1 //===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
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.
16 //===----------------------------------------------------------------------===//
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"
37 STATISTIC(NumSimplified, "Number of library calls simplified");
38 STATISTIC(NumAnnotated, "Number of attributes added to library functions");
40 //===----------------------------------------------------------------------===//
41 // Optimizer Base Class
42 //===----------------------------------------------------------------------===//
44 /// This class is the abstract base class for the set of optimizations that
45 /// corresponds to one library call.
47 class LibCallOptimization {
53 LibCallOptimization() { }
54 virtual ~LibCallOptimization() {}
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
61 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
64 Value *OptimizeCall(CallInst *CI, const TargetData *TD, IRBuilder<> &B) {
65 Caller = CI->getParent()->getParent();
67 if (CI->getCalledFunction())
68 Context = &CI->getCalledFunction()->getContext();
70 // We never change the calling convention.
71 if (CI->getCallingConv() != llvm::CallingConv::C)
74 return CallOptimizer(CI->getCalledFunction(), CI, B);
77 } // End anonymous namespace.
80 //===----------------------------------------------------------------------===//
82 //===----------------------------------------------------------------------===//
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();
89 if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
91 if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
94 // Unknown instruction.
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();
105 if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
106 if (IC->isEquality() && IC->getOperand(1) == With)
108 // Unknown instruction.
114 //===----------------------------------------------------------------------===//
115 // String and Memory LibCall Optimizations
116 //===----------------------------------------------------------------------===//
118 //===---------------------------------------===//
119 // 'strcat' Optimizations
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())
131 // Extract some information from the instruction
132 Value *Dst = CI->getArgOperand(0);
133 Value *Src = CI->getArgOperand(1);
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.
140 // Handle the simple, do-nothing case: strcat(x, "") -> x
144 // These optimizations require TargetData.
147 EmitStrLenMemCpy(Src, Dst, Len, B);
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);
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");
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),
169 //===---------------------------------------===//
170 // 'strncat' Optimizations
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())
183 // Extract some information from the instruction
184 Value *Dst = CI->getArgOperand(0);
185 Value *Src = CI->getArgOperand(1);
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();
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.
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;
204 // These optimizations require TargetData.
207 // We don't optimize this case
208 if (Len < SrcLen) return 0;
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);
217 //===---------------------------------------===//
218 // 'strchr' Optimizations
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())
229 Value *SrcStr = CI->getArgOperand(0);
231 // If the second operand is non-constant, see if we can compute the length
232 // of the input string and turn this into memchr.
233 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
235 // These optimizations require TargetData.
238 uint64_t Len = GetStringLength(SrcStr);
239 if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
242 return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
243 ConstantInt::get(TD->getIntPtrType(*Context), Len),
247 // Otherwise, the character is a constant, see if the first argument is
248 // a string literal. If so, we can constant fold.
250 if (!GetConstantStringInfo(SrcStr, Str))
253 // strchr can find the nul character.
255 char CharValue = CharC->getSExtValue();
257 // Compute the offset.
260 if (i == Str.size()) // Didn't find the char. strchr returns null.
261 return Constant::getNullValue(CI->getType());
262 // Did we find our match?
263 if (Str[i] == CharValue)
268 // strchr(s+n,c) -> gep(s+n+i,c)
269 Value *Idx = ConstantInt::get(Type::getInt64Ty(*Context), i);
270 return B.CreateGEP(SrcStr, Idx, "strchr");
274 //===---------------------------------------===//
275 // 'strcmp' Optimizations
277 struct StrCmpOpt : public LibCallOptimization {
278 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
279 // Verify the "strcmp" function prototype.
280 const FunctionType *FT = Callee->getFunctionType();
281 if (FT->getNumParams() != 2 ||
282 !FT->getReturnType()->isIntegerTy(32) ||
283 FT->getParamType(0) != FT->getParamType(1) ||
284 FT->getParamType(0) != Type::getInt8PtrTy(*Context))
287 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
288 if (Str1P == Str2P) // strcmp(x,x) -> 0
289 return ConstantInt::get(CI->getType(), 0);
291 std::string Str1, Str2;
292 bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
293 bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
295 if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
296 return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
298 if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
299 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
301 // strcmp(x, y) -> cnst (if both x and y are constant strings)
302 if (HasStr1 && HasStr2)
303 return ConstantInt::get(CI->getType(),
304 strcmp(Str1.c_str(),Str2.c_str()));
306 // strcmp(P, "x") -> memcmp(P, "x", 2)
307 uint64_t Len1 = GetStringLength(Str1P);
308 uint64_t Len2 = GetStringLength(Str2P);
310 // These optimizations require TargetData.
313 return EmitMemCmp(Str1P, Str2P,
314 ConstantInt::get(TD->getIntPtrType(*Context),
315 std::min(Len1, Len2)), B, TD);
322 //===---------------------------------------===//
323 // 'strncmp' Optimizations
325 struct StrNCmpOpt : public LibCallOptimization {
326 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
327 // Verify the "strncmp" function prototype.
328 const FunctionType *FT = Callee->getFunctionType();
329 if (FT->getNumParams() != 3 ||
330 !FT->getReturnType()->isIntegerTy(32) ||
331 FT->getParamType(0) != FT->getParamType(1) ||
332 FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
333 !FT->getParamType(2)->isIntegerTy())
336 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
337 if (Str1P == Str2P) // strncmp(x,x,n) -> 0
338 return ConstantInt::get(CI->getType(), 0);
340 // Get the length argument if it is constant.
342 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
343 Length = LengthArg->getZExtValue();
347 if (Length == 0) // strncmp(x,y,0) -> 0
348 return ConstantInt::get(CI->getType(), 0);
350 if (TD && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
351 return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, TD);
353 std::string Str1, Str2;
354 bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
355 bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
357 if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> *x
358 return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
360 if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
361 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
363 // strncmp(x, y) -> cnst (if both x and y are constant strings)
364 if (HasStr1 && HasStr2)
365 return ConstantInt::get(CI->getType(),
366 strncmp(Str1.c_str(), Str2.c_str(), Length));
372 //===---------------------------------------===//
373 // 'strcpy' Optimizations
375 struct StrCpyOpt : public LibCallOptimization {
376 bool OptChkCall; // True if it's optimizing a __strcpy_chk libcall.
378 StrCpyOpt(bool c) : OptChkCall(c) {}
380 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
381 // Verify the "strcpy" function prototype.
382 unsigned NumParams = OptChkCall ? 3 : 2;
383 const FunctionType *FT = Callee->getFunctionType();
384 if (FT->getNumParams() != NumParams ||
385 FT->getReturnType() != FT->getParamType(0) ||
386 FT->getParamType(0) != FT->getParamType(1) ||
387 FT->getParamType(0) != Type::getInt8PtrTy(*Context))
390 Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
391 if (Dst == Src) // strcpy(x,x) -> x
394 // These optimizations require TargetData.
397 // See if we can get the length of the input string.
398 uint64_t Len = GetStringLength(Src);
399 if (Len == 0) return 0;
401 // We have enough information to now generate the memcpy call to do the
402 // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
404 EmitMemCpyChk(Dst, Src,
405 ConstantInt::get(TD->getIntPtrType(*Context), Len),
406 CI->getArgOperand(2), B, TD);
409 ConstantInt::get(TD->getIntPtrType(*Context), Len),
415 //===---------------------------------------===//
416 // 'strncpy' Optimizations
418 struct StrNCpyOpt : public LibCallOptimization {
419 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
420 const FunctionType *FT = Callee->getFunctionType();
421 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
422 FT->getParamType(0) != FT->getParamType(1) ||
423 FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
424 !FT->getParamType(2)->isIntegerTy())
427 Value *Dst = CI->getArgOperand(0);
428 Value *Src = CI->getArgOperand(1);
429 Value *LenOp = CI->getArgOperand(2);
431 // See if we can get the length of the input string.
432 uint64_t SrcLen = GetStringLength(Src);
433 if (SrcLen == 0) return 0;
437 // strncpy(x, "", y) -> memset(x, '\0', y, 1)
438 EmitMemSet(Dst, ConstantInt::get(Type::getInt8Ty(*Context), '\0'),
439 LenOp, false, B, TD);
444 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
445 Len = LengthArg->getZExtValue();
449 if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
451 // These optimizations require TargetData.
454 // Let strncpy handle the zero padding
455 if (Len > SrcLen+1) return 0;
457 // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
459 ConstantInt::get(TD->getIntPtrType(*Context), Len),
466 //===---------------------------------------===//
467 // 'strlen' Optimizations
469 struct StrLenOpt : public LibCallOptimization {
470 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
471 const FunctionType *FT = Callee->getFunctionType();
472 if (FT->getNumParams() != 1 ||
473 FT->getParamType(0) != Type::getInt8PtrTy(*Context) ||
474 !FT->getReturnType()->isIntegerTy())
477 Value *Src = CI->getArgOperand(0);
479 // Constant folding: strlen("xyz") -> 3
480 if (uint64_t Len = GetStringLength(Src))
481 return ConstantInt::get(CI->getType(), Len-1);
483 // strlen(x) != 0 --> *x != 0
484 // strlen(x) == 0 --> *x == 0
485 if (IsOnlyUsedInZeroEqualityComparison(CI))
486 return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
491 //===---------------------------------------===//
492 // 'strto*' Optimizations. This handles strtol, strtod, strtof, strtoul, etc.
494 struct StrToOpt : public LibCallOptimization {
495 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
496 const FunctionType *FT = Callee->getFunctionType();
497 if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
498 !FT->getParamType(0)->isPointerTy() ||
499 !FT->getParamType(1)->isPointerTy())
502 Value *EndPtr = CI->getArgOperand(1);
503 if (isa<ConstantPointerNull>(EndPtr)) {
504 CI->setOnlyReadsMemory();
505 CI->addAttribute(1, Attribute::NoCapture);
512 //===---------------------------------------===//
513 // 'strstr' Optimizations
515 struct StrStrOpt : public LibCallOptimization {
516 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
517 const FunctionType *FT = Callee->getFunctionType();
518 if (FT->getNumParams() != 2 ||
519 !FT->getParamType(0)->isPointerTy() ||
520 !FT->getParamType(1)->isPointerTy() ||
521 !FT->getReturnType()->isPointerTy())
524 // fold strstr(x, x) -> x.
525 if (CI->getArgOperand(0) == CI->getArgOperand(1))
526 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
528 // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
529 if (TD && IsOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
530 Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, TD);
531 Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
533 for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end();
535 ICmpInst *Old = cast<ICmpInst>(UI++);
536 Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
537 ConstantInt::getNullValue(StrNCmp->getType()),
539 Old->replaceAllUsesWith(Cmp);
540 Old->eraseFromParent();
545 // See if either input string is a constant string.
546 std::string SearchStr, ToFindStr;
547 bool HasStr1 = GetConstantStringInfo(CI->getArgOperand(0), SearchStr);
548 bool HasStr2 = GetConstantStringInfo(CI->getArgOperand(1), ToFindStr);
550 // fold strstr(x, "") -> x.
551 if (HasStr2 && ToFindStr.empty())
552 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
554 // If both strings are known, constant fold it.
555 if (HasStr1 && HasStr2) {
556 std::string::size_type Offset = SearchStr.find(ToFindStr);
558 if (Offset == std::string::npos) // strstr("foo", "bar") -> null
559 return Constant::getNullValue(CI->getType());
561 // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
562 Value *Result = CastToCStr(CI->getArgOperand(0), B);
563 Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
564 return B.CreateBitCast(Result, CI->getType());
567 // fold strstr(x, "y") -> strchr(x, 'y').
568 if (HasStr2 && ToFindStr.size() == 1)
569 return B.CreateBitCast(EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, TD),
576 //===---------------------------------------===//
577 // 'memcmp' Optimizations
579 struct MemCmpOpt : public LibCallOptimization {
580 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
581 const FunctionType *FT = Callee->getFunctionType();
582 if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
583 !FT->getParamType(1)->isPointerTy() ||
584 !FT->getReturnType()->isIntegerTy(32))
587 Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
589 if (LHS == RHS) // memcmp(s,s,x) -> 0
590 return Constant::getNullValue(CI->getType());
592 // Make sure we have a constant length.
593 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
595 uint64_t Len = LenC->getZExtValue();
597 if (Len == 0) // memcmp(s1,s2,0) -> 0
598 return Constant::getNullValue(CI->getType());
600 // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
602 Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
603 CI->getType(), "lhsv");
604 Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
605 CI->getType(), "rhsv");
606 return B.CreateSub(LHSV, RHSV, "chardiff");
609 // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
610 std::string LHSStr, RHSStr;
611 if (GetConstantStringInfo(LHS, LHSStr) &&
612 GetConstantStringInfo(RHS, RHSStr)) {
613 // Make sure we're not reading out-of-bounds memory.
614 if (Len > LHSStr.length() || Len > RHSStr.length())
616 uint64_t Ret = memcmp(LHSStr.data(), RHSStr.data(), Len);
617 return ConstantInt::get(CI->getType(), Ret);
624 //===---------------------------------------===//
625 // 'memcpy' Optimizations
627 struct MemCpyOpt : public LibCallOptimization {
628 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
629 // These optimizations require TargetData.
632 const FunctionType *FT = Callee->getFunctionType();
633 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
634 !FT->getParamType(0)->isPointerTy() ||
635 !FT->getParamType(1)->isPointerTy() ||
636 FT->getParamType(2) != TD->getIntPtrType(*Context))
639 // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
640 EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
641 CI->getArgOperand(2), 1, false, B, TD);
642 return CI->getArgOperand(0);
646 //===---------------------------------------===//
647 // 'memmove' Optimizations
649 struct MemMoveOpt : public LibCallOptimization {
650 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
651 // These optimizations require TargetData.
654 const FunctionType *FT = Callee->getFunctionType();
655 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
656 !FT->getParamType(0)->isPointerTy() ||
657 !FT->getParamType(1)->isPointerTy() ||
658 FT->getParamType(2) != TD->getIntPtrType(*Context))
661 // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
662 EmitMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
663 CI->getArgOperand(2), 1, false, B, TD);
664 return CI->getArgOperand(0);
668 //===---------------------------------------===//
669 // 'memset' Optimizations
671 struct MemSetOpt : public LibCallOptimization {
672 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
673 // These optimizations require TargetData.
676 const FunctionType *FT = Callee->getFunctionType();
677 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
678 !FT->getParamType(0)->isPointerTy() ||
679 !FT->getParamType(1)->isIntegerTy() ||
680 FT->getParamType(2) != TD->getIntPtrType(*Context))
683 // memset(p, v, n) -> llvm.memset(p, v, n, 1)
684 Value *Val = B.CreateIntCast(CI->getArgOperand(1), Type::getInt8Ty(*Context),
686 EmitMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), false, B, TD);
687 return CI->getArgOperand(0);
691 //===----------------------------------------------------------------------===//
692 // Math Library Optimizations
693 //===----------------------------------------------------------------------===//
695 //===---------------------------------------===//
696 // 'pow*' Optimizations
698 struct PowOpt : public LibCallOptimization {
699 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
700 const FunctionType *FT = Callee->getFunctionType();
701 // Just make sure this has 2 arguments of the same FP type, which match the
703 if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
704 FT->getParamType(0) != FT->getParamType(1) ||
705 !FT->getParamType(0)->isFloatingPointTy())
708 Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
709 if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
710 if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
712 if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
713 return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
716 ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
717 if (Op2C == 0) return 0;
719 if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
720 return ConstantFP::get(CI->getType(), 1.0);
722 if (Op2C->isExactlyValue(0.5)) {
723 // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
724 // This is faster than calling pow, and still handles negative zero
725 // and negative infinite correctly.
726 // TODO: In fast-math mode, this could be just sqrt(x).
727 // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
728 Value *Inf = ConstantFP::getInfinity(CI->getType());
729 Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
730 Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B,
731 Callee->getAttributes());
732 Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B,
733 Callee->getAttributes());
734 Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf, "tmp");
735 Value *Sel = B.CreateSelect(FCmp, Inf, FAbs, "tmp");
739 if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
741 if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
742 return B.CreateFMul(Op1, Op1, "pow2");
743 if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
744 return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0),
750 //===---------------------------------------===//
751 // 'exp2' Optimizations
753 struct Exp2Opt : public LibCallOptimization {
754 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
755 const FunctionType *FT = Callee->getFunctionType();
756 // Just make sure this has 1 argument of FP type, which matches the
758 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
759 !FT->getParamType(0)->isFloatingPointTy())
762 Value *Op = CI->getArgOperand(0);
763 // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32
764 // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32
766 if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
767 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
768 LdExpArg = B.CreateSExt(OpC->getOperand(0),
769 Type::getInt32Ty(*Context), "tmp");
770 } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
771 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
772 LdExpArg = B.CreateZExt(OpC->getOperand(0),
773 Type::getInt32Ty(*Context), "tmp");
778 if (Op->getType()->isFloatTy())
780 else if (Op->getType()->isDoubleTy())
785 Constant *One = ConstantFP::get(*Context, APFloat(1.0f));
786 if (!Op->getType()->isFloatTy())
787 One = ConstantExpr::getFPExtend(One, Op->getType());
789 Module *M = Caller->getParent();
790 Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
792 Type::getInt32Ty(*Context),NULL);
793 CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
794 if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
795 CI->setCallingConv(F->getCallingConv());
803 //===---------------------------------------===//
804 // Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
806 struct UnaryDoubleFPOpt : public LibCallOptimization {
807 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
808 const FunctionType *FT = Callee->getFunctionType();
809 if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
810 !FT->getParamType(0)->isDoubleTy())
813 // If this is something like 'floor((double)floatval)', convert to floorf.
814 FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
815 if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
818 // floor((double)floatval) -> (double)floorf(floatval)
819 Value *V = Cast->getOperand(0);
820 V = EmitUnaryFloatFnCall(V, Callee->getName().data(), B,
821 Callee->getAttributes());
822 return B.CreateFPExt(V, Type::getDoubleTy(*Context));
826 //===----------------------------------------------------------------------===//
827 // Integer Optimizations
828 //===----------------------------------------------------------------------===//
830 //===---------------------------------------===//
831 // 'ffs*' Optimizations
833 struct FFSOpt : public LibCallOptimization {
834 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
835 const FunctionType *FT = Callee->getFunctionType();
836 // Just make sure this has 2 arguments of the same FP type, which match the
838 if (FT->getNumParams() != 1 ||
839 !FT->getReturnType()->isIntegerTy(32) ||
840 !FT->getParamType(0)->isIntegerTy())
843 Value *Op = CI->getArgOperand(0);
846 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
847 if (CI->getValue() == 0) // ffs(0) -> 0.
848 return Constant::getNullValue(CI->getType());
849 return ConstantInt::get(Type::getInt32Ty(*Context), // ffs(c) -> cttz(c)+1
850 CI->getValue().countTrailingZeros()+1);
853 // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
854 const Type *ArgType = Op->getType();
855 Value *F = Intrinsic::getDeclaration(Callee->getParent(),
856 Intrinsic::cttz, &ArgType, 1);
857 Value *V = B.CreateCall(F, Op, "cttz");
858 V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1), "tmp");
859 V = B.CreateIntCast(V, Type::getInt32Ty(*Context), false, "tmp");
861 Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
862 return B.CreateSelect(Cond, V,
863 ConstantInt::get(Type::getInt32Ty(*Context), 0));
867 //===---------------------------------------===//
868 // 'isdigit' Optimizations
870 struct IsDigitOpt : public LibCallOptimization {
871 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
872 const FunctionType *FT = Callee->getFunctionType();
873 // We require integer(i32)
874 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
875 !FT->getParamType(0)->isIntegerTy(32))
878 // isdigit(c) -> (c-'0') <u 10
879 Value *Op = CI->getArgOperand(0);
880 Op = B.CreateSub(Op, ConstantInt::get(Type::getInt32Ty(*Context), '0'),
882 Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 10),
884 return B.CreateZExt(Op, CI->getType());
888 //===---------------------------------------===//
889 // 'isascii' Optimizations
891 struct IsAsciiOpt : public LibCallOptimization {
892 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
893 const FunctionType *FT = Callee->getFunctionType();
894 // We require integer(i32)
895 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
896 !FT->getParamType(0)->isIntegerTy(32))
899 // isascii(c) -> c <u 128
900 Value *Op = CI->getArgOperand(0);
901 Op = B.CreateICmpULT(Op, ConstantInt::get(Type::getInt32Ty(*Context), 128),
903 return B.CreateZExt(Op, CI->getType());
907 //===---------------------------------------===//
908 // 'abs', 'labs', 'llabs' Optimizations
910 struct AbsOpt : public LibCallOptimization {
911 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
912 const FunctionType *FT = Callee->getFunctionType();
913 // We require integer(integer) where the types agree.
914 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
915 FT->getParamType(0) != FT->getReturnType())
918 // abs(x) -> x >s -1 ? x : -x
919 Value *Op = CI->getArgOperand(0);
920 Value *Pos = B.CreateICmpSGT(Op,
921 Constant::getAllOnesValue(Op->getType()),
923 Value *Neg = B.CreateNeg(Op, "neg");
924 return B.CreateSelect(Pos, Op, Neg);
929 //===---------------------------------------===//
930 // 'toascii' Optimizations
932 struct ToAsciiOpt : public LibCallOptimization {
933 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
934 const FunctionType *FT = Callee->getFunctionType();
935 // We require i32(i32)
936 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
937 !FT->getParamType(0)->isIntegerTy(32))
940 // isascii(c) -> c & 0x7f
941 return B.CreateAnd(CI->getArgOperand(0),
942 ConstantInt::get(CI->getType(),0x7F));
946 //===----------------------------------------------------------------------===//
947 // Formatting and IO Optimizations
948 //===----------------------------------------------------------------------===//
950 //===---------------------------------------===//
951 // 'printf' Optimizations
953 struct PrintFOpt : public LibCallOptimization {
954 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
955 // Require one fixed pointer argument and an integer/void result.
956 const FunctionType *FT = Callee->getFunctionType();
957 if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
958 !(FT->getReturnType()->isIntegerTy() ||
959 FT->getReturnType()->isVoidTy()))
962 // Check for a fixed format string.
963 std::string FormatStr;
964 if (!GetConstantStringInfo(CI->getArgOperand(0), FormatStr))
967 // Empty format string -> noop.
968 if (FormatStr.empty()) // Tolerate printf's declared void.
969 return CI->use_empty() ? (Value*)CI :
970 ConstantInt::get(CI->getType(), 0);
972 // printf("x") -> putchar('x'), even for '%'. Return the result of putchar
973 // in case there is an error writing to stdout.
974 if (FormatStr.size() == 1) {
975 Value *Res = EmitPutChar(ConstantInt::get(Type::getInt32Ty(*Context),
976 FormatStr[0]), B, TD);
977 if (CI->use_empty()) return CI;
978 return B.CreateIntCast(Res, CI->getType(), true);
981 // printf("foo\n") --> puts("foo")
982 if (FormatStr[FormatStr.size()-1] == '\n' &&
983 FormatStr.find('%') == std::string::npos) { // no format characters.
984 // Create a string literal with no \n on it. We expect the constant merge
985 // pass to be run after this pass, to merge duplicate strings.
986 FormatStr.erase(FormatStr.end()-1);
987 Constant *C = ConstantArray::get(*Context, FormatStr, true);
988 C = new GlobalVariable(*Callee->getParent(), C->getType(), true,
989 GlobalVariable::InternalLinkage, C, "str");
991 return CI->use_empty() ? (Value*)CI :
992 ConstantInt::get(CI->getType(), FormatStr.size()+1);
995 // Optimize specific format strings.
996 // printf("%c", chr) --> putchar(chr)
997 if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
998 CI->getArgOperand(1)->getType()->isIntegerTy()) {
999 Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD);
1001 if (CI->use_empty()) return CI;
1002 return B.CreateIntCast(Res, CI->getType(), true);
1005 // printf("%s\n", str) --> puts(str)
1006 if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
1007 CI->getArgOperand(1)->getType()->isPointerTy() &&
1009 EmitPutS(CI->getArgOperand(1), B, TD);
1016 //===---------------------------------------===//
1017 // 'sprintf' Optimizations
1019 struct SPrintFOpt : public LibCallOptimization {
1020 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1021 // Require two fixed pointer arguments and an integer result.
1022 const FunctionType *FT = Callee->getFunctionType();
1023 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1024 !FT->getParamType(1)->isPointerTy() ||
1025 !FT->getReturnType()->isIntegerTy())
1028 // Check for a fixed format string.
1029 std::string FormatStr;
1030 if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1033 // If we just have a format string (nothing else crazy) transform it.
1034 if (CI->getNumArgOperands() == 2) {
1035 // Make sure there's no % in the constant array. We could try to handle
1036 // %% -> % in the future if we cared.
1037 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1038 if (FormatStr[i] == '%')
1039 return 0; // we found a format specifier, bail out.
1041 // These optimizations require TargetData.
1044 // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
1045 EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(1), // Copy the nul byte.
1046 ConstantInt::get(TD->getIntPtrType(*Context),
1047 FormatStr.size()+1), 1, false, B, TD);
1048 return ConstantInt::get(CI->getType(), FormatStr.size());
1051 // The remaining optimizations require the format string to be "%s" or "%c"
1052 // and have an extra operand.
1053 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1054 CI->getNumArgOperands() < 3)
1057 // Decode the second character of the format string.
1058 if (FormatStr[1] == 'c') {
1059 // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
1060 if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1061 Value *V = B.CreateTrunc(CI->getArgOperand(2),
1062 Type::getInt8Ty(*Context), "char");
1063 Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
1064 B.CreateStore(V, Ptr);
1065 Ptr = B.CreateGEP(Ptr, ConstantInt::get(Type::getInt32Ty(*Context), 1),
1067 B.CreateStore(Constant::getNullValue(Type::getInt8Ty(*Context)), Ptr);
1069 return ConstantInt::get(CI->getType(), 1);
1072 if (FormatStr[1] == 's') {
1073 // These optimizations require TargetData.
1076 // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1077 if (!CI->getArgOperand(2)->getType()->isPointerTy()) return 0;
1079 Value *Len = EmitStrLen(CI->getArgOperand(2), B, TD);
1080 Value *IncLen = B.CreateAdd(Len,
1081 ConstantInt::get(Len->getType(), 1),
1083 EmitMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1, false, B, TD);
1085 // The sprintf result is the unincremented number of bytes in the string.
1086 return B.CreateIntCast(Len, CI->getType(), false);
1092 //===---------------------------------------===//
1093 // 'fwrite' Optimizations
1095 struct FWriteOpt : public LibCallOptimization {
1096 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1097 // Require a pointer, an integer, an integer, a pointer, returning integer.
1098 const FunctionType *FT = Callee->getFunctionType();
1099 if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
1100 !FT->getParamType(1)->isIntegerTy() ||
1101 !FT->getParamType(2)->isIntegerTy() ||
1102 !FT->getParamType(3)->isPointerTy() ||
1103 !FT->getReturnType()->isIntegerTy())
1106 // Get the element size and count.
1107 ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
1108 ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
1109 if (!SizeC || !CountC) return 0;
1110 uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
1112 // If this is writing zero records, remove the call (it's a noop).
1114 return ConstantInt::get(CI->getType(), 0);
1116 // If this is writing one byte, turn it into fputc.
1117 if (Bytes == 1) { // fwrite(S,1,1,F) -> fputc(S[0],F)
1118 Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
1119 EmitFPutC(Char, CI->getArgOperand(3), B, TD);
1120 return ConstantInt::get(CI->getType(), 1);
1127 //===---------------------------------------===//
1128 // 'fputs' Optimizations
1130 struct FPutsOpt : public LibCallOptimization {
1131 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1132 // These optimizations require TargetData.
1135 // Require two pointers. Also, we can't optimize if return value is used.
1136 const FunctionType *FT = Callee->getFunctionType();
1137 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1138 !FT->getParamType(1)->isPointerTy() ||
1142 // fputs(s,F) --> fwrite(s,1,strlen(s),F)
1143 uint64_t Len = GetStringLength(CI->getArgOperand(0));
1145 EmitFWrite(CI->getArgOperand(0),
1146 ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
1147 CI->getArgOperand(1), B, TD);
1148 return CI; // Known to have no uses (see above).
1152 //===---------------------------------------===//
1153 // 'fprintf' Optimizations
1155 struct FPrintFOpt : public LibCallOptimization {
1156 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1157 // Require two fixed paramters as pointers and integer result.
1158 const FunctionType *FT = Callee->getFunctionType();
1159 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1160 !FT->getParamType(1)->isPointerTy() ||
1161 !FT->getReturnType()->isIntegerTy())
1164 // All the optimizations depend on the format string.
1165 std::string FormatStr;
1166 if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1169 // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
1170 if (CI->getNumArgOperands() == 2) {
1171 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1172 if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
1173 return 0; // We found a format specifier.
1175 // These optimizations require TargetData.
1178 EmitFWrite(CI->getArgOperand(1),
1179 ConstantInt::get(TD->getIntPtrType(*Context),
1181 CI->getArgOperand(0), B, TD);
1182 return ConstantInt::get(CI->getType(), FormatStr.size());
1185 // The remaining optimizations require the format string to be "%s" or "%c"
1186 // and have an extra operand.
1187 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1188 CI->getNumArgOperands() < 3)
1191 // Decode the second character of the format string.
1192 if (FormatStr[1] == 'c') {
1193 // fprintf(F, "%c", chr) --> fputc(chr, F)
1194 if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1195 EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
1196 return ConstantInt::get(CI->getType(), 1);
1199 if (FormatStr[1] == 's') {
1200 // fprintf(F, "%s", str) --> fputs(str, F)
1201 if (!CI->getArgOperand(2)->getType()->isPointerTy() || !CI->use_empty())
1203 EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
1210 } // end anonymous namespace.
1212 //===----------------------------------------------------------------------===//
1213 // SimplifyLibCalls Pass Implementation
1214 //===----------------------------------------------------------------------===//
1217 /// This pass optimizes well known library functions from libc and libm.
1219 class SimplifyLibCalls : public FunctionPass {
1220 StringMap<LibCallOptimization*> Optimizations;
1221 // String and Memory LibCall Optimizations
1222 StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrCmpOpt StrCmp;
1223 StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
1224 StrNCpyOpt StrNCpy; StrLenOpt StrLen;
1225 StrToOpt StrTo; StrStrOpt StrStr;
1226 MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
1227 // Math Library Optimizations
1228 PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
1229 // Integer Optimizations
1230 FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
1232 // Formatting and IO Optimizations
1233 SPrintFOpt SPrintF; PrintFOpt PrintF;
1234 FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
1236 bool Modified; // This is only used by doInitialization.
1238 static char ID; // Pass identification
1239 SimplifyLibCalls() : FunctionPass(&ID), StrCpy(false), StrCpyChk(true) {}
1240 void InitOptimizations();
1241 bool runOnFunction(Function &F);
1243 void setDoesNotAccessMemory(Function &F);
1244 void setOnlyReadsMemory(Function &F);
1245 void setDoesNotThrow(Function &F);
1246 void setDoesNotCapture(Function &F, unsigned n);
1247 void setDoesNotAlias(Function &F, unsigned n);
1248 bool doInitialization(Module &M);
1250 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
1253 char SimplifyLibCalls::ID = 0;
1254 } // end anonymous namespace.
1256 static RegisterPass<SimplifyLibCalls>
1257 X("simplify-libcalls", "Simplify well-known library calls");
1259 // Public interface to the Simplify LibCalls pass.
1260 FunctionPass *llvm::createSimplifyLibCallsPass() {
1261 return new SimplifyLibCalls();
1264 /// Optimizations - Populate the Optimizations map with all the optimizations
1266 void SimplifyLibCalls::InitOptimizations() {
1267 // String and Memory LibCall Optimizations
1268 Optimizations["strcat"] = &StrCat;
1269 Optimizations["strncat"] = &StrNCat;
1270 Optimizations["strchr"] = &StrChr;
1271 Optimizations["strcmp"] = &StrCmp;
1272 Optimizations["strncmp"] = &StrNCmp;
1273 Optimizations["strcpy"] = &StrCpy;
1274 Optimizations["strncpy"] = &StrNCpy;
1275 Optimizations["strlen"] = &StrLen;
1276 Optimizations["strtol"] = &StrTo;
1277 Optimizations["strtod"] = &StrTo;
1278 Optimizations["strtof"] = &StrTo;
1279 Optimizations["strtoul"] = &StrTo;
1280 Optimizations["strtoll"] = &StrTo;
1281 Optimizations["strtold"] = &StrTo;
1282 Optimizations["strtoull"] = &StrTo;
1283 Optimizations["strstr"] = &StrStr;
1284 Optimizations["memcmp"] = &MemCmp;
1285 Optimizations["memcpy"] = &MemCpy;
1286 Optimizations["memmove"] = &MemMove;
1287 Optimizations["memset"] = &MemSet;
1289 // _chk variants of String and Memory LibCall Optimizations.
1290 Optimizations["__strcpy_chk"] = &StrCpyChk;
1292 // Math Library Optimizations
1293 Optimizations["powf"] = &Pow;
1294 Optimizations["pow"] = &Pow;
1295 Optimizations["powl"] = &Pow;
1296 Optimizations["llvm.pow.f32"] = &Pow;
1297 Optimizations["llvm.pow.f64"] = &Pow;
1298 Optimizations["llvm.pow.f80"] = &Pow;
1299 Optimizations["llvm.pow.f128"] = &Pow;
1300 Optimizations["llvm.pow.ppcf128"] = &Pow;
1301 Optimizations["exp2l"] = &Exp2;
1302 Optimizations["exp2"] = &Exp2;
1303 Optimizations["exp2f"] = &Exp2;
1304 Optimizations["llvm.exp2.ppcf128"] = &Exp2;
1305 Optimizations["llvm.exp2.f128"] = &Exp2;
1306 Optimizations["llvm.exp2.f80"] = &Exp2;
1307 Optimizations["llvm.exp2.f64"] = &Exp2;
1308 Optimizations["llvm.exp2.f32"] = &Exp2;
1311 Optimizations["floor"] = &UnaryDoubleFP;
1314 Optimizations["ceil"] = &UnaryDoubleFP;
1317 Optimizations["round"] = &UnaryDoubleFP;
1320 Optimizations["rint"] = &UnaryDoubleFP;
1322 #ifdef HAVE_NEARBYINTF
1323 Optimizations["nearbyint"] = &UnaryDoubleFP;
1326 // Integer Optimizations
1327 Optimizations["ffs"] = &FFS;
1328 Optimizations["ffsl"] = &FFS;
1329 Optimizations["ffsll"] = &FFS;
1330 Optimizations["abs"] = &Abs;
1331 Optimizations["labs"] = &Abs;
1332 Optimizations["llabs"] = &Abs;
1333 Optimizations["isdigit"] = &IsDigit;
1334 Optimizations["isascii"] = &IsAscii;
1335 Optimizations["toascii"] = &ToAscii;
1337 // Formatting and IO Optimizations
1338 Optimizations["sprintf"] = &SPrintF;
1339 Optimizations["printf"] = &PrintF;
1340 Optimizations["fwrite"] = &FWrite;
1341 Optimizations["fputs"] = &FPuts;
1342 Optimizations["fprintf"] = &FPrintF;
1346 /// runOnFunction - Top level algorithm.
1348 bool SimplifyLibCalls::runOnFunction(Function &F) {
1349 if (Optimizations.empty())
1350 InitOptimizations();
1352 const TargetData *TD = getAnalysisIfAvailable<TargetData>();
1354 IRBuilder<> Builder(F.getContext());
1356 bool Changed = false;
1357 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
1358 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
1359 // Ignore non-calls.
1360 CallInst *CI = dyn_cast<CallInst>(I++);
1363 // Ignore indirect calls and calls to non-external functions.
1364 Function *Callee = CI->getCalledFunction();
1365 if (Callee == 0 || !Callee->isDeclaration() ||
1366 !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
1369 // Ignore unknown calls.
1370 LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
1373 // Set the builder to the instruction after the call.
1374 Builder.SetInsertPoint(BB, I);
1376 // Try to optimize this call.
1377 Value *Result = LCO->OptimizeCall(CI, TD, Builder);
1378 if (Result == 0) continue;
1380 DEBUG(dbgs() << "SimplifyLibCalls simplified: " << *CI;
1381 dbgs() << " into: " << *Result << "\n");
1383 // Something changed!
1387 // Inspect the instruction after the call (which was potentially just
1391 if (CI != Result && !CI->use_empty()) {
1392 CI->replaceAllUsesWith(Result);
1393 if (!Result->hasName())
1394 Result->takeName(CI);
1396 CI->eraseFromParent();
1402 // Utility methods for doInitialization.
1404 void SimplifyLibCalls::setDoesNotAccessMemory(Function &F) {
1405 if (!F.doesNotAccessMemory()) {
1406 F.setDoesNotAccessMemory();
1411 void SimplifyLibCalls::setOnlyReadsMemory(Function &F) {
1412 if (!F.onlyReadsMemory()) {
1413 F.setOnlyReadsMemory();
1418 void SimplifyLibCalls::setDoesNotThrow(Function &F) {
1419 if (!F.doesNotThrow()) {
1420 F.setDoesNotThrow();
1425 void SimplifyLibCalls::setDoesNotCapture(Function &F, unsigned n) {
1426 if (!F.doesNotCapture(n)) {
1427 F.setDoesNotCapture(n);
1432 void SimplifyLibCalls::setDoesNotAlias(Function &F, unsigned n) {
1433 if (!F.doesNotAlias(n)) {
1434 F.setDoesNotAlias(n);
1440 /// doInitialization - Add attributes to well-known functions.
1442 bool SimplifyLibCalls::doInitialization(Module &M) {
1444 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
1446 if (!F.isDeclaration())
1452 const FunctionType *FTy = F.getFunctionType();
1454 StringRef Name = F.getName();
1457 if (Name == "strlen") {
1458 if (FTy->getNumParams() != 1 ||
1459 !FTy->getParamType(0)->isPointerTy())
1461 setOnlyReadsMemory(F);
1463 setDoesNotCapture(F, 1);
1464 } else if (Name == "strchr" ||
1465 Name == "strrchr") {
1466 if (FTy->getNumParams() != 2 ||
1467 !FTy->getParamType(0)->isPointerTy() ||
1468 !FTy->getParamType(1)->isIntegerTy())
1470 setOnlyReadsMemory(F);
1472 } else if (Name == "strcpy" ||
1478 Name == "strtoul" ||
1479 Name == "strtoll" ||
1480 Name == "strtold" ||
1481 Name == "strncat" ||
1482 Name == "strncpy" ||
1483 Name == "strtoull") {
1484 if (FTy->getNumParams() < 2 ||
1485 !FTy->getParamType(1)->isPointerTy())
1488 setDoesNotCapture(F, 2);
1489 } else if (Name == "strxfrm") {
1490 if (FTy->getNumParams() != 3 ||
1491 !FTy->getParamType(0)->isPointerTy() ||
1492 !FTy->getParamType(1)->isPointerTy())
1495 setDoesNotCapture(F, 1);
1496 setDoesNotCapture(F, 2);
1497 } else if (Name == "strcmp" ||
1499 Name == "strncmp" ||
1500 Name == "strcspn" ||
1501 Name == "strcoll" ||
1502 Name == "strcasecmp" ||
1503 Name == "strncasecmp") {
1504 if (FTy->getNumParams() < 2 ||
1505 !FTy->getParamType(0)->isPointerTy() ||
1506 !FTy->getParamType(1)->isPointerTy())
1508 setOnlyReadsMemory(F);
1510 setDoesNotCapture(F, 1);
1511 setDoesNotCapture(F, 2);
1512 } else if (Name == "strstr" ||
1513 Name == "strpbrk") {
1514 if (FTy->getNumParams() != 2 ||
1515 !FTy->getParamType(1)->isPointerTy())
1517 setOnlyReadsMemory(F);
1519 setDoesNotCapture(F, 2);
1520 } else if (Name == "strtok" ||
1521 Name == "strtok_r") {
1522 if (FTy->getNumParams() < 2 ||
1523 !FTy->getParamType(1)->isPointerTy())
1526 setDoesNotCapture(F, 2);
1527 } else if (Name == "scanf" ||
1529 Name == "setvbuf") {
1530 if (FTy->getNumParams() < 1 ||
1531 !FTy->getParamType(0)->isPointerTy())
1534 setDoesNotCapture(F, 1);
1535 } else if (Name == "strdup" ||
1536 Name == "strndup") {
1537 if (FTy->getNumParams() < 1 ||
1538 !FTy->getReturnType()->isPointerTy() ||
1539 !FTy->getParamType(0)->isPointerTy())
1542 setDoesNotAlias(F, 0);
1543 setDoesNotCapture(F, 1);
1544 } else if (Name == "stat" ||
1546 Name == "sprintf" ||
1547 Name == "statvfs") {
1548 if (FTy->getNumParams() < 2 ||
1549 !FTy->getParamType(0)->isPointerTy() ||
1550 !FTy->getParamType(1)->isPointerTy())
1553 setDoesNotCapture(F, 1);
1554 setDoesNotCapture(F, 2);
1555 } else if (Name == "snprintf") {
1556 if (FTy->getNumParams() != 3 ||
1557 !FTy->getParamType(0)->isPointerTy() ||
1558 !FTy->getParamType(2)->isPointerTy())
1561 setDoesNotCapture(F, 1);
1562 setDoesNotCapture(F, 3);
1563 } else if (Name == "setitimer") {
1564 if (FTy->getNumParams() != 3 ||
1565 !FTy->getParamType(1)->isPointerTy() ||
1566 !FTy->getParamType(2)->isPointerTy())
1569 setDoesNotCapture(F, 2);
1570 setDoesNotCapture(F, 3);
1571 } else if (Name == "system") {
1572 if (FTy->getNumParams() != 1 ||
1573 !FTy->getParamType(0)->isPointerTy())
1575 // May throw; "system" is a valid pthread cancellation point.
1576 setDoesNotCapture(F, 1);
1580 if (Name == "malloc") {
1581 if (FTy->getNumParams() != 1 ||
1582 !FTy->getReturnType()->isPointerTy())
1585 setDoesNotAlias(F, 0);
1586 } else if (Name == "memcmp") {
1587 if (FTy->getNumParams() != 3 ||
1588 !FTy->getParamType(0)->isPointerTy() ||
1589 !FTy->getParamType(1)->isPointerTy())
1591 setOnlyReadsMemory(F);
1593 setDoesNotCapture(F, 1);
1594 setDoesNotCapture(F, 2);
1595 } else if (Name == "memchr" ||
1596 Name == "memrchr") {
1597 if (FTy->getNumParams() != 3)
1599 setOnlyReadsMemory(F);
1601 } else if (Name == "modf" ||
1605 Name == "memccpy" ||
1606 Name == "memmove") {
1607 if (FTy->getNumParams() < 2 ||
1608 !FTy->getParamType(1)->isPointerTy())
1611 setDoesNotCapture(F, 2);
1612 } else if (Name == "memalign") {
1613 if (!FTy->getReturnType()->isPointerTy())
1615 setDoesNotAlias(F, 0);
1616 } else if (Name == "mkdir" ||
1618 if (FTy->getNumParams() == 0 ||
1619 !FTy->getParamType(0)->isPointerTy())
1622 setDoesNotCapture(F, 1);
1626 if (Name == "realloc") {
1627 if (FTy->getNumParams() != 2 ||
1628 !FTy->getParamType(0)->isPointerTy() ||
1629 !FTy->getReturnType()->isPointerTy())
1632 setDoesNotAlias(F, 0);
1633 setDoesNotCapture(F, 1);
1634 } else if (Name == "read") {
1635 if (FTy->getNumParams() != 3 ||
1636 !FTy->getParamType(1)->isPointerTy())
1638 // May throw; "read" is a valid pthread cancellation point.
1639 setDoesNotCapture(F, 2);
1640 } else if (Name == "rmdir" ||
1643 Name == "realpath") {
1644 if (FTy->getNumParams() < 1 ||
1645 !FTy->getParamType(0)->isPointerTy())
1648 setDoesNotCapture(F, 1);
1649 } else if (Name == "rename" ||
1650 Name == "readlink") {
1651 if (FTy->getNumParams() < 2 ||
1652 !FTy->getParamType(0)->isPointerTy() ||
1653 !FTy->getParamType(1)->isPointerTy())
1656 setDoesNotCapture(F, 1);
1657 setDoesNotCapture(F, 2);
1661 if (Name == "write") {
1662 if (FTy->getNumParams() != 3 ||
1663 !FTy->getParamType(1)->isPointerTy())
1665 // May throw; "write" is a valid pthread cancellation point.
1666 setDoesNotCapture(F, 2);
1670 if (Name == "bcopy") {
1671 if (FTy->getNumParams() != 3 ||
1672 !FTy->getParamType(0)->isPointerTy() ||
1673 !FTy->getParamType(1)->isPointerTy())
1676 setDoesNotCapture(F, 1);
1677 setDoesNotCapture(F, 2);
1678 } else if (Name == "bcmp") {
1679 if (FTy->getNumParams() != 3 ||
1680 !FTy->getParamType(0)->isPointerTy() ||
1681 !FTy->getParamType(1)->isPointerTy())
1684 setOnlyReadsMemory(F);
1685 setDoesNotCapture(F, 1);
1686 setDoesNotCapture(F, 2);
1687 } else if (Name == "bzero") {
1688 if (FTy->getNumParams() != 2 ||
1689 !FTy->getParamType(0)->isPointerTy())
1692 setDoesNotCapture(F, 1);
1696 if (Name == "calloc") {
1697 if (FTy->getNumParams() != 2 ||
1698 !FTy->getReturnType()->isPointerTy())
1701 setDoesNotAlias(F, 0);
1702 } else if (Name == "chmod" ||
1704 Name == "ctermid" ||
1705 Name == "clearerr" ||
1706 Name == "closedir") {
1707 if (FTy->getNumParams() == 0 ||
1708 !FTy->getParamType(0)->isPointerTy())
1711 setDoesNotCapture(F, 1);
1715 if (Name == "atoi" ||
1719 if (FTy->getNumParams() != 1 ||
1720 !FTy->getParamType(0)->isPointerTy())
1723 setOnlyReadsMemory(F);
1724 setDoesNotCapture(F, 1);
1725 } else if (Name == "access") {
1726 if (FTy->getNumParams() != 2 ||
1727 !FTy->getParamType(0)->isPointerTy())
1730 setDoesNotCapture(F, 1);
1734 if (Name == "fopen") {
1735 if (FTy->getNumParams() != 2 ||
1736 !FTy->getReturnType()->isPointerTy() ||
1737 !FTy->getParamType(0)->isPointerTy() ||
1738 !FTy->getParamType(1)->isPointerTy())
1741 setDoesNotAlias(F, 0);
1742 setDoesNotCapture(F, 1);
1743 setDoesNotCapture(F, 2);
1744 } else if (Name == "fdopen") {
1745 if (FTy->getNumParams() != 2 ||
1746 !FTy->getReturnType()->isPointerTy() ||
1747 !FTy->getParamType(1)->isPointerTy())
1750 setDoesNotAlias(F, 0);
1751 setDoesNotCapture(F, 2);
1752 } else if (Name == "feof" ||
1762 Name == "fsetpos" ||
1763 Name == "flockfile" ||
1764 Name == "funlockfile" ||
1765 Name == "ftrylockfile") {
1766 if (FTy->getNumParams() == 0 ||
1767 !FTy->getParamType(0)->isPointerTy())
1770 setDoesNotCapture(F, 1);
1771 } else if (Name == "ferror") {
1772 if (FTy->getNumParams() != 1 ||
1773 !FTy->getParamType(0)->isPointerTy())
1776 setDoesNotCapture(F, 1);
1777 setOnlyReadsMemory(F);
1778 } else if (Name == "fputc" ||
1783 Name == "fstatvfs") {
1784 if (FTy->getNumParams() != 2 ||
1785 !FTy->getParamType(1)->isPointerTy())
1788 setDoesNotCapture(F, 2);
1789 } else if (Name == "fgets") {
1790 if (FTy->getNumParams() != 3 ||
1791 !FTy->getParamType(0)->isPointerTy() ||
1792 !FTy->getParamType(2)->isPointerTy())
1795 setDoesNotCapture(F, 3);
1796 } else if (Name == "fread" ||
1798 if (FTy->getNumParams() != 4 ||
1799 !FTy->getParamType(0)->isPointerTy() ||
1800 !FTy->getParamType(3)->isPointerTy())
1803 setDoesNotCapture(F, 1);
1804 setDoesNotCapture(F, 4);
1805 } else if (Name == "fputs" ||
1807 Name == "fprintf" ||
1808 Name == "fgetpos") {
1809 if (FTy->getNumParams() < 2 ||
1810 !FTy->getParamType(0)->isPointerTy() ||
1811 !FTy->getParamType(1)->isPointerTy())
1814 setDoesNotCapture(F, 1);
1815 setDoesNotCapture(F, 2);
1819 if (Name == "getc" ||
1820 Name == "getlogin_r" ||
1821 Name == "getc_unlocked") {
1822 if (FTy->getNumParams() == 0 ||
1823 !FTy->getParamType(0)->isPointerTy())
1826 setDoesNotCapture(F, 1);
1827 } else if (Name == "getenv") {
1828 if (FTy->getNumParams() != 1 ||
1829 !FTy->getParamType(0)->isPointerTy())
1832 setOnlyReadsMemory(F);
1833 setDoesNotCapture(F, 1);
1834 } else if (Name == "gets" ||
1835 Name == "getchar") {
1837 } else if (Name == "getitimer") {
1838 if (FTy->getNumParams() != 2 ||
1839 !FTy->getParamType(1)->isPointerTy())
1842 setDoesNotCapture(F, 2);
1843 } else if (Name == "getpwnam") {
1844 if (FTy->getNumParams() != 1 ||
1845 !FTy->getParamType(0)->isPointerTy())
1848 setDoesNotCapture(F, 1);
1852 if (Name == "ungetc") {
1853 if (FTy->getNumParams() != 2 ||
1854 !FTy->getParamType(1)->isPointerTy())
1857 setDoesNotCapture(F, 2);
1858 } else if (Name == "uname" ||
1860 Name == "unsetenv") {
1861 if (FTy->getNumParams() != 1 ||
1862 !FTy->getParamType(0)->isPointerTy())
1865 setDoesNotCapture(F, 1);
1866 } else if (Name == "utime" ||
1868 if (FTy->getNumParams() != 2 ||
1869 !FTy->getParamType(0)->isPointerTy() ||
1870 !FTy->getParamType(1)->isPointerTy())
1873 setDoesNotCapture(F, 1);
1874 setDoesNotCapture(F, 2);
1878 if (Name == "putc") {
1879 if (FTy->getNumParams() != 2 ||
1880 !FTy->getParamType(1)->isPointerTy())
1883 setDoesNotCapture(F, 2);
1884 } else if (Name == "puts" ||
1887 if (FTy->getNumParams() != 1 ||
1888 !FTy->getParamType(0)->isPointerTy())
1891 setDoesNotCapture(F, 1);
1892 } else if (Name == "pread" ||
1894 if (FTy->getNumParams() != 4 ||
1895 !FTy->getParamType(1)->isPointerTy())
1897 // May throw; these are valid pthread cancellation points.
1898 setDoesNotCapture(F, 2);
1899 } else if (Name == "putchar") {
1901 } else if (Name == "popen") {
1902 if (FTy->getNumParams() != 2 ||
1903 !FTy->getReturnType()->isPointerTy() ||
1904 !FTy->getParamType(0)->isPointerTy() ||
1905 !FTy->getParamType(1)->isPointerTy())
1908 setDoesNotAlias(F, 0);
1909 setDoesNotCapture(F, 1);
1910 setDoesNotCapture(F, 2);
1911 } else if (Name == "pclose") {
1912 if (FTy->getNumParams() != 1 ||
1913 !FTy->getParamType(0)->isPointerTy())
1916 setDoesNotCapture(F, 1);
1920 if (Name == "vscanf") {
1921 if (FTy->getNumParams() != 2 ||
1922 !FTy->getParamType(1)->isPointerTy())
1925 setDoesNotCapture(F, 1);
1926 } else if (Name == "vsscanf" ||
1927 Name == "vfscanf") {
1928 if (FTy->getNumParams() != 3 ||
1929 !FTy->getParamType(1)->isPointerTy() ||
1930 !FTy->getParamType(2)->isPointerTy())
1933 setDoesNotCapture(F, 1);
1934 setDoesNotCapture(F, 2);
1935 } else if (Name == "valloc") {
1936 if (!FTy->getReturnType()->isPointerTy())
1939 setDoesNotAlias(F, 0);
1940 } else if (Name == "vprintf") {
1941 if (FTy->getNumParams() != 2 ||
1942 !FTy->getParamType(0)->isPointerTy())
1945 setDoesNotCapture(F, 1);
1946 } else if (Name == "vfprintf" ||
1947 Name == "vsprintf") {
1948 if (FTy->getNumParams() != 3 ||
1949 !FTy->getParamType(0)->isPointerTy() ||
1950 !FTy->getParamType(1)->isPointerTy())
1953 setDoesNotCapture(F, 1);
1954 setDoesNotCapture(F, 2);
1955 } else if (Name == "vsnprintf") {
1956 if (FTy->getNumParams() != 4 ||
1957 !FTy->getParamType(0)->isPointerTy() ||
1958 !FTy->getParamType(2)->isPointerTy())
1961 setDoesNotCapture(F, 1);
1962 setDoesNotCapture(F, 3);
1966 if (Name == "open") {
1967 if (FTy->getNumParams() < 2 ||
1968 !FTy->getParamType(0)->isPointerTy())
1970 // May throw; "open" is a valid pthread cancellation point.
1971 setDoesNotCapture(F, 1);
1972 } else if (Name == "opendir") {
1973 if (FTy->getNumParams() != 1 ||
1974 !FTy->getReturnType()->isPointerTy() ||
1975 !FTy->getParamType(0)->isPointerTy())
1978 setDoesNotAlias(F, 0);
1979 setDoesNotCapture(F, 1);
1983 if (Name == "tmpfile") {
1984 if (!FTy->getReturnType()->isPointerTy())
1987 setDoesNotAlias(F, 0);
1988 } else if (Name == "times") {
1989 if (FTy->getNumParams() != 1 ||
1990 !FTy->getParamType(0)->isPointerTy())
1993 setDoesNotCapture(F, 1);
1997 if (Name == "htonl" ||
2000 setDoesNotAccessMemory(F);
2004 if (Name == "ntohl" ||
2007 setDoesNotAccessMemory(F);
2011 if (Name == "lstat") {
2012 if (FTy->getNumParams() != 2 ||
2013 !FTy->getParamType(0)->isPointerTy() ||
2014 !FTy->getParamType(1)->isPointerTy())
2017 setDoesNotCapture(F, 1);
2018 setDoesNotCapture(F, 2);
2019 } else if (Name == "lchown") {
2020 if (FTy->getNumParams() != 3 ||
2021 !FTy->getParamType(0)->isPointerTy())
2024 setDoesNotCapture(F, 1);
2028 if (Name == "qsort") {
2029 if (FTy->getNumParams() != 4 ||
2030 !FTy->getParamType(3)->isPointerTy())
2032 // May throw; places call through function pointer.
2033 setDoesNotCapture(F, 4);
2037 if (Name == "__strdup" ||
2038 Name == "__strndup") {
2039 if (FTy->getNumParams() < 1 ||
2040 !FTy->getReturnType()->isPointerTy() ||
2041 !FTy->getParamType(0)->isPointerTy())
2044 setDoesNotAlias(F, 0);
2045 setDoesNotCapture(F, 1);
2046 } else if (Name == "__strtok_r") {
2047 if (FTy->getNumParams() != 3 ||
2048 !FTy->getParamType(1)->isPointerTy())
2051 setDoesNotCapture(F, 2);
2052 } else if (Name == "_IO_getc") {
2053 if (FTy->getNumParams() != 1 ||
2054 !FTy->getParamType(0)->isPointerTy())
2057 setDoesNotCapture(F, 1);
2058 } else if (Name == "_IO_putc") {
2059 if (FTy->getNumParams() != 2 ||
2060 !FTy->getParamType(1)->isPointerTy())
2063 setDoesNotCapture(F, 2);
2067 if (Name == "\1__isoc99_scanf") {
2068 if (FTy->getNumParams() < 1 ||
2069 !FTy->getParamType(0)->isPointerTy())
2072 setDoesNotCapture(F, 1);
2073 } else if (Name == "\1stat64" ||
2074 Name == "\1lstat64" ||
2075 Name == "\1statvfs64" ||
2076 Name == "\1__isoc99_sscanf") {
2077 if (FTy->getNumParams() < 1 ||
2078 !FTy->getParamType(0)->isPointerTy() ||
2079 !FTy->getParamType(1)->isPointerTy())
2082 setDoesNotCapture(F, 1);
2083 setDoesNotCapture(F, 2);
2084 } else if (Name == "\1fopen64") {
2085 if (FTy->getNumParams() != 2 ||
2086 !FTy->getReturnType()->isPointerTy() ||
2087 !FTy->getParamType(0)->isPointerTy() ||
2088 !FTy->getParamType(1)->isPointerTy())
2091 setDoesNotAlias(F, 0);
2092 setDoesNotCapture(F, 1);
2093 setDoesNotCapture(F, 2);
2094 } else if (Name == "\1fseeko64" ||
2095 Name == "\1ftello64") {
2096 if (FTy->getNumParams() == 0 ||
2097 !FTy->getParamType(0)->isPointerTy())
2100 setDoesNotCapture(F, 1);
2101 } else if (Name == "\1tmpfile64") {
2102 if (!FTy->getReturnType()->isPointerTy())
2105 setDoesNotAlias(F, 0);
2106 } else if (Name == "\1fstat64" ||
2107 Name == "\1fstatvfs64") {
2108 if (FTy->getNumParams() != 2 ||
2109 !FTy->getParamType(1)->isPointerTy())
2112 setDoesNotCapture(F, 2);
2113 } else if (Name == "\1open64") {
2114 if (FTy->getNumParams() < 2 ||
2115 !FTy->getParamType(0)->isPointerTy())
2117 // May throw; "open" is a valid pthread cancellation point.
2118 setDoesNotCapture(F, 1);
2127 // Additional cases that we need to add to this file:
2130 // * cbrt(expN(X)) -> expN(x/3)
2131 // * cbrt(sqrt(x)) -> pow(x,1/6)
2132 // * cbrt(sqrt(x)) -> pow(x,1/9)
2135 // * cos(-x) -> cos(x)
2138 // * exp(log(x)) -> x
2141 // * log(exp(x)) -> x
2142 // * log(x**y) -> y*log(x)
2143 // * log(exp(y)) -> y*log(e)
2144 // * log(exp2(y)) -> y*log(2)
2145 // * log(exp10(y)) -> y*log(10)
2146 // * log(sqrt(x)) -> 0.5*log(x)
2147 // * log(pow(x,y)) -> y*log(x)
2149 // lround, lroundf, lroundl:
2150 // * lround(cnst) -> cnst'
2153 // * pow(exp(x),y) -> exp(x*y)
2154 // * pow(sqrt(x),y) -> pow(x,y*0.5)
2155 // * pow(pow(x,y),z)-> pow(x,y*z)
2158 // * puts("") -> putchar("\n")
2160 // round, roundf, roundl:
2161 // * round(cnst) -> cnst'
2164 // * signbit(cnst) -> cnst'
2165 // * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2167 // sqrt, sqrtf, sqrtl:
2168 // * sqrt(expN(x)) -> expN(x*0.5)
2169 // * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2170 // * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2173 // * stpcpy(str, "literal") ->
2174 // llvm.memcpy(str,"literal",strlen("literal")+1,1)
2176 // * strrchr(s,c) -> reverse_offset_of_in(c,s)
2177 // (if c is a constant integer and s is a constant string)
2178 // * strrchr(s1,0) -> strchr(s1,0)
2181 // * strpbrk(s,a) -> offset_in_for(s,a)
2182 // (if s and a are both constant strings)
2183 // * strpbrk(s,"") -> 0
2184 // * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
2187 // * strspn(s,a) -> const_int (if both args are constant)
2188 // * strspn("",a) -> 0
2189 // * strspn(s,"") -> 0
2190 // * strcspn(s,a) -> const_int (if both args are constant)
2191 // * strcspn("",a) -> 0
2192 // * strcspn(s,"") -> strlen(a)
2195 // * tan(atan(x)) -> x
2197 // trunc, truncf, truncl:
2198 // * trunc(cnst) -> cnst'