lib/Transforms/Scalar/SimplifyLibCalls.cpp

   1 //===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9 //
  10 // This file implements a simple pass that applies a variety of small
  11 // optimizations for calls to specific well-known function calls (e.g. runtime
  12 // library functions).   Any optimization that takes the very simple form
  13 // "replace call to library function with simpler code that provides the same
  14 // result" belongs in this file.
  15 //
  16 //===----------------------------------------------------------------------===//
  17
  18 #define DEBUG_TYPE "simplify-libcalls"
  19 #include "llvm/Transforms/Scalar.h"
  20 #include "llvm/Transforms/Utils/BuildLibCalls.h"
  21 #include "llvm/Intrinsics.h"
  22 #include "llvm/LLVMContext.h"
  23 #include "llvm/Module.h"
  24 #include "llvm/Pass.h"
  25 #include "llvm/Support/IRBuilder.h"
  26 #include "llvm/Analysis/ValueTracking.h"
  27 #include "llvm/Target/TargetData.h"
  28 #include "llvm/ADT/SmallPtrSet.h"
  29 #include "llvm/ADT/StringMap.h"
  30 #include "llvm/ADT/Statistic.h"
  31 #include "llvm/ADT/STLExtras.h"
  32 #include "llvm/Support/Debug.h"
  33 #include "llvm/Support/raw_ostream.h"
  34 #include "llvm/Config/config.h"
  35 using namespace llvm;
  36
  37 STATISTIC(NumSimplified, "Number of library calls simplified");
  38 STATISTIC(NumAnnotated, "Number of attributes added to library functions");
  39
  40 //===----------------------------------------------------------------------===//
  41 // Optimizer Base Class
  42 //===----------------------------------------------------------------------===//
  43
  44 /// This class is the abstract base class for the set of optimizations that
  45 /// corresponds to one library call.
  46 namespace {
  47 class LibCallOptimization {
  48 protected:
  49   Function *Caller;
  50   const TargetData *TD;
  51   LLVMContext* Context;
  52 public:
  53   LibCallOptimization() { }
  54   virtual ~LibCallOptimization() {}
  55
  56   /// CallOptimizer - This pure virtual method is implemented by base classes to
  57   /// do various optimizations.  If this returns null then no transformation was
  58   /// performed.  If it returns CI, then it transformed the call and CI is to be
  59   /// deleted.  If it returns something else, replace CI with the new value and
  60   /// delete CI.
  61   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
  62     =0;
  63
  64   Value *OptimizeCall(CallInst *CI, const TargetData *TD, IRBuilder<> &B) {
  65     Caller = CI->getParent()->getParent();
  66     this->TD = TD;
  67     if (CI->getCalledFunction())
  68       Context = &CI->getCalledFunction()->getContext();
  69
  70     // We never change the calling convention.
  71     if (CI->getCallingConv() != llvm::CallingConv::C)
  72       return NULL;
  73
  74     return CallOptimizer(CI->getCalledFunction(), CI, B);
  75   }
  76 };
  77 } // End anonymous namespace.
  78
  79
  80 //===----------------------------------------------------------------------===//
  81 // Helper Functions
  82 //===----------------------------------------------------------------------===//
  83
  84 /// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
  85 /// value is equal or not-equal to zero.
  86 static bool IsOnlyUsedInZeroEqualityComparison(Value *V) {
  87   for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
  88        UI != E; ++UI) {
  89     if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
  90       if (IC->isEquality())
  91         if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
  92           if (C->isNullValue())
  93             continue;
  94     // Unknown instruction.
  95     return false;
  96   }
  97   return true;
  98 }
  99
 100 /// IsOnlyUsedInEqualityComparison - Return true if it is only used in equality
 101 /// comparisons with With.
 102 static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
 103   for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
 104        UI != E; ++UI) {
 105     if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
 106       if (IC->isEquality() && IC->getOperand(1) == With)
 107         continue;
 108     // Unknown instruction.
 109     return false;
 110   }
 111   return true;
 112 }
 113
 114 //===----------------------------------------------------------------------===//
 115 // String and Memory LibCall Optimizations
 116 //===----------------------------------------------------------------------===//
 117
 118 //===---------------------------------------===//
 119 // 'strcat' Optimizations
 120 namespace {
 121 struct StrCatOpt : public LibCallOptimization {
 122   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 123     // Verify the "strcat" function prototype.
 124     const FunctionType *FT = Callee->getFunctionType();
 125     if (FT->getNumParams() != 2 ||
 126         FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
 127         FT->getParamType(0) != FT->getReturnType() ||
 128         FT->getParamType(1) != FT->getReturnType())
 129       return 0;
 130
 131     // Extract some information from the instruction
 132     Value *Dst = CI->getArgOperand(0);
 133     Value *Src = CI->getArgOperand(1);
 134
 135     // See if we can get the length of the input string.
 136     uint64_t Len = GetStringLength(Src);
 137     if (Len == 0) return 0;
 138     --Len;  // Unbias length.
 139
 140     // Handle the simple, do-nothing case: strcat(x, "") -> x
 141     if (Len == 0)
 142       return Dst;
 143
 144     // These optimizations require TargetData.
 145     if (!TD) return 0;
 146
 147     EmitStrLenMemCpy(Src, Dst, Len, B);
 148     return Dst;
 149   }
 150
 151   void EmitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len, IRBuilder<> &B) {
 152     // We need to find the end of the destination string.  That's where the
 153     // memory is to be moved to. We just generate a call to strlen.
 154     Value *DstLen = EmitStrLen(Dst, B, TD);
 155
 156     // Now that we have the destination's length, we must index into the
 157     // destination's pointer to get the actual memcpy destination (end of
 158     // the string .. we're concatenating).
 159     Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
 160
 161     // We have enough information to now generate the memcpy call to do the
 162     // concatenation for us.  Make a memcpy to copy the nul byte with align = 1.
 163     EmitMemCpy(CpyDst, Src,
 164                ConstantInt::get(TD->getIntPtrType(*Context), Len+1),
 165                                 1, false, B, TD);
 166   }
 167 };
 168
 169 //===---------------------------------------===//
 170 // 'strncat' Optimizations
 171
 172 struct StrNCatOpt : public StrCatOpt {
 173   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 174     // Verify the "strncat" function prototype.
 175     const FunctionType *FT = Callee->getFunctionType();
 176     if (FT->getNumParams() != 3 ||
 177         FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
 178         FT->getParamType(0) != FT->getReturnType() ||
 179         FT->getParamType(1) != FT->getReturnType() ||
 180         !FT->getParamType(2)->isIntegerTy())
 181       return 0;
 182
 183     // Extract some information from the instruction
 184     Value *Dst = CI->getArgOperand(0);
 185     Value *Src = CI->getArgOperand(1);
 186     uint64_t Len;
 187
 188     // We don't do anything if length is not constant
 189     if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
 190       Len = LengthArg->getZExtValue();
 191     else
 192       return 0;
 193
 194     // See if we can get the length of the input string.
 195     uint64_t SrcLen = GetStringLength(Src);
 196     if (SrcLen == 0) return 0;
 197     --SrcLen;  // Unbias length.
 198
 199     // Handle the simple, do-nothing cases:
 200     // strncat(x, "", c) -> x
 201     // strncat(x,  c, 0) -> x
 202     if (SrcLen == 0 || Len == 0) return Dst;
 203
 204     // These optimizations require TargetData.
 205     if (!TD) return 0;
 206
 207     // We don't optimize this case
 208     if (Len < SrcLen) return 0;
 209
 210     // strncat(x, s, c) -> strcat(x, s)
 211     // s is constant so the strcat can be optimized further
 212     EmitStrLenMemCpy(Src, Dst, SrcLen, B);
 213     return Dst;
 214   }
 215 };
 216
 217 //===---------------------------------------===//
 218 // 'strchr' Optimizations
 219
 220 struct StrChrOpt : public LibCallOptimization {
 221   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 222     // Verify the "strchr" function prototype.
 223     const FunctionType *FT = Callee->getFunctionType();
 224     if (FT->getNumParams() != 2 ||
 225         FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
 226         FT->getParamType(0) != FT->getReturnType() ||
 227         !FT->getParamType(1)->isIntegerTy(32))
 228       return 0;
 229
 230     Value *SrcStr = CI->getArgOperand(0);
 231
 232     // If the second operand is non-constant, see if we can compute the length
 233     // of the input string and turn this into memchr.
 234     ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
 235     if (CharC == 0) {
 236       // These optimizations require TargetData.
 237       if (!TD) return 0;
 238
 239       uint64_t Len = GetStringLength(SrcStr);
 240       if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
 241         return 0;
 242
 243       return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
 244                         ConstantInt::get(TD->getIntPtrType(*Context), Len),
 245                         B, TD);
 246     }
 247
 248     // Otherwise, the character is a constant, see if the first argument is
 249     // a string literal.  If so, we can constant fold.
 250     std::string Str;
 251     if (!GetConstantStringInfo(SrcStr, Str))
 252       return 0;
 253
 254     // strchr can find the nul character.
 255     Str += '\0';
 256
 257     // Compute the offset.
 258     size_t I = Str.find(CharC->getSExtValue());
 259     if (I == std::string::npos) // Didn't find the char.  strchr returns null.
 260       return Constant::getNullValue(CI->getType());
 261
 262     // strchr(s+n,c)  -> gep(s+n+i,c)
 263     Value *Idx = ConstantInt::get(Type::getInt64Ty(*Context), I);
 264     return B.CreateGEP(SrcStr, Idx, "strchr");
 265   }
 266 };
 267
 268 //===---------------------------------------===//
 269 // 'strrchr' Optimizations
 270
 271 struct StrRChrOpt : public LibCallOptimization {
 272   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 273     // Verify the "strrchr" function prototype.
 274     const FunctionType *FT = Callee->getFunctionType();
 275     if (FT->getNumParams() != 2 ||
 276         FT->getReturnType() != Type::getInt8PtrTy(*Context) ||
 277         FT->getParamType(0) != FT->getReturnType() ||
 278         !FT->getParamType(1)->isIntegerTy(32))
 279       return 0;
 280
 281     Value *SrcStr = CI->getArgOperand(0);
 282     ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
 283
 284     // Cannot fold anything if we're not looking for a constant.
 285     if (!CharC)
 286       return 0;
 287
 288     std::string Str;
 289     if (!GetConstantStringInfo(SrcStr, Str)) {
 290       // strrchr(s, 0) -> strchr(s, 0)
 291       if (TD && CharC->isZero())
 292         return EmitStrChr(SrcStr, '\0', B, TD);
 293       return 0;
 294     }
 295
 296     // strrchr can find the nul character.
 297     Str += '\0';
 298
 299     // Compute the offset.
 300     size_t I = Str.rfind(CharC->getSExtValue());
 301     if (I == std::string::npos) // Didn't find the char. Return null.
 302       return Constant::getNullValue(CI->getType());
 303
 304     // strrchr(s+n,c) -> gep(s+n+i,c)
 305     Value *Idx = ConstantInt::get(Type::getInt64Ty(*Context), I);
 306     return B.CreateGEP(SrcStr, Idx, "strrchr");
 307   }
 308 };
 309
 310 //===---------------------------------------===//
 311 // 'strcmp' Optimizations
 312
 313 struct StrCmpOpt : public LibCallOptimization {
 314   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 315     // Verify the "strcmp" function prototype.
 316     const FunctionType *FT = Callee->getFunctionType();
 317     if (FT->getNumParams() != 2 ||
 318         !FT->getReturnType()->isIntegerTy(32) ||
 319         FT->getParamType(0) != FT->getParamType(1) ||
 320         FT->getParamType(0) != Type::getInt8PtrTy(*Context))
 321       return 0;
 322
 323     Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
 324     if (Str1P == Str2P)      // strcmp(x,x)  -> 0
 325       return ConstantInt::get(CI->getType(), 0);
 326
 327     std::string Str1, Str2;
 328     bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
 329     bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
 330
 331     if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
 332       return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
 333
 334     if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
 335       return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
 336
 337     // strcmp(x, y)  -> cnst  (if both x and y are constant strings)
 338     if (HasStr1 && HasStr2)
 339       return ConstantInt::get(CI->getType(),
 340                                      strcmp(Str1.c_str(),Str2.c_str()));
 341
 342     // strcmp(P, "x") -> memcmp(P, "x", 2)
 343     uint64_t Len1 = GetStringLength(Str1P);
 344     uint64_t Len2 = GetStringLength(Str2P);
 345     if (Len1 && Len2) {
 346       // These optimizations require TargetData.
 347       if (!TD) return 0;
 348
 349       return EmitMemCmp(Str1P, Str2P,
 350                         ConstantInt::get(TD->getIntPtrType(*Context),
 351                         std::min(Len1, Len2)), B, TD);
 352     }
 353
 354     return 0;
 355   }
 356 };
 357
 358 //===---------------------------------------===//
 359 // 'strncmp' Optimizations
 360
 361 struct StrNCmpOpt : public LibCallOptimization {
 362   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 363     // Verify the "strncmp" function prototype.
 364     const FunctionType *FT = Callee->getFunctionType();
 365     if (FT->getNumParams() != 3 ||
 366         !FT->getReturnType()->isIntegerTy(32) ||
 367         FT->getParamType(0) != FT->getParamType(1) ||
 368         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 369         !FT->getParamType(2)->isIntegerTy())
 370       return 0;
 371
 372     Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
 373     if (Str1P == Str2P)      // strncmp(x,x,n)  -> 0
 374       return ConstantInt::get(CI->getType(), 0);
 375
 376     // Get the length argument if it is constant.
 377     uint64_t Length;
 378     if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
 379       Length = LengthArg->getZExtValue();
 380     else
 381       return 0;
 382
 383     if (Length == 0) // strncmp(x,y,0)   -> 0
 384       return ConstantInt::get(CI->getType(), 0);
 385
 386     if (TD && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
 387       return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, TD);
 388
 389     std::string Str1, Str2;
 390     bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
 391     bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
 392
 393     if (HasStr1 && Str1.empty())  // strncmp("", x, n) -> *x
 394       return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
 395
 396     if (HasStr2 && Str2.empty())  // strncmp(x, "", n) -> *x
 397       return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
 398
 399     // strncmp(x, y)  -> cnst  (if both x and y are constant strings)
 400     if (HasStr1 && HasStr2)
 401       return ConstantInt::get(CI->getType(),
 402                               strncmp(Str1.c_str(), Str2.c_str(), Length));
 403     return 0;
 404   }
 405 };
 406
 407
 408 //===---------------------------------------===//
 409 // 'strcpy' Optimizations
 410
 411 struct StrCpyOpt : public LibCallOptimization {
 412   bool OptChkCall;  // True if it's optimizing a __strcpy_chk libcall.
 413
 414   StrCpyOpt(bool c) : OptChkCall(c) {}
 415
 416   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 417     // Verify the "strcpy" function prototype.
 418     unsigned NumParams = OptChkCall ? 3 : 2;
 419     const FunctionType *FT = Callee->getFunctionType();
 420     if (FT->getNumParams() != NumParams ||
 421         FT->getReturnType() != FT->getParamType(0) ||
 422         FT->getParamType(0) != FT->getParamType(1) ||
 423         FT->getParamType(0) != Type::getInt8PtrTy(*Context))
 424       return 0;
 425
 426     Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
 427     if (Dst == Src)      // strcpy(x,x)  -> x
 428       return Src;
 429
 430     // These optimizations require TargetData.
 431     if (!TD) return 0;
 432
 433     // See if we can get the length of the input string.
 434     uint64_t Len = GetStringLength(Src);
 435     if (Len == 0) return 0;
 436
 437     // We have enough information to now generate the memcpy call to do the
 438     // concatenation for us.  Make a memcpy to copy the nul byte with align = 1.
 439     if (OptChkCall)
 440       EmitMemCpyChk(Dst, Src,
 441                     ConstantInt::get(TD->getIntPtrType(*Context), Len),
 442                     CI->getArgOperand(2), B, TD);
 443     else
 444       EmitMemCpy(Dst, Src,
 445                  ConstantInt::get(TD->getIntPtrType(*Context), Len),
 446                                   1, false, B, TD);
 447     return Dst;
 448   }
 449 };
 450
 451 //===---------------------------------------===//
 452 // 'strncpy' Optimizations
 453
 454 struct StrNCpyOpt : public LibCallOptimization {
 455   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 456     const FunctionType *FT = Callee->getFunctionType();
 457     if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
 458         FT->getParamType(0) != FT->getParamType(1) ||
 459         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 460         !FT->getParamType(2)->isIntegerTy())
 461       return 0;
 462
 463     Value *Dst = CI->getArgOperand(0);
 464     Value *Src = CI->getArgOperand(1);
 465     Value *LenOp = CI->getArgOperand(2);
 466
 467     // See if we can get the length of the input string.
 468     uint64_t SrcLen = GetStringLength(Src);
 469     if (SrcLen == 0) return 0;
 470     --SrcLen;
 471
 472     if (SrcLen == 0) {
 473       // strncpy(x, "", y) -> memset(x, '\0', y, 1)
 474       EmitMemSet(Dst, ConstantInt::get(Type::getInt8Ty(*Context), '\0'),
 475                  LenOp, false, B, TD);
 476       return Dst;
 477     }
 478
 479     uint64_t Len;
 480     if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
 481       Len = LengthArg->getZExtValue();
 482     else
 483       return 0;
 484
 485     if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
 486
 487     // These optimizations require TargetData.
 488     if (!TD) return 0;
 489
 490     // Let strncpy handle the zero padding
 491     if (Len > SrcLen+1) return 0;
 492
 493     // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
 494     EmitMemCpy(Dst, Src,
 495                ConstantInt::get(TD->getIntPtrType(*Context), Len),
 496                                 1, false, B, TD);
 497
 498     return Dst;
 499   }
 500 };
 501
 502 //===---------------------------------------===//
 503 // 'strlen' Optimizations
 504
 505 struct StrLenOpt : public LibCallOptimization {
 506   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 507     const FunctionType *FT = Callee->getFunctionType();
 508     if (FT->getNumParams() != 1 ||
 509         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 510         !FT->getReturnType()->isIntegerTy())
 511       return 0;
 512
 513     Value *Src = CI->getArgOperand(0);
 514
 515     // Constant folding: strlen("xyz") -> 3
 516     if (uint64_t Len = GetStringLength(Src))
 517       return ConstantInt::get(CI->getType(), Len-1);
 518
 519     // strlen(x) != 0 --> *x != 0
 520     // strlen(x) == 0 --> *x == 0
 521     if (IsOnlyUsedInZeroEqualityComparison(CI))
 522       return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
 523     return 0;
 524   }
 525 };
 526
 527
 528 //===---------------------------------------===//
 529 // 'strpbrk' Optimizations
 530
 531 struct StrPBrkOpt : public LibCallOptimization {
 532   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 533     const FunctionType *FT = Callee->getFunctionType();
 534     if (FT->getNumParams() != 2 ||
 535         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 536         FT->getParamType(1) != FT->getParamType(0) ||
 537         FT->getReturnType() != FT->getParamType(0))
 538       return 0;
 539
 540     std::string S1, S2;
 541     bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
 542     bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
 543
 544     // strpbrk(s, "") -> NULL
 545     // strpbrk("", s) -> NULL
 546     if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
 547       return Constant::getNullValue(CI->getType());
 548
 549     // Constant folding.
 550     if (HasS1 && HasS2) {
 551       size_t I = S1.find_first_of(S2);
 552       if (I == std::string::npos) // No match.
 553         return Constant::getNullValue(CI->getType());
 554
 555       Value *Idx = ConstantInt::get(Type::getInt64Ty(*Context), I);
 556       return B.CreateGEP(CI->getArgOperand(0), Idx, "strpbrk");
 557     }
 558
 559     // strpbrk(s, "a") -> strchr(s, 'a')
 560     if (TD && HasS2 && S2.size() == 1)
 561       return EmitStrChr(CI->getArgOperand(0), S2[0], B, TD);
 562
 563     return 0;
 564   }
 565 };
 566
 567 //===---------------------------------------===//
 568 // 'strto*' Optimizations.  This handles strtol, strtod, strtof, strtoul, etc.
 569
 570 struct StrToOpt : public LibCallOptimization {
 571   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 572     const FunctionType *FT = Callee->getFunctionType();
 573     if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
 574         !FT->getParamType(0)->isPointerTy() ||
 575         !FT->getParamType(1)->isPointerTy())
 576       return 0;
 577
 578     Value *EndPtr = CI->getArgOperand(1);
 579     if (isa<ConstantPointerNull>(EndPtr)) {
 580       CI->setOnlyReadsMemory();
 581       CI->addAttribute(1, Attribute::NoCapture);
 582     }
 583
 584     return 0;
 585   }
 586 };
 587
 588 //===---------------------------------------===//
 589 // 'strspn' Optimizations
 590
 591 struct StrSpnOpt : public LibCallOptimization {
 592   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 593     const FunctionType *FT = Callee->getFunctionType();
 594     if (FT->getNumParams() != 2 ||
 595         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 596         FT->getParamType(1) != FT->getParamType(0) ||
 597         !FT->getReturnType()->isIntegerTy())
 598       return 0;
 599
 600     std::string S1, S2;
 601     bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
 602     bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
 603
 604     // strspn(s, "") -> 0
 605     // strspn("", s) -> 0
 606     if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
 607       return Constant::getNullValue(CI->getType());
 608
 609     // Constant folding.
 610     if (HasS1 && HasS2)
 611       return ConstantInt::get(CI->getType(), strspn(S1.c_str(), S2.c_str()));
 612
 613     return 0;
 614   }
 615 };
 616
 617 //===---------------------------------------===//
 618 // 'strcspn' Optimizations
 619
 620 struct StrCSpnOpt : public LibCallOptimization {
 621   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 622     const FunctionType *FT = Callee->getFunctionType();
 623     if (FT->getNumParams() != 2 ||
 624         FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
 625         FT->getParamType(1) != FT->getParamType(0) ||
 626         !FT->getReturnType()->isIntegerTy())
 627       return 0;
 628
 629     std::string S1, S2;
 630     bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
 631     bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
 632
 633     // strcspn("", s) -> 0
 634     if (HasS1 && S1.empty())
 635       return Constant::getNullValue(CI->getType());
 636
 637     // Constant folding.
 638     if (HasS1 && HasS2)
 639       return ConstantInt::get(CI->getType(), strcspn(S1.c_str(), S2.c_str()));
 640
 641     // strcspn(s, "") -> strlen(s)
 642     if (TD && HasS2 && S2.empty())
 643       return EmitStrLen(CI->getArgOperand(0), B, TD);
 644
 645     return 0;
 646   }
 647 };
 648
 649 //===---------------------------------------===//
 650 // 'strstr' Optimizations
 651
 652 struct StrStrOpt : public LibCallOptimization {
 653   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 654     const FunctionType *FT = Callee->getFunctionType();
 655     if (FT->getNumParams() != 2 ||
 656         !FT->getParamType(0)->isPointerTy() ||
 657         !FT->getParamType(1)->isPointerTy() ||
 658         !FT->getReturnType()->isPointerTy())
 659       return 0;
 660
 661     // fold strstr(x, x) -> x.
 662     if (CI->getArgOperand(0) == CI->getArgOperand(1))
 663       return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
 664
 665     // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
 666     if (TD && IsOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
 667       Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, TD);
 668       Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
 669                                    StrLen, B, TD);
 670       for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end();
 671            UI != UE; ) {
 672         ICmpInst *Old = cast<ICmpInst>(*UI++);
 673         Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
 674                                   ConstantInt::getNullValue(StrNCmp->getType()),
 675                                   "cmp");
 676         Old->replaceAllUsesWith(Cmp);
 677         Old->eraseFromParent();
 678       }
 679       return CI;
 680     }
 681
 682     // See if either input string is a constant string.
 683     std::string SearchStr, ToFindStr;
 684     bool HasStr1 = GetConstantStringInfo(CI->getArgOperand(0), SearchStr);
 685     bool HasStr2 = GetConstantStringInfo(CI->getArgOperand(1), ToFindStr);
 686
 687     // fold strstr(x, "") -> x.
 688     if (HasStr2 && ToFindStr.empty())
 689       return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
 690
 691     // If both strings are known, constant fold it.
 692     if (HasStr1 && HasStr2) {
 693       std::string::size_type Offset = SearchStr.find(ToFindStr);
 694
 695       if (Offset == std::string::npos) // strstr("foo", "bar") -> null
 696         return Constant::getNullValue(CI->getType());
 697
 698       // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
 699       Value *Result = CastToCStr(CI->getArgOperand(0), B);
 700       Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
 701       return B.CreateBitCast(Result, CI->getType());
 702     }
 703
 704     // fold strstr(x, "y") -> strchr(x, 'y').
 705     if (HasStr2 && ToFindStr.size() == 1)
 706       return B.CreateBitCast(EmitStrChr(CI->getArgOperand(0),
 707                              ToFindStr[0], B, TD), CI->getType());
 708     return 0;
 709   }
 710 };
 711
 712
 713 //===---------------------------------------===//
 714 // 'memcmp' Optimizations
 715
 716 struct MemCmpOpt : public LibCallOptimization {
 717   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 718     const FunctionType *FT = Callee->getFunctionType();
 719     if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
 720         !FT->getParamType(1)->isPointerTy() ||
 721         !FT->getReturnType()->isIntegerTy(32))
 722       return 0;
 723
 724     Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
 725
 726     if (LHS == RHS)  // memcmp(s,s,x) -> 0
 727       return Constant::getNullValue(CI->getType());
 728
 729     // Make sure we have a constant length.
 730     ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
 731     if (!LenC) return 0;
 732     uint64_t Len = LenC->getZExtValue();
 733
 734     if (Len == 0) // memcmp(s1,s2,0) -> 0
 735       return Constant::getNullValue(CI->getType());
 736
 737     // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
 738     if (Len == 1) {
 739       Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
 740                                  CI->getType(), "lhsv");
 741       Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
 742                                  CI->getType(), "rhsv");
 743       return B.CreateSub(LHSV, RHSV, "chardiff");
 744     }
 745
 746     // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
 747     std::string LHSStr, RHSStr;
 748     if (GetConstantStringInfo(LHS, LHSStr) &&
 749         GetConstantStringInfo(RHS, RHSStr)) {
 750       // Make sure we're not reading out-of-bounds memory.
 751       if (Len > LHSStr.length() || Len > RHSStr.length())
 752         return 0;
 753       uint64_t Ret = memcmp(LHSStr.data(), RHSStr.data(), Len);
 754       return ConstantInt::get(CI->getType(), Ret);
 755     }
 756
 757     return 0;
 758   }
 759 };
 760
 761 //===---------------------------------------===//
 762 // 'memcpy' Optimizations
 763
 764 struct MemCpyOpt : public LibCallOptimization {
 765   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 766     // These optimizations require TargetData.
 767     if (!TD) return 0;
 768
 769     const FunctionType *FT = Callee->getFunctionType();
 770     if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
 771         !FT->getParamType(0)->isPointerTy() ||
 772         !FT->getParamType(1)->isPointerTy() ||
 773         FT->getParamType(2) != TD->getIntPtrType(*Context))
 774       return 0;
 775
 776     // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
 777     EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
 778                CI->getArgOperand(2), 1, false, B, TD);
 779     return CI->getArgOperand(0);
 780   }
 781 };
 782
 783 //===---------------------------------------===//
 784 // 'memmove' Optimizations
 785
 786 struct MemMoveOpt : public LibCallOptimization {
 787   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 788     // These optimizations require TargetData.
 789     if (!TD) return 0;
 790
 791     const FunctionType *FT = Callee->getFunctionType();
 792     if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
 793         !FT->getParamType(0)->isPointerTy() ||
 794         !FT->getParamType(1)->isPointerTy() ||
 795         FT->getParamType(2) != TD->getIntPtrType(*Context))
 796       return 0;
 797
 798     // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
 799     EmitMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
 800                 CI->getArgOperand(2), 1, false, B, TD);
 801     return CI->getArgOperand(0);
 802   }
 803 };
 804
 805 //===---------------------------------------===//
 806 // 'memset' Optimizations
 807
 808 struct MemSetOpt : public LibCallOptimization {
 809   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 810     // These optimizations require TargetData.
 811     if (!TD) return 0;
 812
 813     const FunctionType *FT = Callee->getFunctionType();
 814     if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
 815         !FT->getParamType(0)->isPointerTy() ||
 816         !FT->getParamType(1)->isIntegerTy() ||
 817         FT->getParamType(2) != TD->getIntPtrType(*Context))
 818       return 0;
 819
 820     // memset(p, v, n) -> llvm.memset(p, v, n, 1)
 821     Value *Val = B.CreateIntCast(CI->getArgOperand(1),
 822                                  Type::getInt8Ty(*Context), false);
 823     EmitMemSet(CI->getArgOperand(0), Val,  CI->getArgOperand(2), false, B, TD);
 824     return CI->getArgOperand(0);
 825   }
 826 };
 827
 828 //===----------------------------------------------------------------------===//
 829 // Math Library Optimizations
 830 //===----------------------------------------------------------------------===//
 831
 832 //===---------------------------------------===//
 833 // 'pow*' Optimizations
 834
 835 struct PowOpt : public LibCallOptimization {
 836   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 837     const FunctionType *FT = Callee->getFunctionType();
 838     // Just make sure this has 2 arguments of the same FP type, which match the
 839     // result type.
 840     if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
 841         FT->getParamType(0) != FT->getParamType(1) ||
 842         !FT->getParamType(0)->isFloatingPointTy())
 843       return 0;
 844
 845     Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
 846     if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
 847       if (Op1C->isExactlyValue(1.0))  // pow(1.0, x) -> 1.0
 848         return Op1C;
 849       if (Op1C->isExactlyValue(2.0))  // pow(2.0, x) -> exp2(x)
 850         return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
 851     }
 852
 853     ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
 854     if (Op2C == 0) return 0;
 855
 856     if (Op2C->getValueAPF().isZero())  // pow(x, 0.0) -> 1.0
 857       return ConstantFP::get(CI->getType(), 1.0);
 858
 859     if (Op2C->isExactlyValue(0.5)) {
 860       // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
 861       // This is faster than calling pow, and still handles negative zero
 862       // and negative infinite correctly.
 863       // TODO: In fast-math mode, this could be just sqrt(x).
 864       // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
 865       Value *Inf = ConstantFP::getInfinity(CI->getType());
 866       Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
 867       Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B,
 868                                          Callee->getAttributes());
 869       Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B,
 870                                          Callee->getAttributes());
 871       Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf, "tmp");
 872       Value *Sel = B.CreateSelect(FCmp, Inf, FAbs, "tmp");
 873       return Sel;
 874     }
 875
 876     if (Op2C->isExactlyValue(1.0))  // pow(x, 1.0) -> x
 877       return Op1;
 878     if (Op2C->isExactlyValue(2.0))  // pow(x, 2.0) -> x*x
 879       return B.CreateFMul(Op1, Op1, "pow2");
 880     if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
 881       return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0),
 882                           Op1, "powrecip");
 883     return 0;
 884   }
 885 };
 886
 887 //===---------------------------------------===//
 888 // 'exp2' Optimizations
 889
 890 struct Exp2Opt : public LibCallOptimization {
 891   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 892     const FunctionType *FT = Callee->getFunctionType();
 893     // Just make sure this has 1 argument of FP type, which matches the
 894     // result type.
 895     if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
 896         !FT->getParamType(0)->isFloatingPointTy())
 897       return 0;
 898
 899     Value *Op = CI->getArgOperand(0);
 900     // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x))  if sizeof(x) <= 32
 901     // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x))  if sizeof(x) < 32
 902     Value *LdExpArg = 0;
 903     if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
 904       if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
 905         LdExpArg = B.CreateSExt(OpC->getOperand(0),
 906                                 Type::getInt32Ty(*Context), "tmp");
 907     } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
 908       if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
 909         LdExpArg = B.CreateZExt(OpC->getOperand(0),
 910                                 Type::getInt32Ty(*Context), "tmp");
 911     }
 912
 913     if (LdExpArg) {
 914       const char *Name;
 915       if (Op->getType()->isFloatTy())
 916         Name = "ldexpf";
 917       else if (Op->getType()->isDoubleTy())
 918         Name = "ldexp";
 919       else
 920         Name = "ldexpl";
 921
 922       Constant *One = ConstantFP::get(*Context, APFloat(1.0f));
 923       if (!Op->getType()->isFloatTy())
 924         One = ConstantExpr::getFPExtend(One, Op->getType());
 925
 926       Module *M = Caller->getParent();
 927       Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
 928                                              Op->getType(),
 929                                              Type::getInt32Ty(*Context),NULL);
 930       CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
 931       if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
 932         CI->setCallingConv(F->getCallingConv());
 933
 934       return CI;
 935     }
 936     return 0;
 937   }
 938 };
 939
 940 //===---------------------------------------===//
 941 // Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
 942
 943 struct UnaryDoubleFPOpt : public LibCallOptimization {
 944   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 945     const FunctionType *FT = Callee->getFunctionType();
 946     if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
 947         !FT->getParamType(0)->isDoubleTy())
 948       return 0;
 949
 950     // If this is something like 'floor((double)floatval)', convert to floorf.
 951     FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
 952     if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
 953       return 0;
 954
 955     // floor((double)floatval) -> (double)floorf(floatval)
 956     Value *V = Cast->getOperand(0);
 957     V = EmitUnaryFloatFnCall(V, Callee->getName().data(), B,
 958                              Callee->getAttributes());
 959     return B.CreateFPExt(V, Type::getDoubleTy(*Context));
 960   }
 961 };
 962
 963 //===----------------------------------------------------------------------===//
 964 // Integer Optimizations
 965 //===----------------------------------------------------------------------===//
 966
 967 //===---------------------------------------===//
 968 // 'ffs*' Optimizations
 969
 970 struct FFSOpt : public LibCallOptimization {
 971   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
 972     const FunctionType *FT = Callee->getFunctionType();
 973     // Just make sure this has 2 arguments of the same FP type, which match the
 974     // result type.
 975     if (FT->getNumParams() != 1 ||
 976         !FT->getReturnType()->isIntegerTy(32) ||
 977         !FT->getParamType(0)->isIntegerTy())
 978       return 0;
 979
 980     Value *Op = CI->getArgOperand(0);
 981
 982     // Constant fold.
 983     if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
 984       if (CI->getValue() == 0)  // ffs(0) -> 0.
 985         return Constant::getNullValue(CI->getType());
 986       return ConstantInt::get(Type::getInt32Ty(*Context), // ffs(c) -> cttz(c)+1
 987                               CI->getValue().countTrailingZeros()+1);
 988     }
 989
 990     // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
 991     const Type *ArgType = Op->getType();
 992     Value *F = Intrinsic::getDeclaration(Callee->getParent(),
 993                                          Intrinsic::cttz, &ArgType, 1);
 994     Value *V = B.CreateCall(F, Op, "cttz");
 995     V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1), "tmp");
 996     V = B.CreateIntCast(V, Type::getInt32Ty(*Context), false, "tmp");
 997
 998     Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
 999     return B.CreateSelect(Cond, V,
1000                           ConstantInt::get(Type::getInt32Ty(*Context), 0));
1001   }
1002 };
1003
1004 //===---------------------------------------===//
1005 // 'isdigit' Optimizations
1006
1007 struct IsDigitOpt : public LibCallOptimization {
1008   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1009     const FunctionType *FT = Callee->getFunctionType();
1010     // We require integer(i32)
1011     if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1012         !FT->getParamType(0)->isIntegerTy(32))
1013       return 0;
1014
1015     // isdigit(c) -> (c-'0') <u 10
1016     Value *Op = CI->getArgOperand(0);
1017     Op = B.CreateSub(Op, ConstantInt::get(Type::getInt32Ty(*Context), '0'),
1018                      "isdigittmp");
1019     Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 10),
1020                          "isdigit");
1021     return B.CreateZExt(Op, CI->getType());
1022   }
1023 };
1024
1025 //===---------------------------------------===//
1026 // 'isascii' Optimizations
1027
1028 struct IsAsciiOpt : public LibCallOptimization {
1029   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1030     const FunctionType *FT = Callee->getFunctionType();
1031     // We require integer(i32)
1032     if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1033         !FT->getParamType(0)->isIntegerTy(32))
1034       return 0;
1035
1036     // isascii(c) -> c <u 128
1037     Value *Op = CI->getArgOperand(0);
1038     Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 128),
1039                          "isascii");
1040     return B.CreateZExt(Op, CI->getType());
1041   }
1042 };
1043
1044 //===---------------------------------------===//
1045 // 'abs', 'labs', 'llabs' Optimizations
1046
1047 struct AbsOpt : public LibCallOptimization {
1048   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1049     const FunctionType *FT = Callee->getFunctionType();
1050     // We require integer(integer) where the types agree.
1051     if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1052         FT->getParamType(0) != FT->getReturnType())
1053       return 0;
1054
1055     // abs(x) -> x >s -1 ? x : -x
1056     Value *Op = CI->getArgOperand(0);
1057     Value *Pos = B.CreateICmpSGT(Op,
1058                              Constant::getAllOnesValue(Op->getType()),
1059                                  "ispos");
1060     Value *Neg = B.CreateNeg(Op, "neg");
1061     return B.CreateSelect(Pos, Op, Neg);
1062   }
1063 };
1064
1065
1066 //===---------------------------------------===//
1067 // 'toascii' Optimizations
1068
1069 struct ToAsciiOpt : public LibCallOptimization {
1070   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1071     const FunctionType *FT = Callee->getFunctionType();
1072     // We require i32(i32)
1073     if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1074         !FT->getParamType(0)->isIntegerTy(32))
1075       return 0;
1076
1077     // isascii(c) -> c & 0x7f
1078     return B.CreateAnd(CI->getArgOperand(0),
1079                        ConstantInt::get(CI->getType(),0x7F));
1080   }
1081 };
1082
1083 //===----------------------------------------------------------------------===//
1084 // Formatting and IO Optimizations
1085 //===----------------------------------------------------------------------===//
1086
1087 //===---------------------------------------===//
1088 // 'printf' Optimizations
1089
1090 struct PrintFOpt : public LibCallOptimization {
1091   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1092     // Require one fixed pointer argument and an integer/void result.
1093     const FunctionType *FT = Callee->getFunctionType();
1094     if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
1095         !(FT->getReturnType()->isIntegerTy() ||
1096           FT->getReturnType()->isVoidTy()))
1097       return 0;
1098
1099     // Check for a fixed format string.
1100     std::string FormatStr;
1101     if (!GetConstantStringInfo(CI->getArgOperand(0), FormatStr))
1102       return 0;
1103
1104     // Empty format string -> noop.
1105     if (FormatStr.empty())  // Tolerate printf's declared void.
1106       return CI->use_empty() ? (Value*)CI :
1107                                ConstantInt::get(CI->getType(), 0);
1108
1109     // printf("x") -> putchar('x'), even for '%'.  Return the result of putchar
1110     // in case there is an error writing to stdout.
1111     if (FormatStr.size() == 1) {
1112       Value *Res = EmitPutChar(ConstantInt::get(Type::getInt32Ty(*Context),
1113                                                 FormatStr[0]), B, TD);
1114       if (CI->use_empty()) return CI;
1115       return B.CreateIntCast(Res, CI->getType(), true);
1116     }
1117
1118     // printf("foo\n") --> puts("foo")
1119     if (FormatStr[FormatStr.size()-1] == '\n' &&
1120         FormatStr.find('%') == std::string::npos) {  // no format characters.
1121       // Create a string literal with no \n on it.  We expect the constant merge
1122       // pass to be run after this pass, to merge duplicate strings.
1123       FormatStr.erase(FormatStr.end()-1);
1124       Constant *C = ConstantArray::get(*Context, FormatStr, true);
1125       C = new GlobalVariable(*Callee->getParent(), C->getType(), true,
1126                              GlobalVariable::InternalLinkage, C, "str");
1127       EmitPutS(C, B, TD);
1128       return CI->use_empty() ? (Value*)CI :
1129                     ConstantInt::get(CI->getType(), FormatStr.size()+1);
1130     }
1131
1132     // Optimize specific format strings.
1133     // printf("%c", chr) --> putchar(chr)
1134     if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
1135         CI->getArgOperand(1)->getType()->isIntegerTy()) {
1136       Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD);
1137
1138       if (CI->use_empty()) return CI;
1139       return B.CreateIntCast(Res, CI->getType(), true);
1140     }
1141
1142     // printf("%s\n", str) --> puts(str)
1143     if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
1144         CI->getArgOperand(1)->getType()->isPointerTy() &&
1145         CI->use_empty()) {
1146       EmitPutS(CI->getArgOperand(1), B, TD);
1147       return CI;
1148     }
1149     return 0;
1150   }
1151 };
1152
1153 //===---------------------------------------===//
1154 // 'sprintf' Optimizations
1155
1156 struct SPrintFOpt : public LibCallOptimization {
1157   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1158     // Require two fixed pointer arguments and an integer result.
1159     const FunctionType *FT = Callee->getFunctionType();
1160     if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1161         !FT->getParamType(1)->isPointerTy() ||
1162         !FT->getReturnType()->isIntegerTy())
1163       return 0;
1164
1165     // Check for a fixed format string.
1166     std::string FormatStr;
1167     if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1168       return 0;
1169
1170     // If we just have a format string (nothing else crazy) transform it.
1171     if (CI->getNumArgOperands() == 2) {
1172       // Make sure there's no % in the constant array.  We could try to handle
1173       // %% -> % in the future if we cared.
1174       for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1175         if (FormatStr[i] == '%')
1176           return 0; // we found a format specifier, bail out.
1177
1178       // These optimizations require TargetData.
1179       if (!TD) return 0;
1180
1181       // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
1182       EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),   // Copy the
1183                  ConstantInt::get(TD->getIntPtrType(*Context), // nul byte.
1184                  FormatStr.size() + 1), 1, false, B, TD);
1185       return ConstantInt::get(CI->getType(), FormatStr.size());
1186     }
1187
1188     // The remaining optimizations require the format string to be "%s" or "%c"
1189     // and have an extra operand.
1190     if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1191         CI->getNumArgOperands() < 3)
1192       return 0;
1193
1194     // Decode the second character of the format string.
1195     if (FormatStr[1] == 'c') {
1196       // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
1197       if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1198       Value *V = B.CreateTrunc(CI->getArgOperand(2),
1199                                Type::getInt8Ty(*Context), "char");
1200       Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
1201       B.CreateStore(V, Ptr);
1202       Ptr = B.CreateGEP(Ptr, ConstantInt::get(Type::getInt32Ty(*Context), 1),
1203                         "nul");
1204       B.CreateStore(Constant::getNullValue(Type::getInt8Ty(*Context)), Ptr);
1205
1206       return ConstantInt::get(CI->getType(), 1);
1207     }
1208
1209     if (FormatStr[1] == 's') {
1210       // These optimizations require TargetData.
1211       if (!TD) return 0;
1212
1213       // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1214       if (!CI->getArgOperand(2)->getType()->isPointerTy()) return 0;
1215
1216       Value *Len = EmitStrLen(CI->getArgOperand(2), B, TD);
1217       Value *IncLen = B.CreateAdd(Len,
1218                                   ConstantInt::get(Len->getType(), 1),
1219                                   "leninc");
1220       EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(2),
1221                  IncLen, 1, false, B, TD);
1222
1223       // The sprintf result is the unincremented number of bytes in the string.
1224       return B.CreateIntCast(Len, CI->getType(), false);
1225     }
1226     return 0;
1227   }
1228 };
1229
1230 //===---------------------------------------===//
1231 // 'fwrite' Optimizations
1232
1233 struct FWriteOpt : public LibCallOptimization {
1234   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1235     // Require a pointer, an integer, an integer, a pointer, returning integer.
1236     const FunctionType *FT = Callee->getFunctionType();
1237     if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
1238         !FT->getParamType(1)->isIntegerTy() ||
1239         !FT->getParamType(2)->isIntegerTy() ||
1240         !FT->getParamType(3)->isPointerTy() ||
1241         !FT->getReturnType()->isIntegerTy())
1242       return 0;
1243
1244     // Get the element size and count.
1245     ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
1246     ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
1247     if (!SizeC || !CountC) return 0;
1248     uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
1249
1250     // If this is writing zero records, remove the call (it's a noop).
1251     if (Bytes == 0)
1252       return ConstantInt::get(CI->getType(), 0);
1253
1254     // If this is writing one byte, turn it into fputc.
1255     if (Bytes == 1) {  // fwrite(S,1,1,F) -> fputc(S[0],F)
1256       Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
1257       EmitFPutC(Char, CI->getArgOperand(3), B, TD);
1258       return ConstantInt::get(CI->getType(), 1);
1259     }
1260
1261     return 0;
1262   }
1263 };
1264
1265 //===---------------------------------------===//
1266 // 'fputs' Optimizations
1267
1268 struct FPutsOpt : public LibCallOptimization {
1269   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1270     // These optimizations require TargetData.
1271     if (!TD) return 0;
1272
1273     // Require two pointers.  Also, we can't optimize if return value is used.
1274     const FunctionType *FT = Callee->getFunctionType();
1275     if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1276         !FT->getParamType(1)->isPointerTy() ||
1277         !CI->use_empty())
1278       return 0;
1279
1280     // fputs(s,F) --> fwrite(s,1,strlen(s),F)
1281     uint64_t Len = GetStringLength(CI->getArgOperand(0));
1282     if (!Len) return 0;
1283     EmitFWrite(CI->getArgOperand(0),
1284                ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
1285                CI->getArgOperand(1), B, TD);
1286     return CI;  // Known to have no uses (see above).
1287   }
1288 };
1289
1290 //===---------------------------------------===//
1291 // 'fprintf' Optimizations
1292
1293 struct FPrintFOpt : public LibCallOptimization {
1294   virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1295     // Require two fixed paramters as pointers and integer result.
1296     const FunctionType *FT = Callee->getFunctionType();
1297     if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1298         !FT->getParamType(1)->isPointerTy() ||
1299         !FT->getReturnType()->isIntegerTy())
1300       return 0;
1301
1302     // All the optimizations depend on the format string.
1303     std::string FormatStr;
1304     if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1305       return 0;
1306
1307     // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
1308     if (CI->getNumArgOperands() == 2) {
1309       for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1310         if (FormatStr[i] == '%')  // Could handle %% -> % if we cared.
1311           return 0; // We found a format specifier.
1312
1313       // These optimizations require TargetData.
1314       if (!TD) return 0;
1315
1316       EmitFWrite(CI->getArgOperand(1),
1317                  ConstantInt::get(TD->getIntPtrType(*Context),
1318                                   FormatStr.size()),
1319                  CI->getArgOperand(0), B, TD);
1320       return ConstantInt::get(CI->getType(), FormatStr.size());
1321     }
1322
1323     // The remaining optimizations require the format string to be "%s" or "%c"
1324     // and have an extra operand.
1325     if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1326         CI->getNumArgOperands() < 3)
1327       return 0;
1328
1329     // Decode the second character of the format string.
1330     if (FormatStr[1] == 'c') {
1331       // fprintf(F, "%c", chr) --> fputc(chr, F)
1332       if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1333       EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
1334       return ConstantInt::get(CI->getType(), 1);
1335     }
1336
1337     if (FormatStr[1] == 's') {
1338       // fprintf(F, "%s", str) --> fputs(str, F)
1339       if (!CI->getArgOperand(2)->getType()->isPointerTy() || !CI->use_empty())
1340         return 0;
1341       EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
1342       return CI;
1343     }
1344     return 0;
1345   }
1346 };
1347
1348 } // end anonymous namespace.
1349
1350 //===----------------------------------------------------------------------===//
1351 // SimplifyLibCalls Pass Implementation
1352 //===----------------------------------------------------------------------===//
1353
1354 namespace {
1355   /// This pass optimizes well known library functions from libc and libm.
1356   ///
1357   class SimplifyLibCalls : public FunctionPass {
1358     StringMap<LibCallOptimization*> Optimizations;
1359     // String and Memory LibCall Optimizations
1360     StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrRChrOpt StrRChr;
1361     StrCmpOpt StrCmp; StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
1362     StrNCpyOpt StrNCpy; StrLenOpt StrLen; StrPBrkOpt StrPBrk;
1363     StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
1364     MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
1365     // Math Library Optimizations
1366     PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
1367     // Integer Optimizations
1368     FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
1369     ToAsciiOpt ToAscii;
1370     // Formatting and IO Optimizations
1371     SPrintFOpt SPrintF; PrintFOpt PrintF;
1372     FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
1373
1374     bool Modified;  // This is only used by doInitialization.
1375   public:
1376     static char ID; // Pass identification
1377     SimplifyLibCalls() : FunctionPass(ID), StrCpy(false), StrCpyChk(true) {
1378       initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
1379     }
1380     void InitOptimizations();
1381     bool runOnFunction(Function &F);
1382
1383     void setDoesNotAccessMemory(Function &F);
1384     void setOnlyReadsMemory(Function &F);
1385     void setDoesNotThrow(Function &F);
1386     void setDoesNotCapture(Function &F, unsigned n);
1387     void setDoesNotAlias(Function &F, unsigned n);
1388     bool doInitialization(Module &M);
1389
1390     virtual void getAnalysisUsage(AnalysisUsage &AU) const {
1391     }
1392   };
1393   char SimplifyLibCalls::ID = 0;
1394 } // end anonymous namespace.
1395
1396 INITIALIZE_PASS(SimplifyLibCalls, "simplify-libcalls",
1397                 "Simplify well-known library calls", false, false)
1398
1399 // Public interface to the Simplify LibCalls pass.
1400 FunctionPass *llvm::createSimplifyLibCallsPass() {
1401   return new SimplifyLibCalls();
1402 }
1403
1404 /// Optimizations - Populate the Optimizations map with all the optimizations
1405 /// we know.
1406 void SimplifyLibCalls::InitOptimizations() {
1407   // String and Memory LibCall Optimizations
1408   Optimizations["strcat"] = &StrCat;
1409   Optimizations["strncat"] = &StrNCat;
1410   Optimizations["strchr"] = &StrChr;
1411   Optimizations["strrchr"] = &StrRChr;
1412   Optimizations["strcmp"] = &StrCmp;
1413   Optimizations["strncmp"] = &StrNCmp;
1414   Optimizations["strcpy"] = &StrCpy;
1415   Optimizations["strncpy"] = &StrNCpy;
1416   Optimizations["strlen"] = &StrLen;
1417   Optimizations["strpbrk"] = &StrPBrk;
1418   Optimizations["strtol"] = &StrTo;
1419   Optimizations["strtod"] = &StrTo;
1420   Optimizations["strtof"] = &StrTo;
1421   Optimizations["strtoul"] = &StrTo;
1422   Optimizations["strtoll"] = &StrTo;
1423   Optimizations["strtold"] = &StrTo;
1424   Optimizations["strtoull"] = &StrTo;
1425   Optimizations["strspn"] = &StrSpn;
1426   Optimizations["strcspn"] = &StrCSpn;
1427   Optimizations["strstr"] = &StrStr;
1428   Optimizations["memcmp"] = &MemCmp;
1429   Optimizations["memcpy"] = &MemCpy;
1430   Optimizations["memmove"] = &MemMove;
1431   Optimizations["memset"] = &MemSet;
1432
1433   // _chk variants of String and Memory LibCall Optimizations.
1434   Optimizations["__strcpy_chk"] = &StrCpyChk;
1435
1436   // Math Library Optimizations
1437   Optimizations["powf"] = &Pow;
1438   Optimizations["pow"] = &Pow;
1439   Optimizations["powl"] = &Pow;
1440   Optimizations["llvm.pow.f32"] = &Pow;
1441   Optimizations["llvm.pow.f64"] = &Pow;
1442   Optimizations["llvm.pow.f80"] = &Pow;
1443   Optimizations["llvm.pow.f128"] = &Pow;
1444   Optimizations["llvm.pow.ppcf128"] = &Pow;
1445   Optimizations["exp2l"] = &Exp2;
1446   Optimizations["exp2"] = &Exp2;
1447   Optimizations["exp2f"] = &Exp2;
1448   Optimizations["llvm.exp2.ppcf128"] = &Exp2;
1449   Optimizations["llvm.exp2.f128"] = &Exp2;
1450   Optimizations["llvm.exp2.f80"] = &Exp2;
1451   Optimizations["llvm.exp2.f64"] = &Exp2;
1452   Optimizations["llvm.exp2.f32"] = &Exp2;
1453
1454 #ifdef HAVE_FLOORF
1455   Optimizations["floor"] = &UnaryDoubleFP;
1456 #endif
1457 #ifdef HAVE_CEILF
1458   Optimizations["ceil"] = &UnaryDoubleFP;
1459 #endif
1460 #ifdef HAVE_ROUNDF
1461   Optimizations["round"] = &UnaryDoubleFP;
1462 #endif
1463 #ifdef HAVE_RINTF
1464   Optimizations["rint"] = &UnaryDoubleFP;
1465 #endif
1466 #ifdef HAVE_NEARBYINTF
1467   Optimizations["nearbyint"] = &UnaryDoubleFP;
1468 #endif
1469
1470   // Integer Optimizations
1471   Optimizations["ffs"] = &FFS;
1472   Optimizations["ffsl"] = &FFS;
1473   Optimizations["ffsll"] = &FFS;
1474   Optimizations["abs"] = &Abs;
1475   Optimizations["labs"] = &Abs;
1476   Optimizations["llabs"] = &Abs;
1477   Optimizations["isdigit"] = &IsDigit;
1478   Optimizations["isascii"] = &IsAscii;
1479   Optimizations["toascii"] = &ToAscii;
1480
1481   // Formatting and IO Optimizations
1482   Optimizations["sprintf"] = &SPrintF;
1483   Optimizations["printf"] = &PrintF;
1484   Optimizations["fwrite"] = &FWrite;
1485   Optimizations["fputs"] = &FPuts;
1486   Optimizations["fprintf"] = &FPrintF;
1487 }
1488
1489
1490 /// runOnFunction - Top level algorithm.
1491 ///
1492 bool SimplifyLibCalls::runOnFunction(Function &F) {
1493   if (Optimizations.empty())
1494     InitOptimizations();
1495
1496   const TargetData *TD = getAnalysisIfAvailable<TargetData>();
1497
1498   IRBuilder<> Builder(F.getContext());
1499
1500   bool Changed = false;
1501   for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
1502     for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
1503       // Ignore non-calls.
1504       CallInst *CI = dyn_cast<CallInst>(I++);
1505       if (!CI) continue;
1506
1507       // Ignore indirect calls and calls to non-external functions.
1508       Function *Callee = CI->getCalledFunction();
1509       if (Callee == 0 || !Callee->isDeclaration() ||
1510           !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
1511         continue;
1512
1513       // Ignore unknown calls.
1514       LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
1515       if (!LCO) continue;
1516
1517       // Set the builder to the instruction after the call.
1518       Builder.SetInsertPoint(BB, I);
1519
1520       // Try to optimize this call.
1521       Value *Result = LCO->OptimizeCall(CI, TD, Builder);
1522       if (Result == 0) continue;
1523
1524       DEBUG(dbgs() << "SimplifyLibCalls simplified: " << *CI;
1525             dbgs() << "  into: " << *Result << "\n");
1526
1527       // Something changed!
1528       Changed = true;
1529       ++NumSimplified;
1530
1531       // Inspect the instruction after the call (which was potentially just
1532       // added) next.
1533       I = CI; ++I;
1534
1535       if (CI != Result && !CI->use_empty()) {
1536         CI->replaceAllUsesWith(Result);
1537         if (!Result->hasName())
1538           Result->takeName(CI);
1539       }
1540       CI->eraseFromParent();
1541     }
1542   }
1543   return Changed;
1544 }
1545
1546 // Utility methods for doInitialization.
1547
1548 void SimplifyLibCalls::setDoesNotAccessMemory(Function &F) {
1549   if (!F.doesNotAccessMemory()) {
1550     F.setDoesNotAccessMemory();
1551     ++NumAnnotated;
1552     Modified = true;
1553   }
1554 }
1555 void SimplifyLibCalls::setOnlyReadsMemory(Function &F) {
1556   if (!F.onlyReadsMemory()) {
1557     F.setOnlyReadsMemory();
1558     ++NumAnnotated;
1559     Modified = true;
1560   }
1561 }
1562 void SimplifyLibCalls::setDoesNotThrow(Function &F) {
1563   if (!F.doesNotThrow()) {
1564     F.setDoesNotThrow();
1565     ++NumAnnotated;
1566     Modified = true;
1567   }
1568 }
1569 void SimplifyLibCalls::setDoesNotCapture(Function &F, unsigned n) {
1570   if (!F.doesNotCapture(n)) {
1571     F.setDoesNotCapture(n);
1572     ++NumAnnotated;
1573     Modified = true;
1574   }
1575 }
1576 void SimplifyLibCalls::setDoesNotAlias(Function &F, unsigned n) {
1577   if (!F.doesNotAlias(n)) {
1578     F.setDoesNotAlias(n);
1579     ++NumAnnotated;
1580     Modified = true;
1581   }
1582 }
1583
1584 /// doInitialization - Add attributes to well-known functions.
1585 ///
1586 bool SimplifyLibCalls::doInitialization(Module &M) {
1587   Modified = false;
1588   for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
1589     Function &F = *I;
1590     if (!F.isDeclaration())
1591       continue;
1592
1593     if (!F.hasName())
1594       continue;
1595
1596     const FunctionType *FTy = F.getFunctionType();
1597
1598     StringRef Name = F.getName();
1599     switch (Name[0]) {
1600       case 's':
1601         if (Name == "strlen") {
1602           if (FTy->getNumParams() != 1 ||
1603               !FTy->getParamType(0)->isPointerTy())
1604             continue;
1605           setOnlyReadsMemory(F);
1606           setDoesNotThrow(F);
1607           setDoesNotCapture(F, 1);
1608         } else if (Name == "strchr" ||
1609                    Name == "strrchr") {
1610           if (FTy->getNumParams() != 2 ||
1611               !FTy->getParamType(0)->isPointerTy() ||
1612               !FTy->getParamType(1)->isIntegerTy())
1613             continue;
1614           setOnlyReadsMemory(F);
1615           setDoesNotThrow(F);
1616         } else if (Name == "strcpy" ||
1617                    Name == "stpcpy" ||
1618                    Name == "strcat" ||
1619                    Name == "strtol" ||
1620                    Name == "strtod" ||
1621                    Name == "strtof" ||
1622                    Name == "strtoul" ||
1623                    Name == "strtoll" ||
1624                    Name == "strtold" ||
1625                    Name == "strncat" ||
1626                    Name == "strncpy" ||
1627                    Name == "strtoull") {
1628           if (FTy->getNumParams() < 2 ||
1629               !FTy->getParamType(1)->isPointerTy())
1630             continue;
1631           setDoesNotThrow(F);
1632           setDoesNotCapture(F, 2);
1633         } else if (Name == "strxfrm") {
1634           if (FTy->getNumParams() != 3 ||
1635               !FTy->getParamType(0)->isPointerTy() ||
1636               !FTy->getParamType(1)->isPointerTy())
1637             continue;
1638           setDoesNotThrow(F);
1639           setDoesNotCapture(F, 1);
1640           setDoesNotCapture(F, 2);
1641         } else if (Name == "strcmp" ||
1642                    Name == "strspn" ||
1643                    Name == "strncmp" ||
1644                    Name == "strcspn" ||
1645                    Name == "strcoll" ||
1646                    Name == "strcasecmp" ||
1647                    Name == "strncasecmp") {
1648           if (FTy->getNumParams() < 2 ||
1649               !FTy->getParamType(0)->isPointerTy() ||
1650               !FTy->getParamType(1)->isPointerTy())
1651             continue;
1652           setOnlyReadsMemory(F);
1653           setDoesNotThrow(F);
1654           setDoesNotCapture(F, 1);
1655           setDoesNotCapture(F, 2);
1656         } else if (Name == "strstr" ||
1657                    Name == "strpbrk") {
1658           if (FTy->getNumParams() != 2 ||
1659               !FTy->getParamType(1)->isPointerTy())
1660             continue;
1661           setOnlyReadsMemory(F);
1662           setDoesNotThrow(F);
1663           setDoesNotCapture(F, 2);
1664         } else if (Name == "strtok" ||
1665                    Name == "strtok_r") {
1666           if (FTy->getNumParams() < 2 ||
1667               !FTy->getParamType(1)->isPointerTy())
1668             continue;
1669           setDoesNotThrow(F);
1670           setDoesNotCapture(F, 2);
1671         } else if (Name == "scanf" ||
1672                    Name == "setbuf" ||
1673                    Name == "setvbuf") {
1674           if (FTy->getNumParams() < 1 ||
1675               !FTy->getParamType(0)->isPointerTy())
1676             continue;
1677           setDoesNotThrow(F);
1678           setDoesNotCapture(F, 1);
1679         } else if (Name == "strdup" ||
1680                    Name == "strndup") {
1681           if (FTy->getNumParams() < 1 ||
1682               !FTy->getReturnType()->isPointerTy() ||
1683               !FTy->getParamType(0)->isPointerTy())
1684             continue;
1685           setDoesNotThrow(F);
1686           setDoesNotAlias(F, 0);
1687           setDoesNotCapture(F, 1);
1688         } else if (Name == "stat" ||
1689                    Name == "sscanf" ||
1690                    Name == "sprintf" ||
1691                    Name == "statvfs") {
1692           if (FTy->getNumParams() < 2 ||
1693               !FTy->getParamType(0)->isPointerTy() ||
1694               !FTy->getParamType(1)->isPointerTy())
1695             continue;
1696           setDoesNotThrow(F);
1697           setDoesNotCapture(F, 1);
1698           setDoesNotCapture(F, 2);
1699         } else if (Name == "snprintf") {
1700           if (FTy->getNumParams() != 3 ||
1701               !FTy->getParamType(0)->isPointerTy() ||
1702               !FTy->getParamType(2)->isPointerTy())
1703             continue;
1704           setDoesNotThrow(F);
1705           setDoesNotCapture(F, 1);
1706           setDoesNotCapture(F, 3);
1707         } else if (Name == "setitimer") {
1708           if (FTy->getNumParams() != 3 ||
1709               !FTy->getParamType(1)->isPointerTy() ||
1710               !FTy->getParamType(2)->isPointerTy())
1711             continue;
1712           setDoesNotThrow(F);
1713           setDoesNotCapture(F, 2);
1714           setDoesNotCapture(F, 3);
1715         } else if (Name == "system") {
1716           if (FTy->getNumParams() != 1 ||
1717               !FTy->getParamType(0)->isPointerTy())
1718             continue;
1719           // May throw; "system" is a valid pthread cancellation point.
1720           setDoesNotCapture(F, 1);
1721         }
1722         break;
1723       case 'm':
1724         if (Name == "malloc") {
1725           if (FTy->getNumParams() != 1 ||
1726               !FTy->getReturnType()->isPointerTy())
1727             continue;
1728           setDoesNotThrow(F);
1729           setDoesNotAlias(F, 0);
1730         } else if (Name == "memcmp") {
1731           if (FTy->getNumParams() != 3 ||
1732               !FTy->getParamType(0)->isPointerTy() ||
1733               !FTy->getParamType(1)->isPointerTy())
1734             continue;
1735           setOnlyReadsMemory(F);
1736           setDoesNotThrow(F);
1737           setDoesNotCapture(F, 1);
1738           setDoesNotCapture(F, 2);
1739         } else if (Name == "memchr" ||
1740                    Name == "memrchr") {
1741           if (FTy->getNumParams() != 3)
1742             continue;
1743           setOnlyReadsMemory(F);
1744           setDoesNotThrow(F);
1745         } else if (Name == "modf" ||
1746                    Name == "modff" ||
1747                    Name == "modfl" ||
1748                    Name == "memcpy" ||
1749                    Name == "memccpy" ||
1750                    Name == "memmove") {
1751           if (FTy->getNumParams() < 2 ||
1752               !FTy->getParamType(1)->isPointerTy())
1753             continue;
1754           setDoesNotThrow(F);
1755           setDoesNotCapture(F, 2);
1756         } else if (Name == "memalign") {
1757           if (!FTy->getReturnType()->isPointerTy())
1758             continue;
1759           setDoesNotAlias(F, 0);
1760         } else if (Name == "mkdir" ||
1761                    Name == "mktime") {
1762           if (FTy->getNumParams() == 0 ||
1763               !FTy->getParamType(0)->isPointerTy())
1764             continue;
1765           setDoesNotThrow(F);
1766           setDoesNotCapture(F, 1);
1767         }
1768         break;
1769       case 'r':
1770         if (Name == "realloc") {
1771           if (FTy->getNumParams() != 2 ||
1772               !FTy->getParamType(0)->isPointerTy() ||
1773               !FTy->getReturnType()->isPointerTy())
1774             continue;
1775           setDoesNotThrow(F);
1776           setDoesNotAlias(F, 0);
1777           setDoesNotCapture(F, 1);
1778         } else if (Name == "read") {
1779           if (FTy->getNumParams() != 3 ||
1780               !FTy->getParamType(1)->isPointerTy())
1781             continue;
1782           // May throw; "read" is a valid pthread cancellation point.
1783           setDoesNotCapture(F, 2);
1784         } else if (Name == "rmdir" ||
1785                    Name == "rewind" ||
1786                    Name == "remove" ||
1787                    Name == "realpath") {
1788           if (FTy->getNumParams() < 1 ||
1789               !FTy->getParamType(0)->isPointerTy())
1790             continue;
1791           setDoesNotThrow(F);
1792           setDoesNotCapture(F, 1);
1793         } else if (Name == "rename" ||
1794                    Name == "readlink") {
1795           if (FTy->getNumParams() < 2 ||
1796               !FTy->getParamType(0)->isPointerTy() ||
1797               !FTy->getParamType(1)->isPointerTy())
1798             continue;
1799           setDoesNotThrow(F);
1800           setDoesNotCapture(F, 1);
1801           setDoesNotCapture(F, 2);
1802         }
1803         break;
1804       case 'w':
1805         if (Name == "write") {
1806           if (FTy->getNumParams() != 3 ||
1807               !FTy->getParamType(1)->isPointerTy())
1808             continue;
1809           // May throw; "write" is a valid pthread cancellation point.
1810           setDoesNotCapture(F, 2);
1811         }
1812         break;
1813       case 'b':
1814         if (Name == "bcopy") {
1815           if (FTy->getNumParams() != 3 ||
1816               !FTy->getParamType(0)->isPointerTy() ||
1817               !FTy->getParamType(1)->isPointerTy())
1818             continue;
1819           setDoesNotThrow(F);
1820           setDoesNotCapture(F, 1);
1821           setDoesNotCapture(F, 2);
1822         } else if (Name == "bcmp") {
1823           if (FTy->getNumParams() != 3 ||
1824               !FTy->getParamType(0)->isPointerTy() ||
1825               !FTy->getParamType(1)->isPointerTy())
1826             continue;
1827           setDoesNotThrow(F);
1828           setOnlyReadsMemory(F);
1829           setDoesNotCapture(F, 1);
1830           setDoesNotCapture(F, 2);
1831         } else if (Name == "bzero") {
1832           if (FTy->getNumParams() != 2 ||
1833               !FTy->getParamType(0)->isPointerTy())
1834             continue;
1835           setDoesNotThrow(F);
1836           setDoesNotCapture(F, 1);
1837         }
1838         break;
1839       case 'c':
1840         if (Name == "calloc") {
1841           if (FTy->getNumParams() != 2 ||
1842               !FTy->getReturnType()->isPointerTy())
1843             continue;
1844           setDoesNotThrow(F);
1845           setDoesNotAlias(F, 0);
1846         } else if (Name == "chmod" ||
1847                    Name == "chown" ||
1848                    Name == "ctermid" ||
1849                    Name == "clearerr" ||
1850                    Name == "closedir") {
1851           if (FTy->getNumParams() == 0 ||
1852               !FTy->getParamType(0)->isPointerTy())
1853             continue;
1854           setDoesNotThrow(F);
1855           setDoesNotCapture(F, 1);
1856         }
1857         break;
1858       case 'a':
1859         if (Name == "atoi" ||
1860             Name == "atol" ||
1861             Name == "atof" ||
1862             Name == "atoll") {
1863           if (FTy->getNumParams() != 1 ||
1864               !FTy->getParamType(0)->isPointerTy())
1865             continue;
1866           setDoesNotThrow(F);
1867           setOnlyReadsMemory(F);
1868           setDoesNotCapture(F, 1);
1869         } else if (Name == "access") {
1870           if (FTy->getNumParams() != 2 ||
1871               !FTy->getParamType(0)->isPointerTy())
1872             continue;
1873           setDoesNotThrow(F);
1874           setDoesNotCapture(F, 1);
1875         }
1876         break;
1877       case 'f':
1878         if (Name == "fopen") {
1879           if (FTy->getNumParams() != 2 ||
1880               !FTy->getReturnType()->isPointerTy() ||
1881               !FTy->getParamType(0)->isPointerTy() ||
1882               !FTy->getParamType(1)->isPointerTy())
1883             continue;
1884           setDoesNotThrow(F);
1885           setDoesNotAlias(F, 0);
1886           setDoesNotCapture(F, 1);
1887           setDoesNotCapture(F, 2);
1888         } else if (Name == "fdopen") {
1889           if (FTy->getNumParams() != 2 ||
1890               !FTy->getReturnType()->isPointerTy() ||
1891               !FTy->getParamType(1)->isPointerTy())
1892             continue;
1893           setDoesNotThrow(F);
1894           setDoesNotAlias(F, 0);
1895           setDoesNotCapture(F, 2);
1896         } else if (Name == "feof" ||
1897                    Name == "free" ||
1898                    Name == "fseek" ||
1899                    Name == "ftell" ||
1900                    Name == "fgetc" ||
1901                    Name == "fseeko" ||
1902                    Name == "ftello" ||
1903                    Name == "fileno" ||
1904                    Name == "fflush" ||
1905                    Name == "fclose" ||
1906                    Name == "fsetpos" ||
1907                    Name == "flockfile" ||
1908                    Name == "funlockfile" ||
1909                    Name == "ftrylockfile") {
1910           if (FTy->getNumParams() == 0 ||
1911               !FTy->getParamType(0)->isPointerTy())
1912             continue;
1913           setDoesNotThrow(F);
1914           setDoesNotCapture(F, 1);
1915         } else if (Name == "ferror") {
1916           if (FTy->getNumParams() != 1 ||
1917               !FTy->getParamType(0)->isPointerTy())
1918             continue;
1919           setDoesNotThrow(F);
1920           setDoesNotCapture(F, 1);
1921           setOnlyReadsMemory(F);
1922         } else if (Name == "fputc" ||
1923                    Name == "fstat" ||
1924                    Name == "frexp" ||
1925                    Name == "frexpf" ||
1926                    Name == "frexpl" ||
1927                    Name == "fstatvfs") {
1928           if (FTy->getNumParams() != 2 ||
1929               !FTy->getParamType(1)->isPointerTy())
1930             continue;
1931           setDoesNotThrow(F);
1932           setDoesNotCapture(F, 2);
1933         } else if (Name == "fgets") {
1934           if (FTy->getNumParams() != 3 ||
1935               !FTy->getParamType(0)->isPointerTy() ||
1936               !FTy->getParamType(2)->isPointerTy())
1937             continue;
1938           setDoesNotThrow(F);
1939           setDoesNotCapture(F, 3);
1940         } else if (Name == "fread" ||
1941                    Name == "fwrite") {
1942           if (FTy->getNumParams() != 4 ||
1943               !FTy->getParamType(0)->isPointerTy() ||
1944               !FTy->getParamType(3)->isPointerTy())
1945             continue;
1946           setDoesNotThrow(F);
1947           setDoesNotCapture(F, 1);
1948           setDoesNotCapture(F, 4);
1949         } else if (Name == "fputs" ||
1950                    Name == "fscanf" ||
1951                    Name == "fprintf" ||
1952                    Name == "fgetpos") {
1953           if (FTy->getNumParams() < 2 ||
1954               !FTy->getParamType(0)->isPointerTy() ||
1955               !FTy->getParamType(1)->isPointerTy())
1956             continue;
1957           setDoesNotThrow(F);
1958           setDoesNotCapture(F, 1);
1959           setDoesNotCapture(F, 2);
1960         }
1961         break;
1962       case 'g':
1963         if (Name == "getc" ||
1964             Name == "getlogin_r" ||
1965             Name == "getc_unlocked") {
1966           if (FTy->getNumParams() == 0 ||
1967               !FTy->getParamType(0)->isPointerTy())
1968             continue;
1969           setDoesNotThrow(F);
1970           setDoesNotCapture(F, 1);
1971         } else if (Name == "getenv") {
1972           if (FTy->getNumParams() != 1 ||
1973               !FTy->getParamType(0)->isPointerTy())
1974             continue;
1975           setDoesNotThrow(F);
1976           setOnlyReadsMemory(F);
1977           setDoesNotCapture(F, 1);
1978         } else if (Name == "gets" ||
1979                    Name == "getchar") {
1980           setDoesNotThrow(F);
1981         } else if (Name == "getitimer") {
1982           if (FTy->getNumParams() != 2 ||
1983               !FTy->getParamType(1)->isPointerTy())
1984             continue;
1985           setDoesNotThrow(F);
1986           setDoesNotCapture(F, 2);
1987         } else if (Name == "getpwnam") {
1988           if (FTy->getNumParams() != 1 ||
1989               !FTy->getParamType(0)->isPointerTy())
1990             continue;
1991           setDoesNotThrow(F);
1992           setDoesNotCapture(F, 1);
1993         }
1994         break;
1995       case 'u':
1996         if (Name == "ungetc") {
1997           if (FTy->getNumParams() != 2 ||
1998               !FTy->getParamType(1)->isPointerTy())
1999             continue;
2000           setDoesNotThrow(F);
2001           setDoesNotCapture(F, 2);
2002         } else if (Name == "uname" ||
2003                    Name == "unlink" ||
2004                    Name == "unsetenv") {
2005           if (FTy->getNumParams() != 1 ||
2006               !FTy->getParamType(0)->isPointerTy())
2007             continue;
2008           setDoesNotThrow(F);
2009           setDoesNotCapture(F, 1);
2010         } else if (Name == "utime" ||
2011                    Name == "utimes") {
2012           if (FTy->getNumParams() != 2 ||
2013               !FTy->getParamType(0)->isPointerTy() ||
2014               !FTy->getParamType(1)->isPointerTy())
2015             continue;
2016           setDoesNotThrow(F);
2017           setDoesNotCapture(F, 1);
2018           setDoesNotCapture(F, 2);
2019         }
2020         break;
2021       case 'p':
2022         if (Name == "putc") {
2023           if (FTy->getNumParams() != 2 ||
2024               !FTy->getParamType(1)->isPointerTy())
2025             continue;
2026           setDoesNotThrow(F);
2027           setDoesNotCapture(F, 2);
2028         } else if (Name == "puts" ||
2029                    Name == "printf" ||
2030                    Name == "perror") {
2031           if (FTy->getNumParams() != 1 ||
2032               !FTy->getParamType(0)->isPointerTy())
2033             continue;
2034           setDoesNotThrow(F);
2035           setDoesNotCapture(F, 1);
2036         } else if (Name == "pread" ||
2037                    Name == "pwrite") {
2038           if (FTy->getNumParams() != 4 ||
2039               !FTy->getParamType(1)->isPointerTy())
2040             continue;
2041           // May throw; these are valid pthread cancellation points.
2042           setDoesNotCapture(F, 2);
2043         } else if (Name == "putchar") {
2044           setDoesNotThrow(F);
2045         } else if (Name == "popen") {
2046           if (FTy->getNumParams() != 2 ||
2047               !FTy->getReturnType()->isPointerTy() ||
2048               !FTy->getParamType(0)->isPointerTy() ||
2049               !FTy->getParamType(1)->isPointerTy())
2050             continue;
2051           setDoesNotThrow(F);
2052           setDoesNotAlias(F, 0);
2053           setDoesNotCapture(F, 1);
2054           setDoesNotCapture(F, 2);
2055         } else if (Name == "pclose") {
2056           if (FTy->getNumParams() != 1 ||
2057               !FTy->getParamType(0)->isPointerTy())
2058             continue;
2059           setDoesNotThrow(F);
2060           setDoesNotCapture(F, 1);
2061         }
2062         break;
2063       case 'v':
2064         if (Name == "vscanf") {
2065           if (FTy->getNumParams() != 2 ||
2066               !FTy->getParamType(1)->isPointerTy())
2067             continue;
2068           setDoesNotThrow(F);
2069           setDoesNotCapture(F, 1);
2070         } else if (Name == "vsscanf" ||
2071                    Name == "vfscanf") {
2072           if (FTy->getNumParams() != 3 ||
2073               !FTy->getParamType(1)->isPointerTy() ||
2074               !FTy->getParamType(2)->isPointerTy())
2075             continue;
2076           setDoesNotThrow(F);
2077           setDoesNotCapture(F, 1);
2078           setDoesNotCapture(F, 2);
2079         } else if (Name == "valloc") {
2080           if (!FTy->getReturnType()->isPointerTy())
2081             continue;
2082           setDoesNotThrow(F);
2083           setDoesNotAlias(F, 0);
2084         } else if (Name == "vprintf") {
2085           if (FTy->getNumParams() != 2 ||
2086               !FTy->getParamType(0)->isPointerTy())
2087             continue;
2088           setDoesNotThrow(F);
2089           setDoesNotCapture(F, 1);
2090         } else if (Name == "vfprintf" ||
2091                    Name == "vsprintf") {
2092           if (FTy->getNumParams() != 3 ||
2093               !FTy->getParamType(0)->isPointerTy() ||
2094               !FTy->getParamType(1)->isPointerTy())
2095             continue;
2096           setDoesNotThrow(F);
2097           setDoesNotCapture(F, 1);
2098           setDoesNotCapture(F, 2);
2099         } else if (Name == "vsnprintf") {
2100           if (FTy->getNumParams() != 4 ||
2101               !FTy->getParamType(0)->isPointerTy() ||
2102               !FTy->getParamType(2)->isPointerTy())
2103             continue;
2104           setDoesNotThrow(F);
2105           setDoesNotCapture(F, 1);
2106           setDoesNotCapture(F, 3);
2107         }
2108         break;
2109       case 'o':
2110         if (Name == "open") {
2111           if (FTy->getNumParams() < 2 ||
2112               !FTy->getParamType(0)->isPointerTy())
2113             continue;
2114           // May throw; "open" is a valid pthread cancellation point.
2115           setDoesNotCapture(F, 1);
2116         } else if (Name == "opendir") {
2117           if (FTy->getNumParams() != 1 ||
2118               !FTy->getReturnType()->isPointerTy() ||
2119               !FTy->getParamType(0)->isPointerTy())
2120             continue;
2121           setDoesNotThrow(F);
2122           setDoesNotAlias(F, 0);
2123           setDoesNotCapture(F, 1);
2124         }
2125         break;
2126       case 't':
2127         if (Name == "tmpfile") {
2128           if (!FTy->getReturnType()->isPointerTy())
2129             continue;
2130           setDoesNotThrow(F);
2131           setDoesNotAlias(F, 0);
2132         } else if (Name == "times") {
2133           if (FTy->getNumParams() != 1 ||
2134               !FTy->getParamType(0)->isPointerTy())
2135             continue;
2136           setDoesNotThrow(F);
2137           setDoesNotCapture(F, 1);
2138         }
2139         break;
2140       case 'h':
2141         if (Name == "htonl" ||
2142             Name == "htons") {
2143           setDoesNotThrow(F);
2144           setDoesNotAccessMemory(F);
2145         }
2146         break;
2147       case 'n':
2148         if (Name == "ntohl" ||
2149             Name == "ntohs") {
2150           setDoesNotThrow(F);
2151           setDoesNotAccessMemory(F);
2152         }
2153         break;
2154       case 'l':
2155         if (Name == "lstat") {
2156           if (FTy->getNumParams() != 2 ||
2157               !FTy->getParamType(0)->isPointerTy() ||
2158               !FTy->getParamType(1)->isPointerTy())
2159             continue;
2160           setDoesNotThrow(F);
2161           setDoesNotCapture(F, 1);
2162           setDoesNotCapture(F, 2);
2163         } else if (Name == "lchown") {
2164           if (FTy->getNumParams() != 3 ||
2165               !FTy->getParamType(0)->isPointerTy())
2166             continue;
2167           setDoesNotThrow(F);
2168           setDoesNotCapture(F, 1);
2169         }
2170         break;
2171       case 'q':
2172         if (Name == "qsort") {
2173           if (FTy->getNumParams() != 4 ||
2174               !FTy->getParamType(3)->isPointerTy())
2175             continue;
2176           // May throw; places call through function pointer.
2177           setDoesNotCapture(F, 4);
2178         }
2179         break;
2180       case '_':
2181         if (Name == "__strdup" ||
2182             Name == "__strndup") {
2183           if (FTy->getNumParams() < 1 ||
2184               !FTy->getReturnType()->isPointerTy() ||
2185               !FTy->getParamType(0)->isPointerTy())
2186             continue;
2187           setDoesNotThrow(F);
2188           setDoesNotAlias(F, 0);
2189           setDoesNotCapture(F, 1);
2190         } else if (Name == "__strtok_r") {
2191           if (FTy->getNumParams() != 3 ||
2192               !FTy->getParamType(1)->isPointerTy())
2193             continue;
2194           setDoesNotThrow(F);
2195           setDoesNotCapture(F, 2);
2196         } else if (Name == "_IO_getc") {
2197           if (FTy->getNumParams() != 1 ||
2198               !FTy->getParamType(0)->isPointerTy())
2199             continue;
2200           setDoesNotThrow(F);
2201           setDoesNotCapture(F, 1);
2202         } else if (Name == "_IO_putc") {
2203           if (FTy->getNumParams() != 2 ||
2204               !FTy->getParamType(1)->isPointerTy())
2205             continue;
2206           setDoesNotThrow(F);
2207           setDoesNotCapture(F, 2);
2208         }
2209         break;
2210       case 1:
2211         if (Name == "\1__isoc99_scanf") {
2212           if (FTy->getNumParams() < 1 ||
2213               !FTy->getParamType(0)->isPointerTy())
2214             continue;
2215           setDoesNotThrow(F);
2216           setDoesNotCapture(F, 1);
2217         } else if (Name == "\1stat64" ||
2218                    Name == "\1lstat64" ||
2219                    Name == "\1statvfs64" ||
2220                    Name == "\1__isoc99_sscanf") {
2221           if (FTy->getNumParams() < 1 ||
2222               !FTy->getParamType(0)->isPointerTy() ||
2223               !FTy->getParamType(1)->isPointerTy())
2224             continue;
2225           setDoesNotThrow(F);
2226           setDoesNotCapture(F, 1);
2227           setDoesNotCapture(F, 2);
2228         } else if (Name == "\1fopen64") {
2229           if (FTy->getNumParams() != 2 ||
2230               !FTy->getReturnType()->isPointerTy() ||
2231               !FTy->getParamType(0)->isPointerTy() ||
2232               !FTy->getParamType(1)->isPointerTy())
2233             continue;
2234           setDoesNotThrow(F);
2235           setDoesNotAlias(F, 0);
2236           setDoesNotCapture(F, 1);
2237           setDoesNotCapture(F, 2);
2238         } else if (Name == "\1fseeko64" ||
2239                    Name == "\1ftello64") {
2240           if (FTy->getNumParams() == 0 ||
2241               !FTy->getParamType(0)->isPointerTy())
2242             continue;
2243           setDoesNotThrow(F);
2244           setDoesNotCapture(F, 1);
2245         } else if (Name == "\1tmpfile64") {
2246           if (!FTy->getReturnType()->isPointerTy())
2247             continue;
2248           setDoesNotThrow(F);
2249           setDoesNotAlias(F, 0);
2250         } else if (Name == "\1fstat64" ||
2251                    Name == "\1fstatvfs64") {
2252           if (FTy->getNumParams() != 2 ||
2253               !FTy->getParamType(1)->isPointerTy())
2254             continue;
2255           setDoesNotThrow(F);
2256           setDoesNotCapture(F, 2);
2257         } else if (Name == "\1open64") {
2258           if (FTy->getNumParams() < 2 ||
2259               !FTy->getParamType(0)->isPointerTy())
2260             continue;
2261           // May throw; "open" is a valid pthread cancellation point.
2262           setDoesNotCapture(F, 1);
2263         }
2264         break;
2265     }
2266   }
2267   return Modified;
2268 }
2269
2270 // TODO:
2271 //   Additional cases that we need to add to this file:
2272 //
2273 // cbrt:
2274 //   * cbrt(expN(X))  -> expN(x/3)
2275 //   * cbrt(sqrt(x))  -> pow(x,1/6)
2276 //   * cbrt(sqrt(x))  -> pow(x,1/9)
2277 //
2278 // cos, cosf, cosl:
2279 //   * cos(-x)  -> cos(x)
2280 //
2281 // exp, expf, expl:
2282 //   * exp(log(x))  -> x
2283 //
2284 // log, logf, logl:
2285 //   * log(exp(x))   -> x
2286 //   * log(x**y)     -> y*log(x)
2287 //   * log(exp(y))   -> y*log(e)
2288 //   * log(exp2(y))  -> y*log(2)
2289 //   * log(exp10(y)) -> y*log(10)
2290 //   * log(sqrt(x))  -> 0.5*log(x)
2291 //   * log(pow(x,y)) -> y*log(x)
2292 //
2293 // lround, lroundf, lroundl:
2294 //   * lround(cnst) -> cnst'
2295 //
2296 // pow, powf, powl:
2297 //   * pow(exp(x),y)  -> exp(x*y)
2298 //   * pow(sqrt(x),y) -> pow(x,y*0.5)
2299 //   * pow(pow(x,y),z)-> pow(x,y*z)
2300 //
2301 // puts:
2302 //   * puts("") -> putchar('\n')
2303 //
2304 // round, roundf, roundl:
2305 //   * round(cnst) -> cnst'
2306 //
2307 // signbit:
2308 //   * signbit(cnst) -> cnst'
2309 //   * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2310 //
2311 // sqrt, sqrtf, sqrtl:
2312 //   * sqrt(expN(x))  -> expN(x*0.5)
2313 //   * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2314 //   * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2315 //
2316 // stpcpy:
2317 //   * stpcpy(str, "literal") ->
2318 //           llvm.memcpy(str,"literal",strlen("literal")+1,1)
2319 //
2320 // tan, tanf, tanl:
2321 //   * tan(atan(x)) -> x
2322 //
2323 // trunc, truncf, truncl:
2324 //   * trunc(cnst) -> cnst'
2325 //
2326 //