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/Target/TargetLibraryInfo.h"
29 #include "llvm/ADT/SmallPtrSet.h"
30 #include "llvm/ADT/StringMap.h"
31 #include "llvm/ADT/Statistic.h"
32 #include "llvm/ADT/STLExtras.h"
33 #include "llvm/Support/Debug.h"
34 #include "llvm/Support/raw_ostream.h"
35 #include "llvm/Config/config.h" // FIXME: Shouldn't depend on host!
38 STATISTIC(NumSimplified, "Number of library calls simplified");
39 STATISTIC(NumAnnotated, "Number of attributes added to library functions");
41 //===----------------------------------------------------------------------===//
42 // Optimizer Base Class
43 //===----------------------------------------------------------------------===//
45 /// This class is the abstract base class for the set of optimizations that
46 /// corresponds to one library call.
48 class LibCallOptimization {
52 const TargetLibraryInfo *TLI;
55 LibCallOptimization() { }
56 virtual ~LibCallOptimization() {}
58 /// CallOptimizer - This pure virtual method is implemented by base classes to
59 /// do various optimizations. If this returns null then no transformation was
60 /// performed. If it returns CI, then it transformed the call and CI is to be
61 /// deleted. If it returns something else, replace CI with the new value and
63 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
66 Value *OptimizeCall(CallInst *CI, const TargetData *TD,
67 const TargetLibraryInfo *TLI, IRBuilder<> &B) {
68 Caller = CI->getParent()->getParent();
71 if (CI->getCalledFunction())
72 Context = &CI->getCalledFunction()->getContext();
74 // We never change the calling convention.
75 if (CI->getCallingConv() != llvm::CallingConv::C)
78 return CallOptimizer(CI->getCalledFunction(), CI, B);
81 } // End anonymous namespace.
84 //===----------------------------------------------------------------------===//
86 //===----------------------------------------------------------------------===//
88 /// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
89 /// value is equal or not-equal to zero.
90 static bool IsOnlyUsedInZeroEqualityComparison(Value *V) {
91 for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
93 if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
95 if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
98 // Unknown instruction.
104 static bool CallHasFloatingPointArgument(const CallInst *CI) {
105 for (CallInst::const_op_iterator it = CI->op_begin(), e = CI->op_end();
107 if ((*it)->getType()->isFloatingPointTy())
113 /// IsOnlyUsedInEqualityComparison - Return true if it is only used in equality
114 /// comparisons with With.
115 static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
116 for (Value::use_iterator UI = V->use_begin(), E = V->use_end();
118 if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
119 if (IC->isEquality() && IC->getOperand(1) == With)
121 // Unknown instruction.
127 //===----------------------------------------------------------------------===//
128 // String and Memory LibCall Optimizations
129 //===----------------------------------------------------------------------===//
131 //===---------------------------------------===//
132 // 'strcat' Optimizations
134 struct StrCatOpt : public LibCallOptimization {
135 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
136 // Verify the "strcat" function prototype.
137 FunctionType *FT = Callee->getFunctionType();
138 if (FT->getNumParams() != 2 ||
139 FT->getReturnType() != B.getInt8PtrTy() ||
140 FT->getParamType(0) != FT->getReturnType() ||
141 FT->getParamType(1) != FT->getReturnType())
144 // Extract some information from the instruction
145 Value *Dst = CI->getArgOperand(0);
146 Value *Src = CI->getArgOperand(1);
148 // See if we can get the length of the input string.
149 uint64_t Len = GetStringLength(Src);
150 if (Len == 0) return 0;
151 --Len; // Unbias length.
153 // Handle the simple, do-nothing case: strcat(x, "") -> x
157 // These optimizations require TargetData.
160 EmitStrLenMemCpy(Src, Dst, Len, B);
164 void EmitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len, IRBuilder<> &B) {
165 // We need to find the end of the destination string. That's where the
166 // memory is to be moved to. We just generate a call to strlen.
167 Value *DstLen = EmitStrLen(Dst, B, TD);
169 // Now that we have the destination's length, we must index into the
170 // destination's pointer to get the actual memcpy destination (end of
171 // the string .. we're concatenating).
172 Value *CpyDst = B.CreateGEP(Dst, DstLen, "endptr");
174 // We have enough information to now generate the memcpy call to do the
175 // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
176 B.CreateMemCpy(CpyDst, Src,
177 ConstantInt::get(TD->getIntPtrType(*Context), Len + 1), 1);
181 //===---------------------------------------===//
182 // 'strncat' Optimizations
184 struct StrNCatOpt : public StrCatOpt {
185 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
186 // Verify the "strncat" function prototype.
187 FunctionType *FT = Callee->getFunctionType();
188 if (FT->getNumParams() != 3 ||
189 FT->getReturnType() != B.getInt8PtrTy() ||
190 FT->getParamType(0) != FT->getReturnType() ||
191 FT->getParamType(1) != FT->getReturnType() ||
192 !FT->getParamType(2)->isIntegerTy())
195 // Extract some information from the instruction
196 Value *Dst = CI->getArgOperand(0);
197 Value *Src = CI->getArgOperand(1);
200 // We don't do anything if length is not constant
201 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
202 Len = LengthArg->getZExtValue();
206 // See if we can get the length of the input string.
207 uint64_t SrcLen = GetStringLength(Src);
208 if (SrcLen == 0) return 0;
209 --SrcLen; // Unbias length.
211 // Handle the simple, do-nothing cases:
212 // strncat(x, "", c) -> x
213 // strncat(x, c, 0) -> x
214 if (SrcLen == 0 || Len == 0) return Dst;
216 // These optimizations require TargetData.
219 // We don't optimize this case
220 if (Len < SrcLen) return 0;
222 // strncat(x, s, c) -> strcat(x, s)
223 // s is constant so the strcat can be optimized further
224 EmitStrLenMemCpy(Src, Dst, SrcLen, B);
229 //===---------------------------------------===//
230 // 'strchr' Optimizations
232 struct StrChrOpt : public LibCallOptimization {
233 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
234 // Verify the "strchr" function prototype.
235 FunctionType *FT = Callee->getFunctionType();
236 if (FT->getNumParams() != 2 ||
237 FT->getReturnType() != B.getInt8PtrTy() ||
238 FT->getParamType(0) != FT->getReturnType() ||
239 !FT->getParamType(1)->isIntegerTy(32))
242 Value *SrcStr = CI->getArgOperand(0);
244 // If the second operand is non-constant, see if we can compute the length
245 // of the input string and turn this into memchr.
246 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
248 // These optimizations require TargetData.
251 uint64_t Len = GetStringLength(SrcStr);
252 if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
255 return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
256 ConstantInt::get(TD->getIntPtrType(*Context), Len),
260 // Otherwise, the character is a constant, see if the first argument is
261 // a string literal. If so, we can constant fold.
263 if (!GetConstantStringInfo(SrcStr, Str))
266 // strchr can find the nul character.
269 // Compute the offset.
270 size_t I = Str.find(CharC->getSExtValue());
271 if (I == std::string::npos) // Didn't find the char. strchr returns null.
272 return Constant::getNullValue(CI->getType());
274 // strchr(s+n,c) -> gep(s+n+i,c)
275 return B.CreateGEP(SrcStr, B.getInt64(I), "strchr");
279 //===---------------------------------------===//
280 // 'strrchr' Optimizations
282 struct StrRChrOpt : public LibCallOptimization {
283 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
284 // Verify the "strrchr" function prototype.
285 FunctionType *FT = Callee->getFunctionType();
286 if (FT->getNumParams() != 2 ||
287 FT->getReturnType() != B.getInt8PtrTy() ||
288 FT->getParamType(0) != FT->getReturnType() ||
289 !FT->getParamType(1)->isIntegerTy(32))
292 Value *SrcStr = CI->getArgOperand(0);
293 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
295 // Cannot fold anything if we're not looking for a constant.
300 if (!GetConstantStringInfo(SrcStr, Str)) {
301 // strrchr(s, 0) -> strchr(s, 0)
302 if (TD && CharC->isZero())
303 return EmitStrChr(SrcStr, '\0', B, TD);
307 // strrchr can find the nul character.
310 // Compute the offset.
311 size_t I = Str.rfind(CharC->getSExtValue());
312 if (I == std::string::npos) // Didn't find the char. Return null.
313 return Constant::getNullValue(CI->getType());
315 // strrchr(s+n,c) -> gep(s+n+i,c)
316 return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr");
320 //===---------------------------------------===//
321 // 'strcmp' Optimizations
323 struct StrCmpOpt : public LibCallOptimization {
324 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
325 // Verify the "strcmp" function prototype.
326 FunctionType *FT = Callee->getFunctionType();
327 if (FT->getNumParams() != 2 ||
328 !FT->getReturnType()->isIntegerTy(32) ||
329 FT->getParamType(0) != FT->getParamType(1) ||
330 FT->getParamType(0) != B.getInt8PtrTy())
333 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
334 if (Str1P == Str2P) // strcmp(x,x) -> 0
335 return ConstantInt::get(CI->getType(), 0);
337 std::string Str1, Str2;
338 bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
339 bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
341 // strcmp(x, y) -> cnst (if both x and y are constant strings)
342 if (HasStr1 && HasStr2)
343 return ConstantInt::get(CI->getType(),
344 StringRef(Str1).compare(Str2));
346 if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x
347 return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"),
350 if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
351 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
353 // strcmp(P, "x") -> memcmp(P, "x", 2)
354 uint64_t Len1 = GetStringLength(Str1P);
355 uint64_t Len2 = GetStringLength(Str2P);
357 // These optimizations require TargetData.
360 return EmitMemCmp(Str1P, Str2P,
361 ConstantInt::get(TD->getIntPtrType(*Context),
362 std::min(Len1, Len2)), B, TD);
369 //===---------------------------------------===//
370 // 'strncmp' Optimizations
372 struct StrNCmpOpt : public LibCallOptimization {
373 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
374 // Verify the "strncmp" function prototype.
375 FunctionType *FT = Callee->getFunctionType();
376 if (FT->getNumParams() != 3 ||
377 !FT->getReturnType()->isIntegerTy(32) ||
378 FT->getParamType(0) != FT->getParamType(1) ||
379 FT->getParamType(0) != B.getInt8PtrTy() ||
380 !FT->getParamType(2)->isIntegerTy())
383 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
384 if (Str1P == Str2P) // strncmp(x,x,n) -> 0
385 return ConstantInt::get(CI->getType(), 0);
387 // Get the length argument if it is constant.
389 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
390 Length = LengthArg->getZExtValue();
394 if (Length == 0) // strncmp(x,y,0) -> 0
395 return ConstantInt::get(CI->getType(), 0);
397 if (TD && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
398 return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, TD);
400 std::string Str1, Str2;
401 bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
402 bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
404 // strncmp(x, y) -> cnst (if both x and y are constant strings)
405 if (HasStr1 && HasStr2) {
406 StringRef SubStr1 = StringRef(Str1).substr(0, Length);
407 StringRef SubStr2 = StringRef(Str2).substr(0, Length);
408 return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2));
411 if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> -*x
412 return B.CreateNeg(B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"),
415 if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
416 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
423 //===---------------------------------------===//
424 // 'strcpy' Optimizations
426 struct StrCpyOpt : public LibCallOptimization {
427 bool OptChkCall; // True if it's optimizing a __strcpy_chk libcall.
429 StrCpyOpt(bool c) : OptChkCall(c) {}
431 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
432 // Verify the "strcpy" function prototype.
433 unsigned NumParams = OptChkCall ? 3 : 2;
434 FunctionType *FT = Callee->getFunctionType();
435 if (FT->getNumParams() != NumParams ||
436 FT->getReturnType() != FT->getParamType(0) ||
437 FT->getParamType(0) != FT->getParamType(1) ||
438 FT->getParamType(0) != B.getInt8PtrTy())
441 Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
442 if (Dst == Src) // strcpy(x,x) -> x
445 // These optimizations require TargetData.
448 // See if we can get the length of the input string.
449 uint64_t Len = GetStringLength(Src);
450 if (Len == 0) return 0;
452 // We have enough information to now generate the memcpy call to do the
453 // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
455 EmitMemCpyChk(Dst, Src,
456 ConstantInt::get(TD->getIntPtrType(*Context), Len),
457 CI->getArgOperand(2), B, TD);
459 B.CreateMemCpy(Dst, Src,
460 ConstantInt::get(TD->getIntPtrType(*Context), Len), 1);
465 //===---------------------------------------===//
466 // 'strncpy' Optimizations
468 struct StrNCpyOpt : public LibCallOptimization {
469 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
470 FunctionType *FT = Callee->getFunctionType();
471 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
472 FT->getParamType(0) != FT->getParamType(1) ||
473 FT->getParamType(0) != B.getInt8PtrTy() ||
474 !FT->getParamType(2)->isIntegerTy())
477 Value *Dst = CI->getArgOperand(0);
478 Value *Src = CI->getArgOperand(1);
479 Value *LenOp = CI->getArgOperand(2);
481 // See if we can get the length of the input string.
482 uint64_t SrcLen = GetStringLength(Src);
483 if (SrcLen == 0) return 0;
487 // strncpy(x, "", y) -> memset(x, '\0', y, 1)
488 B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
493 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
494 Len = LengthArg->getZExtValue();
498 if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
500 // These optimizations require TargetData.
503 // Let strncpy handle the zero padding
504 if (Len > SrcLen+1) return 0;
506 // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
507 B.CreateMemCpy(Dst, Src,
508 ConstantInt::get(TD->getIntPtrType(*Context), Len), 1);
514 //===---------------------------------------===//
515 // 'strlen' Optimizations
517 struct StrLenOpt : public LibCallOptimization {
518 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
519 FunctionType *FT = Callee->getFunctionType();
520 if (FT->getNumParams() != 1 ||
521 FT->getParamType(0) != B.getInt8PtrTy() ||
522 !FT->getReturnType()->isIntegerTy())
525 Value *Src = CI->getArgOperand(0);
527 // Constant folding: strlen("xyz") -> 3
528 if (uint64_t Len = GetStringLength(Src))
529 return ConstantInt::get(CI->getType(), Len-1);
531 // strlen(x) != 0 --> *x != 0
532 // strlen(x) == 0 --> *x == 0
533 if (IsOnlyUsedInZeroEqualityComparison(CI))
534 return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
540 //===---------------------------------------===//
541 // 'strpbrk' Optimizations
543 struct StrPBrkOpt : public LibCallOptimization {
544 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
545 FunctionType *FT = Callee->getFunctionType();
546 if (FT->getNumParams() != 2 ||
547 FT->getParamType(0) != B.getInt8PtrTy() ||
548 FT->getParamType(1) != FT->getParamType(0) ||
549 FT->getReturnType() != FT->getParamType(0))
553 bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
554 bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
556 // strpbrk(s, "") -> NULL
557 // strpbrk("", s) -> NULL
558 if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
559 return Constant::getNullValue(CI->getType());
562 if (HasS1 && HasS2) {
563 size_t I = S1.find_first_of(S2);
564 if (I == std::string::npos) // No match.
565 return Constant::getNullValue(CI->getType());
567 return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk");
570 // strpbrk(s, "a") -> strchr(s, 'a')
571 if (TD && HasS2 && S2.size() == 1)
572 return EmitStrChr(CI->getArgOperand(0), S2[0], B, TD);
578 //===---------------------------------------===//
579 // 'strto*' Optimizations. This handles strtol, strtod, strtof, strtoul, etc.
581 struct StrToOpt : public LibCallOptimization {
582 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
583 FunctionType *FT = Callee->getFunctionType();
584 if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
585 !FT->getParamType(0)->isPointerTy() ||
586 !FT->getParamType(1)->isPointerTy())
589 Value *EndPtr = CI->getArgOperand(1);
590 if (isa<ConstantPointerNull>(EndPtr)) {
591 // With a null EndPtr, this function won't capture the main argument.
592 // It would be readonly too, except that it still may write to errno.
593 CI->addAttribute(1, Attribute::NoCapture);
600 //===---------------------------------------===//
601 // 'strspn' Optimizations
603 struct StrSpnOpt : public LibCallOptimization {
604 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
605 FunctionType *FT = Callee->getFunctionType();
606 if (FT->getNumParams() != 2 ||
607 FT->getParamType(0) != B.getInt8PtrTy() ||
608 FT->getParamType(1) != FT->getParamType(0) ||
609 !FT->getReturnType()->isIntegerTy())
613 bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
614 bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
616 // strspn(s, "") -> 0
617 // strspn("", s) -> 0
618 if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
619 return Constant::getNullValue(CI->getType());
623 return ConstantInt::get(CI->getType(), strspn(S1.c_str(), S2.c_str()));
629 //===---------------------------------------===//
630 // 'strcspn' Optimizations
632 struct StrCSpnOpt : public LibCallOptimization {
633 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
634 FunctionType *FT = Callee->getFunctionType();
635 if (FT->getNumParams() != 2 ||
636 FT->getParamType(0) != B.getInt8PtrTy() ||
637 FT->getParamType(1) != FT->getParamType(0) ||
638 !FT->getReturnType()->isIntegerTy())
642 bool HasS1 = GetConstantStringInfo(CI->getArgOperand(0), S1);
643 bool HasS2 = GetConstantStringInfo(CI->getArgOperand(1), S2);
645 // strcspn("", s) -> 0
646 if (HasS1 && S1.empty())
647 return Constant::getNullValue(CI->getType());
651 return ConstantInt::get(CI->getType(), strcspn(S1.c_str(), S2.c_str()));
653 // strcspn(s, "") -> strlen(s)
654 if (TD && HasS2 && S2.empty())
655 return EmitStrLen(CI->getArgOperand(0), B, TD);
661 //===---------------------------------------===//
662 // 'strstr' Optimizations
664 struct StrStrOpt : public LibCallOptimization {
665 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
666 FunctionType *FT = Callee->getFunctionType();
667 if (FT->getNumParams() != 2 ||
668 !FT->getParamType(0)->isPointerTy() ||
669 !FT->getParamType(1)->isPointerTy() ||
670 !FT->getReturnType()->isPointerTy())
673 // fold strstr(x, x) -> x.
674 if (CI->getArgOperand(0) == CI->getArgOperand(1))
675 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
677 // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
678 if (TD && IsOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
679 Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, TD);
680 Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
682 for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end();
684 ICmpInst *Old = cast<ICmpInst>(*UI++);
685 Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
686 ConstantInt::getNullValue(StrNCmp->getType()),
688 Old->replaceAllUsesWith(Cmp);
689 Old->eraseFromParent();
694 // See if either input string is a constant string.
695 std::string SearchStr, ToFindStr;
696 bool HasStr1 = GetConstantStringInfo(CI->getArgOperand(0), SearchStr);
697 bool HasStr2 = GetConstantStringInfo(CI->getArgOperand(1), ToFindStr);
699 // fold strstr(x, "") -> x.
700 if (HasStr2 && ToFindStr.empty())
701 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
703 // If both strings are known, constant fold it.
704 if (HasStr1 && HasStr2) {
705 std::string::size_type Offset = SearchStr.find(ToFindStr);
707 if (Offset == std::string::npos) // strstr("foo", "bar") -> null
708 return Constant::getNullValue(CI->getType());
710 // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
711 Value *Result = CastToCStr(CI->getArgOperand(0), B);
712 Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
713 return B.CreateBitCast(Result, CI->getType());
716 // fold strstr(x, "y") -> strchr(x, 'y').
717 if (HasStr2 && ToFindStr.size() == 1)
718 return B.CreateBitCast(EmitStrChr(CI->getArgOperand(0),
719 ToFindStr[0], B, TD), CI->getType());
725 //===---------------------------------------===//
726 // 'memcmp' Optimizations
728 struct MemCmpOpt : public LibCallOptimization {
729 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
730 FunctionType *FT = Callee->getFunctionType();
731 if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
732 !FT->getParamType(1)->isPointerTy() ||
733 !FT->getReturnType()->isIntegerTy(32))
736 Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
738 if (LHS == RHS) // memcmp(s,s,x) -> 0
739 return Constant::getNullValue(CI->getType());
741 // Make sure we have a constant length.
742 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
744 uint64_t Len = LenC->getZExtValue();
746 if (Len == 0) // memcmp(s1,s2,0) -> 0
747 return Constant::getNullValue(CI->getType());
749 // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
751 Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
752 CI->getType(), "lhsv");
753 Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
754 CI->getType(), "rhsv");
755 return B.CreateSub(LHSV, RHSV, "chardiff");
758 // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
759 std::string LHSStr, RHSStr;
760 if (GetConstantStringInfo(LHS, LHSStr) &&
761 GetConstantStringInfo(RHS, RHSStr)) {
762 // Make sure we're not reading out-of-bounds memory.
763 if (Len > LHSStr.length() || Len > RHSStr.length())
765 uint64_t Ret = memcmp(LHSStr.data(), RHSStr.data(), Len);
766 return ConstantInt::get(CI->getType(), Ret);
773 //===---------------------------------------===//
774 // 'memcpy' Optimizations
776 struct MemCpyOpt : public LibCallOptimization {
777 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
778 // These optimizations require TargetData.
781 FunctionType *FT = Callee->getFunctionType();
782 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
783 !FT->getParamType(0)->isPointerTy() ||
784 !FT->getParamType(1)->isPointerTy() ||
785 FT->getParamType(2) != TD->getIntPtrType(*Context))
788 // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
789 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
790 CI->getArgOperand(2), 1);
791 return CI->getArgOperand(0);
795 //===---------------------------------------===//
796 // 'memmove' Optimizations
798 struct MemMoveOpt : public LibCallOptimization {
799 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
800 // These optimizations require TargetData.
803 FunctionType *FT = Callee->getFunctionType();
804 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
805 !FT->getParamType(0)->isPointerTy() ||
806 !FT->getParamType(1)->isPointerTy() ||
807 FT->getParamType(2) != TD->getIntPtrType(*Context))
810 // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
811 B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
812 CI->getArgOperand(2), 1);
813 return CI->getArgOperand(0);
817 //===---------------------------------------===//
818 // 'memset' Optimizations
820 struct MemSetOpt : public LibCallOptimization {
821 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
822 // These optimizations require TargetData.
825 FunctionType *FT = Callee->getFunctionType();
826 if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
827 !FT->getParamType(0)->isPointerTy() ||
828 !FT->getParamType(1)->isIntegerTy() ||
829 FT->getParamType(2) != TD->getIntPtrType(*Context))
832 // memset(p, v, n) -> llvm.memset(p, v, n, 1)
833 Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
834 B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
835 return CI->getArgOperand(0);
839 //===----------------------------------------------------------------------===//
840 // Math Library Optimizations
841 //===----------------------------------------------------------------------===//
843 //===---------------------------------------===//
844 // 'pow*' Optimizations
846 struct PowOpt : public LibCallOptimization {
847 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
848 FunctionType *FT = Callee->getFunctionType();
849 // Just make sure this has 2 arguments of the same FP type, which match the
851 if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
852 FT->getParamType(0) != FT->getParamType(1) ||
853 !FT->getParamType(0)->isFloatingPointTy())
856 Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
857 if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
858 if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
860 if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
861 return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
864 ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
865 if (Op2C == 0) return 0;
867 if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
868 return ConstantFP::get(CI->getType(), 1.0);
870 if (Op2C->isExactlyValue(0.5)) {
871 // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
872 // This is faster than calling pow, and still handles negative zero
873 // and negative infinite correctly.
874 // TODO: In fast-math mode, this could be just sqrt(x).
875 // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
876 Value *Inf = ConstantFP::getInfinity(CI->getType());
877 Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
878 Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B,
879 Callee->getAttributes());
880 Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B,
881 Callee->getAttributes());
882 Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf);
883 Value *Sel = B.CreateSelect(FCmp, Inf, FAbs);
887 if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
889 if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
890 return B.CreateFMul(Op1, Op1, "pow2");
891 if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
892 return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0),
898 //===---------------------------------------===//
899 // 'exp2' Optimizations
901 struct Exp2Opt : public LibCallOptimization {
902 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
903 FunctionType *FT = Callee->getFunctionType();
904 // Just make sure this has 1 argument of FP type, which matches the
906 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
907 !FT->getParamType(0)->isFloatingPointTy())
910 Value *Op = CI->getArgOperand(0);
911 // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32
912 // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32
914 if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
915 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
916 LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty());
917 } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
918 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
919 LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty());
924 if (Op->getType()->isFloatTy())
926 else if (Op->getType()->isDoubleTy())
931 Constant *One = ConstantFP::get(*Context, APFloat(1.0f));
932 if (!Op->getType()->isFloatTy())
933 One = ConstantExpr::getFPExtend(One, Op->getType());
935 Module *M = Caller->getParent();
936 Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
938 B.getInt32Ty(), NULL);
939 CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
940 if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
941 CI->setCallingConv(F->getCallingConv());
949 //===---------------------------------------===//
950 // Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
952 struct UnaryDoubleFPOpt : public LibCallOptimization {
953 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
954 FunctionType *FT = Callee->getFunctionType();
955 if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
956 !FT->getParamType(0)->isDoubleTy())
959 // If this is something like 'floor((double)floatval)', convert to floorf.
960 FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
961 if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
964 // floor((double)floatval) -> (double)floorf(floatval)
965 Value *V = Cast->getOperand(0);
966 V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
967 return B.CreateFPExt(V, B.getDoubleTy());
971 //===----------------------------------------------------------------------===//
972 // Integer Optimizations
973 //===----------------------------------------------------------------------===//
975 //===---------------------------------------===//
976 // 'ffs*' Optimizations
978 struct FFSOpt : public LibCallOptimization {
979 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
980 FunctionType *FT = Callee->getFunctionType();
981 // Just make sure this has 2 arguments of the same FP type, which match the
983 if (FT->getNumParams() != 1 ||
984 !FT->getReturnType()->isIntegerTy(32) ||
985 !FT->getParamType(0)->isIntegerTy())
988 Value *Op = CI->getArgOperand(0);
991 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
992 if (CI->getValue() == 0) // ffs(0) -> 0.
993 return Constant::getNullValue(CI->getType());
994 // ffs(c) -> cttz(c)+1
995 return B.getInt32(CI->getValue().countTrailingZeros() + 1);
998 // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
999 Type *ArgType = Op->getType();
1000 Value *F = Intrinsic::getDeclaration(Callee->getParent(),
1001 Intrinsic::cttz, ArgType);
1002 Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
1003 V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
1004 V = B.CreateIntCast(V, B.getInt32Ty(), false);
1006 Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
1007 return B.CreateSelect(Cond, V, B.getInt32(0));
1011 //===---------------------------------------===//
1012 // 'isdigit' Optimizations
1014 struct IsDigitOpt : public LibCallOptimization {
1015 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1016 FunctionType *FT = Callee->getFunctionType();
1017 // We require integer(i32)
1018 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1019 !FT->getParamType(0)->isIntegerTy(32))
1022 // isdigit(c) -> (c-'0') <u 10
1023 Value *Op = CI->getArgOperand(0);
1024 Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp");
1025 Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit");
1026 return B.CreateZExt(Op, CI->getType());
1030 //===---------------------------------------===//
1031 // 'isascii' Optimizations
1033 struct IsAsciiOpt : public LibCallOptimization {
1034 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1035 FunctionType *FT = Callee->getFunctionType();
1036 // We require integer(i32)
1037 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1038 !FT->getParamType(0)->isIntegerTy(32))
1041 // isascii(c) -> c <u 128
1042 Value *Op = CI->getArgOperand(0);
1043 Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii");
1044 return B.CreateZExt(Op, CI->getType());
1048 //===---------------------------------------===//
1049 // 'abs', 'labs', 'llabs' Optimizations
1051 struct AbsOpt : public LibCallOptimization {
1052 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1053 FunctionType *FT = Callee->getFunctionType();
1054 // We require integer(integer) where the types agree.
1055 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1056 FT->getParamType(0) != FT->getReturnType())
1059 // abs(x) -> x >s -1 ? x : -x
1060 Value *Op = CI->getArgOperand(0);
1061 Value *Pos = B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()),
1063 Value *Neg = B.CreateNeg(Op, "neg");
1064 return B.CreateSelect(Pos, Op, Neg);
1069 //===---------------------------------------===//
1070 // 'toascii' Optimizations
1072 struct ToAsciiOpt : public LibCallOptimization {
1073 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1074 FunctionType *FT = Callee->getFunctionType();
1075 // We require i32(i32)
1076 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1077 !FT->getParamType(0)->isIntegerTy(32))
1080 // isascii(c) -> c & 0x7f
1081 return B.CreateAnd(CI->getArgOperand(0),
1082 ConstantInt::get(CI->getType(),0x7F));
1086 //===----------------------------------------------------------------------===//
1087 // Formatting and IO Optimizations
1088 //===----------------------------------------------------------------------===//
1090 //===---------------------------------------===//
1091 // 'printf' Optimizations
1093 struct PrintFOpt : public LibCallOptimization {
1094 Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI,
1096 // Check for a fixed format string.
1097 std::string FormatStr;
1098 if (!GetConstantStringInfo(CI->getArgOperand(0), FormatStr))
1101 // Empty format string -> noop.
1102 if (FormatStr.empty()) // Tolerate printf's declared void.
1103 return CI->use_empty() ? (Value*)CI :
1104 ConstantInt::get(CI->getType(), 0);
1106 // Do not do any of the following transformations if the printf return value
1107 // is used, in general the printf return value is not compatible with either
1108 // putchar() or puts().
1109 if (!CI->use_empty())
1112 // printf("x") -> putchar('x'), even for '%'.
1113 if (FormatStr.size() == 1) {
1114 Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TD);
1115 if (CI->use_empty()) return CI;
1116 return B.CreateIntCast(Res, CI->getType(), true);
1119 // printf("foo\n") --> puts("foo")
1120 if (FormatStr[FormatStr.size()-1] == '\n' &&
1121 FormatStr.find('%') == std::string::npos) { // no format characters.
1122 // Create a string literal with no \n on it. We expect the constant merge
1123 // pass to be run after this pass, to merge duplicate strings.
1124 FormatStr.erase(FormatStr.end()-1);
1125 Value *GV = B.CreateGlobalString(FormatStr, "str");
1126 EmitPutS(GV, B, TD);
1127 return CI->use_empty() ? (Value*)CI :
1128 ConstantInt::get(CI->getType(), FormatStr.size()+1);
1131 // Optimize specific format strings.
1132 // printf("%c", chr) --> putchar(chr)
1133 if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
1134 CI->getArgOperand(1)->getType()->isIntegerTy()) {
1135 Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD);
1137 if (CI->use_empty()) return CI;
1138 return B.CreateIntCast(Res, CI->getType(), true);
1141 // printf("%s\n", str) --> puts(str)
1142 if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
1143 CI->getArgOperand(1)->getType()->isPointerTy()) {
1144 EmitPutS(CI->getArgOperand(1), B, TD);
1150 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1151 // Require one fixed pointer argument and an integer/void result.
1152 FunctionType *FT = Callee->getFunctionType();
1153 if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
1154 !(FT->getReturnType()->isIntegerTy() ||
1155 FT->getReturnType()->isVoidTy()))
1158 if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) {
1162 // printf(format, ...) -> iprintf(format, ...) if no floating point
1164 if (TLI->has(LibFunc::iprintf) && !CallHasFloatingPointArgument(CI)) {
1165 Module *M = B.GetInsertBlock()->getParent()->getParent();
1166 Constant *IPrintFFn =
1167 M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
1168 CallInst *New = cast<CallInst>(CI->clone());
1169 New->setCalledFunction(IPrintFFn);
1177 //===---------------------------------------===//
1178 // 'sprintf' Optimizations
1180 struct SPrintFOpt : public LibCallOptimization {
1181 Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI,
1183 // Check for a fixed format string.
1184 std::string FormatStr;
1185 if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1188 // If we just have a format string (nothing else crazy) transform it.
1189 if (CI->getNumArgOperands() == 2) {
1190 // Make sure there's no % in the constant array. We could try to handle
1191 // %% -> % in the future if we cared.
1192 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1193 if (FormatStr[i] == '%')
1194 return 0; // we found a format specifier, bail out.
1196 // These optimizations require TargetData.
1199 // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
1200 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
1201 ConstantInt::get(TD->getIntPtrType(*Context), // Copy the
1202 FormatStr.size() + 1), 1); // nul byte.
1203 return ConstantInt::get(CI->getType(), FormatStr.size());
1206 // The remaining optimizations require the format string to be "%s" or "%c"
1207 // and have an extra operand.
1208 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1209 CI->getNumArgOperands() < 3)
1212 // Decode the second character of the format string.
1213 if (FormatStr[1] == 'c') {
1214 // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
1215 if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1216 Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
1217 Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
1218 B.CreateStore(V, Ptr);
1219 Ptr = B.CreateGEP(Ptr, B.getInt32(1), "nul");
1220 B.CreateStore(B.getInt8(0), Ptr);
1222 return ConstantInt::get(CI->getType(), 1);
1225 if (FormatStr[1] == 's') {
1226 // These optimizations require TargetData.
1229 // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1230 if (!CI->getArgOperand(2)->getType()->isPointerTy()) return 0;
1232 Value *Len = EmitStrLen(CI->getArgOperand(2), B, TD);
1233 Value *IncLen = B.CreateAdd(Len,
1234 ConstantInt::get(Len->getType(), 1),
1236 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
1238 // The sprintf result is the unincremented number of bytes in the string.
1239 return B.CreateIntCast(Len, CI->getType(), false);
1244 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1245 // Require two fixed pointer arguments and an integer result.
1246 FunctionType *FT = Callee->getFunctionType();
1247 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1248 !FT->getParamType(1)->isPointerTy() ||
1249 !FT->getReturnType()->isIntegerTy())
1252 if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) {
1256 // sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating
1258 if (TLI->has(LibFunc::siprintf) && !CallHasFloatingPointArgument(CI)) {
1259 Module *M = B.GetInsertBlock()->getParent()->getParent();
1260 Constant *SIPrintFFn =
1261 M->getOrInsertFunction("siprintf", FT, Callee->getAttributes());
1262 CallInst *New = cast<CallInst>(CI->clone());
1263 New->setCalledFunction(SIPrintFFn);
1271 //===---------------------------------------===//
1272 // 'fwrite' Optimizations
1274 struct FWriteOpt : public LibCallOptimization {
1275 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1276 // Require a pointer, an integer, an integer, a pointer, returning integer.
1277 FunctionType *FT = Callee->getFunctionType();
1278 if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
1279 !FT->getParamType(1)->isIntegerTy() ||
1280 !FT->getParamType(2)->isIntegerTy() ||
1281 !FT->getParamType(3)->isPointerTy() ||
1282 !FT->getReturnType()->isIntegerTy())
1285 // Get the element size and count.
1286 ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
1287 ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
1288 if (!SizeC || !CountC) return 0;
1289 uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
1291 // If this is writing zero records, remove the call (it's a noop).
1293 return ConstantInt::get(CI->getType(), 0);
1295 // If this is writing one byte, turn it into fputc.
1296 // This optimisation is only valid, if the return value is unused.
1297 if (Bytes == 1 && CI->use_empty()) { // fwrite(S,1,1,F) -> fputc(S[0],F)
1298 Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
1299 EmitFPutC(Char, CI->getArgOperand(3), B, TD);
1300 return ConstantInt::get(CI->getType(), 1);
1307 //===---------------------------------------===//
1308 // 'fputs' Optimizations
1310 struct FPutsOpt : public LibCallOptimization {
1311 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1312 // These optimizations require TargetData.
1315 // Require two pointers. Also, we can't optimize if return value is used.
1316 FunctionType *FT = Callee->getFunctionType();
1317 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1318 !FT->getParamType(1)->isPointerTy() ||
1322 // fputs(s,F) --> fwrite(s,1,strlen(s),F)
1323 uint64_t Len = GetStringLength(CI->getArgOperand(0));
1325 EmitFWrite(CI->getArgOperand(0),
1326 ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
1327 CI->getArgOperand(1), B, TD, TLI);
1328 return CI; // Known to have no uses (see above).
1332 //===---------------------------------------===//
1333 // 'fprintf' Optimizations
1335 struct FPrintFOpt : public LibCallOptimization {
1336 Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI,
1338 // All the optimizations depend on the format string.
1339 std::string FormatStr;
1340 if (!GetConstantStringInfo(CI->getArgOperand(1), FormatStr))
1343 // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
1344 if (CI->getNumArgOperands() == 2) {
1345 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1346 if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
1347 return 0; // We found a format specifier.
1349 // These optimizations require TargetData.
1352 EmitFWrite(CI->getArgOperand(1),
1353 ConstantInt::get(TD->getIntPtrType(*Context),
1355 CI->getArgOperand(0), B, TD, TLI);
1356 return ConstantInt::get(CI->getType(), FormatStr.size());
1359 // The remaining optimizations require the format string to be "%s" or "%c"
1360 // and have an extra operand.
1361 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1362 CI->getNumArgOperands() < 3)
1365 // Decode the second character of the format string.
1366 if (FormatStr[1] == 'c') {
1367 // fprintf(F, "%c", chr) --> fputc(chr, F)
1368 if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
1369 EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TD);
1370 return ConstantInt::get(CI->getType(), 1);
1373 if (FormatStr[1] == 's') {
1374 // fprintf(F, "%s", str) --> fputs(str, F)
1375 if (!CI->getArgOperand(2)->getType()->isPointerTy() || !CI->use_empty())
1377 EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TD, TLI);
1383 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1384 // Require two fixed paramters as pointers and integer result.
1385 FunctionType *FT = Callee->getFunctionType();
1386 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1387 !FT->getParamType(1)->isPointerTy() ||
1388 !FT->getReturnType()->isIntegerTy())
1391 if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) {
1395 // fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no
1396 // floating point arguments.
1397 if (TLI->has(LibFunc::fiprintf) && !CallHasFloatingPointArgument(CI)) {
1398 Module *M = B.GetInsertBlock()->getParent()->getParent();
1399 Constant *FIPrintFFn =
1400 M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes());
1401 CallInst *New = cast<CallInst>(CI->clone());
1402 New->setCalledFunction(FIPrintFFn);
1410 //===---------------------------------------===//
1411 // 'puts' Optimizations
1413 struct PutsOpt : public LibCallOptimization {
1414 virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
1415 // Require one fixed pointer argument and an integer/void result.
1416 FunctionType *FT = Callee->getFunctionType();
1417 if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
1418 !(FT->getReturnType()->isIntegerTy() ||
1419 FT->getReturnType()->isVoidTy()))
1422 // Check for a constant string.
1424 if (!GetConstantStringInfo(CI->getArgOperand(0), Str))
1427 if (Str.empty() && CI->use_empty()) {
1428 // puts("") -> putchar('\n')
1429 Value *Res = EmitPutChar(B.getInt32('\n'), B, TD);
1430 if (CI->use_empty()) return CI;
1431 return B.CreateIntCast(Res, CI->getType(), true);
1438 } // end anonymous namespace.
1440 //===----------------------------------------------------------------------===//
1441 // SimplifyLibCalls Pass Implementation
1442 //===----------------------------------------------------------------------===//
1445 /// This pass optimizes well known library functions from libc and libm.
1447 class SimplifyLibCalls : public FunctionPass {
1448 TargetLibraryInfo *TLI;
1450 StringMap<LibCallOptimization*> Optimizations;
1451 // String and Memory LibCall Optimizations
1452 StrCatOpt StrCat; StrNCatOpt StrNCat; StrChrOpt StrChr; StrRChrOpt StrRChr;
1453 StrCmpOpt StrCmp; StrNCmpOpt StrNCmp; StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
1454 StrNCpyOpt StrNCpy; StrLenOpt StrLen; StrPBrkOpt StrPBrk;
1455 StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
1456 MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
1457 // Math Library Optimizations
1458 PowOpt Pow; Exp2Opt Exp2; UnaryDoubleFPOpt UnaryDoubleFP;
1459 // Integer Optimizations
1460 FFSOpt FFS; AbsOpt Abs; IsDigitOpt IsDigit; IsAsciiOpt IsAscii;
1462 // Formatting and IO Optimizations
1463 SPrintFOpt SPrintF; PrintFOpt PrintF;
1464 FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
1467 bool Modified; // This is only used by doInitialization.
1469 static char ID; // Pass identification
1470 SimplifyLibCalls() : FunctionPass(ID), StrCpy(false), StrCpyChk(true) {
1471 initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
1473 void AddOpt(LibFunc::Func F, LibCallOptimization* Opt);
1474 void InitOptimizations();
1475 bool runOnFunction(Function &F);
1477 void setDoesNotAccessMemory(Function &F);
1478 void setOnlyReadsMemory(Function &F);
1479 void setDoesNotThrow(Function &F);
1480 void setDoesNotCapture(Function &F, unsigned n);
1481 void setDoesNotAlias(Function &F, unsigned n);
1482 bool doInitialization(Module &M);
1484 void inferPrototypeAttributes(Function &F);
1485 virtual void getAnalysisUsage(AnalysisUsage &AU) const {
1486 AU.addRequired<TargetLibraryInfo>();
1489 } // end anonymous namespace.
1491 char SimplifyLibCalls::ID = 0;
1493 INITIALIZE_PASS_BEGIN(SimplifyLibCalls, "simplify-libcalls",
1494 "Simplify well-known library calls", false, false)
1495 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
1496 INITIALIZE_PASS_END(SimplifyLibCalls, "simplify-libcalls",
1497 "Simplify well-known library calls", false, false)
1499 // Public interface to the Simplify LibCalls pass.
1500 FunctionPass *llvm::createSimplifyLibCallsPass() {
1501 return new SimplifyLibCalls();
1504 void SimplifyLibCalls::AddOpt(LibFunc::Func F, LibCallOptimization* Opt) {
1506 Optimizations[TLI->getName(F)] = Opt;
1509 /// Optimizations - Populate the Optimizations map with all the optimizations
1511 void SimplifyLibCalls::InitOptimizations() {
1512 // String and Memory LibCall Optimizations
1513 Optimizations["strcat"] = &StrCat;
1514 Optimizations["strncat"] = &StrNCat;
1515 Optimizations["strchr"] = &StrChr;
1516 Optimizations["strrchr"] = &StrRChr;
1517 Optimizations["strcmp"] = &StrCmp;
1518 Optimizations["strncmp"] = &StrNCmp;
1519 Optimizations["strcpy"] = &StrCpy;
1520 Optimizations["strncpy"] = &StrNCpy;
1521 Optimizations["strlen"] = &StrLen;
1522 Optimizations["strpbrk"] = &StrPBrk;
1523 Optimizations["strtol"] = &StrTo;
1524 Optimizations["strtod"] = &StrTo;
1525 Optimizations["strtof"] = &StrTo;
1526 Optimizations["strtoul"] = &StrTo;
1527 Optimizations["strtoll"] = &StrTo;
1528 Optimizations["strtold"] = &StrTo;
1529 Optimizations["strtoull"] = &StrTo;
1530 Optimizations["strspn"] = &StrSpn;
1531 Optimizations["strcspn"] = &StrCSpn;
1532 Optimizations["strstr"] = &StrStr;
1533 Optimizations["memcmp"] = &MemCmp;
1534 AddOpt(LibFunc::memcpy, &MemCpy);
1535 Optimizations["memmove"] = &MemMove;
1536 AddOpt(LibFunc::memset, &MemSet);
1538 // _chk variants of String and Memory LibCall Optimizations.
1539 Optimizations["__strcpy_chk"] = &StrCpyChk;
1541 // Math Library Optimizations
1542 Optimizations["powf"] = &Pow;
1543 Optimizations["pow"] = &Pow;
1544 Optimizations["powl"] = &Pow;
1545 Optimizations["llvm.pow.f32"] = &Pow;
1546 Optimizations["llvm.pow.f64"] = &Pow;
1547 Optimizations["llvm.pow.f80"] = &Pow;
1548 Optimizations["llvm.pow.f128"] = &Pow;
1549 Optimizations["llvm.pow.ppcf128"] = &Pow;
1550 Optimizations["exp2l"] = &Exp2;
1551 Optimizations["exp2"] = &Exp2;
1552 Optimizations["exp2f"] = &Exp2;
1553 Optimizations["llvm.exp2.ppcf128"] = &Exp2;
1554 Optimizations["llvm.exp2.f128"] = &Exp2;
1555 Optimizations["llvm.exp2.f80"] = &Exp2;
1556 Optimizations["llvm.exp2.f64"] = &Exp2;
1557 Optimizations["llvm.exp2.f32"] = &Exp2;
1560 Optimizations["floor"] = &UnaryDoubleFP;
1563 Optimizations["ceil"] = &UnaryDoubleFP;
1566 Optimizations["round"] = &UnaryDoubleFP;
1569 Optimizations["rint"] = &UnaryDoubleFP;
1571 #ifdef HAVE_NEARBYINTF
1572 Optimizations["nearbyint"] = &UnaryDoubleFP;
1575 // Integer Optimizations
1576 Optimizations["ffs"] = &FFS;
1577 Optimizations["ffsl"] = &FFS;
1578 Optimizations["ffsll"] = &FFS;
1579 Optimizations["abs"] = &Abs;
1580 Optimizations["labs"] = &Abs;
1581 Optimizations["llabs"] = &Abs;
1582 Optimizations["isdigit"] = &IsDigit;
1583 Optimizations["isascii"] = &IsAscii;
1584 Optimizations["toascii"] = &ToAscii;
1586 // Formatting and IO Optimizations
1587 Optimizations["sprintf"] = &SPrintF;
1588 Optimizations["printf"] = &PrintF;
1589 AddOpt(LibFunc::fwrite, &FWrite);
1590 AddOpt(LibFunc::fputs, &FPuts);
1591 Optimizations["fprintf"] = &FPrintF;
1592 Optimizations["puts"] = &Puts;
1596 /// runOnFunction - Top level algorithm.
1598 bool SimplifyLibCalls::runOnFunction(Function &F) {
1599 TLI = &getAnalysis<TargetLibraryInfo>();
1601 if (Optimizations.empty())
1602 InitOptimizations();
1604 const TargetData *TD = getAnalysisIfAvailable<TargetData>();
1606 IRBuilder<> Builder(F.getContext());
1608 bool Changed = false;
1609 for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
1610 for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
1611 // Ignore non-calls.
1612 CallInst *CI = dyn_cast<CallInst>(I++);
1615 // Ignore indirect calls and calls to non-external functions.
1616 Function *Callee = CI->getCalledFunction();
1617 if (Callee == 0 || !Callee->isDeclaration() ||
1618 !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
1621 // Ignore unknown calls.
1622 LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
1625 // Set the builder to the instruction after the call.
1626 Builder.SetInsertPoint(BB, I);
1628 // Use debug location of CI for all new instructions.
1629 Builder.SetCurrentDebugLocation(CI->getDebugLoc());
1631 // Try to optimize this call.
1632 Value *Result = LCO->OptimizeCall(CI, TD, TLI, Builder);
1633 if (Result == 0) continue;
1635 DEBUG(dbgs() << "SimplifyLibCalls simplified: " << *CI;
1636 dbgs() << " into: " << *Result << "\n");
1638 // Something changed!
1642 // Inspect the instruction after the call (which was potentially just
1646 if (CI != Result && !CI->use_empty()) {
1647 CI->replaceAllUsesWith(Result);
1648 if (!Result->hasName())
1649 Result->takeName(CI);
1651 CI->eraseFromParent();
1657 // Utility methods for doInitialization.
1659 void SimplifyLibCalls::setDoesNotAccessMemory(Function &F) {
1660 if (!F.doesNotAccessMemory()) {
1661 F.setDoesNotAccessMemory();
1666 void SimplifyLibCalls::setOnlyReadsMemory(Function &F) {
1667 if (!F.onlyReadsMemory()) {
1668 F.setOnlyReadsMemory();
1673 void SimplifyLibCalls::setDoesNotThrow(Function &F) {
1674 if (!F.doesNotThrow()) {
1675 F.setDoesNotThrow();
1680 void SimplifyLibCalls::setDoesNotCapture(Function &F, unsigned n) {
1681 if (!F.doesNotCapture(n)) {
1682 F.setDoesNotCapture(n);
1687 void SimplifyLibCalls::setDoesNotAlias(Function &F, unsigned n) {
1688 if (!F.doesNotAlias(n)) {
1689 F.setDoesNotAlias(n);
1696 void SimplifyLibCalls::inferPrototypeAttributes(Function &F) {
1697 FunctionType *FTy = F.getFunctionType();
1699 StringRef Name = F.getName();
1702 if (Name == "strlen") {
1703 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
1705 setOnlyReadsMemory(F);
1707 setDoesNotCapture(F, 1);
1708 } else if (Name == "strchr" ||
1709 Name == "strrchr") {
1710 if (FTy->getNumParams() != 2 ||
1711 !FTy->getParamType(0)->isPointerTy() ||
1712 !FTy->getParamType(1)->isIntegerTy())
1714 setOnlyReadsMemory(F);
1716 } else if (Name == "strcpy" ||
1722 Name == "strtoul" ||
1723 Name == "strtoll" ||
1724 Name == "strtold" ||
1725 Name == "strncat" ||
1726 Name == "strncpy" ||
1727 Name == "strtoull") {
1728 if (FTy->getNumParams() < 2 ||
1729 !FTy->getParamType(1)->isPointerTy())
1732 setDoesNotCapture(F, 2);
1733 } else if (Name == "strxfrm") {
1734 if (FTy->getNumParams() != 3 ||
1735 !FTy->getParamType(0)->isPointerTy() ||
1736 !FTy->getParamType(1)->isPointerTy())
1739 setDoesNotCapture(F, 1);
1740 setDoesNotCapture(F, 2);
1741 } else if (Name == "strcmp" ||
1743 Name == "strncmp" ||
1744 Name == "strcspn" ||
1745 Name == "strcoll" ||
1746 Name == "strcasecmp" ||
1747 Name == "strncasecmp") {
1748 if (FTy->getNumParams() < 2 ||
1749 !FTy->getParamType(0)->isPointerTy() ||
1750 !FTy->getParamType(1)->isPointerTy())
1752 setOnlyReadsMemory(F);
1754 setDoesNotCapture(F, 1);
1755 setDoesNotCapture(F, 2);
1756 } else if (Name == "strstr" ||
1757 Name == "strpbrk") {
1758 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
1760 setOnlyReadsMemory(F);
1762 setDoesNotCapture(F, 2);
1763 } else if (Name == "strtok" ||
1764 Name == "strtok_r") {
1765 if (FTy->getNumParams() < 2 || !FTy->getParamType(1)->isPointerTy())
1768 setDoesNotCapture(F, 2);
1769 } else if (Name == "scanf" ||
1771 Name == "setvbuf") {
1772 if (FTy->getNumParams() < 1 || !FTy->getParamType(0)->isPointerTy())
1775 setDoesNotCapture(F, 1);
1776 } else if (Name == "strdup" ||
1777 Name == "strndup") {
1778 if (FTy->getNumParams() < 1 || !FTy->getReturnType()->isPointerTy() ||
1779 !FTy->getParamType(0)->isPointerTy())
1782 setDoesNotAlias(F, 0);
1783 setDoesNotCapture(F, 1);
1784 } else if (Name == "stat" ||
1786 Name == "sprintf" ||
1787 Name == "statvfs") {
1788 if (FTy->getNumParams() < 2 ||
1789 !FTy->getParamType(0)->isPointerTy() ||
1790 !FTy->getParamType(1)->isPointerTy())
1793 setDoesNotCapture(F, 1);
1794 setDoesNotCapture(F, 2);
1795 } else if (Name == "snprintf") {
1796 if (FTy->getNumParams() != 3 ||
1797 !FTy->getParamType(0)->isPointerTy() ||
1798 !FTy->getParamType(2)->isPointerTy())
1801 setDoesNotCapture(F, 1);
1802 setDoesNotCapture(F, 3);
1803 } else if (Name == "setitimer") {
1804 if (FTy->getNumParams() != 3 ||
1805 !FTy->getParamType(1)->isPointerTy() ||
1806 !FTy->getParamType(2)->isPointerTy())
1809 setDoesNotCapture(F, 2);
1810 setDoesNotCapture(F, 3);
1811 } else if (Name == "system") {
1812 if (FTy->getNumParams() != 1 ||
1813 !FTy->getParamType(0)->isPointerTy())
1815 // May throw; "system" is a valid pthread cancellation point.
1816 setDoesNotCapture(F, 1);
1820 if (Name == "malloc") {
1821 if (FTy->getNumParams() != 1 ||
1822 !FTy->getReturnType()->isPointerTy())
1825 setDoesNotAlias(F, 0);
1826 } else if (Name == "memcmp") {
1827 if (FTy->getNumParams() != 3 ||
1828 !FTy->getParamType(0)->isPointerTy() ||
1829 !FTy->getParamType(1)->isPointerTy())
1831 setOnlyReadsMemory(F);
1833 setDoesNotCapture(F, 1);
1834 setDoesNotCapture(F, 2);
1835 } else if (Name == "memchr" ||
1836 Name == "memrchr") {
1837 if (FTy->getNumParams() != 3)
1839 setOnlyReadsMemory(F);
1841 } else if (Name == "modf" ||
1845 Name == "memccpy" ||
1846 Name == "memmove") {
1847 if (FTy->getNumParams() < 2 ||
1848 !FTy->getParamType(1)->isPointerTy())
1851 setDoesNotCapture(F, 2);
1852 } else if (Name == "memalign") {
1853 if (!FTy->getReturnType()->isPointerTy())
1855 setDoesNotAlias(F, 0);
1856 } else if (Name == "mkdir" ||
1858 if (FTy->getNumParams() == 0 ||
1859 !FTy->getParamType(0)->isPointerTy())
1862 setDoesNotCapture(F, 1);
1866 if (Name == "realloc") {
1867 if (FTy->getNumParams() != 2 ||
1868 !FTy->getParamType(0)->isPointerTy() ||
1869 !FTy->getReturnType()->isPointerTy())
1872 setDoesNotAlias(F, 0);
1873 setDoesNotCapture(F, 1);
1874 } else if (Name == "read") {
1875 if (FTy->getNumParams() != 3 ||
1876 !FTy->getParamType(1)->isPointerTy())
1878 // May throw; "read" is a valid pthread cancellation point.
1879 setDoesNotCapture(F, 2);
1880 } else if (Name == "rmdir" ||
1883 Name == "realpath") {
1884 if (FTy->getNumParams() < 1 ||
1885 !FTy->getParamType(0)->isPointerTy())
1888 setDoesNotCapture(F, 1);
1889 } else if (Name == "rename" ||
1890 Name == "readlink") {
1891 if (FTy->getNumParams() < 2 ||
1892 !FTy->getParamType(0)->isPointerTy() ||
1893 !FTy->getParamType(1)->isPointerTy())
1896 setDoesNotCapture(F, 1);
1897 setDoesNotCapture(F, 2);
1901 if (Name == "write") {
1902 if (FTy->getNumParams() != 3 || !FTy->getParamType(1)->isPointerTy())
1904 // May throw; "write" is a valid pthread cancellation point.
1905 setDoesNotCapture(F, 2);
1909 if (Name == "bcopy") {
1910 if (FTy->getNumParams() != 3 ||
1911 !FTy->getParamType(0)->isPointerTy() ||
1912 !FTy->getParamType(1)->isPointerTy())
1915 setDoesNotCapture(F, 1);
1916 setDoesNotCapture(F, 2);
1917 } else if (Name == "bcmp") {
1918 if (FTy->getNumParams() != 3 ||
1919 !FTy->getParamType(0)->isPointerTy() ||
1920 !FTy->getParamType(1)->isPointerTy())
1923 setOnlyReadsMemory(F);
1924 setDoesNotCapture(F, 1);
1925 setDoesNotCapture(F, 2);
1926 } else if (Name == "bzero") {
1927 if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
1930 setDoesNotCapture(F, 1);
1934 if (Name == "calloc") {
1935 if (FTy->getNumParams() != 2 ||
1936 !FTy->getReturnType()->isPointerTy())
1939 setDoesNotAlias(F, 0);
1940 } else if (Name == "chmod" ||
1942 Name == "ctermid" ||
1943 Name == "clearerr" ||
1944 Name == "closedir") {
1945 if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
1948 setDoesNotCapture(F, 1);
1952 if (Name == "atoi" ||
1956 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
1959 setOnlyReadsMemory(F);
1960 setDoesNotCapture(F, 1);
1961 } else if (Name == "access") {
1962 if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
1965 setDoesNotCapture(F, 1);
1969 if (Name == "fopen") {
1970 if (FTy->getNumParams() != 2 ||
1971 !FTy->getReturnType()->isPointerTy() ||
1972 !FTy->getParamType(0)->isPointerTy() ||
1973 !FTy->getParamType(1)->isPointerTy())
1976 setDoesNotAlias(F, 0);
1977 setDoesNotCapture(F, 1);
1978 setDoesNotCapture(F, 2);
1979 } else if (Name == "fdopen") {
1980 if (FTy->getNumParams() != 2 ||
1981 !FTy->getReturnType()->isPointerTy() ||
1982 !FTy->getParamType(1)->isPointerTy())
1985 setDoesNotAlias(F, 0);
1986 setDoesNotCapture(F, 2);
1987 } else if (Name == "feof" ||
1997 Name == "fsetpos" ||
1998 Name == "flockfile" ||
1999 Name == "funlockfile" ||
2000 Name == "ftrylockfile") {
2001 if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
2004 setDoesNotCapture(F, 1);
2005 } else if (Name == "ferror") {
2006 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2009 setDoesNotCapture(F, 1);
2010 setOnlyReadsMemory(F);
2011 } else if (Name == "fputc" ||
2016 Name == "fstatvfs") {
2017 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2020 setDoesNotCapture(F, 2);
2021 } else if (Name == "fgets") {
2022 if (FTy->getNumParams() != 3 ||
2023 !FTy->getParamType(0)->isPointerTy() ||
2024 !FTy->getParamType(2)->isPointerTy())
2027 setDoesNotCapture(F, 3);
2028 } else if (Name == "fread" ||
2030 if (FTy->getNumParams() != 4 ||
2031 !FTy->getParamType(0)->isPointerTy() ||
2032 !FTy->getParamType(3)->isPointerTy())
2035 setDoesNotCapture(F, 1);
2036 setDoesNotCapture(F, 4);
2037 } else if (Name == "fputs" ||
2039 Name == "fprintf" ||
2040 Name == "fgetpos") {
2041 if (FTy->getNumParams() < 2 ||
2042 !FTy->getParamType(0)->isPointerTy() ||
2043 !FTy->getParamType(1)->isPointerTy())
2046 setDoesNotCapture(F, 1);
2047 setDoesNotCapture(F, 2);
2051 if (Name == "getc" ||
2052 Name == "getlogin_r" ||
2053 Name == "getc_unlocked") {
2054 if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
2057 setDoesNotCapture(F, 1);
2058 } else if (Name == "getenv") {
2059 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2062 setOnlyReadsMemory(F);
2063 setDoesNotCapture(F, 1);
2064 } else if (Name == "gets" ||
2065 Name == "getchar") {
2067 } else if (Name == "getitimer") {
2068 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2071 setDoesNotCapture(F, 2);
2072 } else if (Name == "getpwnam") {
2073 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2076 setDoesNotCapture(F, 1);
2080 if (Name == "ungetc") {
2081 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2084 setDoesNotCapture(F, 2);
2085 } else if (Name == "uname" ||
2087 Name == "unsetenv") {
2088 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2091 setDoesNotCapture(F, 1);
2092 } else if (Name == "utime" ||
2094 if (FTy->getNumParams() != 2 ||
2095 !FTy->getParamType(0)->isPointerTy() ||
2096 !FTy->getParamType(1)->isPointerTy())
2099 setDoesNotCapture(F, 1);
2100 setDoesNotCapture(F, 2);
2104 if (Name == "putc") {
2105 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2108 setDoesNotCapture(F, 2);
2109 } else if (Name == "puts" ||
2112 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2115 setDoesNotCapture(F, 1);
2116 } else if (Name == "pread" ||
2118 if (FTy->getNumParams() != 4 || !FTy->getParamType(1)->isPointerTy())
2120 // May throw; these are valid pthread cancellation points.
2121 setDoesNotCapture(F, 2);
2122 } else if (Name == "putchar") {
2124 } else if (Name == "popen") {
2125 if (FTy->getNumParams() != 2 ||
2126 !FTy->getReturnType()->isPointerTy() ||
2127 !FTy->getParamType(0)->isPointerTy() ||
2128 !FTy->getParamType(1)->isPointerTy())
2131 setDoesNotAlias(F, 0);
2132 setDoesNotCapture(F, 1);
2133 setDoesNotCapture(F, 2);
2134 } else if (Name == "pclose") {
2135 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2138 setDoesNotCapture(F, 1);
2142 if (Name == "vscanf") {
2143 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2146 setDoesNotCapture(F, 1);
2147 } else if (Name == "vsscanf" ||
2148 Name == "vfscanf") {
2149 if (FTy->getNumParams() != 3 ||
2150 !FTy->getParamType(1)->isPointerTy() ||
2151 !FTy->getParamType(2)->isPointerTy())
2154 setDoesNotCapture(F, 1);
2155 setDoesNotCapture(F, 2);
2156 } else if (Name == "valloc") {
2157 if (!FTy->getReturnType()->isPointerTy())
2160 setDoesNotAlias(F, 0);
2161 } else if (Name == "vprintf") {
2162 if (FTy->getNumParams() != 2 || !FTy->getParamType(0)->isPointerTy())
2165 setDoesNotCapture(F, 1);
2166 } else if (Name == "vfprintf" ||
2167 Name == "vsprintf") {
2168 if (FTy->getNumParams() != 3 ||
2169 !FTy->getParamType(0)->isPointerTy() ||
2170 !FTy->getParamType(1)->isPointerTy())
2173 setDoesNotCapture(F, 1);
2174 setDoesNotCapture(F, 2);
2175 } else if (Name == "vsnprintf") {
2176 if (FTy->getNumParams() != 4 ||
2177 !FTy->getParamType(0)->isPointerTy() ||
2178 !FTy->getParamType(2)->isPointerTy())
2181 setDoesNotCapture(F, 1);
2182 setDoesNotCapture(F, 3);
2186 if (Name == "open") {
2187 if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
2189 // May throw; "open" is a valid pthread cancellation point.
2190 setDoesNotCapture(F, 1);
2191 } else if (Name == "opendir") {
2192 if (FTy->getNumParams() != 1 ||
2193 !FTy->getReturnType()->isPointerTy() ||
2194 !FTy->getParamType(0)->isPointerTy())
2197 setDoesNotAlias(F, 0);
2198 setDoesNotCapture(F, 1);
2202 if (Name == "tmpfile") {
2203 if (!FTy->getReturnType()->isPointerTy())
2206 setDoesNotAlias(F, 0);
2207 } else if (Name == "times") {
2208 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2211 setDoesNotCapture(F, 1);
2215 if (Name == "htonl" ||
2218 setDoesNotAccessMemory(F);
2222 if (Name == "ntohl" ||
2225 setDoesNotAccessMemory(F);
2229 if (Name == "lstat") {
2230 if (FTy->getNumParams() != 2 ||
2231 !FTy->getParamType(0)->isPointerTy() ||
2232 !FTy->getParamType(1)->isPointerTy())
2235 setDoesNotCapture(F, 1);
2236 setDoesNotCapture(F, 2);
2237 } else if (Name == "lchown") {
2238 if (FTy->getNumParams() != 3 || !FTy->getParamType(0)->isPointerTy())
2241 setDoesNotCapture(F, 1);
2245 if (Name == "qsort") {
2246 if (FTy->getNumParams() != 4 || !FTy->getParamType(3)->isPointerTy())
2248 // May throw; places call through function pointer.
2249 setDoesNotCapture(F, 4);
2253 if (Name == "__strdup" ||
2254 Name == "__strndup") {
2255 if (FTy->getNumParams() < 1 ||
2256 !FTy->getReturnType()->isPointerTy() ||
2257 !FTy->getParamType(0)->isPointerTy())
2260 setDoesNotAlias(F, 0);
2261 setDoesNotCapture(F, 1);
2262 } else if (Name == "__strtok_r") {
2263 if (FTy->getNumParams() != 3 ||
2264 !FTy->getParamType(1)->isPointerTy())
2267 setDoesNotCapture(F, 2);
2268 } else if (Name == "_IO_getc") {
2269 if (FTy->getNumParams() != 1 || !FTy->getParamType(0)->isPointerTy())
2272 setDoesNotCapture(F, 1);
2273 } else if (Name == "_IO_putc") {
2274 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2277 setDoesNotCapture(F, 2);
2281 if (Name == "\1__isoc99_scanf") {
2282 if (FTy->getNumParams() < 1 ||
2283 !FTy->getParamType(0)->isPointerTy())
2286 setDoesNotCapture(F, 1);
2287 } else if (Name == "\1stat64" ||
2288 Name == "\1lstat64" ||
2289 Name == "\1statvfs64" ||
2290 Name == "\1__isoc99_sscanf") {
2291 if (FTy->getNumParams() < 1 ||
2292 !FTy->getParamType(0)->isPointerTy() ||
2293 !FTy->getParamType(1)->isPointerTy())
2296 setDoesNotCapture(F, 1);
2297 setDoesNotCapture(F, 2);
2298 } else if (Name == "\1fopen64") {
2299 if (FTy->getNumParams() != 2 ||
2300 !FTy->getReturnType()->isPointerTy() ||
2301 !FTy->getParamType(0)->isPointerTy() ||
2302 !FTy->getParamType(1)->isPointerTy())
2305 setDoesNotAlias(F, 0);
2306 setDoesNotCapture(F, 1);
2307 setDoesNotCapture(F, 2);
2308 } else if (Name == "\1fseeko64" ||
2309 Name == "\1ftello64") {
2310 if (FTy->getNumParams() == 0 || !FTy->getParamType(0)->isPointerTy())
2313 setDoesNotCapture(F, 1);
2314 } else if (Name == "\1tmpfile64") {
2315 if (!FTy->getReturnType()->isPointerTy())
2318 setDoesNotAlias(F, 0);
2319 } else if (Name == "\1fstat64" ||
2320 Name == "\1fstatvfs64") {
2321 if (FTy->getNumParams() != 2 || !FTy->getParamType(1)->isPointerTy())
2324 setDoesNotCapture(F, 2);
2325 } else if (Name == "\1open64") {
2326 if (FTy->getNumParams() < 2 || !FTy->getParamType(0)->isPointerTy())
2328 // May throw; "open" is a valid pthread cancellation point.
2329 setDoesNotCapture(F, 1);
2335 /// doInitialization - Add attributes to well-known functions.
2337 bool SimplifyLibCalls::doInitialization(Module &M) {
2339 for (Module::iterator I = M.begin(), E = M.end(); I != E; ++I) {
2341 if (F.isDeclaration() && F.hasName())
2342 inferPrototypeAttributes(F);
2348 // Additional cases that we need to add to this file:
2351 // * cbrt(expN(X)) -> expN(x/3)
2352 // * cbrt(sqrt(x)) -> pow(x,1/6)
2353 // * cbrt(sqrt(x)) -> pow(x,1/9)
2356 // * cos(-x) -> cos(x)
2359 // * exp(log(x)) -> x
2362 // * log(exp(x)) -> x
2363 // * log(x**y) -> y*log(x)
2364 // * log(exp(y)) -> y*log(e)
2365 // * log(exp2(y)) -> y*log(2)
2366 // * log(exp10(y)) -> y*log(10)
2367 // * log(sqrt(x)) -> 0.5*log(x)
2368 // * log(pow(x,y)) -> y*log(x)
2370 // lround, lroundf, lroundl:
2371 // * lround(cnst) -> cnst'
2374 // * pow(exp(x),y) -> exp(x*y)
2375 // * pow(sqrt(x),y) -> pow(x,y*0.5)
2376 // * pow(pow(x,y),z)-> pow(x,y*z)
2378 // round, roundf, roundl:
2379 // * round(cnst) -> cnst'
2382 // * signbit(cnst) -> cnst'
2383 // * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2385 // sqrt, sqrtf, sqrtl:
2386 // * sqrt(expN(x)) -> expN(x*0.5)
2387 // * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2388 // * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2391 // * stpcpy(str, "literal") ->
2392 // llvm.memcpy(str,"literal",strlen("literal")+1,1)
2395 // * tan(atan(x)) -> x
2397 // trunc, truncf, truncl:
2398 // * trunc(cnst) -> cnst'