llvm.org GIT mirror llvm / 8be7707 tools / llvm-stress / llvm-stress.cpp
8be7707

Tree @8be7707 (Download .tar.gz)

llvm-stress.cpp @8be7707raw · history · blame

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
//===-- llvm-stress.cpp - Generate random LL files to stress-test LLVM ----===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This program is a utility that generates random .ll files to stress-test
// different components in LLVM.
//
//===----------------------------------------------------------------------===//

#include "llvm/Analysis/CallGraphSCCPass.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/IRPrintingPasses.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/LegacyPassNameParser.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Verifier.h"
#include "llvm/IR/LegacyPassManager.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/FileSystem.h"
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/PluginLoader.h"
#include "llvm/Support/PrettyStackTrace.h"
#include "llvm/Support/ToolOutputFile.h"
#include <algorithm>
#include <set>
#include <sstream>
#include <vector>

namespace llvm {

static cl::opt<unsigned> SeedCL("seed",
  cl::desc("Seed used for randomness"), cl::init(0));
static cl::opt<unsigned> SizeCL("size",
  cl::desc("The estimated size of the generated function (# of instrs)"),
  cl::init(100));
static cl::opt<std::string>
OutputFilename("o", cl::desc("Override output filename"),
               cl::value_desc("filename"));

static LLVMContext Context;

namespace cl {
template <> class parser<Type*> final : public basic_parser<Type*> {
public:
  parser(Option &O) : basic_parser(O) {}

  // Parse options as IR types. Return true on error.
  bool parse(Option &O, StringRef, StringRef Arg, Type *&Value) {
    if      (Arg == "half")      Value = Type::getHalfTy(Context);
    else if (Arg == "fp128")     Value = Type::getFP128Ty(Context);
    else if (Arg == "x86_fp80")  Value = Type::getX86_FP80Ty(Context);
    else if (Arg == "ppc_fp128") Value = Type::getPPC_FP128Ty(Context);
    else if (Arg == "x86_mmx")   Value = Type::getX86_MMXTy(Context);
    else if (Arg.startswith("i")) {
      unsigned N = 0;
      Arg.drop_front().getAsInteger(10, N);
      if (N > 0)
        Value = Type::getIntNTy(Context, N);
    }

    if (!Value)
      return O.error("Invalid IR scalar type: '" + Arg + "'!");
    return false;
  }

  const char *getValueName() const override { return "IR scalar type"; }
};
}


static cl::list<Type*> AdditionalScalarTypes("types", cl::CommaSeparated,
  cl::desc("Additional IR scalar types "
           "(always includes i1, i8, i16, i32, i64, float and double)"));

namespace {
/// A utility class to provide a pseudo-random number generator which is
/// the same across all platforms. This is somewhat close to the libc
/// implementation. Note: This is not a cryptographically secure pseudorandom
/// number generator.
class Random {
public:
  /// C'tor
  Random(unsigned _seed):Seed(_seed) {}

  /// Return a random integer, up to a
  /// maximum of 2**19 - 1.
  uint32_t Rand() {
    uint32_t Val = Seed + 0x000b07a1;
    Seed = (Val * 0x3c7c0ac1);
    // Only lowest 19 bits are random-ish.
    return Seed & 0x7ffff;
  }

  /// Return a random 32 bit integer.
  uint32_t Rand32() {
    uint32_t Val = Rand();
    Val &= 0xffff;
    return Val | (Rand() << 16);
  }

  /// Return a random 64 bit integer.
  uint64_t Rand64() {
    uint64_t Val = Rand32();
    return Val | (uint64_t(Rand32()) << 32);
  }

  /// Rand operator for STL algorithms.
  ptrdiff_t operator()(ptrdiff_t y) {
    return  Rand64() % y;
  }

private:
  unsigned Seed;
};

/// Generate an empty function with a default argument list.
Function *GenEmptyFunction(Module *M) {
  // Define a few arguments
  LLVMContext &Context = M->getContext();
  Type* ArgsTy[] = {
    Type::getInt8PtrTy(Context),
    Type::getInt32PtrTy(Context),
    Type::getInt64PtrTy(Context),
    Type::getInt32Ty(Context),
    Type::getInt64Ty(Context),
    Type::getInt8Ty(Context)
  };

  auto *FuncTy = FunctionType::get(Type::getVoidTy(Context), ArgsTy, false);
  // Pick a unique name to describe the input parameters
  Twine Name = "autogen_SD" + Twine{SeedCL};
  auto *Func = Function::Create(FuncTy, GlobalValue::ExternalLinkage, Name, M);
  Func->setCallingConv(CallingConv::C);
  return Func;
}

/// A base class, implementing utilities needed for
/// modifying and adding new random instructions.
struct Modifier {
  /// Used to store the randomly generated values.
  typedef std::vector<Value*> PieceTable;

public:
  /// C'tor
  Modifier(BasicBlock *Block, PieceTable *PT, Random *R):
    BB(Block),PT(PT),Ran(R),Context(BB->getContext()) {}

  /// virtual D'tor to silence warnings.
  virtual ~Modifier() {}

  /// Add a new instruction.
  virtual void Act() = 0;
  /// Add N new instructions,
  virtual void ActN(unsigned n) {
    for (unsigned i=0; i<n; ++i)
      Act();
  }

protected:
  /// Return a random value from the list of known values.
  Value *getRandomVal() {
    assert(PT->size());
    return PT->at(Ran->Rand() % PT->size());
  }

  Constant *getRandomConstant(Type *Tp) {
    if (Tp->isIntegerTy()) {
      if (Ran->Rand() & 1)
        return ConstantInt::getAllOnesValue(Tp);
      return ConstantInt::getNullValue(Tp);
    } else if (Tp->isFloatingPointTy()) {
      if (Ran->Rand() & 1)
        return ConstantFP::getAllOnesValue(Tp);
      return ConstantFP::getNullValue(Tp);
    }
    return UndefValue::get(Tp);
  }

  /// Return a random value with a known type.
  Value *getRandomValue(Type *Tp) {
    unsigned index = Ran->Rand();
    for (unsigned i=0; i<PT->size(); ++i) {
      Value *V = PT->at((index + i) % PT->size());
      if (V->getType() == Tp)
        return V;
    }

    // If the requested type was not found, generate a constant value.
    if (Tp->isIntegerTy()) {
      if (Ran->Rand() & 1)
        return ConstantInt::getAllOnesValue(Tp);
      return ConstantInt::getNullValue(Tp);
    } else if (Tp->isFloatingPointTy()) {
      if (Ran->Rand() & 1)
        return ConstantFP::getAllOnesValue(Tp);
      return ConstantFP::getNullValue(Tp);
    } else if (Tp->isVectorTy()) {
      VectorType *VTp = cast<VectorType>(Tp);

      std::vector<Constant*> TempValues;
      TempValues.reserve(VTp->getNumElements());
      for (unsigned i = 0; i < VTp->getNumElements(); ++i)
        TempValues.push_back(getRandomConstant(VTp->getScalarType()));

      ArrayRef<Constant*> VectorValue(TempValues);
      return ConstantVector::get(VectorValue);
    }

    return UndefValue::get(Tp);
  }

  /// Return a random value of any pointer type.
  Value *getRandomPointerValue() {
    unsigned index = Ran->Rand();
    for (unsigned i=0; i<PT->size(); ++i) {
      Value *V = PT->at((index + i) % PT->size());
      if (V->getType()->isPointerTy())
        return V;
    }
    return UndefValue::get(pickPointerType());
  }

  /// Return a random value of any vector type.
  Value *getRandomVectorValue() {
    unsigned index = Ran->Rand();
    for (unsigned i=0; i<PT->size(); ++i) {
      Value *V = PT->at((index + i) % PT->size());
      if (V->getType()->isVectorTy())
        return V;
    }
    return UndefValue::get(pickVectorType());
  }

  /// Pick a random type.
  Type *pickType() {
    return (Ran->Rand() & 1 ? pickVectorType() : pickScalarType());
  }

  /// Pick a random pointer type.
  Type *pickPointerType() {
    Type *Ty = pickType();
    return PointerType::get(Ty, 0);
  }

  /// Pick a random vector type.
  Type *pickVectorType(unsigned len = (unsigned)-1) {
    // Pick a random vector width in the range 2**0 to 2**4.
    // by adding two randoms we are generating a normal-like distribution
    // around 2**3.
    unsigned width = 1<<((Ran->Rand() % 3) + (Ran->Rand() % 3));
    Type *Ty;

    // Vectors of x86mmx are illegal; keep trying till we get something else.
    do {
      Ty = pickScalarType();
    } while (Ty->isX86_MMXTy());

    if (len != (unsigned)-1)
      width = len;
    return VectorType::get(Ty, width);
  }

  /// Pick a random scalar type.
  Type *pickScalarType() {
    static std::vector<Type*> ScalarTypes;
    if (ScalarTypes.empty()) {
      ScalarTypes.assign({
        Type::getInt1Ty(Context),
        Type::getInt8Ty(Context),
        Type::getInt16Ty(Context),
        Type::getInt32Ty(Context),
        Type::getInt64Ty(Context),
        Type::getFloatTy(Context),
        Type::getDoubleTy(Context)
      });
      ScalarTypes.insert(ScalarTypes.end(),
        AdditionalScalarTypes.begin(), AdditionalScalarTypes.end());
    }

    return ScalarTypes[Ran->Rand() % ScalarTypes.size()];
  }

  /// Basic block to populate
  BasicBlock *BB;
  /// Value table
  PieceTable *PT;
  /// Random number generator
  Random *Ran;
  /// Context
  LLVMContext &Context;
};

struct LoadModifier: public Modifier {
  LoadModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {
    // Try to use predefined pointers. If non-exist, use undef pointer value;
    Value *Ptr = getRandomPointerValue();
    Value *V = new LoadInst(Ptr, "L", BB->getTerminator());
    PT->push_back(V);
  }
};

struct StoreModifier: public Modifier {
  StoreModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {
    // Try to use predefined pointers. If non-exist, use undef pointer value;
    Value *Ptr = getRandomPointerValue();
    Type  *Tp = Ptr->getType();
    Value *Val = getRandomValue(Tp->getContainedType(0));
    Type  *ValTy = Val->getType();

    // Do not store vectors of i1s because they are unsupported
    // by the codegen.
    if (ValTy->isVectorTy() && ValTy->getScalarSizeInBits() == 1)
      return;

    new StoreInst(Val, Ptr, BB->getTerminator());
  }
};

struct BinModifier: public Modifier {
  BinModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}

  void Act() override {
    Value *Val0 = getRandomVal();
    Value *Val1 = getRandomValue(Val0->getType());

    // Don't handle pointer types.
    if (Val0->getType()->isPointerTy() ||
        Val1->getType()->isPointerTy())
      return;

    // Don't handle i1 types.
    if (Val0->getType()->getScalarSizeInBits() == 1)
      return;


    bool isFloat = Val0->getType()->getScalarType()->isFloatingPointTy();
    Instruction* Term = BB->getTerminator();
    unsigned R = Ran->Rand() % (isFloat ? 7 : 13);
    Instruction::BinaryOps Op;

    switch (R) {
    default: llvm_unreachable("Invalid BinOp");
    case 0:{Op = (isFloat?Instruction::FAdd : Instruction::Add); break; }
    case 1:{Op = (isFloat?Instruction::FSub : Instruction::Sub); break; }
    case 2:{Op = (isFloat?Instruction::FMul : Instruction::Mul); break; }
    case 3:{Op = (isFloat?Instruction::FDiv : Instruction::SDiv); break; }
    case 4:{Op = (isFloat?Instruction::FDiv : Instruction::UDiv); break; }
    case 5:{Op = (isFloat?Instruction::FRem : Instruction::SRem); break; }
    case 6:{Op = (isFloat?Instruction::FRem : Instruction::URem); break; }
    case 7: {Op = Instruction::Shl;  break; }
    case 8: {Op = Instruction::LShr; break; }
    case 9: {Op = Instruction::AShr; break; }
    case 10:{Op = Instruction::And;  break; }
    case 11:{Op = Instruction::Or;   break; }
    case 12:{Op = Instruction::Xor;  break; }
    }

    PT->push_back(BinaryOperator::Create(Op, Val0, Val1, "B", Term));
  }
};

/// Generate constant values.
struct ConstModifier: public Modifier {
  ConstModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {
    Type *Ty = pickType();

    if (Ty->isVectorTy()) {
      switch (Ran->Rand() % 2) {
      case 0: if (Ty->getScalarType()->isIntegerTy())
                return PT->push_back(ConstantVector::getAllOnesValue(Ty));
      case 1: if (Ty->getScalarType()->isIntegerTy())
                return PT->push_back(ConstantVector::getNullValue(Ty));
      }
    }

    if (Ty->isFloatingPointTy()) {
      // Generate 128 random bits, the size of the (currently)
      // largest floating-point types.
      uint64_t RandomBits[2];
      for (unsigned i = 0; i < 2; ++i)
        RandomBits[i] = Ran->Rand64();

      APInt RandomInt(Ty->getPrimitiveSizeInBits(), makeArrayRef(RandomBits));
      APFloat RandomFloat(Ty->getFltSemantics(), RandomInt);

      if (Ran->Rand() & 1)
        return PT->push_back(ConstantFP::getNullValue(Ty));
      return PT->push_back(ConstantFP::get(Ty->getContext(), RandomFloat));
    }

    if (Ty->isIntegerTy()) {
      switch (Ran->Rand() % 7) {
      case 0: if (Ty->isIntegerTy())
                return PT->push_back(ConstantInt::get(Ty,
                  APInt::getAllOnesValue(Ty->getPrimitiveSizeInBits())));
      case 1: if (Ty->isIntegerTy())
                return PT->push_back(ConstantInt::get(Ty,
                  APInt::getNullValue(Ty->getPrimitiveSizeInBits())));
      case 2: case 3: case 4: case 5:
      case 6: if (Ty->isIntegerTy())
                PT->push_back(ConstantInt::get(Ty, Ran->Rand()));
      }
    }

  }
};

struct AllocaModifier: public Modifier {
  AllocaModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R){}

  void Act() override {
    Type *Tp = pickType();
    PT->push_back(new AllocaInst(Tp, "A", BB->getFirstNonPHI()));
  }
};

struct ExtractElementModifier: public Modifier {
  ExtractElementModifier(BasicBlock *BB, PieceTable *PT, Random *R):
    Modifier(BB, PT, R) {}

  void Act() override {
    Value *Val0 = getRandomVectorValue();
    Value *V = ExtractElementInst::Create(Val0,
             ConstantInt::get(Type::getInt32Ty(BB->getContext()),
             Ran->Rand() % cast<VectorType>(Val0->getType())->getNumElements()),
             "E", BB->getTerminator());
    return PT->push_back(V);
  }
};

struct ShuffModifier: public Modifier {
  ShuffModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {

    Value *Val0 = getRandomVectorValue();
    Value *Val1 = getRandomValue(Val0->getType());

    unsigned Width = cast<VectorType>(Val0->getType())->getNumElements();
    std::vector<Constant*> Idxs;

    Type *I32 = Type::getInt32Ty(BB->getContext());
    for (unsigned i=0; i<Width; ++i) {
      Constant *CI = ConstantInt::get(I32, Ran->Rand() % (Width*2));
      // Pick some undef values.
      if (!(Ran->Rand() % 5))
        CI = UndefValue::get(I32);
      Idxs.push_back(CI);
    }

    Constant *Mask = ConstantVector::get(Idxs);

    Value *V = new ShuffleVectorInst(Val0, Val1, Mask, "Shuff",
                                     BB->getTerminator());
    PT->push_back(V);
  }
};

struct InsertElementModifier: public Modifier {
  InsertElementModifier(BasicBlock *BB, PieceTable *PT, Random *R):
    Modifier(BB, PT, R) {}

  void Act() override {
    Value *Val0 = getRandomVectorValue();
    Value *Val1 = getRandomValue(Val0->getType()->getScalarType());

    Value *V = InsertElementInst::Create(Val0, Val1,
              ConstantInt::get(Type::getInt32Ty(BB->getContext()),
              Ran->Rand() % cast<VectorType>(Val0->getType())->getNumElements()),
              "I",  BB->getTerminator());
    return PT->push_back(V);
  }

};

struct CastModifier: public Modifier {
  CastModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {

    Value *V = getRandomVal();
    Type *VTy = V->getType();
    Type *DestTy = pickScalarType();

    // Handle vector casts vectors.
    if (VTy->isVectorTy()) {
      VectorType *VecTy = cast<VectorType>(VTy);
      DestTy = pickVectorType(VecTy->getNumElements());
    }

    // no need to cast.
    if (VTy == DestTy) return;

    // Pointers:
    if (VTy->isPointerTy()) {
      if (!DestTy->isPointerTy())
        DestTy = PointerType::get(DestTy, 0);
      return PT->push_back(
        new BitCastInst(V, DestTy, "PC", BB->getTerminator()));
    }

    unsigned VSize = VTy->getScalarType()->getPrimitiveSizeInBits();
    unsigned DestSize = DestTy->getScalarType()->getPrimitiveSizeInBits();

    // Generate lots of bitcasts.
    if ((Ran->Rand() & 1) && VSize == DestSize) {
      return PT->push_back(
        new BitCastInst(V, DestTy, "BC", BB->getTerminator()));
    }

    // Both types are integers:
    if (VTy->getScalarType()->isIntegerTy() &&
        DestTy->getScalarType()->isIntegerTy()) {
      if (VSize > DestSize) {
        return PT->push_back(
          new TruncInst(V, DestTy, "Tr", BB->getTerminator()));
      } else {
        assert(VSize < DestSize && "Different int types with the same size?");
        if (Ran->Rand() & 1)
          return PT->push_back(
            new ZExtInst(V, DestTy, "ZE", BB->getTerminator()));
        return PT->push_back(new SExtInst(V, DestTy, "Se", BB->getTerminator()));
      }
    }

    // Fp to int.
    if (VTy->getScalarType()->isFloatingPointTy() &&
        DestTy->getScalarType()->isIntegerTy()) {
      if (Ran->Rand() & 1)
        return PT->push_back(
          new FPToSIInst(V, DestTy, "FC", BB->getTerminator()));
      return PT->push_back(new FPToUIInst(V, DestTy, "FC", BB->getTerminator()));
    }

    // Int to fp.
    if (VTy->getScalarType()->isIntegerTy() &&
        DestTy->getScalarType()->isFloatingPointTy()) {
      if (Ran->Rand() & 1)
        return PT->push_back(
          new SIToFPInst(V, DestTy, "FC", BB->getTerminator()));
      return PT->push_back(new UIToFPInst(V, DestTy, "FC", BB->getTerminator()));

    }

    // Both floats.
    if (VTy->getScalarType()->isFloatingPointTy() &&
        DestTy->getScalarType()->isFloatingPointTy()) {
      if (VSize > DestSize) {
        return PT->push_back(
          new FPTruncInst(V, DestTy, "Tr", BB->getTerminator()));
      } else if (VSize < DestSize) {
        return PT->push_back(
          new FPExtInst(V, DestTy, "ZE", BB->getTerminator()));
      }
      // If VSize == DestSize, then the two types must be fp128 and ppc_fp128,
      // for which there is no defined conversion. So do nothing.
    }
  }

};

struct SelectModifier: public Modifier {
  SelectModifier(BasicBlock *BB, PieceTable *PT, Random *R):
    Modifier(BB, PT, R) {}

  void Act() override {
    // Try a bunch of different select configuration until a valid one is found.
      Value *Val0 = getRandomVal();
      Value *Val1 = getRandomValue(Val0->getType());

      Type *CondTy = Type::getInt1Ty(Context);

      // If the value type is a vector, and we allow vector select, then in 50%
      // of the cases generate a vector select.
      if (Val0->getType()->isVectorTy() && (Ran->Rand() % 1)) {
        unsigned NumElem = cast<VectorType>(Val0->getType())->getNumElements();
        CondTy = VectorType::get(CondTy, NumElem);
      }

      Value *Cond = getRandomValue(CondTy);
      Value *V = SelectInst::Create(Cond, Val0, Val1, "Sl", BB->getTerminator());
      return PT->push_back(V);
  }
};


struct CmpModifier: public Modifier {
  CmpModifier(BasicBlock *BB, PieceTable *PT, Random *R):Modifier(BB, PT, R) {}
  void Act() override {

    Value *Val0 = getRandomVal();
    Value *Val1 = getRandomValue(Val0->getType());

    if (Val0->getType()->isPointerTy()) return;
    bool fp = Val0->getType()->getScalarType()->isFloatingPointTy();

    int op;
    if (fp) {
      op = Ran->Rand() %
      (CmpInst::LAST_FCMP_PREDICATE - CmpInst::FIRST_FCMP_PREDICATE) +
       CmpInst::FIRST_FCMP_PREDICATE;
    } else {
      op = Ran->Rand() %
      (CmpInst::LAST_ICMP_PREDICATE - CmpInst::FIRST_ICMP_PREDICATE) +
       CmpInst::FIRST_ICMP_PREDICATE;
    }

    Value *V = CmpInst::Create(fp ? Instruction::FCmp : Instruction::ICmp,
                               (CmpInst::Predicate)op, Val0, Val1, "Cmp",
                               BB->getTerminator());
    return PT->push_back(V);
  }
};

} // end anonymous namespace

static void FillFunction(Function *F, Random &R) {
  // Create a legal entry block.
  BasicBlock *BB = BasicBlock::Create(F->getContext(), "BB", F);
  ReturnInst::Create(F->getContext(), BB);

  // Create the value table.
  Modifier::PieceTable PT;

  // Consider arguments as legal values.
  for (auto &arg : F->args())
    PT.push_back(&arg);

  // List of modifiers which add new random instructions.
  std::vector<std::unique_ptr<Modifier>> Modifiers;
  Modifiers.emplace_back(new LoadModifier(BB, &PT, &R));
  Modifiers.emplace_back(new StoreModifier(BB, &PT, &R));
  auto SM = Modifiers.back().get();
  Modifiers.emplace_back(new ExtractElementModifier(BB, &PT, &R));
  Modifiers.emplace_back(new ShuffModifier(BB, &PT, &R));
  Modifiers.emplace_back(new InsertElementModifier(BB, &PT, &R));
  Modifiers.emplace_back(new BinModifier(BB, &PT, &R));
  Modifiers.emplace_back(new CastModifier(BB, &PT, &R));
  Modifiers.emplace_back(new SelectModifier(BB, &PT, &R));
  Modifiers.emplace_back(new CmpModifier(BB, &PT, &R));

  // Generate the random instructions
  AllocaModifier{BB, &PT, &R}.ActN(5); // Throw in a few allocas
  ConstModifier{BB, &PT, &R}.ActN(40); // Throw in a few constants

  for (unsigned i = 0; i < SizeCL / Modifiers.size(); ++i)
    for (auto &Mod : Modifiers)
      Mod->Act();

  SM->ActN(5); // Throw in a few stores.
}

static void IntroduceControlFlow(Function *F, Random &R) {
  std::vector<Instruction*> BoolInst;
  for (auto &Instr : F->front()) {
    if (Instr.getType() == IntegerType::getInt1Ty(F->getContext()))
      BoolInst.push_back(&Instr);
  }

  std::random_shuffle(BoolInst.begin(), BoolInst.end(), R);

  for (auto *Instr : BoolInst) {
    BasicBlock *Curr = Instr->getParent();
    BasicBlock::iterator Loc = Instr->getIterator();
    BasicBlock *Next = Curr->splitBasicBlock(Loc, "CF");
    Instr->moveBefore(Curr->getTerminator());
    if (Curr != &F->getEntryBlock()) {
      BranchInst::Create(Curr, Next, Instr, Curr->getTerminator());
      Curr->getTerminator()->eraseFromParent();
    }
  }
}

}

int main(int argc, char **argv) {
  using namespace llvm;

  // Init LLVM, call llvm_shutdown() on exit, parse args, etc.
  PrettyStackTraceProgram X(argc, argv);
  cl::ParseCommandLineOptions(argc, argv, "llvm codegen stress-tester\n");
  llvm_shutdown_obj Y;

  auto M = make_unique<Module>("/tmp/autogen.bc", Context);
  Function *F = GenEmptyFunction(M.get());

  // Pick an initial seed value
  Random R(SeedCL);
  // Generate lots of random instructions inside a single basic block.
  FillFunction(F, R);
  // Break the basic block into many loops.
  IntroduceControlFlow(F, R);

  // Figure out what stream we are supposed to write to...
  std::unique_ptr<tool_output_file> Out;
  // Default to standard output.
  if (OutputFilename.empty())
    OutputFilename = "-";

  std::error_code EC;
  Out.reset(new tool_output_file(OutputFilename, EC, sys::fs::F_None));
  if (EC) {
    errs() << EC.message() << '\n';
    return 1;
  }

  legacy::PassManager Passes;
  Passes.add(createVerifierPass());
  Passes.add(createPrintModulePass(Out->os()));
  Passes.run(*M.get());
  Out->keep();

  return 0;
}