significant bit to the most | ||||
149 | /// stopping at the first 1. | ||||
150 | /// | ||||
151 | /// Only unsigned integral types are allowed. | ||||
152 | /// | ||||
153 | /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are | ||||
154 | /// valid arguments. | ||||
155 | template <typename T> | ||||
156 | unsigned countTrailingZeros(T Val, ZeroBehavior ZB = ZB_Width) { | ||||
157 | static_assert(std::numeric_limits<T>::is_integer && | ||||
158 | !std::numeric_limits<T>::is_signed, | ||||
159 | "Only unsigned integral types are allowed."); | ||||
160 | return llvm::detail::TrailingZerosCounter<T, sizeof(T)>::count(Val, ZB); | ||||
161 | } | ||||
162 | |||||
163 | namespace detail { | ||||
164 | template <typename T, std::size_t SizeOfT> struct LeadingZerosCounter { | ||||
165 | static unsigned count(T Val, ZeroBehavior) { | ||||
166 | if (!Val) | ||||
167 | return std::numeric_limits<T>::digits; | ||||
168 | |||||
169 | // Bisection method. | ||||
170 | unsigned ZeroBits = 0; | ||||
171 | for (T Shift = std::numeric_limits<T>::digits >> 1; Shift; Shift >>= 1) { | ||||
172 | T Tmp = Val >> Shift; | ||||
173 | if (Tmp) | ||||
174 | Val = Tmp; | ||||
175 | else | ||||
176 | ZeroBits |= Shift; | ||||
177 | } | ||||
178 | return ZeroBits; | ||||
179 | } | ||||
180 | }; | ||||
181 | |||||
182 | #if defined(__GNUC__4) || defined(_MSC_VER) | ||||
183 | template <typename T> struct LeadingZerosCounter<T, 4> { | ||||
184 | static unsigned count(T Val, ZeroBehavior ZB) { | ||||
185 | if (ZB != ZB_Undefined && Val == 0) | ||||
186 | return 32; | ||||
187 | |||||
188 | #if __has_builtin(__builtin_clz)1 || defined(__GNUC__4) | ||||
189 | return __builtin_clz(Val); | ||||
190 | #elif defined(_MSC_VER) | ||||
191 | unsigned long Index; | ||||
192 | _BitScanReverse(&Index, Val); | ||||
193 | return Index ^ 31; | ||||
194 | #endif | ||||
195 | } | ||||
196 | }; | ||||
197 | |||||
198 | #if !defined(_MSC_VER) || defined(_M_X64) | ||||
199 | template <typename T> struct LeadingZerosCounter<T, 8> { | ||||
200 | static unsigned count(T Val, ZeroBehavior ZB) { | ||||
201 | if (ZB != ZB_Undefined && Val == 0) | ||||
202 | return 64; | ||||
203 | |||||
204 | #if __has_builtin(__builtin_clzll)1 || defined(__GNUC__4) | ||||
205 | return __builtin_clzll(Val); | ||||
206 | #elif defined(_MSC_VER) | ||||
207 | unsigned long Index; | ||||
208 | _BitScanReverse64(&Index, Val); | ||||
209 | return Index ^ 63; | ||||
210 | #endif | ||||
211 | } | ||||
212 | }; | ||||
213 | #endif | ||||
214 | #endif | ||||
215 | } // namespace detail | ||||
216 | |||||
217 | /// Count number of 0's from the most significant bit to the least | ||||
218 | /// stopping at the first 1. | ||||
219 | /// | ||||
220 | /// Only unsigned integral types are allowed. | ||||
221 | /// | ||||
222 | /// \param ZB the behavior on an input of 0. Only ZB_Width and ZB_Undefined are | ||||
223 | /// valid arguments. | ||||
224 | template <typename T> | ||||
225 | unsigned countLeadingZeros(T Val, ZeroBehavior ZB = ZB_Width) { | ||||
226 | static_assert(std::numeric_limits<T>::is_integer && | ||||
227 | !std::numeric_limits<T>::is_signed, | ||||
228 | "Only unsigned integral types are allowed."); | ||||
229 | return llvm::detail::LeadingZerosCounter<T, sizeof(T)>::count(Val, ZB); | ||||
230 | } | ||||
231 | |||||
232 | /// Get the index of the first set bit starting from the least | ||||
233 | /// significant bit. | ||||
234 | /// | ||||
235 | /// Only unsigned integral types are allowed. | ||||
236 | /// | ||||
237 | /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are | ||||
238 | /// valid arguments. | ||||
239 | template <typename T> T findFirstSet(T Val, ZeroBehavior ZB = ZB_Max) { | ||||
240 | if (ZB == ZB_Max && Val == 0) | ||||
241 | return std::numeric_limits<T>::max(); | ||||
242 | |||||
243 | return countTrailingZeros(Val, ZB_Undefined); | ||||
244 | } | ||||
245 | |||||
246 | /// Create a bitmask with the N right-most bits set to 1, and all other | ||||
247 | /// bits set to 0. Only unsigned types are allowed. | ||||
248 | template <typename T> T maskTrailingOnes(unsigned N) { | ||||
249 | static_assert(std::is_unsigned<T>::value, "Invalid type!"); | ||||
250 | const unsigned Bits = CHAR_BIT8 * sizeof(T); | ||||
251 | assert(N <= Bits && "Invalid bit index")(static_cast <bool> (N <= Bits && "Invalid bit index" ) ? void (0) : __assert_fail ("N <= Bits && \"Invalid bit index\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 251, __extension__ __PRETTY_FUNCTION__)); | ||||
252 | return N == 0 ? 0 : (T(-1) >> (Bits - N)); | ||||
253 | } | ||||
254 | |||||
255 | /// Create a bitmask with the N left-most bits set to 1, and all other | ||||
256 | /// bits set to 0. Only unsigned types are allowed. | ||||
257 | template <typename T> T maskLeadingOnes(unsigned N) { | ||||
258 | return ~maskTrailingOnes<T>(CHAR_BIT8 * sizeof(T) - N); | ||||
259 | } | ||||
260 | |||||
261 | /// Create a bitmask with the N right-most bits set to 0, and all other | ||||
262 | /// bits set to 1. Only unsigned types are allowed. | ||||
263 | template <typename T> T maskTrailingZeros(unsigned N) { | ||||
264 | return maskLeadingOnes<T>(CHAR_BIT8 * sizeof(T) - N); | ||||
265 | } | ||||
266 | |||||
267 | /// Create a bitmask with the N left-most bits set to 0, and all other | ||||
268 | /// bits set to 1. Only unsigned types are allowed. | ||||
269 | template <typename T> T maskLeadingZeros(unsigned N) { | ||||
270 | return maskTrailingOnes<T>(CHAR_BIT8 * sizeof(T) - N); | ||||
271 | } | ||||
272 | |||||
273 | /// Get the index of the last set bit starting from the least | ||||
274 | /// significant bit. | ||||
275 | /// | ||||
276 | /// Only unsigned integral types are allowed. | ||||
277 | /// | ||||
278 | /// \param ZB the behavior on an input of 0. Only ZB_Max and ZB_Undefined are | ||||
279 | /// valid arguments. | ||||
280 | template <typename T> T findLastSet(T Val, ZeroBehavior ZB = ZB_Max) { | ||||
281 | if (ZB == ZB_Max && Val == 0) | ||||
282 | return std::numeric_limits<T>::max(); | ||||
283 | |||||
284 | // Use ^ instead of - because both gcc and llvm can remove the associated ^ | ||||
285 | // in the __builtin_clz intrinsic on x86. | ||||
286 | return countLeadingZeros(Val, ZB_Undefined) ^ | ||||
287 | (std::numeric_limits<T>::digits - 1); | ||||
288 | } | ||||
289 | |||||
290 | /// Macro compressed bit reversal table for 256 bits. | ||||
291 | /// | ||||
292 | /// http://graphics.stanford.edu/~seander/bithacks.html#BitReverseTable | ||||
293 | static const unsigned char BitReverseTable256[256] = { | ||||
294 | #define R2(n) n, n + 2 * 64, n + 1 * 64, n + 3 * 64 | ||||
295 | #define R4(n) R2(n), R2(n + 2 * 16), R2(n + 1 * 16), R2(n + 3 * 16) | ||||
296 | #define R6(n) R4(n), R4(n + 2 * 4), R4(n + 1 * 4), R4(n + 3 * 4) | ||||
297 | R6(0), R6(2), R6(1), R6(3) | ||||
298 | #undef R2 | ||||
299 | #undef R4 | ||||
300 | #undef R6 | ||||
301 | }; | ||||
302 | |||||
303 | /// Reverse the bits in \p Val. | ||||
304 | template <typename T> | ||||
305 | T reverseBits(T Val) { | ||||
306 | unsigned char in[sizeof(Val)]; | ||||
307 | unsigned char out[sizeof(Val)]; | ||||
308 | std::memcpy(in, &Val, sizeof(Val)); | ||||
309 | for (unsigned i = 0; i < sizeof(Val); ++i) | ||||
310 | out[(sizeof(Val) - i) - 1] = BitReverseTable256[in[i]]; | ||||
311 | std::memcpy(&Val, out, sizeof(Val)); | ||||
312 | return Val; | ||||
313 | } | ||||
314 | |||||
315 | #if __has_builtin(__builtin_bitreverse8)1 | ||||
316 | template<> | ||||
317 | inline uint8_t reverseBits<uint8_t>(uint8_t Val) { | ||||
318 | return __builtin_bitreverse8(Val); | ||||
319 | } | ||||
320 | #endif | ||||
321 | |||||
322 | #if __has_builtin(__builtin_bitreverse16)1 | ||||
323 | template<> | ||||
324 | inline uint16_t reverseBits<uint16_t>(uint16_t Val) { | ||||
325 | return __builtin_bitreverse16(Val); | ||||
326 | } | ||||
327 | #endif | ||||
328 | |||||
329 | #if __has_builtin(__builtin_bitreverse32)1 | ||||
330 | template<> | ||||
331 | inline uint32_t reverseBits<uint32_t>(uint32_t Val) { | ||||
332 | return __builtin_bitreverse32(Val); | ||||
333 | } | ||||
334 | #endif | ||||
335 | |||||
336 | #if __has_builtin(__builtin_bitreverse64)1 | ||||
337 | template<> | ||||
338 | inline uint64_t reverseBits<uint64_t>(uint64_t Val) { | ||||
339 | return __builtin_bitreverse64(Val); | ||||
340 | } | ||||
341 | #endif | ||||
342 | |||||
343 | // NOTE: The following support functions use the _32/_64 extensions instead of | ||||
344 | // type overloading so that signed and unsigned integers can be used without | ||||
345 | // ambiguity. | ||||
346 | |||||
347 | /// Return the high 32 bits of a 64 bit value. | ||||
348 | constexpr inline uint32_t Hi_32(uint64_t Value) { | ||||
349 | return static_cast<uint32_t>(Value >> 32); | ||||
350 | } | ||||
351 | |||||
352 | /// Return the low 32 bits of a 64 bit value. | ||||
353 | constexpr inline uint32_t Lo_32(uint64_t Value) { | ||||
354 | return static_cast<uint32_t>(Value); | ||||
355 | } | ||||
356 | |||||
357 | /// Make a 64-bit integer from a high / low pair of 32-bit integers. | ||||
358 | constexpr inline uint64_t Make_64(uint32_t High, uint32_t Low) { | ||||
359 | return ((uint64_t)High << 32) | (uint64_t)Low; | ||||
360 | } | ||||
361 | |||||
362 | /// Checks if an integer fits into the given bit width. | ||||
363 | template <unsigned N> constexpr inline bool isInt(int64_t x) { | ||||
364 | return N >= 64 || (-(INT64_C(1)1L<<(N-1)) <= x && x < (INT64_C(1)1L<<(N-1))); | ||||
365 | } | ||||
366 | // Template specializations to get better code for common cases. | ||||
367 | template <> constexpr inline bool isInt<8>(int64_t x) { | ||||
368 | return static_cast<int8_t>(x) == x; | ||||
369 | } | ||||
370 | template <> constexpr inline bool isInt<16>(int64_t x) { | ||||
371 | return static_cast<int16_t>(x) == x; | ||||
372 | } | ||||
373 | template <> constexpr inline bool isInt<32>(int64_t x) { | ||||
374 | return static_cast<int32_t>(x) == x; | ||||
375 | } | ||||
376 | |||||
377 | /// Checks if a signed integer is an N bit number shifted left by S. | ||||
378 | template <unsigned N, unsigned S> | ||||
379 | constexpr inline bool isShiftedInt(int64_t x) { | ||||
380 | static_assert( | ||||
381 | N > 0, "isShiftedInt<0> doesn't make sense (refers to a 0-bit number."); | ||||
382 | static_assert(N + S <= 64, "isShiftedInt<N, S> with N + S > 64 is too wide."); | ||||
383 | return isInt<N + S>(x) && (x % (UINT64_C(1)1UL << S) == 0); | ||||
384 | } | ||||
385 | |||||
386 | /// Checks if an unsigned integer fits into the given bit width. | ||||
387 | /// | ||||
388 | /// This is written as two functions rather than as simply | ||||
389 | /// | ||||
390 | /// return N >= 64 || X < (UINT64_C(1) << N); | ||||
391 | /// | ||||
392 | /// to keep MSVC from (incorrectly) warning on isUInt<64> that we're shifting | ||||
393 | /// left too many places. | ||||
394 | template <unsigned N> | ||||
395 | constexpr inline std::enable_if_t<(N < 64), bool> isUInt(uint64_t X) { | ||||
396 | static_assert(N > 0, "isUInt<0> doesn't make sense"); | ||||
397 | return X < (UINT64_C(1)1UL << (N)); | ||||
398 | } | ||||
399 | template <unsigned N> | ||||
400 | constexpr inline std::enable_if_t<N >= 64, bool> isUInt(uint64_t) { | ||||
401 | return true; | ||||
402 | } | ||||
403 | |||||
404 | // Template specializations to get better code for common cases. | ||||
405 | template <> constexpr inline bool isUInt<8>(uint64_t x) { | ||||
406 | return static_cast<uint8_t>(x) == x; | ||||
407 | } | ||||
408 | template <> constexpr inline bool isUInt<16>(uint64_t x) { | ||||
409 | return static_cast<uint16_t>(x) == x; | ||||
410 | } | ||||
411 | template <> constexpr inline bool isUInt<32>(uint64_t x) { | ||||
412 | return static_cast<uint32_t>(x) == x; | ||||
413 | } | ||||
414 | |||||
415 | /// Checks if a unsigned integer is an N bit number shifted left by S. | ||||
416 | template <unsigned N, unsigned S> | ||||
417 | constexpr inline bool isShiftedUInt(uint64_t x) { | ||||
418 | static_assert( | ||||
419 | N > 0, "isShiftedUInt<0> doesn't make sense (refers to a 0-bit number)"); | ||||
420 | static_assert(N + S <= 64, | ||||
421 | "isShiftedUInt<N, S> with N + S > 64 is too wide."); | ||||
422 | // Per the two static_asserts above, S must be strictly less than 64. So | ||||
423 | // 1 << S is not undefined behavior. | ||||
424 | return isUInt<N + S>(x) && (x % (UINT64_C(1)1UL << S) == 0); | ||||
425 | } | ||||
426 | |||||
427 | /// Gets the maximum value for a N-bit unsigned integer. | ||||
428 | inline uint64_t maxUIntN(uint64_t N) { | ||||
429 | assert(N > 0 && N <= 64 && "integer width out of range")(static_cast <bool> (N > 0 && N <= 64 && "integer width out of range") ? void (0) : __assert_fail ("N > 0 && N <= 64 && \"integer width out of range\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 429, __extension__ __PRETTY_FUNCTION__)); | ||||
430 | |||||
431 | // uint64_t(1) << 64 is undefined behavior, so we can't do | ||||
432 | // (uint64_t(1) << N) - 1 | ||||
433 | // without checking first that N != 64. But this works and doesn't have a | ||||
434 | // branch. | ||||
435 | return UINT64_MAX(18446744073709551615UL) >> (64 - N); | ||||
436 | } | ||||
437 | |||||
438 | /// Gets the minimum value for a N-bit signed integer. | ||||
439 | inline int64_t minIntN(int64_t N) { | ||||
440 | assert(N > 0 && N <= 64 && "integer width out of range")(static_cast <bool> (N > 0 && N <= 64 && "integer width out of range") ? void (0) : __assert_fail ("N > 0 && N <= 64 && \"integer width out of range\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 440, __extension__ __PRETTY_FUNCTION__)); | ||||
441 | |||||
442 | return UINT64_C(1)1UL + ~(UINT64_C(1)1UL << (N - 1)); | ||||
443 | } | ||||
444 | |||||
445 | /// Gets the maximum value for a N-bit signed integer. | ||||
446 | inline int64_t maxIntN(int64_t N) { | ||||
447 | assert(N > 0 && N <= 64 && "integer width out of range")(static_cast <bool> (N > 0 && N <= 64 && "integer width out of range") ? void (0) : __assert_fail ("N > 0 && N <= 64 && \"integer width out of range\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 447, __extension__ __PRETTY_FUNCTION__)); | ||||
448 | |||||
449 | // This relies on two's complement wraparound when N == 64, so we convert to | ||||
450 | // int64_t only at the very end to avoid UB. | ||||
451 | return (UINT64_C(1)1UL << (N - 1)) - 1; | ||||
452 | } | ||||
453 | |||||
454 | /// Checks if an unsigned integer fits into the given (dynamic) bit width. | ||||
455 | inline bool isUIntN(unsigned N, uint64_t x) { | ||||
456 | return N >= 64 || x <= maxUIntN(N); | ||||
457 | } | ||||
458 | |||||
459 | /// Checks if an signed integer fits into the given (dynamic) bit width. | ||||
460 | inline bool isIntN(unsigned N, int64_t x) { | ||||
461 | return N >= 64 || (minIntN(N) <= x && x <= maxIntN(N)); | ||||
462 | } | ||||
463 | |||||
464 | /// Return true if the argument is a non-empty sequence of ones starting at the | ||||
465 | /// least significant bit with the remainder zero (32 bit version). | ||||
466 | /// Ex. isMask_32(0x0000FFFFU) == true. | ||||
467 | constexpr inline bool isMask_32(uint32_t Value) { | ||||
468 | return Value && ((Value + 1) & Value) == 0; | ||||
469 | } | ||||
470 | |||||
471 | /// Return true if the argument is a non-empty sequence of ones starting at the | ||||
472 | /// least significant bit with the remainder zero (64 bit version). | ||||
473 | constexpr inline bool isMask_64(uint64_t Value) { | ||||
474 | return Value && ((Value + 1) & Value) == 0; | ||||
475 | } | ||||
476 | |||||
477 | /// Return true if the argument contains a non-empty sequence of ones with the | ||||
478 | /// remainder zero (32 bit version.) Ex. isShiftedMask_32(0x0000FF00U) == true. | ||||
479 | constexpr inline bool isShiftedMask_32(uint32_t Value) { | ||||
480 | return Value && isMask_32((Value - 1) | Value); | ||||
481 | } | ||||
482 | |||||
483 | /// Return true if the argument contains a non-empty sequence of ones with the | ||||
484 | /// remainder zero (64 bit version.) | ||||
485 | constexpr inline bool isShiftedMask_64(uint64_t Value) { | ||||
486 | return Value && isMask_64((Value - 1) | Value); | ||||
487 | } | ||||
488 | |||||
489 | /// Return true if the argument is a power of two > 0. | ||||
490 | /// Ex. isPowerOf2_32(0x00100000U) == true (32 bit edition.) | ||||
491 | constexpr inline bool isPowerOf2_32(uint32_t Value) { | ||||
492 | return Value && !(Value & (Value - 1)); | ||||
493 | } | ||||
494 | |||||
495 | /// Return true if the argument is a power of two > 0 (64 bit edition.) | ||||
496 | constexpr inline bool isPowerOf2_64(uint64_t Value) { | ||||
497 | return Value && !(Value & (Value - 1)); | ||||
498 | } | ||||
499 | |||||
500 | /// Count the number of ones from the most significant bit to the first | ||||
501 | /// zero bit. | ||||
502 | /// | ||||
503 | /// Ex. countLeadingOnes(0xFF0FFF00) == 8. | ||||
504 | /// Only unsigned integral types are allowed. | ||||
505 | /// | ||||
506 | /// \param ZB the behavior on an input of all ones. Only ZB_Width and | ||||
507 | /// ZB_Undefined are valid arguments. | ||||
508 | template <typename T> | ||||
509 | unsigned countLeadingOnes(T Value, ZeroBehavior ZB = ZB_Width) { | ||||
510 | static_assert(std::numeric_limits<T>::is_integer && | ||||
511 | !std::numeric_limits<T>::is_signed, | ||||
512 | "Only unsigned integral types are allowed."); | ||||
513 | return countLeadingZeros<T>(~Value, ZB); | ||||
514 | } | ||||
515 | |||||
516 | /// Count the number of ones from the least significant bit to the first | ||||
517 | /// zero bit. | ||||
518 | /// | ||||
519 | /// Ex. countTrailingOnes(0x00FF00FF) == 8. | ||||
520 | /// Only unsigned integral types are allowed. | ||||
521 | /// | ||||
522 | /// \param ZB the behavior on an input of all ones. Only ZB_Width and | ||||
523 | /// ZB_Undefined are valid arguments. | ||||
524 | template <typename T> | ||||
525 | unsigned countTrailingOnes(T Value, ZeroBehavior ZB = ZB_Width) { | ||||
526 | static_assert(std::numeric_limits<T>::is_integer && | ||||
527 | !std::numeric_limits<T>::is_signed, | ||||
528 | "Only unsigned integral types are allowed."); | ||||
529 | return countTrailingZeros<T>(~Value, ZB); | ||||
530 | } | ||||
531 | |||||
532 | namespace detail { | ||||
533 | template <typename T, std::size_t SizeOfT> struct PopulationCounter { | ||||
534 | static unsigned count(T Value) { | ||||
535 | // Generic version, forward to 32 bits. | ||||
536 | static_assert(SizeOfT <= 4, "Not implemented!"); | ||||
537 | #if defined(__GNUC__4) | ||||
538 | return __builtin_popcount(Value); | ||||
539 | #else | ||||
540 | uint32_t v = Value; | ||||
541 | v = v - ((v >> 1) & 0x55555555); | ||||
542 | v = (v & 0x33333333) + ((v >> 2) & 0x33333333); | ||||
543 | return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; | ||||
544 | #endif | ||||
545 | } | ||||
546 | }; | ||||
547 | |||||
548 | template <typename T> struct PopulationCounter<T, 8> { | ||||
549 | static unsigned count(T Value) { | ||||
550 | #if defined(__GNUC__4) | ||||
551 | return __builtin_popcountll(Value); | ||||
552 | #else | ||||
553 | uint64_t v = Value; | ||||
554 | v = v - ((v >> 1) & 0x5555555555555555ULL); | ||||
555 | v = (v & 0x3333333333333333ULL) + ((v >> 2) & 0x3333333333333333ULL); | ||||
556 | v = (v + (v >> 4)) & 0x0F0F0F0F0F0F0F0FULL; | ||||
557 | return unsigned((uint64_t)(v * 0x0101010101010101ULL) >> 56); | ||||
558 | #endif | ||||
559 | } | ||||
560 | }; | ||||
561 | } // namespace detail | ||||
562 | |||||
563 | /// Count the number of set bits in a value. | ||||
564 | /// Ex. countPopulation(0xF000F000) = 8 | ||||
565 | /// Returns 0 if the word is zero. | ||||
566 | template <typename T> | ||||
567 | inline unsigned countPopulation(T Value) { | ||||
568 | static_assert(std::numeric_limits<T>::is_integer && | ||||
569 | !std::numeric_limits<T>::is_signed, | ||||
570 | "Only unsigned integral types are allowed."); | ||||
571 | return detail::PopulationCounter<T, sizeof(T)>::count(Value); | ||||
572 | } | ||||
573 | |||||
574 | /// Compile time Log2. | ||||
575 | /// Valid only for positive powers of two. | ||||
576 | template <size_t kValue> constexpr inline size_t CTLog2() { | ||||
577 | static_assert(kValue > 0 && llvm::isPowerOf2_64(kValue), | ||||
578 | "Value is not a valid power of 2"); | ||||
579 | return 1 + CTLog2<kValue / 2>(); | ||||
580 | } | ||||
581 | |||||
582 | template <> constexpr inline size_t CTLog2<1>() { return 0; } | ||||
583 | |||||
584 | /// Return the log base 2 of the specified value. | ||||
585 | inline double Log2(double Value) { | ||||
586 | #if defined(__ANDROID_API__) && __ANDROID_API__ < 18 | ||||
587 | return __builtin_log(Value) / __builtin_log(2.0); | ||||
588 | #else | ||||
589 | return log2(Value); | ||||
590 | #endif | ||||
591 | } | ||||
592 | |||||
593 | /// Return the floor log base 2 of the specified value, -1 if the value is zero. | ||||
594 | /// (32 bit edition.) | ||||
595 | /// Ex. Log2_32(32) == 5, Log2_32(1) == 0, Log2_32(0) == -1, Log2_32(6) == 2 | ||||
596 | inline unsigned Log2_32(uint32_t Value) { | ||||
597 | return 31 - countLeadingZeros(Value); | ||||
598 | } | ||||
599 | |||||
600 | /// Return the floor log base 2 of the specified value, -1 if the value is zero. | ||||
601 | /// (64 bit edition.) | ||||
602 | inline unsigned Log2_64(uint64_t Value) { | ||||
603 | return 63 - countLeadingZeros(Value); | ||||
604 | } | ||||
605 | |||||
606 | /// Return the ceil log base 2 of the specified value, 32 if the value is zero. | ||||
607 | /// (32 bit edition). | ||||
608 | /// Ex. Log2_32_Ceil(32) == 5, Log2_32_Ceil(1) == 0, Log2_32_Ceil(6) == 3 | ||||
609 | inline unsigned Log2_32_Ceil(uint32_t Value) { | ||||
610 | return 32 - countLeadingZeros(Value - 1); | ||||
611 | } | ||||
612 | |||||
613 | /// Return the ceil log base 2 of the specified value, 64 if the value is zero. | ||||
614 | /// (64 bit edition.) | ||||
615 | inline unsigned Log2_64_Ceil(uint64_t Value) { | ||||
616 | return 64 - countLeadingZeros(Value - 1); | ||||
617 | } | ||||
618 | |||||
619 | /// Return the greatest common divisor of the values using Euclid's algorithm. | ||||
620 | template <typename T> | ||||
621 | inline T greatestCommonDivisor(T A, T B) { | ||||
622 | while (B) { | ||||
623 | T Tmp = B; | ||||
624 | B = A % B; | ||||
625 | A = Tmp; | ||||
626 | } | ||||
627 | return A; | ||||
628 | } | ||||
629 | |||||
630 | inline uint64_t GreatestCommonDivisor64(uint64_t A, uint64_t B) { | ||||
631 | return greatestCommonDivisor<uint64_t>(A, B); | ||||
632 | } | ||||
633 | |||||
634 | /// This function takes a 64-bit integer and returns the bit equivalent double. | ||||
635 | inline double BitsToDouble(uint64_t Bits) { | ||||
636 | double D; | ||||
637 | static_assert(sizeof(uint64_t) == sizeof(double), "Unexpected type sizes"); | ||||
638 | memcpy(&D, &Bits, sizeof(Bits)); | ||||
639 | return D; | ||||
640 | } | ||||
641 | |||||
642 | /// This function takes a 32-bit integer and returns the bit equivalent float. | ||||
643 | inline float BitsToFloat(uint32_t Bits) { | ||||
644 | float F; | ||||
645 | static_assert(sizeof(uint32_t) == sizeof(float), "Unexpected type sizes"); | ||||
646 | memcpy(&F, &Bits, sizeof(Bits)); | ||||
647 | return F; | ||||
648 | } | ||||
649 | |||||
650 | /// This function takes a double and returns the bit equivalent 64-bit integer. | ||||
651 | /// Note that copying doubles around changes the bits of NaNs on some hosts, | ||||
652 | /// notably x86, so this routine cannot be used if these bits are needed. | ||||
653 | inline uint64_t DoubleToBits(double Double) { | ||||
654 | uint64_t Bits; | ||||
655 | static_assert(sizeof(uint64_t) == sizeof(double), "Unexpected type sizes"); | ||||
656 | memcpy(&Bits, &Double, sizeof(Double)); | ||||
657 | return Bits; | ||||
658 | } | ||||
659 | |||||
660 | /// This function takes a float and returns the bit equivalent 32-bit integer. | ||||
661 | /// Note that copying floats around changes the bits of NaNs on some hosts, | ||||
662 | /// notably x86, so this routine cannot be used if these bits are needed. | ||||
663 | inline uint32_t FloatToBits(float Float) { | ||||
664 | uint32_t Bits; | ||||
665 | static_assert(sizeof(uint32_t) == sizeof(float), "Unexpected type sizes"); | ||||
666 | memcpy(&Bits, &Float, sizeof(Float)); | ||||
667 | return Bits; | ||||
668 | } | ||||
669 | |||||
670 | /// A and B are either alignments or offsets. Return the minimum alignment that | ||||
671 | /// may be assumed after adding the two together. | ||||
672 | constexpr inline uint64_t MinAlign(uint64_t A, uint64_t B) { | ||||
673 | // The largest power of 2 that divides both A and B. | ||||
674 | // | ||||
675 | // Replace "-Value" by "1+~Value" in the following commented code to avoid | ||||
676 | // MSVC warning C4146 | ||||
677 | // return (A | B) & -(A | B); | ||||
678 | return (A | B) & (1 + ~(A | B)); | ||||
679 | } | ||||
680 | |||||
681 | /// Returns the next power of two (in 64-bits) that is strictly greater than A. | ||||
682 | /// Returns zero on overflow. | ||||
683 | inline uint64_t NextPowerOf2(uint64_t A) { | ||||
684 | A |= (A >> 1); | ||||
685 | A |= (A >> 2); | ||||
686 | A |= (A >> 4); | ||||
687 | A |= (A >> 8); | ||||
688 | A |= (A >> 16); | ||||
689 | A |= (A >> 32); | ||||
690 | return A + 1; | ||||
691 | } | ||||
692 | |||||
693 | /// Returns the power of two which is less than or equal to the given value. | ||||
694 | /// Essentially, it is a floor operation across the domain of powers of two. | ||||
695 | inline uint64_t PowerOf2Floor(uint64_t A) { | ||||
696 | if (!A) return 0; | ||||
697 | return 1ull << (63 - countLeadingZeros(A, ZB_Undefined)); | ||||
698 | } | ||||
699 | |||||
700 | /// Returns the power of two which is greater than or equal to the given value. | ||||
701 | /// Essentially, it is a ceil operation across the domain of powers of two. | ||||
702 | inline uint64_t PowerOf2Ceil(uint64_t A) { | ||||
703 | if (!A) | ||||
704 | return 0; | ||||
705 | return NextPowerOf2(A - 1); | ||||
706 | } | ||||
707 | |||||
708 | /// Returns the next integer (mod 2**64) that is greater than or equal to | ||||
709 | /// \p Value and is a multiple of \p Align. \p Align must be non-zero. | ||||
710 | /// | ||||
711 | /// If non-zero \p Skew is specified, the return value will be a minimal | ||||
712 | /// integer that is greater than or equal to \p Value and equal to | ||||
713 | /// \p Align * N + \p Skew for some integer N. If \p Skew is larger than | ||||
714 | /// \p Align, its value is adjusted to '\p Skew mod \p Align'. | ||||
715 | /// | ||||
716 | /// Examples: | ||||
717 | /// \code | ||||
718 | /// alignTo(5, 8) = 8 | ||||
719 | /// alignTo(17, 8) = 24 | ||||
720 | /// alignTo(~0LL, 8) = 0 | ||||
721 | /// alignTo(321, 255) = 510 | ||||
722 | /// | ||||
723 | /// alignTo(5, 8, 7) = 7 | ||||
724 | /// alignTo(17, 8, 1) = 17 | ||||
725 | /// alignTo(~0LL, 8, 3) = 3 | ||||
726 | /// alignTo(321, 255, 42) = 552 | ||||
727 | /// \endcode | ||||
728 | inline uint64_t alignTo(uint64_t Value, uint64_t Align, uint64_t Skew = 0) { | ||||
729 | assert(Align != 0u && "Align can't be 0.")(static_cast <bool> (Align != 0u && "Align can't be 0." ) ? void (0) : __assert_fail ("Align != 0u && \"Align can't be 0.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 729, __extension__ __PRETTY_FUNCTION__)); | ||||
730 | Skew %= Align; | ||||
731 | return (Value + Align - 1 - Skew) / Align * Align + Skew; | ||||
732 | } | ||||
733 | |||||
734 | /// Returns the next integer (mod 2**64) that is greater than or equal to | ||||
735 | /// \p Value and is a multiple of \c Align. \c Align must be non-zero. | ||||
736 | template <uint64_t Align> constexpr inline uint64_t alignTo(uint64_t Value) { | ||||
737 | static_assert(Align != 0u, "Align must be non-zero"); | ||||
738 | return (Value + Align - 1) / Align * Align; | ||||
739 | } | ||||
740 | |||||
741 | /// Returns the integer ceil(Numerator / Denominator). | ||||
742 | inline uint64_t divideCeil(uint64_t Numerator, uint64_t Denominator) { | ||||
743 | return alignTo(Numerator, Denominator) / Denominator; | ||||
744 | } | ||||
745 | |||||
746 | /// Returns the integer nearest(Numerator / Denominator). | ||||
747 | inline uint64_t divideNearest(uint64_t Numerator, uint64_t Denominator) { | ||||
748 | return (Numerator + (Denominator / 2)) / Denominator; | ||||
749 | } | ||||
750 | |||||
751 | /// Returns the largest uint64_t less than or equal to \p Value and is | ||||
752 | /// \p Skew mod \p Align. \p Align must be non-zero | ||||
753 | inline uint64_t alignDown(uint64_t Value, uint64_t Align, uint64_t Skew = 0) { | ||||
754 | assert(Align != 0u && "Align can't be 0.")(static_cast <bool> (Align != 0u && "Align can't be 0." ) ? void (0) : __assert_fail ("Align != 0u && \"Align can't be 0.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 754, __extension__ __PRETTY_FUNCTION__)); | ||||
755 | Skew %= Align; | ||||
756 | return (Value - Skew) / Align * Align + Skew; | ||||
757 | } | ||||
758 | |||||
759 | /// Sign-extend the number in the bottom B bits of X to a 32-bit integer. | ||||
760 | /// Requires 0 < B <= 32. | ||||
761 | template <unsigned B> constexpr inline int32_t SignExtend32(uint32_t X) { | ||||
762 | static_assert(B > 0, "Bit width can't be 0."); | ||||
763 | static_assert(B <= 32, "Bit width out of range."); | ||||
764 | return int32_t(X << (32 - B)) >> (32 - B); | ||||
765 | } | ||||
766 | |||||
767 | /// Sign-extend the number in the bottom B bits of X to a 32-bit integer. | ||||
768 | /// Requires 0 < B <= 32. | ||||
769 | inline int32_t SignExtend32(uint32_t X, unsigned B) { | ||||
770 | assert(B > 0 && "Bit width can't be 0.")(static_cast <bool> (B > 0 && "Bit width can't be 0." ) ? void (0) : __assert_fail ("B > 0 && \"Bit width can't be 0.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 770, __extension__ __PRETTY_FUNCTION__)); | ||||
771 | assert(B <= 32 && "Bit width out of range.")(static_cast <bool> (B <= 32 && "Bit width out of range." ) ? void (0) : __assert_fail ("B <= 32 && \"Bit width out of range.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 771, __extension__ __PRETTY_FUNCTION__)); | ||||
772 | return int32_t(X << (32 - B)) >> (32 - B); | ||||
773 | } | ||||
774 | |||||
775 | /// Sign-extend the number in the bottom B bits of X to a 64-bit integer. | ||||
776 | /// Requires 0 < B <= 64. | ||||
777 | template <unsigned B> constexpr inline int64_t SignExtend64(uint64_t x) { | ||||
778 | static_assert(B > 0, "Bit width can't be 0."); | ||||
779 | static_assert(B <= 64, "Bit width out of range."); | ||||
780 | return int64_t(x << (64 - B)) >> (64 - B); | ||||
781 | } | ||||
782 | |||||
783 | /// Sign-extend the number in the bottom B bits of X to a 64-bit integer. | ||||
784 | /// Requires 0 < B <= 64. | ||||
785 | inline int64_t SignExtend64(uint64_t X, unsigned B) { | ||||
786 | assert(B > 0 && "Bit width can't be 0.")(static_cast <bool> (B > 0 && "Bit width can't be 0." ) ? void (0) : __assert_fail ("B > 0 && \"Bit width can't be 0.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 786, __extension__ __PRETTY_FUNCTION__)); | ||||
787 | assert(B <= 64 && "Bit width out of range.")(static_cast <bool> (B <= 64 && "Bit width out of range." ) ? void (0) : __assert_fail ("B <= 64 && \"Bit width out of range.\"" , "/build/llvm-toolchain-snapshot-14~++20210828111110+16086d47c0d0/llvm/include/llvm/Support/MathExtras.h" , 787, __extension__ __PRETTY_FUNCTION__)); | ||||
788 | return int64_t(X << (64 - B)) >> (64 - B); | ||||
789 | } | ||||
790 | |||||
791 | /// Subtract two unsigned integers, X and Y, of type T and return the absolute | ||||
792 | /// value of the result. | ||||
793 | template <typename T> | ||||
794 | std::enable_if_t<std::is_unsigned<T>::value, T> AbsoluteDifference(T X, T Y) { | ||||
795 | return X > Y ? (X - Y) : (Y - X); | ||||
796 | } | ||||
797 | |||||
798 | /// Add two unsigned integers, X and Y, of type T. Clamp the result to the | ||||
799 | /// maximum representable value of T on overflow. ResultOverflowed indicates if | ||||
800 | /// the result is larger than the maximum representable value of type T. | ||||
801 | template <typename T> | ||||
802 | std::enable_if_t<std::is_unsigned<T>::value, T> | ||||
803 | SaturatingAdd(T X, T Y, bool *ResultOverflowed = nullptr) { | ||||
804 | bool Dummy; | ||||
805 | bool &Overflowed = ResultOverflowed ? *ResultOverflowed : Dummy; | ||||
806 | // Hacker's Delight, p. 29 | ||||
807 | T Z = X + Y; | ||||
808 | Overflowed = (Z < X || Z < Y); | ||||
809 | if (Overflowed) | ||||
810 | return std::numeric_limits<T>::max(); | ||||
811 | else | ||||
812 | return Z; | ||||
813 | } | ||||
814 | |||||
815 | /// Multiply two unsigned integers, X and Y, of type T. Clamp the result to the | ||||
816 | /// maximum representable value of T on overflow. ResultOverflowed indicates if | ||||
817 | /// the result is larger than the maximum representable value of type T. | ||||
818 | template <typename T> | ||||
819 | std::enable_if_t<std::is_unsigned<T>::value, T> | ||||
820 | SaturatingMultiply(T X, T Y, bool *ResultOverflowed = nullptr) { | ||||
821 | bool Dummy; | ||||
822 | bool &Overflowed = ResultOverflowed ? *ResultOverflowed : Dummy; | ||||
823 | |||||
824 | // Hacker's Delight, p. 30 has a different algorithm, but we don't use that | ||||
825 | // because it fails for uint16_t (where multiplication can have undefined | ||||
826 | // behavior due to promotion to int), and requires a division in addition | ||||
827 | // to the multiplication. | ||||
828 | |||||
829 | Overflowed = false; | ||||
830 | |||||
831 | // Log2(Z) would be either Log2Z or Log2Z + 1. | ||||
832 | // Special case: if X or Y is 0, Log2_64 gives -1, and Log2Z | ||||
833 | // will necessarily be less than Log2Max as desired. | ||||
834 | int Log2Z = Log2_64(X) + Log2_64(Y); | ||||
835 | const T Max = std::numeric_limits<T>::max(); | ||||
836 | int Log2Max = Log2_64(Max); | ||||
837 | if (Log2Z < Log2Max) { | ||||
838 | return X * Y; | ||||
839 | } | ||||
840 | if (Log2Z > Log2Max) { | ||||
841 | Overflowed = true; | ||||
842 | return Max; | ||||
843 | } | ||||
844 | |||||
845 | // We're going to use the top bit, and maybe overflow one | ||||
846 | // bit past it. Multiply all but the bottom bit then add | ||||
847 | // that on at the end. | ||||
848 | T Z = (X >> 1) * Y; | ||||
849 | if (Z & ~(Max >> 1)) { | ||||
850 | Overflowed = true; | ||||
851 | return Max; | ||||
852 | } | ||||
853 | Z <<= 1; | ||||
854 | if (X & 1) | ||||
855 | return SaturatingAdd(Z, Y, ResultOverflowed); | ||||
856 | |||||
857 | return Z; | ||||
858 | } | ||||
859 | |||||
860 | /// Multiply two unsigned integers, X and Y, and add the unsigned integer, A to | ||||
861 | /// the product. Clamp the result to the maximum representable value of T on | ||||
862 | /// overflow. ResultOverflowed indicates if the result is larger than the | ||||
863 | /// maximum representable value of type T. | ||||
864 | template <typename T> | ||||
865 | std::enable_if_t<std::is_unsigned<T>::value, T> | ||||
866 | SaturatingMultiplyAdd(T X, T Y, T A, bool *ResultOverflowed = nullptr) { | ||||
867 | bool Dummy; | ||||
868 | bool &Overflowed = ResultOverflowed ? *ResultOverflowed : Dummy; | ||||
869 | |||||
870 | T Product = SaturatingMultiply(X, Y, &Overflowed); | ||||
871 | if (Overflowed) | ||||
872 | return Product; | ||||
873 | |||||
874 | return SaturatingAdd(A, Product, &Overflowed); | ||||
875 | } | ||||
876 | |||||
877 | /// Use this rather than HUGE_VALF; the latter causes warnings on MSVC. | ||||
878 | extern const float huge_valf; | ||||
879 | |||||
880 | |||||
881 | /// Add two signed integers, computing the two's complement truncated result, | ||||
882 | /// returning true if overflow occured. | ||||
883 | template <typename T> | ||||
884 | std::enable_if_t<std::is_signed<T>::value, T> AddOverflow(T X, T Y, T &Result) { | ||||
885 | #if __has_builtin(__builtin_add_overflow)1 | ||||
886 | return __builtin_add_overflow(X, Y, &Result); | ||||
887 | #else | ||||
888 | // Perform the unsigned addition. | ||||
889 | using U = std::make_unsigned_t<T>; | ||||
890 | const U UX = static_cast<U>(X); | ||||
891 | const U UY = static_cast<U>(Y); | ||||
892 | const U UResult = UX + UY; | ||||
893 | |||||
894 | // Convert to signed. | ||||
895 | Result = static_cast<T>(UResult); | ||||
896 | |||||
897 | // Adding two positive numbers should result in a positive number. | ||||
898 | if (X > 0 && Y > 0) | ||||
899 | return Result <= 0; | ||||
900 | // Adding two negatives should result in a negative number. | ||||
901 | if (X < 0 && Y < 0) | ||||
902 | return Result >= 0; | ||||
903 | return false; | ||||
904 | #endif | ||||
905 | } | ||||
906 | |||||
907 | /// Subtract two signed integers, computing the two's complement truncated | ||||
908 | /// result, returning true if an overflow ocurred. | ||||
909 | template <typename T> | ||||
910 | std::enable_if_t<std::is_signed<T>::value, T> SubOverflow(T X, T Y, T &Result) { | ||||
911 | #if __has_builtin(__builtin_sub_overflow)1 | ||||
912 | return __builtin_sub_overflow(X, Y, &Result); | ||||
913 | #else | ||||
914 | // Perform the unsigned addition. | ||||
915 | using U = std::make_unsigned_t<T>; | ||||
916 | const U UX = static_cast<U>(X); | ||||
917 | const U UY = static_cast<U>(Y); | ||||
918 | const U UResult = UX - UY; | ||||
919 | |||||
920 | // Convert to signed. | ||||
921 | Result = static_cast<T>(UResult); | ||||
922 | |||||
923 | // Subtracting a positive number from a negative results in a negative number. | ||||
924 | if (X <= 0 && Y > 0) | ||||
925 | return Result >= 0; | ||||
926 | // Subtracting a negative number from a positive results in a positive number. | ||||
927 | if (X >= 0 && Y < 0) | ||||
928 | return Result <= 0; | ||||
929 | return false; | ||||
930 | #endif | ||||
931 | } | ||||
932 | |||||
933 | /// Multiply two signed integers, computing the two's complement truncated | ||||
934 | /// result, returning true if an overflow ocurred. | ||||
935 | template <typename T> | ||||
936 | std::enable_if_t<std::is_signed<T>::value, T> MulOverflow(T X, T Y, T &Result) { | ||||
937 | // Perform the unsigned multiplication on absolute values. | ||||
938 | using U = std::make_unsigned_t<T>; | ||||
939 | const U UX = X < 0 ? (0 - static_cast<U>(X)) : static_cast<U>(X); | ||||
940 | const U UY = Y < 0 ? (0 - static_cast<U>(Y)) : static_cast<U>(Y); | ||||
941 | const U UResult = UX * UY; | ||||
942 | |||||
943 | // Convert to signed. | ||||
944 | const bool IsNegative = (X < 0) ^ (Y < 0); | ||||
945 | Result = IsNegative ? (0 - UResult) : UResult; | ||||
946 | |||||
947 | // If any of the args was 0, result is 0 and no overflow occurs. | ||||
948 | if (UX == 0 || UY == 0) | ||||
949 | return false; | ||||
950 | |||||
951 | // UX and UY are in [1, 2^n], where n is the number of digits. | ||||
952 | // Check how the max allowed absolute value (2^n for negative, 2^(n-1) for | ||||
953 | // positive) divided by an argument compares to the other. | ||||
954 | if (IsNegative) | ||||
955 | return UX > (static_cast<U>(std::numeric_limits<T>::max()) + U(1)) / UY; | ||||
956 | else | ||||
957 | return UX > (static_cast<U>(std::numeric_limits<T>::max())) / UY; | ||||
958 | } | ||||
959 | |||||
960 | } // End llvm namespace | ||||
961 | |||||
962 | #endif |