1 //===------ SimplifyLibCalls.cpp - Library calls simplifier ---------------===//
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 is a utility pass used for testing the InstructionSimplify analysis.
11 // The analysis is applied to every instruction, and if it simplifies then the
12 // instruction is replaced by the simplification. If you are looking for a pass
13 // that performs serious instruction folding, use the instcombine pass instead.
15 //===----------------------------------------------------------------------===//
17 #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/StringMap.h"
20 #include "llvm/ADT/Triple.h"
21 #include "llvm/Analysis/ValueTracking.h"
22 #include "llvm/IR/DataLayout.h"
23 #include "llvm/IR/DiagnosticInfo.h"
24 #include "llvm/IR/Function.h"
25 #include "llvm/IR/IRBuilder.h"
26 #include "llvm/IR/IntrinsicInst.h"
27 #include "llvm/IR/Intrinsics.h"
28 #include "llvm/IR/LLVMContext.h"
29 #include "llvm/IR/Module.h"
30 #include "llvm/IR/PatternMatch.h"
31 #include "llvm/Support/Allocator.h"
32 #include "llvm/Support/CommandLine.h"
33 #include "llvm/Analysis/TargetLibraryInfo.h"
34 #include "llvm/Transforms/Utils/BuildLibCalls.h"
35 #include "llvm/Transforms/Utils/Local.h"
38 using namespace PatternMatch;
41 ColdErrorCalls("error-reporting-is-cold", cl::init(true), cl::Hidden,
42 cl::desc("Treat error-reporting calls as cold"));
45 EnableUnsafeFPShrink("enable-double-float-shrink", cl::Hidden,
47 cl::desc("Enable unsafe double to float "
48 "shrinking for math lib calls"));
51 //===----------------------------------------------------------------------===//
53 //===----------------------------------------------------------------------===//
55 static bool ignoreCallingConv(LibFunc::Func Func) {
56 return Func == LibFunc::abs || Func == LibFunc::labs ||
57 Func == LibFunc::llabs || Func == LibFunc::strlen;
60 /// isOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
61 /// value is equal or not-equal to zero.
62 static bool isOnlyUsedInZeroEqualityComparison(Value *V) {
63 for (User *U : V->users()) {
64 if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
66 if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
69 // Unknown instruction.
75 /// isOnlyUsedInEqualityComparison - Return true if it is only used in equality
76 /// comparisons with With.
77 static bool isOnlyUsedInEqualityComparison(Value *V, Value *With) {
78 for (User *U : V->users()) {
79 if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
80 if (IC->isEquality() && IC->getOperand(1) == With)
82 // Unknown instruction.
88 static bool callHasFloatingPointArgument(const CallInst *CI) {
89 for (CallInst::const_op_iterator it = CI->op_begin(), e = CI->op_end();
91 if ((*it)->getType()->isFloatingPointTy())
97 /// \brief Check whether the overloaded unary floating point function
98 /// corresponding to \a Ty is available.
99 static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
100 LibFunc::Func DoubleFn, LibFunc::Func FloatFn,
101 LibFunc::Func LongDoubleFn) {
102 switch (Ty->getTypeID()) {
103 case Type::FloatTyID:
104 return TLI->has(FloatFn);
105 case Type::DoubleTyID:
106 return TLI->has(DoubleFn);
108 return TLI->has(LongDoubleFn);
112 /// \brief Check whether we can use unsafe floating point math for
113 /// the function passed as input.
114 static bool canUseUnsafeFPMath(Function *F) {
116 // FIXME: For finer-grain optimization, we need intrinsics to have the same
117 // fast-math flag decorations that are applied to FP instructions. For now,
118 // we have to rely on the function-level unsafe-fp-math attribute to do this
119 // optimization because there's no other way to express that the call can be
121 if (F->hasFnAttribute("unsafe-fp-math")) {
122 Attribute Attr = F->getFnAttribute("unsafe-fp-math");
123 if (Attr.getValueAsString() == "true")
129 /// \brief Returns whether \p F matches the signature expected for the
130 /// string/memory copying library function \p Func.
131 /// Acceptable functions are st[rp][n]?cpy, memove, memcpy, and memset.
132 /// Their fortified (_chk) counterparts are also accepted.
133 static bool checkStringCopyLibFuncSignature(Function *F, LibFunc::Func Func) {
134 const DataLayout &DL = F->getParent()->getDataLayout();
135 FunctionType *FT = F->getFunctionType();
136 LLVMContext &Context = F->getContext();
137 Type *PCharTy = Type::getInt8PtrTy(Context);
138 Type *SizeTTy = DL.getIntPtrType(Context);
139 unsigned NumParams = FT->getNumParams();
141 // All string libfuncs return the same type as the first parameter.
142 if (FT->getReturnType() != FT->getParamType(0))
147 llvm_unreachable("Can't check signature for non-string-copy libfunc.");
148 case LibFunc::stpncpy_chk:
149 case LibFunc::strncpy_chk:
150 --NumParams; // fallthrough
151 case LibFunc::stpncpy:
152 case LibFunc::strncpy: {
153 if (NumParams != 3 || FT->getParamType(0) != FT->getParamType(1) ||
154 FT->getParamType(0) != PCharTy || !FT->getParamType(2)->isIntegerTy())
158 case LibFunc::strcpy_chk:
159 case LibFunc::stpcpy_chk:
160 --NumParams; // fallthrough
161 case LibFunc::stpcpy:
162 case LibFunc::strcpy: {
163 if (NumParams != 2 || FT->getParamType(0) != FT->getParamType(1) ||
164 FT->getParamType(0) != PCharTy)
168 case LibFunc::memmove_chk:
169 case LibFunc::memcpy_chk:
170 --NumParams; // fallthrough
171 case LibFunc::memmove:
172 case LibFunc::memcpy: {
173 if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
174 !FT->getParamType(1)->isPointerTy() || FT->getParamType(2) != SizeTTy)
178 case LibFunc::memset_chk:
179 --NumParams; // fallthrough
180 case LibFunc::memset: {
181 if (NumParams != 3 || !FT->getParamType(0)->isPointerTy() ||
182 !FT->getParamType(1)->isIntegerTy() || FT->getParamType(2) != SizeTTy)
187 // If this is a fortified libcall, the last parameter is a size_t.
188 if (NumParams == FT->getNumParams() - 1)
189 return FT->getParamType(FT->getNumParams() - 1) == SizeTTy;
193 //===----------------------------------------------------------------------===//
194 // String and Memory Library Call Optimizations
195 //===----------------------------------------------------------------------===//
197 Value *LibCallSimplifier::optimizeStrCat(CallInst *CI, IRBuilder<> &B) {
198 Function *Callee = CI->getCalledFunction();
199 // Verify the "strcat" function prototype.
200 FunctionType *FT = Callee->getFunctionType();
201 if (FT->getNumParams() != 2||
202 FT->getReturnType() != B.getInt8PtrTy() ||
203 FT->getParamType(0) != FT->getReturnType() ||
204 FT->getParamType(1) != FT->getReturnType())
207 // Extract some information from the instruction
208 Value *Dst = CI->getArgOperand(0);
209 Value *Src = CI->getArgOperand(1);
211 // See if we can get the length of the input string.
212 uint64_t Len = GetStringLength(Src);
215 --Len; // Unbias length.
217 // Handle the simple, do-nothing case: strcat(x, "") -> x
221 return emitStrLenMemCpy(Src, Dst, Len, B);
224 Value *LibCallSimplifier::emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
226 // We need to find the end of the destination string. That's where the
227 // memory is to be moved to. We just generate a call to strlen.
228 Value *DstLen = EmitStrLen(Dst, B, DL, TLI);
232 // Now that we have the destination's length, we must index into the
233 // destination's pointer to get the actual memcpy destination (end of
234 // the string .. we're concatenating).
235 Value *CpyDst = B.CreateGEP(B.getInt8Ty(), Dst, DstLen, "endptr");
237 // We have enough information to now generate the memcpy call to do the
238 // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
239 B.CreateMemCpy(CpyDst, Src,
240 ConstantInt::get(DL.getIntPtrType(Src->getContext()), Len + 1),
245 Value *LibCallSimplifier::optimizeStrNCat(CallInst *CI, IRBuilder<> &B) {
246 Function *Callee = CI->getCalledFunction();
247 // Verify the "strncat" function prototype.
248 FunctionType *FT = Callee->getFunctionType();
249 if (FT->getNumParams() != 3 || FT->getReturnType() != B.getInt8PtrTy() ||
250 FT->getParamType(0) != FT->getReturnType() ||
251 FT->getParamType(1) != FT->getReturnType() ||
252 !FT->getParamType(2)->isIntegerTy())
255 // Extract some information from the instruction
256 Value *Dst = CI->getArgOperand(0);
257 Value *Src = CI->getArgOperand(1);
260 // We don't do anything if length is not constant
261 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
262 Len = LengthArg->getZExtValue();
266 // See if we can get the length of the input string.
267 uint64_t SrcLen = GetStringLength(Src);
270 --SrcLen; // Unbias length.
272 // Handle the simple, do-nothing cases:
273 // strncat(x, "", c) -> x
274 // strncat(x, c, 0) -> x
275 if (SrcLen == 0 || Len == 0)
278 // We don't optimize this case
282 // strncat(x, s, c) -> strcat(x, s)
283 // s is constant so the strcat can be optimized further
284 return emitStrLenMemCpy(Src, Dst, SrcLen, B);
287 Value *LibCallSimplifier::optimizeStrChr(CallInst *CI, IRBuilder<> &B) {
288 Function *Callee = CI->getCalledFunction();
289 // Verify the "strchr" function prototype.
290 FunctionType *FT = Callee->getFunctionType();
291 if (FT->getNumParams() != 2 || FT->getReturnType() != B.getInt8PtrTy() ||
292 FT->getParamType(0) != FT->getReturnType() ||
293 !FT->getParamType(1)->isIntegerTy(32))
296 Value *SrcStr = CI->getArgOperand(0);
298 // If the second operand is non-constant, see if we can compute the length
299 // of the input string and turn this into memchr.
300 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
302 uint64_t Len = GetStringLength(SrcStr);
303 if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32)) // memchr needs i32.
306 return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
307 ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len),
311 // Otherwise, the character is a constant, see if the first argument is
312 // a string literal. If so, we can constant fold.
314 if (!getConstantStringInfo(SrcStr, Str)) {
315 if (CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
316 return B.CreateGEP(B.getInt8Ty(), SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
320 // Compute the offset, make sure to handle the case when we're searching for
321 // zero (a weird way to spell strlen).
322 size_t I = (0xFF & CharC->getSExtValue()) == 0
324 : Str.find(CharC->getSExtValue());
325 if (I == StringRef::npos) // Didn't find the char. strchr returns null.
326 return Constant::getNullValue(CI->getType());
328 // strchr(s+n,c) -> gep(s+n+i,c)
329 return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "strchr");
332 Value *LibCallSimplifier::optimizeStrRChr(CallInst *CI, IRBuilder<> &B) {
333 Function *Callee = CI->getCalledFunction();
334 // Verify the "strrchr" function prototype.
335 FunctionType *FT = Callee->getFunctionType();
336 if (FT->getNumParams() != 2 || FT->getReturnType() != B.getInt8PtrTy() ||
337 FT->getParamType(0) != FT->getReturnType() ||
338 !FT->getParamType(1)->isIntegerTy(32))
341 Value *SrcStr = CI->getArgOperand(0);
342 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
344 // Cannot fold anything if we're not looking for a constant.
349 if (!getConstantStringInfo(SrcStr, Str)) {
350 // strrchr(s, 0) -> strchr(s, 0)
352 return EmitStrChr(SrcStr, '\0', B, TLI);
356 // Compute the offset.
357 size_t I = (0xFF & CharC->getSExtValue()) == 0
359 : Str.rfind(CharC->getSExtValue());
360 if (I == StringRef::npos) // Didn't find the char. Return null.
361 return Constant::getNullValue(CI->getType());
363 // strrchr(s+n,c) -> gep(s+n+i,c)
364 return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "strrchr");
367 Value *LibCallSimplifier::optimizeStrCmp(CallInst *CI, IRBuilder<> &B) {
368 Function *Callee = CI->getCalledFunction();
369 // Verify the "strcmp" function prototype.
370 FunctionType *FT = Callee->getFunctionType();
371 if (FT->getNumParams() != 2 || !FT->getReturnType()->isIntegerTy(32) ||
372 FT->getParamType(0) != FT->getParamType(1) ||
373 FT->getParamType(0) != B.getInt8PtrTy())
376 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
377 if (Str1P == Str2P) // strcmp(x,x) -> 0
378 return ConstantInt::get(CI->getType(), 0);
380 StringRef Str1, Str2;
381 bool HasStr1 = getConstantStringInfo(Str1P, Str1);
382 bool HasStr2 = getConstantStringInfo(Str2P, Str2);
384 // strcmp(x, y) -> cnst (if both x and y are constant strings)
385 if (HasStr1 && HasStr2)
386 return ConstantInt::get(CI->getType(), Str1.compare(Str2));
388 if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x
390 B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType()));
392 if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
393 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
395 // strcmp(P, "x") -> memcmp(P, "x", 2)
396 uint64_t Len1 = GetStringLength(Str1P);
397 uint64_t Len2 = GetStringLength(Str2P);
399 return EmitMemCmp(Str1P, Str2P,
400 ConstantInt::get(DL.getIntPtrType(CI->getContext()),
401 std::min(Len1, Len2)),
408 Value *LibCallSimplifier::optimizeStrNCmp(CallInst *CI, IRBuilder<> &B) {
409 Function *Callee = CI->getCalledFunction();
410 // Verify the "strncmp" function prototype.
411 FunctionType *FT = Callee->getFunctionType();
412 if (FT->getNumParams() != 3 || !FT->getReturnType()->isIntegerTy(32) ||
413 FT->getParamType(0) != FT->getParamType(1) ||
414 FT->getParamType(0) != B.getInt8PtrTy() ||
415 !FT->getParamType(2)->isIntegerTy())
418 Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
419 if (Str1P == Str2P) // strncmp(x,x,n) -> 0
420 return ConstantInt::get(CI->getType(), 0);
422 // Get the length argument if it is constant.
424 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
425 Length = LengthArg->getZExtValue();
429 if (Length == 0) // strncmp(x,y,0) -> 0
430 return ConstantInt::get(CI->getType(), 0);
432 if (Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
433 return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, DL, TLI);
435 StringRef Str1, Str2;
436 bool HasStr1 = getConstantStringInfo(Str1P, Str1);
437 bool HasStr2 = getConstantStringInfo(Str2P, Str2);
439 // strncmp(x, y) -> cnst (if both x and y are constant strings)
440 if (HasStr1 && HasStr2) {
441 StringRef SubStr1 = Str1.substr(0, Length);
442 StringRef SubStr2 = Str2.substr(0, Length);
443 return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2));
446 if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> -*x
448 B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType()));
450 if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
451 return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
456 Value *LibCallSimplifier::optimizeStrCpy(CallInst *CI, IRBuilder<> &B) {
457 Function *Callee = CI->getCalledFunction();
459 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strcpy))
462 Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
463 if (Dst == Src) // strcpy(x,x) -> x
466 // See if we can get the length of the input string.
467 uint64_t Len = GetStringLength(Src);
471 // We have enough information to now generate the memcpy call to do the
472 // copy for us. Make a memcpy to copy the nul byte with align = 1.
473 B.CreateMemCpy(Dst, Src,
474 ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len), 1);
478 Value *LibCallSimplifier::optimizeStpCpy(CallInst *CI, IRBuilder<> &B) {
479 Function *Callee = CI->getCalledFunction();
480 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::stpcpy))
483 Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
484 if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
485 Value *StrLen = EmitStrLen(Src, B, DL, TLI);
486 return StrLen ? B.CreateInBoundsGEP(B.getInt8Ty(), Dst, StrLen) : nullptr;
489 // See if we can get the length of the input string.
490 uint64_t Len = GetStringLength(Src);
494 Type *PT = Callee->getFunctionType()->getParamType(0);
495 Value *LenV = ConstantInt::get(DL.getIntPtrType(PT), Len);
497 B.CreateGEP(B.getInt8Ty(), Dst, ConstantInt::get(DL.getIntPtrType(PT), Len - 1));
499 // We have enough information to now generate the memcpy call to do the
500 // copy for us. Make a memcpy to copy the nul byte with align = 1.
501 B.CreateMemCpy(Dst, Src, LenV, 1);
505 Value *LibCallSimplifier::optimizeStrNCpy(CallInst *CI, IRBuilder<> &B) {
506 Function *Callee = CI->getCalledFunction();
507 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::strncpy))
510 Value *Dst = CI->getArgOperand(0);
511 Value *Src = CI->getArgOperand(1);
512 Value *LenOp = CI->getArgOperand(2);
514 // See if we can get the length of the input string.
515 uint64_t SrcLen = GetStringLength(Src);
521 // strncpy(x, "", y) -> memset(x, '\0', y, 1)
522 B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
527 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
528 Len = LengthArg->getZExtValue();
533 return Dst; // strncpy(x, y, 0) -> x
535 // Let strncpy handle the zero padding
536 if (Len > SrcLen + 1)
539 Type *PT = Callee->getFunctionType()->getParamType(0);
540 // strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
541 B.CreateMemCpy(Dst, Src, ConstantInt::get(DL.getIntPtrType(PT), Len), 1);
546 Value *LibCallSimplifier::optimizeStrLen(CallInst *CI, IRBuilder<> &B) {
547 Function *Callee = CI->getCalledFunction();
548 FunctionType *FT = Callee->getFunctionType();
549 if (FT->getNumParams() != 1 || FT->getParamType(0) != B.getInt8PtrTy() ||
550 !FT->getReturnType()->isIntegerTy())
553 Value *Src = CI->getArgOperand(0);
555 // Constant folding: strlen("xyz") -> 3
556 if (uint64_t Len = GetStringLength(Src))
557 return ConstantInt::get(CI->getType(), Len - 1);
559 // strlen(x?"foo":"bars") --> x ? 3 : 4
560 if (SelectInst *SI = dyn_cast<SelectInst>(Src)) {
561 uint64_t LenTrue = GetStringLength(SI->getTrueValue());
562 uint64_t LenFalse = GetStringLength(SI->getFalseValue());
563 if (LenTrue && LenFalse) {
564 Function *Caller = CI->getParent()->getParent();
565 emitOptimizationRemark(CI->getContext(), "simplify-libcalls", *Caller,
567 "folded strlen(select) to select of constants");
568 return B.CreateSelect(SI->getCondition(),
569 ConstantInt::get(CI->getType(), LenTrue - 1),
570 ConstantInt::get(CI->getType(), LenFalse - 1));
574 // strlen(x) != 0 --> *x != 0
575 // strlen(x) == 0 --> *x == 0
576 if (isOnlyUsedInZeroEqualityComparison(CI))
577 return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
582 Value *LibCallSimplifier::optimizeStrPBrk(CallInst *CI, IRBuilder<> &B) {
583 Function *Callee = CI->getCalledFunction();
584 FunctionType *FT = Callee->getFunctionType();
585 if (FT->getNumParams() != 2 || FT->getParamType(0) != B.getInt8PtrTy() ||
586 FT->getParamType(1) != FT->getParamType(0) ||
587 FT->getReturnType() != FT->getParamType(0))
591 bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
592 bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
594 // strpbrk(s, "") -> nullptr
595 // strpbrk("", s) -> nullptr
596 if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
597 return Constant::getNullValue(CI->getType());
600 if (HasS1 && HasS2) {
601 size_t I = S1.find_first_of(S2);
602 if (I == StringRef::npos) // No match.
603 return Constant::getNullValue(CI->getType());
605 return B.CreateGEP(B.getInt8Ty(), CI->getArgOperand(0), B.getInt64(I), "strpbrk");
608 // strpbrk(s, "a") -> strchr(s, 'a')
609 if (HasS2 && S2.size() == 1)
610 return EmitStrChr(CI->getArgOperand(0), S2[0], B, TLI);
615 Value *LibCallSimplifier::optimizeStrTo(CallInst *CI, IRBuilder<> &B) {
616 Function *Callee = CI->getCalledFunction();
617 FunctionType *FT = Callee->getFunctionType();
618 if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
619 !FT->getParamType(0)->isPointerTy() ||
620 !FT->getParamType(1)->isPointerTy())
623 Value *EndPtr = CI->getArgOperand(1);
624 if (isa<ConstantPointerNull>(EndPtr)) {
625 // With a null EndPtr, this function won't capture the main argument.
626 // It would be readonly too, except that it still may write to errno.
627 CI->addAttribute(1, Attribute::NoCapture);
633 Value *LibCallSimplifier::optimizeStrSpn(CallInst *CI, IRBuilder<> &B) {
634 Function *Callee = CI->getCalledFunction();
635 FunctionType *FT = Callee->getFunctionType();
636 if (FT->getNumParams() != 2 || 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 // strspn(s, "") -> 0
646 // strspn("", s) -> 0
647 if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
648 return Constant::getNullValue(CI->getType());
651 if (HasS1 && HasS2) {
652 size_t Pos = S1.find_first_not_of(S2);
653 if (Pos == StringRef::npos)
655 return ConstantInt::get(CI->getType(), Pos);
661 Value *LibCallSimplifier::optimizeStrCSpn(CallInst *CI, IRBuilder<> &B) {
662 Function *Callee = CI->getCalledFunction();
663 FunctionType *FT = Callee->getFunctionType();
664 if (FT->getNumParams() != 2 || FT->getParamType(0) != B.getInt8PtrTy() ||
665 FT->getParamType(1) != FT->getParamType(0) ||
666 !FT->getReturnType()->isIntegerTy())
670 bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
671 bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
673 // strcspn("", s) -> 0
674 if (HasS1 && S1.empty())
675 return Constant::getNullValue(CI->getType());
678 if (HasS1 && HasS2) {
679 size_t Pos = S1.find_first_of(S2);
680 if (Pos == StringRef::npos)
682 return ConstantInt::get(CI->getType(), Pos);
685 // strcspn(s, "") -> strlen(s)
686 if (HasS2 && S2.empty())
687 return EmitStrLen(CI->getArgOperand(0), B, DL, TLI);
692 Value *LibCallSimplifier::optimizeStrStr(CallInst *CI, IRBuilder<> &B) {
693 Function *Callee = CI->getCalledFunction();
694 FunctionType *FT = Callee->getFunctionType();
695 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
696 !FT->getParamType(1)->isPointerTy() ||
697 !FT->getReturnType()->isPointerTy())
700 // fold strstr(x, x) -> x.
701 if (CI->getArgOperand(0) == CI->getArgOperand(1))
702 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
704 // fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
705 if (isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
706 Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, DL, TLI);
709 Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
713 for (auto UI = CI->user_begin(), UE = CI->user_end(); UI != UE;) {
714 ICmpInst *Old = cast<ICmpInst>(*UI++);
716 B.CreateICmp(Old->getPredicate(), StrNCmp,
717 ConstantInt::getNullValue(StrNCmp->getType()), "cmp");
718 replaceAllUsesWith(Old, Cmp);
723 // See if either input string is a constant string.
724 StringRef SearchStr, ToFindStr;
725 bool HasStr1 = getConstantStringInfo(CI->getArgOperand(0), SearchStr);
726 bool HasStr2 = getConstantStringInfo(CI->getArgOperand(1), ToFindStr);
728 // fold strstr(x, "") -> x.
729 if (HasStr2 && ToFindStr.empty())
730 return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
732 // If both strings are known, constant fold it.
733 if (HasStr1 && HasStr2) {
734 size_t Offset = SearchStr.find(ToFindStr);
736 if (Offset == StringRef::npos) // strstr("foo", "bar") -> null
737 return Constant::getNullValue(CI->getType());
739 // strstr("abcd", "bc") -> gep((char*)"abcd", 1)
740 Value *Result = CastToCStr(CI->getArgOperand(0), B);
741 Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
742 return B.CreateBitCast(Result, CI->getType());
745 // fold strstr(x, "y") -> strchr(x, 'y').
746 if (HasStr2 && ToFindStr.size() == 1) {
747 Value *StrChr = EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, TLI);
748 return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : nullptr;
753 Value *LibCallSimplifier::optimizeMemChr(CallInst *CI, IRBuilder<> &B) {
754 Function *Callee = CI->getCalledFunction();
755 FunctionType *FT = Callee->getFunctionType();
756 if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
757 !FT->getParamType(1)->isIntegerTy(32) ||
758 !FT->getParamType(2)->isIntegerTy() ||
759 !FT->getReturnType()->isPointerTy())
762 Value *SrcStr = CI->getArgOperand(0);
763 ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
764 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
766 // memchr(x, y, 0) -> null
767 if (LenC && LenC->isNullValue())
768 return Constant::getNullValue(CI->getType());
770 // From now on we need at least constant length and string.
772 if (!LenC || !getConstantStringInfo(SrcStr, Str, 0, /*TrimAtNul=*/false))
775 // Truncate the string to LenC. If Str is smaller than LenC we will still only
776 // scan the string, as reading past the end of it is undefined and we can just
777 // return null if we don't find the char.
778 Str = Str.substr(0, LenC->getZExtValue());
780 // If the char is variable but the input str and length are not we can turn
781 // this memchr call into a simple bit field test. Of course this only works
782 // when the return value is only checked against null.
784 // It would be really nice to reuse switch lowering here but we can't change
785 // the CFG at this point.
787 // memchr("\r\n", C, 2) != nullptr -> (C & ((1 << '\r') | (1 << '\n'))) != 0
788 // after bounds check.
789 if (!CharC && !Str.empty() && isOnlyUsedInZeroEqualityComparison(CI)) {
791 *std::max_element(reinterpret_cast<const unsigned char *>(Str.begin()),
792 reinterpret_cast<const unsigned char *>(Str.end()));
794 // Make sure the bit field we're about to create fits in a register on the
796 // FIXME: On a 64 bit architecture this prevents us from using the
797 // interesting range of alpha ascii chars. We could do better by emitting
798 // two bitfields or shifting the range by 64 if no lower chars are used.
799 if (!DL.fitsInLegalInteger(Max + 1))
802 // For the bit field use a power-of-2 type with at least 8 bits to avoid
803 // creating unnecessary illegal types.
804 unsigned char Width = NextPowerOf2(std::max((unsigned char)7, Max));
806 // Now build the bit field.
807 APInt Bitfield(Width, 0);
809 Bitfield.setBit((unsigned char)C);
810 Value *BitfieldC = B.getInt(Bitfield);
812 // First check that the bit field access is within bounds.
813 Value *C = B.CreateZExtOrTrunc(CI->getArgOperand(1), BitfieldC->getType());
814 Value *Bounds = B.CreateICmp(ICmpInst::ICMP_ULT, C, B.getIntN(Width, Width),
817 // Create code that checks if the given bit is set in the field.
818 Value *Shl = B.CreateShl(B.getIntN(Width, 1ULL), C);
819 Value *Bits = B.CreateIsNotNull(B.CreateAnd(Shl, BitfieldC), "memchr.bits");
821 // Finally merge both checks and cast to pointer type. The inttoptr
822 // implicitly zexts the i1 to intptr type.
823 return B.CreateIntToPtr(B.CreateAnd(Bounds, Bits, "memchr"), CI->getType());
826 // Check if all arguments are constants. If so, we can constant fold.
830 // Compute the offset.
831 size_t I = Str.find(CharC->getSExtValue() & 0xFF);
832 if (I == StringRef::npos) // Didn't find the char. memchr returns null.
833 return Constant::getNullValue(CI->getType());
835 // memchr(s+n,c,l) -> gep(s+n+i,c)
836 return B.CreateGEP(B.getInt8Ty(), SrcStr, B.getInt64(I), "memchr");
839 Value *LibCallSimplifier::optimizeMemCmp(CallInst *CI, IRBuilder<> &B) {
840 Function *Callee = CI->getCalledFunction();
841 FunctionType *FT = Callee->getFunctionType();
842 if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
843 !FT->getParamType(1)->isPointerTy() ||
844 !FT->getReturnType()->isIntegerTy(32))
847 Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
849 if (LHS == RHS) // memcmp(s,s,x) -> 0
850 return Constant::getNullValue(CI->getType());
852 // Make sure we have a constant length.
853 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
856 uint64_t Len = LenC->getZExtValue();
858 if (Len == 0) // memcmp(s1,s2,0) -> 0
859 return Constant::getNullValue(CI->getType());
861 // memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
863 Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
864 CI->getType(), "lhsv");
865 Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
866 CI->getType(), "rhsv");
867 return B.CreateSub(LHSV, RHSV, "chardiff");
870 // memcmp(S1,S2,N/8)==0 -> (*(intN_t*)S1 != *(intN_t*)S2)==0
871 if (DL.isLegalInteger(Len * 8) && isOnlyUsedInZeroEqualityComparison(CI)) {
873 IntegerType *IntType = IntegerType::get(CI->getContext(), Len * 8);
874 unsigned PrefAlignment = DL.getPrefTypeAlignment(IntType);
876 if (getKnownAlignment(LHS, DL, CI) >= PrefAlignment &&
877 getKnownAlignment(RHS, DL, CI) >= PrefAlignment) {
880 IntType->getPointerTo(LHS->getType()->getPointerAddressSpace());
882 IntType->getPointerTo(RHS->getType()->getPointerAddressSpace());
884 Value *LHSV = B.CreateLoad(B.CreateBitCast(LHS, LHSPtrTy, "lhsc"), "lhsv");
885 Value *RHSV = B.CreateLoad(B.CreateBitCast(RHS, RHSPtrTy, "rhsc"), "rhsv");
887 return B.CreateZExt(B.CreateICmpNE(LHSV, RHSV), CI->getType(), "memcmp");
891 // Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
892 StringRef LHSStr, RHSStr;
893 if (getConstantStringInfo(LHS, LHSStr) &&
894 getConstantStringInfo(RHS, RHSStr)) {
895 // Make sure we're not reading out-of-bounds memory.
896 if (Len > LHSStr.size() || Len > RHSStr.size())
898 // Fold the memcmp and normalize the result. This way we get consistent
899 // results across multiple platforms.
901 int Cmp = memcmp(LHSStr.data(), RHSStr.data(), Len);
906 return ConstantInt::get(CI->getType(), Ret);
912 Value *LibCallSimplifier::optimizeMemCpy(CallInst *CI, IRBuilder<> &B) {
913 Function *Callee = CI->getCalledFunction();
915 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy))
918 // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
919 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
920 CI->getArgOperand(2), 1);
921 return CI->getArgOperand(0);
924 Value *LibCallSimplifier::optimizeMemMove(CallInst *CI, IRBuilder<> &B) {
925 Function *Callee = CI->getCalledFunction();
927 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove))
930 // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
931 B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
932 CI->getArgOperand(2), 1);
933 return CI->getArgOperand(0);
936 Value *LibCallSimplifier::optimizeMemSet(CallInst *CI, IRBuilder<> &B) {
937 Function *Callee = CI->getCalledFunction();
939 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset))
942 // memset(p, v, n) -> llvm.memset(p, v, n, 1)
943 Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
944 B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
945 return CI->getArgOperand(0);
948 //===----------------------------------------------------------------------===//
949 // Math Library Optimizations
950 //===----------------------------------------------------------------------===//
952 /// Return a variant of Val with float type.
953 /// Currently this works in two cases: If Val is an FPExtension of a float
954 /// value to something bigger, simply return the operand.
955 /// If Val is a ConstantFP but can be converted to a float ConstantFP without
956 /// loss of precision do so.
957 static Value *valueHasFloatPrecision(Value *Val) {
958 if (FPExtInst *Cast = dyn_cast<FPExtInst>(Val)) {
959 Value *Op = Cast->getOperand(0);
960 if (Op->getType()->isFloatTy())
963 if (ConstantFP *Const = dyn_cast<ConstantFP>(Val)) {
964 APFloat F = Const->getValueAPF();
966 (void)F.convert(APFloat::IEEEsingle, APFloat::rmNearestTiesToEven,
969 return ConstantFP::get(Const->getContext(), F);
974 //===----------------------------------------------------------------------===//
975 // Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
977 Value *LibCallSimplifier::optimizeUnaryDoubleFP(CallInst *CI, IRBuilder<> &B,
979 Function *Callee = CI->getCalledFunction();
980 FunctionType *FT = Callee->getFunctionType();
981 if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
982 !FT->getParamType(0)->isDoubleTy())
986 // Check if all the uses for function like 'sin' are converted to float.
987 for (User *U : CI->users()) {
988 FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
989 if (!Cast || !Cast->getType()->isFloatTy())
994 // If this is something like 'floor((double)floatval)', convert to floorf.
995 Value *V = valueHasFloatPrecision(CI->getArgOperand(0));
999 // floor((double)floatval) -> (double)floorf(floatval)
1000 if (Callee->isIntrinsic()) {
1001 Module *M = CI->getParent()->getParent()->getParent();
1002 Intrinsic::ID IID = Callee->getIntrinsicID();
1003 Function *F = Intrinsic::getDeclaration(M, IID, B.getFloatTy());
1004 V = B.CreateCall(F, V);
1006 // The call is a library call rather than an intrinsic.
1007 V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
1010 return B.CreateFPExt(V, B.getDoubleTy());
1013 // Double -> Float Shrinking Optimizations for Binary Functions like 'fmin/fmax'
1014 Value *LibCallSimplifier::optimizeBinaryDoubleFP(CallInst *CI, IRBuilder<> &B) {
1015 Function *Callee = CI->getCalledFunction();
1016 FunctionType *FT = Callee->getFunctionType();
1017 // Just make sure this has 2 arguments of the same FP type, which match the
1019 if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
1020 FT->getParamType(0) != FT->getParamType(1) ||
1021 !FT->getParamType(0)->isFloatingPointTy())
1024 // If this is something like 'fmin((double)floatval1, (double)floatval2)',
1025 // or fmin(1.0, (double)floatval), then we convert it to fminf.
1026 Value *V1 = valueHasFloatPrecision(CI->getArgOperand(0));
1029 Value *V2 = valueHasFloatPrecision(CI->getArgOperand(1));
1033 // fmin((double)floatval1, (double)floatval2)
1034 // -> (double)fminf(floatval1, floatval2)
1035 // TODO: Handle intrinsics in the same way as in optimizeUnaryDoubleFP().
1036 Value *V = EmitBinaryFloatFnCall(V1, V2, Callee->getName(), B,
1037 Callee->getAttributes());
1038 return B.CreateFPExt(V, B.getDoubleTy());
1041 Value *LibCallSimplifier::optimizeCos(CallInst *CI, IRBuilder<> &B) {
1042 Function *Callee = CI->getCalledFunction();
1043 Value *Ret = nullptr;
1044 StringRef Name = Callee->getName();
1045 if (UnsafeFPShrink && Name == "cos" && hasFloatVersion(Name))
1046 Ret = optimizeUnaryDoubleFP(CI, B, true);
1048 FunctionType *FT = Callee->getFunctionType();
1049 // Just make sure this has 1 argument of FP type, which matches the
1051 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1052 !FT->getParamType(0)->isFloatingPointTy())
1055 // cos(-x) -> cos(x)
1056 Value *Op1 = CI->getArgOperand(0);
1057 if (BinaryOperator::isFNeg(Op1)) {
1058 BinaryOperator *BinExpr = cast<BinaryOperator>(Op1);
1059 return B.CreateCall(Callee, BinExpr->getOperand(1), "cos");
1064 Value *LibCallSimplifier::optimizePow(CallInst *CI, IRBuilder<> &B) {
1065 Function *Callee = CI->getCalledFunction();
1066 Value *Ret = nullptr;
1067 StringRef Name = Callee->getName();
1068 if (UnsafeFPShrink && Name == "pow" && hasFloatVersion(Name))
1069 Ret = optimizeUnaryDoubleFP(CI, B, true);
1071 FunctionType *FT = Callee->getFunctionType();
1072 // Just make sure this has 2 arguments of the same FP type, which match the
1074 if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
1075 FT->getParamType(0) != FT->getParamType(1) ||
1076 !FT->getParamType(0)->isFloatingPointTy())
1079 Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
1080 if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
1081 // pow(1.0, x) -> 1.0
1082 if (Op1C->isExactlyValue(1.0))
1084 // pow(2.0, x) -> exp2(x)
1085 if (Op1C->isExactlyValue(2.0) &&
1086 hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp2, LibFunc::exp2f,
1088 return EmitUnaryFloatFnCall(Op2, TLI->getName(LibFunc::exp2), B,
1089 Callee->getAttributes());
1090 // pow(10.0, x) -> exp10(x)
1091 if (Op1C->isExactlyValue(10.0) &&
1092 hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp10, LibFunc::exp10f,
1094 return EmitUnaryFloatFnCall(Op2, TLI->getName(LibFunc::exp10), B,
1095 Callee->getAttributes());
1098 bool unsafeFPMath = canUseUnsafeFPMath(CI->getParent()->getParent());
1100 // pow(exp(x), y) -> exp(x*y)
1101 // pow(exp2(x), y) -> exp2(x * y)
1102 // We enable these only under fast-math. Besides rounding
1103 // differences the transformation changes overflow and
1104 // underflow behavior quite dramatically.
1105 // Example: x = 1000, y = 0.001.
1106 // pow(exp(x), y) = pow(inf, 0.001) = inf, whereas exp(x*y) = exp(1).
1108 if (auto *OpC = dyn_cast<CallInst>(Op1)) {
1109 IRBuilder<>::FastMathFlagGuard Guard(B);
1111 FMF.setUnsafeAlgebra();
1112 B.SetFastMathFlags(FMF);
1115 Function *Callee = OpC->getCalledFunction();
1116 StringRef FuncName = Callee->getName();
1118 if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func) &&
1119 (Func == LibFunc::exp || Func == LibFunc::exp2))
1120 return EmitUnaryFloatFnCall(
1121 B.CreateFMul(OpC->getArgOperand(0), Op2, "mul"), FuncName, B,
1122 Callee->getAttributes());
1126 ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
1130 if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
1131 return ConstantFP::get(CI->getType(), 1.0);
1133 if (Op2C->isExactlyValue(0.5) &&
1134 hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::sqrt, LibFunc::sqrtf,
1136 hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::fabs, LibFunc::fabsf,
1139 // In -ffast-math, pow(x, 0.5) -> sqrt(x).
1141 return EmitUnaryFloatFnCall(Op1, TLI->getName(LibFunc::sqrt), B,
1142 Callee->getAttributes());
1144 // Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
1145 // This is faster than calling pow, and still handles negative zero
1146 // and negative infinity correctly.
1147 // TODO: In finite-only mode, this could be just fabs(sqrt(x)).
1148 Value *Inf = ConstantFP::getInfinity(CI->getType());
1149 Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
1150 Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B, Callee->getAttributes());
1152 EmitUnaryFloatFnCall(Sqrt, "fabs", B, Callee->getAttributes());
1153 Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf);
1154 Value *Sel = B.CreateSelect(FCmp, Inf, FAbs);
1158 if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
1160 if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
1161 return B.CreateFMul(Op1, Op1, "pow2");
1162 if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
1163 return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), Op1, "powrecip");
1167 Value *LibCallSimplifier::optimizeExp2(CallInst *CI, IRBuilder<> &B) {
1168 Function *Callee = CI->getCalledFunction();
1169 Function *Caller = CI->getParent()->getParent();
1170 Value *Ret = nullptr;
1171 StringRef Name = Callee->getName();
1172 if (UnsafeFPShrink && Name == "exp2" && hasFloatVersion(Name))
1173 Ret = optimizeUnaryDoubleFP(CI, B, true);
1175 FunctionType *FT = Callee->getFunctionType();
1176 // Just make sure this has 1 argument of FP type, which matches the
1178 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1179 !FT->getParamType(0)->isFloatingPointTy())
1182 Value *Op = CI->getArgOperand(0);
1183 // Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32
1184 // Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32
1185 LibFunc::Func LdExp = LibFunc::ldexpl;
1186 if (Op->getType()->isFloatTy())
1187 LdExp = LibFunc::ldexpf;
1188 else if (Op->getType()->isDoubleTy())
1189 LdExp = LibFunc::ldexp;
1191 if (TLI->has(LdExp)) {
1192 Value *LdExpArg = nullptr;
1193 if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
1194 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
1195 LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty());
1196 } else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
1197 if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
1198 LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty());
1202 Constant *One = ConstantFP::get(CI->getContext(), APFloat(1.0f));
1203 if (!Op->getType()->isFloatTy())
1204 One = ConstantExpr::getFPExtend(One, Op->getType());
1206 Module *M = Caller->getParent();
1208 M->getOrInsertFunction(TLI->getName(LdExp), Op->getType(),
1209 Op->getType(), B.getInt32Ty(), nullptr);
1210 CallInst *CI = B.CreateCall(Callee, {One, LdExpArg});
1211 if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
1212 CI->setCallingConv(F->getCallingConv());
1220 Value *LibCallSimplifier::optimizeFabs(CallInst *CI, IRBuilder<> &B) {
1221 Function *Callee = CI->getCalledFunction();
1222 Value *Ret = nullptr;
1223 StringRef Name = Callee->getName();
1224 if (Name == "fabs" && hasFloatVersion(Name))
1225 Ret = optimizeUnaryDoubleFP(CI, B, false);
1227 FunctionType *FT = Callee->getFunctionType();
1228 // Make sure this has 1 argument of FP type which matches the result type.
1229 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1230 !FT->getParamType(0)->isFloatingPointTy())
1233 Value *Op = CI->getArgOperand(0);
1234 if (Instruction *I = dyn_cast<Instruction>(Op)) {
1235 // Fold fabs(x * x) -> x * x; any squared FP value must already be positive.
1236 if (I->getOpcode() == Instruction::FMul)
1237 if (I->getOperand(0) == I->getOperand(1))
1243 Value *LibCallSimplifier::optimizeFMinFMax(CallInst *CI, IRBuilder<> &B) {
1244 // If we can shrink the call to a float function rather than a double
1245 // function, do that first.
1246 Function *Callee = CI->getCalledFunction();
1247 StringRef Name = Callee->getName();
1248 if ((Name == "fmin" && hasFloatVersion(Name)) ||
1249 (Name == "fmax" && hasFloatVersion(Name))) {
1250 Value *Ret = optimizeBinaryDoubleFP(CI, B);
1255 // Make sure this has 2 arguments of FP type which match the result type.
1256 FunctionType *FT = Callee->getFunctionType();
1257 if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
1258 FT->getParamType(0) != FT->getParamType(1) ||
1259 !FT->getParamType(0)->isFloatingPointTy())
1262 IRBuilder<>::FastMathFlagGuard Guard(B);
1264 Function *F = CI->getParent()->getParent();
1265 if (canUseUnsafeFPMath(F)) {
1266 // Unsafe algebra sets all fast-math-flags to true.
1267 FMF.setUnsafeAlgebra();
1269 // At a minimum, no-nans-fp-math must be true.
1270 Attribute Attr = F->getFnAttribute("no-nans-fp-math");
1271 if (Attr.getValueAsString() != "true")
1273 // No-signed-zeros is implied by the definitions of fmax/fmin themselves:
1274 // "Ideally, fmax would be sensitive to the sign of zero, for example
1275 // fmax(-0. 0, +0. 0) would return +0; however, implementation in software
1276 // might be impractical."
1277 FMF.setNoSignedZeros();
1280 B.SetFastMathFlags(FMF);
1282 // We have a relaxed floating-point environment. We can ignore NaN-handling
1283 // and transform to a compare and select. We do not have to consider errno or
1284 // exceptions, because fmin/fmax do not have those.
1285 Value *Op0 = CI->getArgOperand(0);
1286 Value *Op1 = CI->getArgOperand(1);
1287 Value *Cmp = Callee->getName().startswith("fmin") ?
1288 B.CreateFCmpOLT(Op0, Op1) : B.CreateFCmpOGT(Op0, Op1);
1289 return B.CreateSelect(Cmp, Op0, Op1);
1292 Value *LibCallSimplifier::optimizeSqrt(CallInst *CI, IRBuilder<> &B) {
1293 Function *Callee = CI->getCalledFunction();
1295 Value *Ret = nullptr;
1296 if (TLI->has(LibFunc::sqrtf) && (Callee->getName() == "sqrt" ||
1297 Callee->getIntrinsicID() == Intrinsic::sqrt))
1298 Ret = optimizeUnaryDoubleFP(CI, B, true);
1299 if (!canUseUnsafeFPMath(CI->getParent()->getParent()))
1302 Value *Op = CI->getArgOperand(0);
1303 if (Instruction *I = dyn_cast<Instruction>(Op)) {
1304 if (I->getOpcode() == Instruction::FMul && I->hasUnsafeAlgebra()) {
1305 // We're looking for a repeated factor in a multiplication tree,
1306 // so we can do this fold: sqrt(x * x) -> fabs(x);
1307 // or this fold: sqrt(x * x * y) -> fabs(x) * sqrt(y).
1308 Value *Op0 = I->getOperand(0);
1309 Value *Op1 = I->getOperand(1);
1310 Value *RepeatOp = nullptr;
1311 Value *OtherOp = nullptr;
1313 // Simple match: the operands of the multiply are identical.
1316 // Look for a more complicated pattern: one of the operands is itself
1317 // a multiply, so search for a common factor in that multiply.
1318 // Note: We don't bother looking any deeper than this first level or for
1319 // variations of this pattern because instcombine's visitFMUL and/or the
1320 // reassociation pass should give us this form.
1321 Value *OtherMul0, *OtherMul1;
1322 if (match(Op0, m_FMul(m_Value(OtherMul0), m_Value(OtherMul1)))) {
1323 // Pattern: sqrt((x * y) * z)
1324 if (OtherMul0 == OtherMul1) {
1325 // Matched: sqrt((x * x) * z)
1326 RepeatOp = OtherMul0;
1332 // Fast math flags for any created instructions should match the sqrt
1334 // FIXME: We're not checking the sqrt because it doesn't have
1335 // fast-math-flags (see earlier comment).
1336 IRBuilder<>::FastMathFlagGuard Guard(B);
1337 B.SetFastMathFlags(I->getFastMathFlags());
1338 // If we found a repeated factor, hoist it out of the square root and
1339 // replace it with the fabs of that factor.
1340 Module *M = Callee->getParent();
1341 Type *ArgType = Op->getType();
1342 Value *Fabs = Intrinsic::getDeclaration(M, Intrinsic::fabs, ArgType);
1343 Value *FabsCall = B.CreateCall(Fabs, RepeatOp, "fabs");
1345 // If we found a non-repeated factor, we still need to get its square
1346 // root. We then multiply that by the value that was simplified out
1347 // of the square root calculation.
1348 Value *Sqrt = Intrinsic::getDeclaration(M, Intrinsic::sqrt, ArgType);
1349 Value *SqrtCall = B.CreateCall(Sqrt, OtherOp, "sqrt");
1350 return B.CreateFMul(FabsCall, SqrtCall);
1359 Value *LibCallSimplifier::optimizeTan(CallInst *CI, IRBuilder<> &B) {
1360 Function *Callee = CI->getCalledFunction();
1361 Value *Ret = nullptr;
1362 StringRef Name = Callee->getName();
1363 if (UnsafeFPShrink && Name == "tan" && hasFloatVersion(Name))
1364 Ret = optimizeUnaryDoubleFP(CI, B, true);
1365 FunctionType *FT = Callee->getFunctionType();
1367 // Just make sure this has 1 argument of FP type, which matches the
1369 if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
1370 !FT->getParamType(0)->isFloatingPointTy())
1373 if (!canUseUnsafeFPMath(CI->getParent()->getParent()))
1375 Value *Op1 = CI->getArgOperand(0);
1376 auto *OpC = dyn_cast<CallInst>(Op1);
1380 // tan(atan(x)) -> x
1381 // tanf(atanf(x)) -> x
1382 // tanl(atanl(x)) -> x
1384 Function *F = OpC->getCalledFunction();
1385 StringRef FuncName = F->getName();
1386 if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func) &&
1387 ((Func == LibFunc::atan && Callee->getName() == "tan") ||
1388 (Func == LibFunc::atanf && Callee->getName() == "tanf") ||
1389 (Func == LibFunc::atanl && Callee->getName() == "tanl")))
1390 Ret = OpC->getArgOperand(0);
1394 static bool isTrigLibCall(CallInst *CI);
1395 static void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
1396 bool UseFloat, Value *&Sin, Value *&Cos,
1399 Value *LibCallSimplifier::optimizeSinCosPi(CallInst *CI, IRBuilder<> &B) {
1401 // Make sure the prototype is as expected, otherwise the rest of the
1402 // function is probably invalid and likely to abort.
1403 if (!isTrigLibCall(CI))
1406 Value *Arg = CI->getArgOperand(0);
1407 SmallVector<CallInst *, 1> SinCalls;
1408 SmallVector<CallInst *, 1> CosCalls;
1409 SmallVector<CallInst *, 1> SinCosCalls;
1411 bool IsFloat = Arg->getType()->isFloatTy();
1413 // Look for all compatible sinpi, cospi and sincospi calls with the same
1414 // argument. If there are enough (in some sense) we can make the
1416 for (User *U : Arg->users())
1417 classifyArgUse(U, CI->getParent(), IsFloat, SinCalls, CosCalls,
1420 // It's only worthwhile if both sinpi and cospi are actually used.
1421 if (SinCosCalls.empty() && (SinCalls.empty() || CosCalls.empty()))
1424 Value *Sin, *Cos, *SinCos;
1425 insertSinCosCall(B, CI->getCalledFunction(), Arg, IsFloat, Sin, Cos, SinCos);
1427 replaceTrigInsts(SinCalls, Sin);
1428 replaceTrigInsts(CosCalls, Cos);
1429 replaceTrigInsts(SinCosCalls, SinCos);
1434 static bool isTrigLibCall(CallInst *CI) {
1435 Function *Callee = CI->getCalledFunction();
1436 FunctionType *FT = Callee->getFunctionType();
1438 // We can only hope to do anything useful if we can ignore things like errno
1439 // and floating-point exceptions.
1440 bool AttributesSafe =
1441 CI->hasFnAttr(Attribute::NoUnwind) && CI->hasFnAttr(Attribute::ReadNone);
1443 // Other than that we need float(float) or double(double)
1444 return AttributesSafe && FT->getNumParams() == 1 &&
1445 FT->getReturnType() == FT->getParamType(0) &&
1446 (FT->getParamType(0)->isFloatTy() ||
1447 FT->getParamType(0)->isDoubleTy());
1451 LibCallSimplifier::classifyArgUse(Value *Val, BasicBlock *BB, bool IsFloat,
1452 SmallVectorImpl<CallInst *> &SinCalls,
1453 SmallVectorImpl<CallInst *> &CosCalls,
1454 SmallVectorImpl<CallInst *> &SinCosCalls) {
1455 CallInst *CI = dyn_cast<CallInst>(Val);
1460 Function *Callee = CI->getCalledFunction();
1461 StringRef FuncName = Callee->getName();
1463 if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func) || !isTrigLibCall(CI))
1467 if (Func == LibFunc::sinpif)
1468 SinCalls.push_back(CI);
1469 else if (Func == LibFunc::cospif)
1470 CosCalls.push_back(CI);
1471 else if (Func == LibFunc::sincospif_stret)
1472 SinCosCalls.push_back(CI);
1474 if (Func == LibFunc::sinpi)
1475 SinCalls.push_back(CI);
1476 else if (Func == LibFunc::cospi)
1477 CosCalls.push_back(CI);
1478 else if (Func == LibFunc::sincospi_stret)
1479 SinCosCalls.push_back(CI);
1483 void LibCallSimplifier::replaceTrigInsts(SmallVectorImpl<CallInst *> &Calls,
1485 for (CallInst *C : Calls)
1486 replaceAllUsesWith(C, Res);
1489 void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
1490 bool UseFloat, Value *&Sin, Value *&Cos, Value *&SinCos) {
1491 Type *ArgTy = Arg->getType();
1495 Triple T(OrigCallee->getParent()->getTargetTriple());
1497 Name = "__sincospif_stret";
1499 assert(T.getArch() != Triple::x86 && "x86 messy and unsupported for now");
1500 // x86_64 can't use {float, float} since that would be returned in both
1501 // xmm0 and xmm1, which isn't what a real struct would do.
1502 ResTy = T.getArch() == Triple::x86_64
1503 ? static_cast<Type *>(VectorType::get(ArgTy, 2))
1504 : static_cast<Type *>(StructType::get(ArgTy, ArgTy, nullptr));
1506 Name = "__sincospi_stret";
1507 ResTy = StructType::get(ArgTy, ArgTy, nullptr);
1510 Module *M = OrigCallee->getParent();
1511 Value *Callee = M->getOrInsertFunction(Name, OrigCallee->getAttributes(),
1512 ResTy, ArgTy, nullptr);
1514 if (Instruction *ArgInst = dyn_cast<Instruction>(Arg)) {
1515 // If the argument is an instruction, it must dominate all uses so put our
1516 // sincos call there.
1517 B.SetInsertPoint(ArgInst->getParent(), ++ArgInst->getIterator());
1519 // Otherwise (e.g. for a constant) the beginning of the function is as
1520 // good a place as any.
1521 BasicBlock &EntryBB = B.GetInsertBlock()->getParent()->getEntryBlock();
1522 B.SetInsertPoint(&EntryBB, EntryBB.begin());
1525 SinCos = B.CreateCall(Callee, Arg, "sincospi");
1527 if (SinCos->getType()->isStructTy()) {
1528 Sin = B.CreateExtractValue(SinCos, 0, "sinpi");
1529 Cos = B.CreateExtractValue(SinCos, 1, "cospi");
1531 Sin = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 0),
1533 Cos = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 1),
1538 //===----------------------------------------------------------------------===//
1539 // Integer Library Call Optimizations
1540 //===----------------------------------------------------------------------===//
1542 static bool checkIntUnaryReturnAndParam(Function *Callee) {
1543 FunctionType *FT = Callee->getFunctionType();
1544 return FT->getNumParams() == 1 && FT->getReturnType()->isIntegerTy(32) &&
1545 FT->getParamType(0)->isIntegerTy();
1548 Value *LibCallSimplifier::optimizeFFS(CallInst *CI, IRBuilder<> &B) {
1549 Function *Callee = CI->getCalledFunction();
1550 if (!checkIntUnaryReturnAndParam(Callee))
1552 Value *Op = CI->getArgOperand(0);
1555 if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
1556 if (CI->isZero()) // ffs(0) -> 0.
1557 return B.getInt32(0);
1558 // ffs(c) -> cttz(c)+1
1559 return B.getInt32(CI->getValue().countTrailingZeros() + 1);
1562 // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
1563 Type *ArgType = Op->getType();
1565 Intrinsic::getDeclaration(Callee->getParent(), Intrinsic::cttz, ArgType);
1566 Value *V = B.CreateCall(F, {Op, B.getTrue()}, "cttz");
1567 V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
1568 V = B.CreateIntCast(V, B.getInt32Ty(), false);
1570 Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
1571 return B.CreateSelect(Cond, V, B.getInt32(0));
1574 Value *LibCallSimplifier::optimizeAbs(CallInst *CI, IRBuilder<> &B) {
1575 Function *Callee = CI->getCalledFunction();
1576 FunctionType *FT = Callee->getFunctionType();
1577 // We require integer(integer) where the types agree.
1578 if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
1579 FT->getParamType(0) != FT->getReturnType())
1582 // abs(x) -> x >s -1 ? x : -x
1583 Value *Op = CI->getArgOperand(0);
1585 B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()), "ispos");
1586 Value *Neg = B.CreateNeg(Op, "neg");
1587 return B.CreateSelect(Pos, Op, Neg);
1590 Value *LibCallSimplifier::optimizeIsDigit(CallInst *CI, IRBuilder<> &B) {
1591 if (!checkIntUnaryReturnAndParam(CI->getCalledFunction()))
1594 // isdigit(c) -> (c-'0') <u 10
1595 Value *Op = CI->getArgOperand(0);
1596 Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp");
1597 Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit");
1598 return B.CreateZExt(Op, CI->getType());
1601 Value *LibCallSimplifier::optimizeIsAscii(CallInst *CI, IRBuilder<> &B) {
1602 if (!checkIntUnaryReturnAndParam(CI->getCalledFunction()))
1605 // isascii(c) -> c <u 128
1606 Value *Op = CI->getArgOperand(0);
1607 Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii");
1608 return B.CreateZExt(Op, CI->getType());
1611 Value *LibCallSimplifier::optimizeToAscii(CallInst *CI, IRBuilder<> &B) {
1612 if (!checkIntUnaryReturnAndParam(CI->getCalledFunction()))
1615 // toascii(c) -> c & 0x7f
1616 return B.CreateAnd(CI->getArgOperand(0),
1617 ConstantInt::get(CI->getType(), 0x7F));
1620 //===----------------------------------------------------------------------===//
1621 // Formatting and IO Library Call Optimizations
1622 //===----------------------------------------------------------------------===//
1624 static bool isReportingError(Function *Callee, CallInst *CI, int StreamArg);
1626 Value *LibCallSimplifier::optimizeErrorReporting(CallInst *CI, IRBuilder<> &B,
1628 // Error reporting calls should be cold, mark them as such.
1629 // This applies even to non-builtin calls: it is only a hint and applies to
1630 // functions that the frontend might not understand as builtins.
1632 // This heuristic was suggested in:
1633 // Improving Static Branch Prediction in a Compiler
1634 // Brian L. Deitrich, Ben-Chung Cheng, Wen-mei W. Hwu
1635 // Proceedings of PACT'98, Oct. 1998, IEEE
1636 Function *Callee = CI->getCalledFunction();
1638 if (!CI->hasFnAttr(Attribute::Cold) &&
1639 isReportingError(Callee, CI, StreamArg)) {
1640 CI->addAttribute(AttributeSet::FunctionIndex, Attribute::Cold);
1646 static bool isReportingError(Function *Callee, CallInst *CI, int StreamArg) {
1647 if (!ColdErrorCalls || !Callee || !Callee->isDeclaration())
1653 // These functions might be considered cold, but only if their stream
1654 // argument is stderr.
1656 if (StreamArg >= (int)CI->getNumArgOperands())
1658 LoadInst *LI = dyn_cast<LoadInst>(CI->getArgOperand(StreamArg));
1661 GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand());
1662 if (!GV || !GV->isDeclaration())
1664 return GV->getName() == "stderr";
1667 Value *LibCallSimplifier::optimizePrintFString(CallInst *CI, IRBuilder<> &B) {
1668 // Check for a fixed format string.
1669 StringRef FormatStr;
1670 if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr))
1673 // Empty format string -> noop.
1674 if (FormatStr.empty()) // Tolerate printf's declared void.
1675 return CI->use_empty() ? (Value *)CI : ConstantInt::get(CI->getType(), 0);
1677 // Do not do any of the following transformations if the printf return value
1678 // is used, in general the printf return value is not compatible with either
1679 // putchar() or puts().
1680 if (!CI->use_empty())
1683 // printf("x") -> putchar('x'), even for '%'.
1684 if (FormatStr.size() == 1) {
1685 Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TLI);
1686 if (CI->use_empty() || !Res)
1688 return B.CreateIntCast(Res, CI->getType(), true);
1691 // printf("foo\n") --> puts("foo")
1692 if (FormatStr[FormatStr.size() - 1] == '\n' &&
1693 FormatStr.find('%') == StringRef::npos) { // No format characters.
1694 // Create a string literal with no \n on it. We expect the constant merge
1695 // pass to be run after this pass, to merge duplicate strings.
1696 FormatStr = FormatStr.drop_back();
1697 Value *GV = B.CreateGlobalString(FormatStr, "str");
1698 Value *NewCI = EmitPutS(GV, B, TLI);
1699 return (CI->use_empty() || !NewCI)
1701 : ConstantInt::get(CI->getType(), FormatStr.size() + 1);
1704 // Optimize specific format strings.
1705 // printf("%c", chr) --> putchar(chr)
1706 if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
1707 CI->getArgOperand(1)->getType()->isIntegerTy()) {
1708 Value *Res = EmitPutChar(CI->getArgOperand(1), B, TLI);
1710 if (CI->use_empty() || !Res)
1712 return B.CreateIntCast(Res, CI->getType(), true);
1715 // printf("%s\n", str) --> puts(str)
1716 if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
1717 CI->getArgOperand(1)->getType()->isPointerTy()) {
1718 return EmitPutS(CI->getArgOperand(1), B, TLI);
1723 Value *LibCallSimplifier::optimizePrintF(CallInst *CI, IRBuilder<> &B) {
1725 Function *Callee = CI->getCalledFunction();
1726 // Require one fixed pointer argument and an integer/void result.
1727 FunctionType *FT = Callee->getFunctionType();
1728 if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
1729 !(FT->getReturnType()->isIntegerTy() || FT->getReturnType()->isVoidTy()))
1732 if (Value *V = optimizePrintFString(CI, B)) {
1736 // printf(format, ...) -> iprintf(format, ...) if no floating point
1738 if (TLI->has(LibFunc::iprintf) && !callHasFloatingPointArgument(CI)) {
1739 Module *M = B.GetInsertBlock()->getParent()->getParent();
1740 Constant *IPrintFFn =
1741 M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
1742 CallInst *New = cast<CallInst>(CI->clone());
1743 New->setCalledFunction(IPrintFFn);
1750 Value *LibCallSimplifier::optimizeSPrintFString(CallInst *CI, IRBuilder<> &B) {
1751 // Check for a fixed format string.
1752 StringRef FormatStr;
1753 if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
1756 // If we just have a format string (nothing else crazy) transform it.
1757 if (CI->getNumArgOperands() == 2) {
1758 // Make sure there's no % in the constant array. We could try to handle
1759 // %% -> % in the future if we cared.
1760 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1761 if (FormatStr[i] == '%')
1762 return nullptr; // we found a format specifier, bail out.
1764 // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
1765 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
1766 ConstantInt::get(DL.getIntPtrType(CI->getContext()),
1767 FormatStr.size() + 1),
1768 1); // Copy the null byte.
1769 return ConstantInt::get(CI->getType(), FormatStr.size());
1772 // The remaining optimizations require the format string to be "%s" or "%c"
1773 // and have an extra operand.
1774 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1775 CI->getNumArgOperands() < 3)
1778 // Decode the second character of the format string.
1779 if (FormatStr[1] == 'c') {
1780 // sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
1781 if (!CI->getArgOperand(2)->getType()->isIntegerTy())
1783 Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
1784 Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
1785 B.CreateStore(V, Ptr);
1786 Ptr = B.CreateGEP(B.getInt8Ty(), Ptr, B.getInt32(1), "nul");
1787 B.CreateStore(B.getInt8(0), Ptr);
1789 return ConstantInt::get(CI->getType(), 1);
1792 if (FormatStr[1] == 's') {
1793 // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1794 if (!CI->getArgOperand(2)->getType()->isPointerTy())
1797 Value *Len = EmitStrLen(CI->getArgOperand(2), B, DL, TLI);
1801 B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1), "leninc");
1802 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
1804 // The sprintf result is the unincremented number of bytes in the string.
1805 return B.CreateIntCast(Len, CI->getType(), false);
1810 Value *LibCallSimplifier::optimizeSPrintF(CallInst *CI, IRBuilder<> &B) {
1811 Function *Callee = CI->getCalledFunction();
1812 // Require two fixed pointer arguments and an integer result.
1813 FunctionType *FT = Callee->getFunctionType();
1814 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1815 !FT->getParamType(1)->isPointerTy() ||
1816 !FT->getReturnType()->isIntegerTy())
1819 if (Value *V = optimizeSPrintFString(CI, B)) {
1823 // sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating
1825 if (TLI->has(LibFunc::siprintf) && !callHasFloatingPointArgument(CI)) {
1826 Module *M = B.GetInsertBlock()->getParent()->getParent();
1827 Constant *SIPrintFFn =
1828 M->getOrInsertFunction("siprintf", FT, Callee->getAttributes());
1829 CallInst *New = cast<CallInst>(CI->clone());
1830 New->setCalledFunction(SIPrintFFn);
1837 Value *LibCallSimplifier::optimizeFPrintFString(CallInst *CI, IRBuilder<> &B) {
1838 optimizeErrorReporting(CI, B, 0);
1840 // All the optimizations depend on the format string.
1841 StringRef FormatStr;
1842 if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
1845 // Do not do any of the following transformations if the fprintf return
1846 // value is used, in general the fprintf return value is not compatible
1847 // with fwrite(), fputc() or fputs().
1848 if (!CI->use_empty())
1851 // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
1852 if (CI->getNumArgOperands() == 2) {
1853 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1854 if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
1855 return nullptr; // We found a format specifier.
1858 CI->getArgOperand(1),
1859 ConstantInt::get(DL.getIntPtrType(CI->getContext()), FormatStr.size()),
1860 CI->getArgOperand(0), B, DL, TLI);
1863 // The remaining optimizations require the format string to be "%s" or "%c"
1864 // and have an extra operand.
1865 if (FormatStr.size() != 2 || FormatStr[0] != '%' ||
1866 CI->getNumArgOperands() < 3)
1869 // Decode the second character of the format string.
1870 if (FormatStr[1] == 'c') {
1871 // fprintf(F, "%c", chr) --> fputc(chr, F)
1872 if (!CI->getArgOperand(2)->getType()->isIntegerTy())
1874 return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, TLI);
1877 if (FormatStr[1] == 's') {
1878 // fprintf(F, "%s", str) --> fputs(str, F)
1879 if (!CI->getArgOperand(2)->getType()->isPointerTy())
1881 return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, TLI);
1886 Value *LibCallSimplifier::optimizeFPrintF(CallInst *CI, IRBuilder<> &B) {
1887 Function *Callee = CI->getCalledFunction();
1888 // Require two fixed paramters as pointers and integer result.
1889 FunctionType *FT = Callee->getFunctionType();
1890 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1891 !FT->getParamType(1)->isPointerTy() ||
1892 !FT->getReturnType()->isIntegerTy())
1895 if (Value *V = optimizeFPrintFString(CI, B)) {
1899 // fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no
1900 // floating point arguments.
1901 if (TLI->has(LibFunc::fiprintf) && !callHasFloatingPointArgument(CI)) {
1902 Module *M = B.GetInsertBlock()->getParent()->getParent();
1903 Constant *FIPrintFFn =
1904 M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes());
1905 CallInst *New = cast<CallInst>(CI->clone());
1906 New->setCalledFunction(FIPrintFFn);
1913 Value *LibCallSimplifier::optimizeFWrite(CallInst *CI, IRBuilder<> &B) {
1914 optimizeErrorReporting(CI, B, 3);
1916 Function *Callee = CI->getCalledFunction();
1917 // Require a pointer, an integer, an integer, a pointer, returning integer.
1918 FunctionType *FT = Callee->getFunctionType();
1919 if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
1920 !FT->getParamType(1)->isIntegerTy() ||
1921 !FT->getParamType(2)->isIntegerTy() ||
1922 !FT->getParamType(3)->isPointerTy() ||
1923 !FT->getReturnType()->isIntegerTy())
1926 // Get the element size and count.
1927 ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
1928 ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
1929 if (!SizeC || !CountC)
1931 uint64_t Bytes = SizeC->getZExtValue() * CountC->getZExtValue();
1933 // If this is writing zero records, remove the call (it's a noop).
1935 return ConstantInt::get(CI->getType(), 0);
1937 // If this is writing one byte, turn it into fputc.
1938 // This optimisation is only valid, if the return value is unused.
1939 if (Bytes == 1 && CI->use_empty()) { // fwrite(S,1,1,F) -> fputc(S[0],F)
1940 Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
1941 Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, TLI);
1942 return NewCI ? ConstantInt::get(CI->getType(), 1) : nullptr;
1948 Value *LibCallSimplifier::optimizeFPuts(CallInst *CI, IRBuilder<> &B) {
1949 optimizeErrorReporting(CI, B, 1);
1951 Function *Callee = CI->getCalledFunction();
1953 // Require two pointers. Also, we can't optimize if return value is used.
1954 FunctionType *FT = Callee->getFunctionType();
1955 if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
1956 !FT->getParamType(1)->isPointerTy() || !CI->use_empty())
1959 // fputs(s,F) --> fwrite(s,1,strlen(s),F)
1960 uint64_t Len = GetStringLength(CI->getArgOperand(0));
1964 // Known to have no uses (see above).
1966 CI->getArgOperand(0),
1967 ConstantInt::get(DL.getIntPtrType(CI->getContext()), Len - 1),
1968 CI->getArgOperand(1), B, DL, TLI);
1971 Value *LibCallSimplifier::optimizePuts(CallInst *CI, IRBuilder<> &B) {
1972 Function *Callee = CI->getCalledFunction();
1973 // Require one fixed pointer argument and an integer/void result.
1974 FunctionType *FT = Callee->getFunctionType();
1975 if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
1976 !(FT->getReturnType()->isIntegerTy() || FT->getReturnType()->isVoidTy()))
1979 // Check for a constant string.
1981 if (!getConstantStringInfo(CI->getArgOperand(0), Str))
1984 if (Str.empty() && CI->use_empty()) {
1985 // puts("") -> putchar('\n')
1986 Value *Res = EmitPutChar(B.getInt32('\n'), B, TLI);
1987 if (CI->use_empty() || !Res)
1989 return B.CreateIntCast(Res, CI->getType(), true);
1995 bool LibCallSimplifier::hasFloatVersion(StringRef FuncName) {
1997 SmallString<20> FloatFuncName = FuncName;
1998 FloatFuncName += 'f';
1999 if (TLI->getLibFunc(FloatFuncName, Func))
2000 return TLI->has(Func);
2004 Value *LibCallSimplifier::optimizeStringMemoryLibCall(CallInst *CI,
2005 IRBuilder<> &Builder) {
2007 Function *Callee = CI->getCalledFunction();
2008 StringRef FuncName = Callee->getName();
2010 // Check for string/memory library functions.
2011 if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
2012 // Make sure we never change the calling convention.
2013 assert((ignoreCallingConv(Func) ||
2014 CI->getCallingConv() == llvm::CallingConv::C) &&
2015 "Optimizing string/memory libcall would change the calling convention");
2017 case LibFunc::strcat:
2018 return optimizeStrCat(CI, Builder);
2019 case LibFunc::strncat:
2020 return optimizeStrNCat(CI, Builder);
2021 case LibFunc::strchr:
2022 return optimizeStrChr(CI, Builder);
2023 case LibFunc::strrchr:
2024 return optimizeStrRChr(CI, Builder);
2025 case LibFunc::strcmp:
2026 return optimizeStrCmp(CI, Builder);
2027 case LibFunc::strncmp:
2028 return optimizeStrNCmp(CI, Builder);
2029 case LibFunc::strcpy:
2030 return optimizeStrCpy(CI, Builder);
2031 case LibFunc::stpcpy:
2032 return optimizeStpCpy(CI, Builder);
2033 case LibFunc::strncpy:
2034 return optimizeStrNCpy(CI, Builder);
2035 case LibFunc::strlen:
2036 return optimizeStrLen(CI, Builder);
2037 case LibFunc::strpbrk:
2038 return optimizeStrPBrk(CI, Builder);
2039 case LibFunc::strtol:
2040 case LibFunc::strtod:
2041 case LibFunc::strtof:
2042 case LibFunc::strtoul:
2043 case LibFunc::strtoll:
2044 case LibFunc::strtold:
2045 case LibFunc::strtoull:
2046 return optimizeStrTo(CI, Builder);
2047 case LibFunc::strspn:
2048 return optimizeStrSpn(CI, Builder);
2049 case LibFunc::strcspn:
2050 return optimizeStrCSpn(CI, Builder);
2051 case LibFunc::strstr:
2052 return optimizeStrStr(CI, Builder);
2053 case LibFunc::memchr:
2054 return optimizeMemChr(CI, Builder);
2055 case LibFunc::memcmp:
2056 return optimizeMemCmp(CI, Builder);
2057 case LibFunc::memcpy:
2058 return optimizeMemCpy(CI, Builder);
2059 case LibFunc::memmove:
2060 return optimizeMemMove(CI, Builder);
2061 case LibFunc::memset:
2062 return optimizeMemSet(CI, Builder);
2070 Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
2071 if (CI->isNoBuiltin())
2075 Function *Callee = CI->getCalledFunction();
2076 StringRef FuncName = Callee->getName();
2077 IRBuilder<> Builder(CI);
2078 bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
2080 // Command-line parameter overrides function attribute.
2081 if (EnableUnsafeFPShrink.getNumOccurrences() > 0)
2082 UnsafeFPShrink = EnableUnsafeFPShrink;
2083 else if (canUseUnsafeFPMath(Callee))
2084 UnsafeFPShrink = true;
2086 // First, check for intrinsics.
2087 if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
2088 if (!isCallingConvC)
2090 switch (II->getIntrinsicID()) {
2091 case Intrinsic::pow:
2092 return optimizePow(CI, Builder);
2093 case Intrinsic::exp2:
2094 return optimizeExp2(CI, Builder);
2095 case Intrinsic::fabs:
2096 return optimizeFabs(CI, Builder);
2097 case Intrinsic::sqrt:
2098 return optimizeSqrt(CI, Builder);
2104 // Also try to simplify calls to fortified library functions.
2105 if (Value *SimplifiedFortifiedCI = FortifiedSimplifier.optimizeCall(CI)) {
2106 // Try to further simplify the result.
2107 CallInst *SimplifiedCI = dyn_cast<CallInst>(SimplifiedFortifiedCI);
2108 if (SimplifiedCI && SimplifiedCI->getCalledFunction()) {
2109 // Use an IR Builder from SimplifiedCI if available instead of CI
2110 // to guarantee we reach all uses we might replace later on.
2111 IRBuilder<> TmpBuilder(SimplifiedCI);
2112 if (Value *V = optimizeStringMemoryLibCall(SimplifiedCI, TmpBuilder)) {
2113 // If we were able to further simplify, remove the now redundant call.
2114 SimplifiedCI->replaceAllUsesWith(V);
2115 SimplifiedCI->eraseFromParent();
2119 return SimplifiedFortifiedCI;
2122 // Then check for known library functions.
2123 if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
2124 // We never change the calling convention.
2125 if (!ignoreCallingConv(Func) && !isCallingConvC)
2127 if (Value *V = optimizeStringMemoryLibCall(CI, Builder))
2133 return optimizeCos(CI, Builder);
2134 case LibFunc::sinpif:
2135 case LibFunc::sinpi:
2136 case LibFunc::cospif:
2137 case LibFunc::cospi:
2138 return optimizeSinCosPi(CI, Builder);
2142 return optimizePow(CI, Builder);
2143 case LibFunc::exp2l:
2145 case LibFunc::exp2f:
2146 return optimizeExp2(CI, Builder);
2147 case LibFunc::fabsf:
2149 case LibFunc::fabsl:
2150 return optimizeFabs(CI, Builder);
2151 case LibFunc::sqrtf:
2153 case LibFunc::sqrtl:
2154 return optimizeSqrt(CI, Builder);
2157 case LibFunc::ffsll:
2158 return optimizeFFS(CI, Builder);
2161 case LibFunc::llabs:
2162 return optimizeAbs(CI, Builder);
2163 case LibFunc::isdigit:
2164 return optimizeIsDigit(CI, Builder);
2165 case LibFunc::isascii:
2166 return optimizeIsAscii(CI, Builder);
2167 case LibFunc::toascii:
2168 return optimizeToAscii(CI, Builder);
2169 case LibFunc::printf:
2170 return optimizePrintF(CI, Builder);
2171 case LibFunc::sprintf:
2172 return optimizeSPrintF(CI, Builder);
2173 case LibFunc::fprintf:
2174 return optimizeFPrintF(CI, Builder);
2175 case LibFunc::fwrite:
2176 return optimizeFWrite(CI, Builder);
2177 case LibFunc::fputs:
2178 return optimizeFPuts(CI, Builder);
2180 return optimizePuts(CI, Builder);
2184 return optimizeTan(CI, Builder);
2185 case LibFunc::perror:
2186 return optimizeErrorReporting(CI, Builder);
2187 case LibFunc::vfprintf:
2188 case LibFunc::fiprintf:
2189 return optimizeErrorReporting(CI, Builder, 0);
2190 case LibFunc::fputc:
2191 return optimizeErrorReporting(CI, Builder, 1);
2193 case LibFunc::floor:
2195 case LibFunc::round:
2196 case LibFunc::nearbyint:
2197 case LibFunc::trunc:
2198 if (hasFloatVersion(FuncName))
2199 return optimizeUnaryDoubleFP(CI, Builder, false);
2202 case LibFunc::acosh:
2204 case LibFunc::asinh:
2206 case LibFunc::atanh:
2210 case LibFunc::exp10:
2211 case LibFunc::expm1:
2213 case LibFunc::log10:
2214 case LibFunc::log1p:
2220 if (UnsafeFPShrink && hasFloatVersion(FuncName))
2221 return optimizeUnaryDoubleFP(CI, Builder, true);
2223 case LibFunc::copysign:
2224 if (hasFloatVersion(FuncName))
2225 return optimizeBinaryDoubleFP(CI, Builder);
2227 case LibFunc::fminf:
2229 case LibFunc::fminl:
2230 case LibFunc::fmaxf:
2232 case LibFunc::fmaxl:
2233 return optimizeFMinFMax(CI, Builder);
2241 LibCallSimplifier::LibCallSimplifier(
2242 const DataLayout &DL, const TargetLibraryInfo *TLI,
2243 function_ref<void(Instruction *, Value *)> Replacer)
2244 : FortifiedSimplifier(TLI), DL(DL), TLI(TLI), UnsafeFPShrink(false),
2245 Replacer(Replacer) {}
2247 void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) {
2248 // Indirect through the replacer used in this instance.
2253 // Additional cases that we need to add to this file:
2256 // * cbrt(expN(X)) -> expN(x/3)
2257 // * cbrt(sqrt(x)) -> pow(x,1/6)
2258 // * cbrt(cbrt(x)) -> pow(x,1/9)
2261 // * exp(log(x)) -> x
2264 // * log(exp(x)) -> x
2265 // * log(x**y) -> y*log(x)
2266 // * log(exp(y)) -> y*log(e)
2267 // * log(exp2(y)) -> y*log(2)
2268 // * log(exp10(y)) -> y*log(10)
2269 // * log(sqrt(x)) -> 0.5*log(x)
2270 // * log(pow(x,y)) -> y*log(x)
2272 // lround, lroundf, lroundl:
2273 // * lround(cnst) -> cnst'
2276 // * pow(exp(x),y) -> exp(x*y)
2277 // * pow(sqrt(x),y) -> pow(x,y*0.5)
2278 // * pow(pow(x,y),z)-> pow(x,y*z)
2280 // round, roundf, roundl:
2281 // * round(cnst) -> cnst'
2284 // * signbit(cnst) -> cnst'
2285 // * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2287 // sqrt, sqrtf, sqrtl:
2288 // * sqrt(expN(x)) -> expN(x*0.5)
2289 // * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2290 // * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2293 // * tan(atan(x)) -> x
2295 // trunc, truncf, truncl:
2296 // * trunc(cnst) -> cnst'
2300 //===----------------------------------------------------------------------===//
2301 // Fortified Library Call Optimizations
2302 //===----------------------------------------------------------------------===//
2304 bool FortifiedLibCallSimplifier::isFortifiedCallFoldable(CallInst *CI,
2308 if (CI->getArgOperand(ObjSizeOp) == CI->getArgOperand(SizeOp))
2310 if (ConstantInt *ObjSizeCI =
2311 dyn_cast<ConstantInt>(CI->getArgOperand(ObjSizeOp))) {
2312 if (ObjSizeCI->isAllOnesValue())
2314 // If the object size wasn't -1 (unknown), bail out if we were asked to.
2315 if (OnlyLowerUnknownSize)
2318 uint64_t Len = GetStringLength(CI->getArgOperand(SizeOp));
2319 // If the length is 0 we don't know how long it is and so we can't
2320 // remove the check.
2323 return ObjSizeCI->getZExtValue() >= Len;
2325 if (ConstantInt *SizeCI = dyn_cast<ConstantInt>(CI->getArgOperand(SizeOp)))
2326 return ObjSizeCI->getZExtValue() >= SizeCI->getZExtValue();
2331 Value *FortifiedLibCallSimplifier::optimizeMemCpyChk(CallInst *CI, IRBuilder<> &B) {
2332 Function *Callee = CI->getCalledFunction();
2334 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memcpy_chk))
2337 if (isFortifiedCallFoldable(CI, 3, 2, false)) {
2338 B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
2339 CI->getArgOperand(2), 1);
2340 return CI->getArgOperand(0);
2345 Value *FortifiedLibCallSimplifier::optimizeMemMoveChk(CallInst *CI, IRBuilder<> &B) {
2346 Function *Callee = CI->getCalledFunction();
2348 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memmove_chk))
2351 if (isFortifiedCallFoldable(CI, 3, 2, false)) {
2352 B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
2353 CI->getArgOperand(2), 1);
2354 return CI->getArgOperand(0);
2359 Value *FortifiedLibCallSimplifier::optimizeMemSetChk(CallInst *CI, IRBuilder<> &B) {
2360 Function *Callee = CI->getCalledFunction();
2362 if (!checkStringCopyLibFuncSignature(Callee, LibFunc::memset_chk))
2365 if (isFortifiedCallFoldable(CI, 3, 2, false)) {
2366 Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
2367 B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
2368 return CI->getArgOperand(0);
2373 Value *FortifiedLibCallSimplifier::optimizeStrpCpyChk(CallInst *CI,
2375 LibFunc::Func Func) {
2376 Function *Callee = CI->getCalledFunction();
2377 StringRef Name = Callee->getName();
2378 const DataLayout &DL = CI->getModule()->getDataLayout();
2380 if (!checkStringCopyLibFuncSignature(Callee, Func))
2383 Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1),
2384 *ObjSize = CI->getArgOperand(2);
2386 // __stpcpy_chk(x,x,...) -> x+strlen(x)
2387 if (Func == LibFunc::stpcpy_chk && !OnlyLowerUnknownSize && Dst == Src) {
2388 Value *StrLen = EmitStrLen(Src, B, DL, TLI);
2389 return StrLen ? B.CreateInBoundsGEP(B.getInt8Ty(), Dst, StrLen) : nullptr;
2392 // If a) we don't have any length information, or b) we know this will
2393 // fit then just lower to a plain st[rp]cpy. Otherwise we'll keep our
2394 // st[rp]cpy_chk call which may fail at runtime if the size is too long.
2395 // TODO: It might be nice to get a maximum length out of the possible
2396 // string lengths for varying.
2397 if (isFortifiedCallFoldable(CI, 2, 1, true))
2398 return EmitStrCpy(Dst, Src, B, TLI, Name.substr(2, 6));
2400 if (OnlyLowerUnknownSize)
2403 // Maybe we can stil fold __st[rp]cpy_chk to __memcpy_chk.
2404 uint64_t Len = GetStringLength(Src);
2408 Type *SizeTTy = DL.getIntPtrType(CI->getContext());
2409 Value *LenV = ConstantInt::get(SizeTTy, Len);
2410 Value *Ret = EmitMemCpyChk(Dst, Src, LenV, ObjSize, B, DL, TLI);
2411 // If the function was an __stpcpy_chk, and we were able to fold it into
2412 // a __memcpy_chk, we still need to return the correct end pointer.
2413 if (Ret && Func == LibFunc::stpcpy_chk)
2414 return B.CreateGEP(B.getInt8Ty(), Dst, ConstantInt::get(SizeTTy, Len - 1));
2418 Value *FortifiedLibCallSimplifier::optimizeStrpNCpyChk(CallInst *CI,
2420 LibFunc::Func Func) {
2421 Function *Callee = CI->getCalledFunction();
2422 StringRef Name = Callee->getName();
2424 if (!checkStringCopyLibFuncSignature(Callee, Func))
2426 if (isFortifiedCallFoldable(CI, 3, 2, false)) {
2427 Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
2428 CI->getArgOperand(2), B, TLI, Name.substr(2, 7));
2434 Value *FortifiedLibCallSimplifier::optimizeCall(CallInst *CI) {
2435 // FIXME: We shouldn't be changing "nobuiltin" or TLI unavailable calls here.
2436 // Some clang users checked for _chk libcall availability using:
2437 // __has_builtin(__builtin___memcpy_chk)
2438 // When compiling with -fno-builtin, this is always true.
2439 // When passing -ffreestanding/-mkernel, which both imply -fno-builtin, we
2440 // end up with fortified libcalls, which isn't acceptable in a freestanding
2441 // environment which only provides their non-fortified counterparts.
2443 // Until we change clang and/or teach external users to check for availability
2444 // differently, disregard the "nobuiltin" attribute and TLI::has.
2449 Function *Callee = CI->getCalledFunction();
2450 StringRef FuncName = Callee->getName();
2451 IRBuilder<> Builder(CI);
2452 bool isCallingConvC = CI->getCallingConv() == llvm::CallingConv::C;
2454 // First, check that this is a known library functions.
2455 if (!TLI->getLibFunc(FuncName, Func))
2458 // We never change the calling convention.
2459 if (!ignoreCallingConv(Func) && !isCallingConvC)
2463 case LibFunc::memcpy_chk:
2464 return optimizeMemCpyChk(CI, Builder);
2465 case LibFunc::memmove_chk:
2466 return optimizeMemMoveChk(CI, Builder);
2467 case LibFunc::memset_chk:
2468 return optimizeMemSetChk(CI, Builder);
2469 case LibFunc::stpcpy_chk:
2470 case LibFunc::strcpy_chk:
2471 return optimizeStrpCpyChk(CI, Builder, Func);
2472 case LibFunc::stpncpy_chk:
2473 case LibFunc::strncpy_chk:
2474 return optimizeStrpNCpyChk(CI, Builder, Func);
2481 FortifiedLibCallSimplifier::FortifiedLibCallSimplifier(
2482 const TargetLibraryInfo *TLI, bool OnlyLowerUnknownSize)
2483 : TLI(TLI), OnlyLowerUnknownSize(OnlyLowerUnknownSize) {}