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 module pass that applies a variety of small
11 // optimizations for calls to specific well-known function calls (e.g. runtime
12 // library functions). For example, a call to the function "exit(3)" that
13 // occurs within the main() function can be transformed into a simple "return 3"
14 // instruction. Any optimization that takes this form (replace call to library
15 // function with simpler code that provides the same result) belongs in this
18 //===----------------------------------------------------------------------===//
20 #define DEBUG_TYPE "simplify-libcalls"
21 #include "llvm/Constants.h"
22 #include "llvm/DerivedTypes.h"
23 #include "llvm/Instructions.h"
24 #include "llvm/Module.h"
25 #include "llvm/Pass.h"
26 #include "llvm/ADT/StringMap.h"
27 #include "llvm/ADT/Statistic.h"
28 #include "llvm/Config/config.h"
29 #include "llvm/Support/Compiler.h"
30 #include "llvm/Support/Debug.h"
31 #include "llvm/Target/TargetData.h"
32 #include "llvm/Transforms/IPO.h"
36 /// This statistic keeps track of the total number of library calls that have
37 /// been simplified regardless of which call it is.
38 STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
41 // Forward declarations
42 class LibCallOptimization;
43 class SimplifyLibCalls;
45 /// This list is populated by the constructor for LibCallOptimization class.
46 /// Therefore all subclasses are registered here at static initialization time
47 /// and this list is what the SimplifyLibCalls pass uses to apply the individual
48 /// optimizations to the call sites.
49 /// @brief The list of optimizations deriving from LibCallOptimization
50 static LibCallOptimization *OptList = 0;
52 /// This class is the abstract base class for the set of optimizations that
53 /// corresponds to one library call. The SimplifyLibCalls pass will call the
54 /// ValidateCalledFunction method to ask the optimization if a given Function
55 /// is the kind that the optimization can handle. If the subclass returns true,
56 /// then SImplifyLibCalls will also call the OptimizeCall method to perform,
57 /// or attempt to perform, the optimization(s) for the library call. Otherwise,
58 /// OptimizeCall won't be called. Subclasses are responsible for providing the
59 /// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
60 /// constructor. This is used to efficiently select which call instructions to
61 /// optimize. The criteria for a "lib call" is "anything with well known
62 /// semantics", typically a library function that is defined by an international
63 /// standard. Because the semantics are well known, the optimizations can
64 /// generally short-circuit actually calling the function if there's a simpler
65 /// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
66 /// @brief Base class for library call optimizations
67 class VISIBILITY_HIDDEN LibCallOptimization {
68 LibCallOptimization **Prev, *Next;
69 const char *FunctionName; ///< Name of the library call we optimize
71 Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
74 /// The \p fname argument must be the name of the library function being
75 /// optimized by the subclass.
76 /// @brief Constructor that registers the optimization.
77 LibCallOptimization(const char *FName, const char *Description)
78 : FunctionName(FName) {
81 occurrences.construct("simplify-libcalls", Description);
83 // Register this optimizer in the list of optimizations.
87 if (Next) Next->Prev = &Next;
90 /// getNext - All libcall optimizations are chained together into a list,
91 /// return the next one in the list.
92 LibCallOptimization *getNext() { return Next; }
94 /// @brief Deregister from the optlist
95 virtual ~LibCallOptimization() {
97 if (Next) Next->Prev = Prev;
100 /// The implementation of this function in subclasses should determine if
101 /// \p F is suitable for the optimization. This method is called by
102 /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
103 /// sites of such a function if that function is not suitable in the first
104 /// place. If the called function is suitabe, this method should return true;
105 /// false, otherwise. This function should also perform any lazy
106 /// initialization that the LibCallOptimization needs to do, if its to return
107 /// true. This avoids doing initialization until the optimizer is actually
108 /// going to be called upon to do some optimization.
109 /// @brief Determine if the function is suitable for optimization
110 virtual bool ValidateCalledFunction(
111 const Function* F, ///< The function that is the target of call sites
112 SimplifyLibCalls& SLC ///< The pass object invoking us
115 /// The implementations of this function in subclasses is the heart of the
116 /// SimplifyLibCalls algorithm. Sublcasses of this class implement
117 /// OptimizeCall to determine if (a) the conditions are right for optimizing
118 /// the call and (b) to perform the optimization. If an action is taken
119 /// against ci, the subclass is responsible for returning true and ensuring
120 /// that ci is erased from its parent.
121 /// @brief Optimize a call, if possible.
122 virtual bool OptimizeCall(
123 CallInst* ci, ///< The call instruction that should be optimized.
124 SimplifyLibCalls& SLC ///< The pass object invoking us
127 /// @brief Get the name of the library call being optimized
128 const char *getFunctionName() const { return FunctionName; }
130 bool ReplaceCallWith(CallInst *CI, Value *V) {
131 if (!CI->use_empty())
132 CI->replaceAllUsesWith(V);
133 CI->eraseFromParent();
137 /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
140 DEBUG(++occurrences);
145 /// This class is an LLVM Pass that applies each of the LibCallOptimization
146 /// instances to all the call sites in a module, relatively efficiently. The
147 /// purpose of this pass is to provide optimizations for calls to well-known
148 /// functions with well-known semantics, such as those in the c library. The
149 /// class provides the basic infrastructure for handling runOnModule. Whenever
150 /// this pass finds a function call, it asks the appropriate optimizer to
151 /// validate the call (ValidateLibraryCall). If it is validated, then
152 /// the OptimizeCall method is also called.
153 /// @brief A ModulePass for optimizing well-known function calls.
154 class VISIBILITY_HIDDEN SimplifyLibCalls : public ModulePass {
156 static char ID; // Pass identification, replacement for typeid
157 SimplifyLibCalls() : ModulePass((intptr_t)&ID) {}
159 /// We need some target data for accurate signature details that are
160 /// target dependent. So we require target data in our AnalysisUsage.
161 /// @brief Require TargetData from AnalysisUsage.
162 virtual void getAnalysisUsage(AnalysisUsage& Info) const {
163 // Ask that the TargetData analysis be performed before us so we can use
165 Info.addRequired<TargetData>();
168 /// For this pass, process all of the function calls in the module, calling
169 /// ValidateLibraryCall and OptimizeCall as appropriate.
170 /// @brief Run all the lib call optimizations on a Module.
171 virtual bool runOnModule(Module &M) {
175 StringMap<LibCallOptimization*> OptznMap;
176 for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
177 OptznMap[Optzn->getFunctionName()] = Optzn;
179 // The call optimizations can be recursive. That is, the optimization might
180 // generate a call to another function which can also be optimized. This way
181 // we make the LibCallOptimization instances very specific to the case they
182 // handle. It also means we need to keep running over the function calls in
183 // the module until we don't get any more optimizations possible.
184 bool found_optimization = false;
186 found_optimization = false;
187 for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
188 // All the "well-known" functions are external and have external linkage
189 // because they live in a runtime library somewhere and were (probably)
190 // not compiled by LLVM. So, we only act on external functions that
191 // have external or dllimport linkage and non-empty uses.
192 if (!FI->isDeclaration() ||
193 !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
197 // Get the optimization class that pertains to this function
198 StringMap<LibCallOptimization*>::iterator OMI =
199 OptznMap.find(FI->getName());
200 if (OMI == OptznMap.end()) continue;
202 LibCallOptimization *CO = OMI->second;
204 // Make sure the called function is suitable for the optimization
205 if (!CO->ValidateCalledFunction(FI, *this))
208 // Loop over each of the uses of the function
209 for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
211 // If the use of the function is a call instruction
212 if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
213 // Do the optimization on the LibCallOptimization.
214 if (CO->OptimizeCall(CI, *this)) {
215 ++SimplifiedLibCalls;
216 found_optimization = result = true;
222 } while (found_optimization);
227 /// @brief Return the *current* module we're working on.
228 Module* getModule() const { return M; }
230 /// @brief Return the *current* target data for the module we're working on.
231 TargetData* getTargetData() const { return TD; }
233 /// @brief Return the size_t type -- syntactic shortcut
234 const Type* getIntPtrType() const { return TD->getIntPtrType(); }
236 /// @brief Return a Function* for the putchar libcall
237 Constant *get_putchar() {
240 M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
244 /// @brief Return a Function* for the puts libcall
245 Constant *get_puts() {
247 puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
248 PointerType::getUnqual(Type::Int8Ty),
253 /// @brief Return a Function* for the fputc libcall
254 Constant *get_fputc(const Type* FILEptr_type) {
256 fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
261 /// @brief Return a Function* for the fputs libcall
262 Constant *get_fputs(const Type* FILEptr_type) {
264 fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
265 PointerType::getUnqual(Type::Int8Ty),
270 /// @brief Return a Function* for the fwrite libcall
271 Constant *get_fwrite(const Type* FILEptr_type) {
273 fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
274 PointerType::getUnqual(Type::Int8Ty),
281 /// @brief Return a Function* for the sqrt libcall
282 Constant *get_sqrt() {
284 sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
285 Type::DoubleTy, NULL);
289 /// @brief Return a Function* for the strcpy libcall
290 Constant *get_strcpy() {
292 strcpy_func = M->getOrInsertFunction("strcpy",
293 PointerType::getUnqual(Type::Int8Ty),
294 PointerType::getUnqual(Type::Int8Ty),
295 PointerType::getUnqual(Type::Int8Ty),
300 /// @brief Return a Function* for the strlen libcall
301 Constant *get_strlen() {
303 strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
304 PointerType::getUnqual(Type::Int8Ty),
309 /// @brief Return a Function* for the memchr libcall
310 Constant *get_memchr() {
312 memchr_func = M->getOrInsertFunction("memchr",
313 PointerType::getUnqual(Type::Int8Ty),
314 PointerType::getUnqual(Type::Int8Ty),
315 Type::Int32Ty, TD->getIntPtrType(),
320 /// @brief Return a Function* for the memcpy libcall
321 Constant *get_memcpy() {
323 const Type *SBP = PointerType::getUnqual(Type::Int8Ty);
324 const char *N = TD->getIntPtrType() == Type::Int32Ty ?
325 "llvm.memcpy.i32" : "llvm.memcpy.i64";
326 memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
327 TD->getIntPtrType(), Type::Int32Ty,
333 Constant *getUnaryFloatFunction(const char *Name, Constant *&Cache) {
335 Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
339 Constant *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
340 Constant *get_ceilf() { return getUnaryFloatFunction( "ceilf", ceilf_func);}
341 Constant *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
342 Constant *get_rintf() { return getUnaryFloatFunction( "rintf", rintf_func);}
343 Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
346 /// @brief Reset our cached data for a new Module
347 void reset(Module& mod) {
349 TD = &getAnalysis<TargetData>();
368 /// Caches for function pointers.
369 Constant *putchar_func, *puts_func;
370 Constant *fputc_func, *fputs_func, *fwrite_func;
371 Constant *memcpy_func, *memchr_func;
373 Constant *strcpy_func, *strlen_func;
374 Constant *floorf_func, *ceilf_func, *roundf_func;
375 Constant *rintf_func, *nearbyintf_func;
376 Module *M; ///< Cached Module
377 TargetData *TD; ///< Cached TargetData
380 char SimplifyLibCalls::ID = 0;
382 RegisterPass<SimplifyLibCalls>
383 X("simplify-libcalls", "Simplify well-known library calls");
385 } // anonymous namespace
387 // The only public symbol in this file which just instantiates the pass object
388 ModulePass *llvm::createSimplifyLibCallsPass() {
389 return new SimplifyLibCalls();
392 // Classes below here, in the anonymous namespace, are all subclasses of the
393 // LibCallOptimization class, each implementing all optimizations possible for a
394 // single well-known library call. Each has a static singleton instance that
395 // auto registers it into the "optlist" global above.
398 // Forward declare utility functions.
399 static bool GetConstantStringInfo(Value *V, std::string &Str);
400 static Value *CastToCStr(Value *V, Instruction *IP);
402 /// This LibCallOptimization will find instances of a call to "exit" that occurs
403 /// within the "main" function and change it to a simple "ret" instruction with
404 /// the same value passed to the exit function. When this is done, it splits the
405 /// basic block at the exit(3) call and deletes the call instruction.
406 /// @brief Replace calls to exit in main with a simple return
407 struct VISIBILITY_HIDDEN ExitInMainOptimization : public LibCallOptimization {
408 ExitInMainOptimization() : LibCallOptimization("exit",
409 "Number of 'exit' calls simplified") {}
411 // Make sure the called function looks like exit (int argument, int return
412 // type, external linkage, not varargs).
413 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
414 return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
417 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
418 // To be careful, we check that the call to exit is coming from "main", that
419 // main has external linkage, and the return type of main and the argument
420 // to exit have the same type.
421 Function *from = ci->getParent()->getParent();
422 if (from->hasExternalLinkage())
423 if (from->getReturnType() == ci->getOperand(1)->getType())
424 if (from->getName() == "main") {
425 // Okay, time to actually do the optimization. First, get the basic
426 // block of the call instruction
427 BasicBlock* bb = ci->getParent();
429 // Create a return instruction that we'll replace the call with.
430 // Note that the argument of the return is the argument of the call
432 new ReturnInst(ci->getOperand(1), ci);
434 // Split the block at the call instruction which places it in a new
436 bb->splitBasicBlock(ci);
438 // The block split caused a branch instruction to be inserted into
439 // the end of the original block, right after the return instruction
440 // that we put there. That's not a valid block, so delete the branch
442 bb->getInstList().pop_back();
444 // Now we can finally get rid of the call instruction which now lives
445 // in the new basic block.
446 ci->eraseFromParent();
448 // Optimization succeeded, return true.
451 // We didn't pass the criteria for this optimization so return false
454 } ExitInMainOptimizer;
456 /// This LibCallOptimization will simplify a call to the strcat library
457 /// function. The simplification is possible only if the string being
458 /// concatenated is a constant array or a constant expression that results in
459 /// a constant string. In this case we can replace it with strlen + llvm.memcpy
460 /// of the constant string. Both of these calls are further reduced, if possible
461 /// on subsequent passes.
462 /// @brief Simplify the strcat library function.
463 struct VISIBILITY_HIDDEN StrCatOptimization : public LibCallOptimization {
465 /// @brief Default constructor
466 StrCatOptimization() : LibCallOptimization("strcat",
467 "Number of 'strcat' calls simplified") {}
471 /// @brief Make sure that the "strcat" function has the right prototype
472 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
473 const FunctionType *FT = F->getFunctionType();
474 return FT->getNumParams() == 2 &&
475 FT->getReturnType() == PointerType::getUnqual(Type::Int8Ty) &&
476 FT->getParamType(0) == FT->getReturnType() &&
477 FT->getParamType(1) == FT->getReturnType();
480 /// @brief Optimize the strcat library function
481 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
482 // Extract some information from the instruction
483 Value *Dst = CI->getOperand(1);
484 Value *Src = CI->getOperand(2);
486 // Extract the initializer (while making numerous checks) from the
487 // source operand of the call to strcat.
489 if (!GetConstantStringInfo(Src, SrcStr))
492 // Handle the simple, do-nothing case
494 return ReplaceCallWith(CI, Dst);
496 // We need to find the end of the destination string. That's where the
497 // memory is to be moved to. We just generate a call to strlen.
498 CallInst *DstLen = new CallInst(SLC.get_strlen(), Dst,
499 Dst->getName()+".len", CI);
501 // Now that we have the destination's length, we must index into the
502 // destination's pointer to get the actual memcpy destination (end of
503 // the string .. we're concatenating).
504 Dst = new GetElementPtrInst(Dst, DstLen, Dst->getName()+".indexed", CI);
506 // We have enough information to now generate the memcpy call to
507 // do the concatenation for us.
510 ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1), // copy nul byte.
511 ConstantInt::get(Type::Int32Ty, 1) // alignment
513 new CallInst(SLC.get_memcpy(), Vals, Vals + 4, "", CI);
515 return ReplaceCallWith(CI, Dst);
519 /// This LibCallOptimization will simplify a call to the strchr library
520 /// function. It optimizes out cases where the arguments are both constant
521 /// and the result can be determined statically.
522 /// @brief Simplify the strcmp library function.
523 struct VISIBILITY_HIDDEN StrChrOptimization : public LibCallOptimization {
525 StrChrOptimization() : LibCallOptimization("strchr",
526 "Number of 'strchr' calls simplified") {}
528 /// @brief Make sure that the "strchr" function has the right prototype
529 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
530 const FunctionType *FT = F->getFunctionType();
531 return FT->getNumParams() == 2 &&
532 FT->getReturnType() == PointerType::getUnqual(Type::Int8Ty) &&
533 FT->getParamType(0) == FT->getReturnType() &&
534 isa<IntegerType>(FT->getParamType(1));
537 /// @brief Perform the strchr optimizations
538 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
539 // Check that the first argument to strchr is a constant array of sbyte.
541 if (!GetConstantStringInfo(CI->getOperand(1), Str))
544 // If the second operand is not constant, just lower this to memchr since we
545 // know the length of the input string.
546 ConstantInt *CSI = dyn_cast<ConstantInt>(CI->getOperand(2));
551 ConstantInt::get(SLC.getIntPtrType(), Str.size()+1)
553 return ReplaceCallWith(CI, new CallInst(SLC.get_memchr(), Args, Args + 3,
557 // strchr can find the nul character.
560 // Get the character we're looking for
561 char CharValue = CSI->getSExtValue();
563 // Compute the offset
566 if (i == Str.size()) // Didn't find the char. strchr returns null.
567 return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
568 // Did we find our match?
569 if (Str[i] == CharValue)
574 // strchr(s+n,c) -> gep(s+n+i,c)
575 // (if c is a constant integer and s is a constant string)
576 Value *Idx = ConstantInt::get(Type::Int64Ty, i);
577 Value *GEP = new GetElementPtrInst(CI->getOperand(1), Idx,
578 CI->getOperand(1)->getName() +
580 return ReplaceCallWith(CI, GEP);
584 /// This LibCallOptimization will simplify a call to the strcmp library
585 /// function. It optimizes out cases where one or both arguments are constant
586 /// and the result can be determined statically.
587 /// @brief Simplify the strcmp library function.
588 struct VISIBILITY_HIDDEN StrCmpOptimization : public LibCallOptimization {
590 StrCmpOptimization() : LibCallOptimization("strcmp",
591 "Number of 'strcmp' calls simplified") {}
593 /// @brief Make sure that the "strcmp" function has the right prototype
594 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
595 const FunctionType *FT = F->getFunctionType();
596 return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 2 &&
597 FT->getParamType(0) == FT->getParamType(1) &&
598 FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty);
601 /// @brief Perform the strcmp optimization
602 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
603 // First, check to see if src and destination are the same. If they are,
604 // then the optimization is to replace the CallInst with a constant 0
605 // because the call is a no-op.
606 Value *Str1P = CI->getOperand(1);
607 Value *Str2P = CI->getOperand(2);
608 if (Str1P == Str2P) // strcmp(x,x) -> 0
609 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
612 if (!GetConstantStringInfo(Str1P, Str1))
615 // strcmp("", x) -> *x
616 Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
617 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
618 return ReplaceCallWith(CI, V);
622 if (!GetConstantStringInfo(Str2P, Str2))
625 // strcmp(x,"") -> *x
626 Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
627 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
628 return ReplaceCallWith(CI, V);
631 // strcmp(x, y) -> cnst (if both x and y are constant strings)
632 int R = strcmp(Str1.c_str(), Str2.c_str());
633 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
637 /// This LibCallOptimization will simplify a call to the strncmp library
638 /// function. It optimizes out cases where one or both arguments are constant
639 /// and the result can be determined statically.
640 /// @brief Simplify the strncmp library function.
641 struct VISIBILITY_HIDDEN StrNCmpOptimization : public LibCallOptimization {
643 StrNCmpOptimization() : LibCallOptimization("strncmp",
644 "Number of 'strncmp' calls simplified") {}
646 /// @brief Make sure that the "strncmp" function has the right prototype
647 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
648 const FunctionType *FT = F->getFunctionType();
649 return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 3 &&
650 FT->getParamType(0) == FT->getParamType(1) &&
651 FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
652 isa<IntegerType>(FT->getParamType(2));
656 /// @brief Perform the strncmp optimization
657 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
658 // First, check to see if src and destination are the same. If they are,
659 // then the optimization is to replace the CallInst with a constant 0
660 // because the call is a no-op.
661 Value *Str1P = CI->getOperand(1);
662 Value *Str2P = CI->getOperand(2);
663 if (Str1P == Str2P) // strncmp(x,x, n) -> 0
664 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
666 // Check the length argument, if it is Constant zero then the strings are
669 if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
670 Length = LengthArg->getZExtValue();
674 if (Length == 0) // strncmp(x,y,0) -> 0
675 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
678 if (!GetConstantStringInfo(Str1P, Str1))
681 // strncmp("", x, n) -> *x
682 Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
683 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
684 return ReplaceCallWith(CI, V);
688 if (!GetConstantStringInfo(Str2P, Str2))
691 // strncmp(x, "", n) -> *x
692 Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
693 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
694 return ReplaceCallWith(CI, V);
697 // strncmp(x, y, n) -> cnst (if both x and y are constant strings)
698 int R = strncmp(Str1.c_str(), Str2.c_str(), Length);
699 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
703 /// This LibCallOptimization will simplify a call to the strcpy library
704 /// function. Two optimizations are possible:
705 /// (1) If src and dest are the same and not volatile, just return dest
706 /// (2) If the src is a constant then we can convert to llvm.memmove
707 /// @brief Simplify the strcpy library function.
708 struct VISIBILITY_HIDDEN StrCpyOptimization : public LibCallOptimization {
710 StrCpyOptimization() : LibCallOptimization("strcpy",
711 "Number of 'strcpy' calls simplified") {}
713 /// @brief Make sure that the "strcpy" function has the right prototype
714 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
715 const FunctionType *FT = F->getFunctionType();
716 return FT->getNumParams() == 2 &&
717 FT->getParamType(0) == FT->getParamType(1) &&
718 FT->getReturnType() == FT->getParamType(0) &&
719 FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty);
722 /// @brief Perform the strcpy optimization
723 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
724 // First, check to see if src and destination are the same. If they are,
725 // then the optimization is to replace the CallInst with the destination
726 // because the call is a no-op. Note that this corresponds to the
727 // degenerate strcpy(X,X) case which should have "undefined" results
728 // according to the C specification. However, it occurs sometimes and
729 // we optimize it as a no-op.
730 Value *Dst = CI->getOperand(1);
731 Value *Src = CI->getOperand(2);
734 return ReplaceCallWith(CI, Dst);
737 // Get the length of the constant string referenced by the Src operand.
739 if (!GetConstantStringInfo(Src, SrcStr))
742 // If the constant string's length is zero we can optimize this by just
743 // doing a store of 0 at the first byte of the destination
744 if (SrcStr.empty()) {
745 new StoreInst(ConstantInt::get(Type::Int8Ty, 0), Dst, CI);
746 return ReplaceCallWith(CI, Dst);
749 // We have enough information to now generate the memcpy call to
750 // do the concatenation for us.
751 Value *MemcpyOps[] = {
752 Dst, Src, // Pass length including nul byte.
753 ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1),
754 ConstantInt::get(Type::Int32Ty, 1) // alignment
756 new CallInst(SLC.get_memcpy(), MemcpyOps, MemcpyOps + 4, "", CI);
758 return ReplaceCallWith(CI, Dst);
762 /// This LibCallOptimization will simplify a call to the strlen library
763 /// function by replacing it with a constant value if the string provided to
764 /// it is a constant array.
765 /// @brief Simplify the strlen library function.
766 struct VISIBILITY_HIDDEN StrLenOptimization : public LibCallOptimization {
767 StrLenOptimization() : LibCallOptimization("strlen",
768 "Number of 'strlen' calls simplified") {}
770 /// @brief Make sure that the "strlen" function has the right prototype
771 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
772 const FunctionType *FT = F->getFunctionType();
773 return FT->getNumParams() == 1 &&
774 FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
775 isa<IntegerType>(FT->getReturnType());
778 /// @brief Perform the strlen optimization
779 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
780 // Make sure we're dealing with an sbyte* here.
781 Value *Src = CI->getOperand(1);
783 // Does the call to strlen have exactly one use?
784 if (CI->hasOneUse()) {
785 // Is that single use a icmp operator?
786 if (ICmpInst *Cmp = dyn_cast<ICmpInst>(CI->use_back()))
787 // Is it compared against a constant integer?
788 if (ConstantInt *Cst = dyn_cast<ConstantInt>(Cmp->getOperand(1))) {
789 // If its compared against length 0 with == or !=
790 if (Cst->getZExtValue() == 0 && Cmp->isEquality()) {
791 // strlen(x) != 0 -> *x != 0
792 // strlen(x) == 0 -> *x == 0
793 Value *V = new LoadInst(Src, Src->getName()+".first", CI);
794 V = new ICmpInst(Cmp->getPredicate(), V,
795 ConstantInt::get(Type::Int8Ty, 0),
796 Cmp->getName()+".strlen", CI);
797 Cmp->replaceAllUsesWith(V);
798 Cmp->eraseFromParent();
799 return ReplaceCallWith(CI, 0); // no uses.
804 // Get the length of the constant string operand
806 if (!GetConstantStringInfo(Src, Str))
809 // strlen("xyz") -> 3 (for example)
810 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), Str.size()));
814 /// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
815 /// is equal or not-equal to zero.
816 static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
817 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
819 if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
820 if (IC->isEquality())
821 if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
822 if (C->isNullValue())
824 // Unknown instruction.
830 /// This memcmpOptimization will simplify a call to the memcmp library
832 struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
833 /// @brief Default Constructor
835 : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
837 /// @brief Make sure that the "memcmp" function has the right prototype
838 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
839 Function::const_arg_iterator AI = F->arg_begin();
840 if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
841 if (!isa<PointerType>((++AI)->getType())) return false;
842 if (!(++AI)->getType()->isInteger()) return false;
843 if (!F->getReturnType()->isInteger()) return false;
847 /// Because of alignment and instruction information that we don't have, we
848 /// leave the bulk of this to the code generators.
850 /// Note that we could do much more if we could force alignment on otherwise
851 /// small aligned allocas, or if we could indicate that loads have a small
853 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
854 Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
856 // If the two operands are the same, return zero.
858 // memcmp(s,s,x) -> 0
859 return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
862 // Make sure we have a constant length.
863 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
864 if (!LenC) return false;
865 uint64_t Len = LenC->getZExtValue();
867 // If the length is zero, this returns 0.
870 // memcmp(s1,s2,0) -> 0
871 return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
873 // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
874 const Type *UCharPtr = PointerType::getUnqual(Type::Int8Ty);
875 CastInst *Op1Cast = CastInst::create(
876 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
877 CastInst *Op2Cast = CastInst::create(
878 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
879 Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
880 Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
881 Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
882 if (RV->getType() != CI->getType())
883 RV = CastInst::createIntegerCast(RV, CI->getType(), false,
885 return ReplaceCallWith(CI, RV);
888 if (IsOnlyUsedInEqualsZeroComparison(CI)) {
889 // TODO: IF both are aligned, use a short load/compare.
891 // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
892 const Type *UCharPtr = PointerType::getUnqual(Type::Int8Ty);
893 CastInst *Op1Cast = CastInst::create(
894 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
895 CastInst *Op2Cast = CastInst::create(
896 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
897 Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
898 Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
899 Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
900 CI->getName()+".d1", CI);
901 Constant *One = ConstantInt::get(Type::Int32Ty, 1);
902 Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
903 Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
904 Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
905 Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
906 Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
907 CI->getName()+".d1", CI);
908 Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
909 if (Or->getType() != CI->getType())
910 Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
912 return ReplaceCallWith(CI, Or);
923 /// This LibCallOptimization will simplify a call to the memcpy library
924 /// function. It simply converts them into calls to llvm.memcpy.*;
925 /// the resulting call should be optimized later.
926 /// @brief Simplify the memcpy library function.
927 struct VISIBILITY_HIDDEN MemCpyOptimization : public LibCallOptimization {
929 MemCpyOptimization() : LibCallOptimization("memcpy",
930 "Number of 'memcpy' calls simplified") {}
932 /// @brief Make sure that the "memcpy" function has the right prototype
933 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
934 const FunctionType *FT = F->getFunctionType();
935 const Type* voidPtr = PointerType::getUnqual(Type::Int8Ty);
936 return FT->getReturnType() == voidPtr && FT->getNumParams() == 3 &&
937 FT->getParamType(0) == voidPtr &&
938 FT->getParamType(1) == voidPtr &&
939 FT->getParamType(2) == SLC.getIntPtrType();
942 /// @brief Perform the memcpy optimization
943 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
944 Value *MemcpyOps[] = {
945 CI->getOperand(1), CI->getOperand(2), CI->getOperand(3),
946 ConstantInt::get(Type::Int32Ty, 1) // align = 1 always.
948 new CallInst(SLC.get_memcpy(), MemcpyOps, MemcpyOps + 4, "", CI);
949 // memcpy always returns the destination
950 return ReplaceCallWith(CI, CI->getOperand(1));
954 /// This LibCallOptimization will simplify a call to the memcpy library
955 /// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
956 /// bytes depending on the length of the string and the alignment. Additional
957 /// optimizations are possible in code generation (sequence of immediate store)
958 /// @brief Simplify the memcpy library function.
959 struct VISIBILITY_HIDDEN LLVMMemCpyMoveOptzn : public LibCallOptimization {
960 LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
961 : LibCallOptimization(fname, desc) {}
963 /// @brief Make sure that the "memcpy" function has the right prototype
964 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
965 // Just make sure this has 4 arguments per LLVM spec.
966 return (f->arg_size() == 4);
969 /// Because of alignment and instruction information that we don't have, we
970 /// leave the bulk of this to the code generators. The optimization here just
971 /// deals with a few degenerate cases where the length of the string and the
972 /// alignment match the sizes of our intrinsic types so we can do a load and
973 /// store instead of the memcpy call.
974 /// @brief Perform the memcpy optimization.
975 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
976 // Make sure we have constant int values to work with
977 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
980 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
984 // If the length is larger than the alignment, we can't optimize
985 uint64_t len = LEN->getZExtValue();
986 uint64_t alignment = ALIGN->getZExtValue();
988 alignment = 1; // Alignment 0 is identity for alignment 1
992 // Get the type we will cast to, based on size of the string
993 Value* dest = ci->getOperand(1);
994 Value* src = ci->getOperand(2);
995 const Type* castType = 0;
998 // memcpy(d,s,0,a) -> d
999 return ReplaceCallWith(ci, 0);
1000 case 1: castType = Type::Int8Ty; break;
1001 case 2: castType = Type::Int16Ty; break;
1002 case 4: castType = Type::Int32Ty; break;
1003 case 8: castType = Type::Int64Ty; break;
1008 // Cast source and dest to the right sized primitive and then load/store
1009 CastInst* SrcCast = CastInst::create(Instruction::BitCast,
1010 src, PointerType::getUnqual(castType), src->getName()+".cast", ci);
1011 CastInst* DestCast = CastInst::create(Instruction::BitCast,
1012 dest, PointerType::getUnqual(castType),dest->getName()+".cast", ci);
1013 LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
1014 new StoreInst(LI, DestCast, ci);
1015 return ReplaceCallWith(ci, 0);
1019 /// This LibCallOptimization will simplify a call to the memcpy/memmove library
1021 LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
1022 "Number of 'llvm.memcpy' calls simplified");
1023 LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
1024 "Number of 'llvm.memcpy' calls simplified");
1025 LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
1026 "Number of 'llvm.memmove' calls simplified");
1027 LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
1028 "Number of 'llvm.memmove' calls simplified");
1030 /// This LibCallOptimization will simplify a call to the memset library
1031 /// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
1032 /// bytes depending on the length argument.
1033 struct VISIBILITY_HIDDEN LLVMMemSetOptimization : public LibCallOptimization {
1034 /// @brief Default Constructor
1035 LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
1036 "Number of 'llvm.memset' calls simplified") {}
1038 /// @brief Make sure that the "memset" function has the right prototype
1039 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
1040 // Just make sure this has 3 arguments per LLVM spec.
1041 return F->arg_size() == 4;
1044 /// Because of alignment and instruction information that we don't have, we
1045 /// leave the bulk of this to the code generators. The optimization here just
1046 /// deals with a few degenerate cases where the length parameter is constant
1047 /// and the alignment matches the sizes of our intrinsic types so we can do
1048 /// store instead of the memcpy call. Other calls are transformed into the
1049 /// llvm.memset intrinsic.
1050 /// @brief Perform the memset optimization.
1051 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
1052 // Make sure we have constant int values to work with
1053 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
1056 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
1060 // Extract the length and alignment
1061 uint64_t len = LEN->getZExtValue();
1062 uint64_t alignment = ALIGN->getZExtValue();
1064 // Alignment 0 is identity for alignment 1
1068 // If the length is zero, this is a no-op
1070 // memset(d,c,0,a) -> noop
1071 return ReplaceCallWith(ci, 0);
1074 // If the length is larger than the alignment, we can't optimize
1075 if (len > alignment)
1078 // Make sure we have a constant ubyte to work with so we can extract
1079 // the value to be filled.
1080 ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
1083 if (FILL->getType() != Type::Int8Ty)
1086 // memset(s,c,n) -> store s, c (for n=1,2,4,8)
1088 // Extract the fill character
1089 uint64_t fill_char = FILL->getZExtValue();
1090 uint64_t fill_value = fill_char;
1092 // Get the type we will cast to, based on size of memory area to fill, and
1093 // and the value we will store there.
1094 Value* dest = ci->getOperand(1);
1095 const Type* castType = 0;
1098 castType = Type::Int8Ty;
1101 castType = Type::Int16Ty;
1102 fill_value |= fill_char << 8;
1105 castType = Type::Int32Ty;
1106 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1109 castType = Type::Int64Ty;
1110 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1111 fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
1112 fill_value |= fill_char << 56;
1118 // Cast dest to the right sized primitive and then load/store
1119 CastInst* DestCast = new BitCastInst(dest, PointerType::getUnqual(castType),
1120 dest->getName()+".cast", ci);
1121 new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
1122 return ReplaceCallWith(ci, 0);
1126 LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
1127 LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
1130 /// This LibCallOptimization will simplify calls to the "pow" library
1131 /// function. It looks for cases where the result of pow is well known and
1132 /// substitutes the appropriate value.
1133 /// @brief Simplify the pow library function.
1134 struct VISIBILITY_HIDDEN PowOptimization : public LibCallOptimization {
1136 /// @brief Default Constructor
1137 PowOptimization() : LibCallOptimization("pow",
1138 "Number of 'pow' calls simplified") {}
1140 /// @brief Make sure that the "pow" function has the right prototype
1141 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1142 // Just make sure this has 2 arguments
1143 return (f->arg_size() == 2);
1146 /// @brief Perform the pow optimization.
1147 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1148 const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
1149 if (Ty!=Type::FloatTy && Ty!=Type::DoubleTy)
1150 return false; // FIXME long double not yet supported
1151 Value* base = ci->getOperand(1);
1152 Value* expn = ci->getOperand(2);
1153 if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
1154 if (Op1->isExactlyValue(1.0)) // pow(1.0,x) -> 1.0
1155 return ReplaceCallWith(ci, ConstantFP::get(Ty,
1156 Ty==Type::FloatTy ? APFloat(1.0f) : APFloat(1.0)));
1157 } else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
1158 if (Op2->getValueAPF().isZero()) {
1159 // pow(x,0.0) -> 1.0
1160 return ReplaceCallWith(ci, ConstantFP::get(Ty,
1161 Ty==Type::FloatTy ? APFloat(1.0f) : APFloat(1.0)));
1162 } else if (Op2->isExactlyValue(0.5)) {
1163 // pow(x,0.5) -> sqrt(x)
1164 CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
1165 ci->getName()+".pow",ci);
1166 return ReplaceCallWith(ci, sqrt_inst);
1167 } else if (Op2->isExactlyValue(1.0)) {
1169 return ReplaceCallWith(ci, base);
1170 } else if (Op2->isExactlyValue(-1.0)) {
1171 // pow(x,-1.0) -> 1.0/x
1173 BinaryOperator::createFDiv(ConstantFP::get(Ty,
1174 Ty==Type::FloatTy ? APFloat(1.0f) : APFloat(1.0)),
1175 base, ci->getName()+".pow", ci);
1176 return ReplaceCallWith(ci, div_inst);
1179 return false; // opt failed
1183 /// This LibCallOptimization will simplify calls to the "printf" library
1184 /// function. It looks for cases where the result of printf is not used and the
1185 /// operation can be reduced to something simpler.
1186 /// @brief Simplify the printf library function.
1187 struct VISIBILITY_HIDDEN PrintfOptimization : public LibCallOptimization {
1189 /// @brief Default Constructor
1190 PrintfOptimization() : LibCallOptimization("printf",
1191 "Number of 'printf' calls simplified") {}
1193 /// @brief Make sure that the "printf" function has the right prototype
1194 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1195 // Just make sure this has at least 1 argument and returns an integer or
1197 const FunctionType *FT = F->getFunctionType();
1198 return FT->getNumParams() >= 1 &&
1199 (isa<IntegerType>(FT->getReturnType()) ||
1200 FT->getReturnType() == Type::VoidTy);
1203 /// @brief Perform the printf optimization.
1204 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1205 // All the optimizations depend on the length of the first argument and the
1206 // fact that it is a constant string array. Check that now
1207 std::string FormatStr;
1208 if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
1211 // If this is a simple constant string with no format specifiers that ends
1212 // with a \n, turn it into a puts call.
1213 if (FormatStr.empty()) {
1214 // Tolerate printf's declared void.
1215 if (CI->use_empty()) return ReplaceCallWith(CI, 0);
1216 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
1219 if (FormatStr.size() == 1) {
1220 // Turn this into a putchar call, even if it is a %.
1221 Value *V = ConstantInt::get(Type::Int32Ty, FormatStr[0]);
1222 new CallInst(SLC.get_putchar(), V, "", CI);
1223 if (CI->use_empty()) return ReplaceCallWith(CI, 0);
1224 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
1227 // Check to see if the format str is something like "foo\n", in which case
1228 // we convert it to a puts call. We don't allow it to contain any format
1230 if (FormatStr[FormatStr.size()-1] == '\n' &&
1231 FormatStr.find('%') == std::string::npos) {
1232 // Create a string literal with no \n on it. We expect the constant merge
1233 // pass to be run after this pass, to merge duplicate strings.
1234 FormatStr.erase(FormatStr.end()-1);
1235 Constant *Init = ConstantArray::get(FormatStr, true);
1236 Constant *GV = new GlobalVariable(Init->getType(), true,
1237 GlobalVariable::InternalLinkage,
1239 CI->getParent()->getParent()->getParent());
1240 // Cast GV to be a pointer to char.
1241 GV = ConstantExpr::getBitCast(GV, PointerType::getUnqual(Type::Int8Ty));
1242 new CallInst(SLC.get_puts(), GV, "", CI);
1244 if (CI->use_empty()) return ReplaceCallWith(CI, 0);
1245 // The return value from printf includes the \n we just removed, so +1.
1246 return ReplaceCallWith(CI,
1247 ConstantInt::get(CI->getType(),
1248 FormatStr.size()+1));
1252 // Only support %c or "%s\n" for now.
1253 if (FormatStr.size() < 2 || FormatStr[0] != '%')
1256 // Get the second character and switch on its value
1257 switch (FormatStr[1]) {
1258 default: return false;
1260 if (FormatStr != "%s\n" || CI->getNumOperands() < 3 ||
1261 // TODO: could insert strlen call to compute string length.
1265 // printf("%s\n",str) -> puts(str)
1266 new CallInst(SLC.get_puts(), CastToCStr(CI->getOperand(2), CI),
1268 return ReplaceCallWith(CI, 0);
1270 // printf("%c",c) -> putchar(c)
1271 if (FormatStr.size() != 2 || CI->getNumOperands() < 3)
1274 Value *V = CI->getOperand(2);
1275 if (!isa<IntegerType>(V->getType()) ||
1276 cast<IntegerType>(V->getType())->getBitWidth() > 32)
1279 V = CastInst::createZExtOrBitCast(V, Type::Int32Ty, CI->getName()+".int",
1281 new CallInst(SLC.get_putchar(), V, "", CI);
1282 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
1288 /// This LibCallOptimization will simplify calls to the "fprintf" library
1289 /// function. It looks for cases where the result of fprintf is not used and the
1290 /// operation can be reduced to something simpler.
1291 /// @brief Simplify the fprintf library function.
1292 struct VISIBILITY_HIDDEN FPrintFOptimization : public LibCallOptimization {
1294 /// @brief Default Constructor
1295 FPrintFOptimization() : LibCallOptimization("fprintf",
1296 "Number of 'fprintf' calls simplified") {}
1298 /// @brief Make sure that the "fprintf" function has the right prototype
1299 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1300 const FunctionType *FT = F->getFunctionType();
1301 return FT->getNumParams() == 2 && // two fixed arguments.
1302 FT->getParamType(1) == PointerType::getUnqual(Type::Int8Ty) &&
1303 isa<PointerType>(FT->getParamType(0)) &&
1304 isa<IntegerType>(FT->getReturnType());
1307 /// @brief Perform the fprintf optimization.
1308 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1309 // If the call has more than 3 operands, we can't optimize it
1310 if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
1313 // All the optimizations depend on the format string.
1314 std::string FormatStr;
1315 if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
1318 // If this is just a format string, turn it into fwrite.
1319 if (CI->getNumOperands() == 3) {
1320 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1321 if (FormatStr[i] == '%')
1322 return false; // we found a format specifier
1324 // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
1325 const Type *FILEty = CI->getOperand(1)->getType();
1327 Value *FWriteArgs[] = {
1329 ConstantInt::get(SLC.getIntPtrType(), FormatStr.size()),
1330 ConstantInt::get(SLC.getIntPtrType(), 1),
1333 new CallInst(SLC.get_fwrite(FILEty), FWriteArgs, FWriteArgs + 4, CI->getName(), CI);
1334 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
1338 // The remaining optimizations require the format string to be length 2:
1340 if (FormatStr.size() != 2 || FormatStr[0] != '%')
1343 // Get the second character and switch on its value
1344 switch (FormatStr[1]) {
1346 // fprintf(file,"%c",c) -> fputc(c,file)
1347 const Type *FILETy = CI->getOperand(1)->getType();
1348 Value *C = CastInst::createZExtOrBitCast(CI->getOperand(3), Type::Int32Ty,
1349 CI->getName()+".int", CI);
1350 SmallVector<Value *, 2> Args;
1352 Args.push_back(CI->getOperand(1));
1353 new CallInst(SLC.get_fputc(FILETy), Args.begin(), Args.end(), "", CI);
1354 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
1357 const Type *FILETy = CI->getOperand(1)->getType();
1359 // If the result of the fprintf call is used, we can't do this.
1360 // TODO: we should insert a strlen call.
1361 if (!CI->use_empty())
1364 // fprintf(file,"%s",str) -> fputs(str,file)
1365 SmallVector<Value *, 2> Args;
1366 Args.push_back(CastToCStr(CI->getOperand(3), CI));
1367 Args.push_back(CI->getOperand(1));
1368 new CallInst(SLC.get_fputs(FILETy), Args.begin(),
1369 Args.end(), CI->getName(), CI);
1370 return ReplaceCallWith(CI, 0);
1378 /// This LibCallOptimization will simplify calls to the "sprintf" library
1379 /// function. It looks for cases where the result of sprintf is not used and the
1380 /// operation can be reduced to something simpler.
1381 /// @brief Simplify the sprintf library function.
1382 struct VISIBILITY_HIDDEN SPrintFOptimization : public LibCallOptimization {
1384 /// @brief Default Constructor
1385 SPrintFOptimization() : LibCallOptimization("sprintf",
1386 "Number of 'sprintf' calls simplified") {}
1388 /// @brief Make sure that the "sprintf" function has the right prototype
1389 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1390 const FunctionType *FT = F->getFunctionType();
1391 return FT->getNumParams() == 2 && // two fixed arguments.
1392 FT->getParamType(1) == PointerType::getUnqual(Type::Int8Ty) &&
1393 FT->getParamType(0) == FT->getParamType(1) &&
1394 isa<IntegerType>(FT->getReturnType());
1397 /// @brief Perform the sprintf optimization.
1398 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1399 // If the call has more than 3 operands, we can't optimize it
1400 if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
1403 std::string FormatStr;
1404 if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
1407 if (CI->getNumOperands() == 3) {
1408 // Make sure there's no % in the constant array
1409 for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
1410 if (FormatStr[i] == '%')
1411 return false; // we found a format specifier
1413 // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
1414 Value *MemCpyArgs[] = {
1415 CI->getOperand(1), CI->getOperand(2),
1416 ConstantInt::get(SLC.getIntPtrType(),
1417 FormatStr.size()+1), // Copy the nul byte.
1418 ConstantInt::get(Type::Int32Ty, 1)
1420 new CallInst(SLC.get_memcpy(), MemCpyArgs, MemCpyArgs + 4, "", CI);
1421 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
1425 // The remaining optimizations require the format string to be "%s" or "%c".
1426 if (FormatStr.size() != 2 || FormatStr[0] != '%')
1429 // Get the second character and switch on its value
1430 switch (FormatStr[1]) {
1432 // sprintf(dest,"%c",chr) -> store chr, dest
1433 Value *V = CastInst::createTruncOrBitCast(CI->getOperand(3),
1434 Type::Int8Ty, "char", CI);
1435 new StoreInst(V, CI->getOperand(1), CI);
1436 Value *Ptr = new GetElementPtrInst(CI->getOperand(1),
1437 ConstantInt::get(Type::Int32Ty, 1),
1438 CI->getOperand(1)->getName()+".end",
1440 new StoreInst(ConstantInt::get(Type::Int8Ty,0), Ptr, CI);
1441 return ReplaceCallWith(CI, ConstantInt::get(Type::Int32Ty, 1));
1444 // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1445 Value *Len = new CallInst(SLC.get_strlen(),
1446 CastToCStr(CI->getOperand(3), CI),
1447 CI->getOperand(3)->getName()+".len", CI);
1448 Value *UnincLen = Len;
1449 Len = BinaryOperator::createAdd(Len, ConstantInt::get(Len->getType(), 1),
1450 Len->getName()+"1", CI);
1451 Value *MemcpyArgs[4] = {
1453 CastToCStr(CI->getOperand(3), CI),
1455 ConstantInt::get(Type::Int32Ty, 1)
1457 new CallInst(SLC.get_memcpy(), MemcpyArgs, MemcpyArgs + 4, "", CI);
1459 // The strlen result is the unincremented number of bytes in the string.
1460 if (!CI->use_empty()) {
1461 if (UnincLen->getType() != CI->getType())
1462 UnincLen = CastInst::createIntegerCast(UnincLen, CI->getType(), false,
1463 Len->getName(), CI);
1464 CI->replaceAllUsesWith(UnincLen);
1466 return ReplaceCallWith(CI, 0);
1473 /// This LibCallOptimization will simplify calls to the "fputs" library
1474 /// function. It looks for cases where the result of fputs is not used and the
1475 /// operation can be reduced to something simpler.
1476 /// @brief Simplify the fputs library function.
1477 struct VISIBILITY_HIDDEN FPutsOptimization : public LibCallOptimization {
1479 /// @brief Default Constructor
1480 FPutsOptimization() : LibCallOptimization("fputs",
1481 "Number of 'fputs' calls simplified") {}
1483 /// @brief Make sure that the "fputs" function has the right prototype
1484 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1485 // Just make sure this has 2 arguments
1486 return F->arg_size() == 2;
1489 /// @brief Perform the fputs optimization.
1490 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1491 // If the result is used, none of these optimizations work.
1492 if (!CI->use_empty())
1495 // All the optimizations depend on the length of the first argument and the
1496 // fact that it is a constant string array. Check that now
1498 if (!GetConstantStringInfo(CI->getOperand(1), Str))
1501 const Type *FILETy = CI->getOperand(2)->getType();
1502 // fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
1503 Value *FWriteParms[4] = {
1505 ConstantInt::get(SLC.getIntPtrType(), Str.size()),
1506 ConstantInt::get(SLC.getIntPtrType(), 1),
1509 new CallInst(SLC.get_fwrite(FILETy), FWriteParms, FWriteParms + 4, "", CI);
1510 return ReplaceCallWith(CI, 0); // Known to have no uses (see above).
1514 /// This LibCallOptimization will simplify calls to the "fwrite" function.
1515 struct VISIBILITY_HIDDEN FWriteOptimization : public LibCallOptimization {
1517 /// @brief Default Constructor
1518 FWriteOptimization() : LibCallOptimization("fwrite",
1519 "Number of 'fwrite' calls simplified") {}
1521 /// @brief Make sure that the "fputs" function has the right prototype
1522 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1523 const FunctionType *FT = F->getFunctionType();
1524 return FT->getNumParams() == 4 &&
1525 FT->getParamType(0) == PointerType::getUnqual(Type::Int8Ty) &&
1526 FT->getParamType(1) == FT->getParamType(2) &&
1527 isa<IntegerType>(FT->getParamType(1)) &&
1528 isa<PointerType>(FT->getParamType(3)) &&
1529 isa<IntegerType>(FT->getReturnType());
1532 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1533 // Get the element size and count.
1534 uint64_t EltSize, EltCount;
1535 if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
1536 EltSize = C->getZExtValue();
1539 if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
1540 EltCount = C->getZExtValue();
1544 // If this is writing zero records, remove the call (it's a noop).
1545 if (EltSize * EltCount == 0)
1546 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
1548 // If this is writing one byte, turn it into fputc.
1549 if (EltSize == 1 && EltCount == 1) {
1550 SmallVector<Value *, 2> Args;
1551 // fwrite(s,1,1,F) -> fputc(s[0],F)
1552 Value *Ptr = CI->getOperand(1);
1553 Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
1554 Args.push_back(new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI));
1555 Args.push_back(CI->getOperand(4));
1556 const Type *FILETy = CI->getOperand(4)->getType();
1557 new CallInst(SLC.get_fputc(FILETy), Args.begin(), Args.end(), "", CI);
1558 return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
1564 /// This LibCallOptimization will simplify calls to the "isdigit" library
1565 /// function. It simply does range checks the parameter explicitly.
1566 /// @brief Simplify the isdigit library function.
1567 struct VISIBILITY_HIDDEN isdigitOptimization : public LibCallOptimization {
1569 isdigitOptimization() : LibCallOptimization("isdigit",
1570 "Number of 'isdigit' calls simplified") {}
1572 /// @brief Make sure that the "isdigit" function has the right prototype
1573 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1574 // Just make sure this has 1 argument
1575 return (f->arg_size() == 1);
1578 /// @brief Perform the toascii optimization.
1579 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1580 if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
1581 // isdigit(c) -> 0 or 1, if 'c' is constant
1582 uint64_t val = CI->getZExtValue();
1583 if (val >= '0' && val <= '9')
1584 return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 1));
1586 return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 0));
1589 // isdigit(c) -> (unsigned)c - '0' <= 9
1590 CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
1591 Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
1592 BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
1593 ConstantInt::get(Type::Int32Ty,0x30),
1594 ci->getOperand(1)->getName()+".sub",ci);
1595 ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
1596 ConstantInt::get(Type::Int32Ty,9),
1597 ci->getOperand(1)->getName()+".cmp",ci);
1598 CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
1599 ci->getOperand(1)->getName()+".isdigit", ci);
1600 return ReplaceCallWith(ci, c2);
1604 struct VISIBILITY_HIDDEN isasciiOptimization : public LibCallOptimization {
1606 isasciiOptimization()
1607 : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
1609 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1610 return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
1611 F->getReturnType()->isInteger();
1614 /// @brief Perform the isascii optimization.
1615 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1616 // isascii(c) -> (unsigned)c < 128
1617 Value *V = CI->getOperand(1);
1618 Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
1619 ConstantInt::get(V->getType(), 128),
1620 V->getName()+".isascii", CI);
1621 if (Cmp->getType() != CI->getType())
1622 Cmp = new ZExtInst(Cmp, CI->getType(), Cmp->getName(), CI);
1623 return ReplaceCallWith(CI, Cmp);
1628 /// This LibCallOptimization will simplify calls to the "toascii" library
1629 /// function. It simply does the corresponding and operation to restrict the
1630 /// range of values to the ASCII character set (0-127).
1631 /// @brief Simplify the toascii library function.
1632 struct VISIBILITY_HIDDEN ToAsciiOptimization : public LibCallOptimization {
1634 /// @brief Default Constructor
1635 ToAsciiOptimization() : LibCallOptimization("toascii",
1636 "Number of 'toascii' calls simplified") {}
1638 /// @brief Make sure that the "fputs" function has the right prototype
1639 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1640 // Just make sure this has 2 arguments
1641 return (f->arg_size() == 1);
1644 /// @brief Perform the toascii optimization.
1645 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1646 // toascii(c) -> (c & 0x7f)
1647 Value *chr = ci->getOperand(1);
1648 Value *and_inst = BinaryOperator::createAnd(chr,
1649 ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
1650 return ReplaceCallWith(ci, and_inst);
1654 /// This LibCallOptimization will simplify calls to the "ffs" library
1655 /// calls which find the first set bit in an int, long, or long long. The
1656 /// optimization is to compute the result at compile time if the argument is
1658 /// @brief Simplify the ffs library function.
1659 struct VISIBILITY_HIDDEN FFSOptimization : public LibCallOptimization {
1661 /// @brief Subclass Constructor
1662 FFSOptimization(const char* funcName, const char* description)
1663 : LibCallOptimization(funcName, description) {}
1666 /// @brief Default Constructor
1667 FFSOptimization() : LibCallOptimization("ffs",
1668 "Number of 'ffs' calls simplified") {}
1670 /// @brief Make sure that the "ffs" function has the right prototype
1671 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1672 // Just make sure this has 2 arguments
1673 return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
1676 /// @brief Perform the ffs optimization.
1677 virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
1678 if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
1679 // ffs(cnst) -> bit#
1680 // ffsl(cnst) -> bit#
1681 // ffsll(cnst) -> bit#
1682 uint64_t val = CI->getZExtValue();
1686 while ((val & 1) == 0) {
1691 return ReplaceCallWith(TheCall, ConstantInt::get(Type::Int32Ty, result));
1694 // ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1695 // ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1696 // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1697 const Type *ArgType = TheCall->getOperand(1)->getType();
1698 const char *CTTZName;
1699 assert(ArgType->getTypeID() == Type::IntegerTyID &&
1700 "llvm.cttz argument is not an integer?");
1701 unsigned BitWidth = cast<IntegerType>(ArgType)->getBitWidth();
1703 CTTZName = "llvm.cttz.i8";
1704 else if (BitWidth == 16)
1705 CTTZName = "llvm.cttz.i16";
1706 else if (BitWidth == 32)
1707 CTTZName = "llvm.cttz.i32";
1709 assert(BitWidth == 64 && "Unknown bitwidth");
1710 CTTZName = "llvm.cttz.i64";
1713 Constant *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
1715 Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
1716 false/*ZExt*/, "tmp", TheCall);
1717 Value *V2 = new CallInst(F, V, "tmp", TheCall);
1718 V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
1720 V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
1722 Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
1723 Constant::getNullValue(V->getType()), "tmp",
1725 V2 = new SelectInst(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
1726 TheCall->getName(), TheCall);
1727 return ReplaceCallWith(TheCall, V2);
1731 /// This LibCallOptimization will simplify calls to the "ffsl" library
1732 /// calls. It simply uses FFSOptimization for which the transformation is
1734 /// @brief Simplify the ffsl library function.
1735 struct VISIBILITY_HIDDEN FFSLOptimization : public FFSOptimization {
1737 /// @brief Default Constructor
1738 FFSLOptimization() : FFSOptimization("ffsl",
1739 "Number of 'ffsl' calls simplified") {}
1743 /// This LibCallOptimization will simplify calls to the "ffsll" library
1744 /// calls. It simply uses FFSOptimization for which the transformation is
1746 /// @brief Simplify the ffsl library function.
1747 struct VISIBILITY_HIDDEN FFSLLOptimization : public FFSOptimization {
1749 /// @brief Default Constructor
1750 FFSLLOptimization() : FFSOptimization("ffsll",
1751 "Number of 'ffsll' calls simplified") {}
1755 /// This optimizes unary functions that take and return doubles.
1756 struct UnaryDoubleFPOptimizer : public LibCallOptimization {
1757 UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
1758 : LibCallOptimization(Fn, Desc) {}
1760 // Make sure that this function has the right prototype
1761 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1762 return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
1763 F->getReturnType() == Type::DoubleTy;
1766 /// ShrinkFunctionToFloatVersion - If the input to this function is really a
1767 /// float, strength reduce this to a float version of the function,
1768 /// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
1769 /// when the target supports the destination function and where there can be
1770 /// no precision loss.
1771 static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
1772 Constant *(SimplifyLibCalls::*FP)()){
1773 if (FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1)))
1774 if (Cast->getOperand(0)->getType() == Type::FloatTy) {
1775 Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
1777 New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
1778 CI->replaceAllUsesWith(New);
1779 CI->eraseFromParent();
1780 if (Cast->use_empty())
1781 Cast->eraseFromParent();
1789 struct VISIBILITY_HIDDEN FloorOptimization : public UnaryDoubleFPOptimizer {
1791 : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
1793 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1795 // If this is a float argument passed in, convert to floorf.
1796 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
1799 return false; // opt failed
1803 struct VISIBILITY_HIDDEN CeilOptimization : public UnaryDoubleFPOptimizer {
1805 : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
1807 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1809 // If this is a float argument passed in, convert to ceilf.
1810 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
1813 return false; // opt failed
1817 struct VISIBILITY_HIDDEN RoundOptimization : public UnaryDoubleFPOptimizer {
1819 : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
1821 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1823 // If this is a float argument passed in, convert to roundf.
1824 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
1827 return false; // opt failed
1831 struct VISIBILITY_HIDDEN RintOptimization : public UnaryDoubleFPOptimizer {
1833 : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
1835 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1837 // If this is a float argument passed in, convert to rintf.
1838 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
1841 return false; // opt failed
1845 struct VISIBILITY_HIDDEN NearByIntOptimization : public UnaryDoubleFPOptimizer {
1846 NearByIntOptimization()
1847 : UnaryDoubleFPOptimizer("nearbyint",
1848 "Number of 'nearbyint' calls simplified") {}
1850 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1851 #ifdef HAVE_NEARBYINTF
1852 // If this is a float argument passed in, convert to nearbyintf.
1853 if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
1856 return false; // opt failed
1858 } NearByIntOptimizer;
1860 /// GetConstantStringInfo - This function computes the length of a
1861 /// null-terminated constant array of integers. This function can't rely on the
1862 /// size of the constant array because there could be a null terminator in the
1863 /// middle of the array.
1865 /// We also have to bail out if we find a non-integer constant initializer
1866 /// of one of the elements or if there is no null-terminator. The logic
1867 /// below checks each of these conditions and will return true only if all
1868 /// conditions are met. If the conditions aren't met, this returns false.
1870 /// If successful, the \p Array param is set to the constant array being
1871 /// indexed, the \p Length parameter is set to the length of the null-terminated
1872 /// string pointed to by V, the \p StartIdx value is set to the first
1873 /// element of the Array that V points to, and true is returned.
1874 static bool GetConstantStringInfo(Value *V, std::string &Str) {
1875 // Look through noop bitcast instructions.
1876 if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
1877 if (BCI->getType() == BCI->getOperand(0)->getType())
1878 return GetConstantStringInfo(BCI->getOperand(0), Str);
1882 // If the value is not a GEP instruction nor a constant expression with a
1883 // GEP instruction, then return false because ConstantArray can't occur
1886 if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
1888 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
1889 if (CE->getOpcode() != Instruction::GetElementPtr)
1896 // Make sure the GEP has exactly three arguments.
1897 if (GEP->getNumOperands() != 3)
1900 // Check to make sure that the first operand of the GEP is an integer and
1901 // has value 0 so that we are sure we're indexing into the initializer.
1902 if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
1908 // If the second index isn't a ConstantInt, then this is a variable index
1909 // into the array. If this occurs, we can't say anything meaningful about
1911 uint64_t StartIdx = 0;
1912 if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
1913 StartIdx = CI->getZExtValue();
1917 // The GEP instruction, constant or instruction, must reference a global
1918 // variable that is a constant and is initialized. The referenced constant
1919 // initializer is the array that we'll use for optimization.
1920 GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
1921 if (!GV || !GV->isConstant() || !GV->hasInitializer())
1923 Constant *GlobalInit = GV->getInitializer();
1925 // Handle the ConstantAggregateZero case
1926 if (isa<ConstantAggregateZero>(GlobalInit)) {
1927 // This is a degenerate case. The initializer is constant zero so the
1928 // length of the string must be zero.
1933 // Must be a Constant Array
1934 ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
1935 if (!Array) return false;
1937 // Get the number of elements in the array
1938 uint64_t NumElts = Array->getType()->getNumElements();
1940 // Traverse the constant array from StartIdx (derived above) which is
1941 // the place the GEP refers to in the array.
1942 for (unsigned i = StartIdx; i < NumElts; ++i) {
1943 Constant *Elt = Array->getOperand(i);
1944 ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
1945 if (!CI) // This array isn't suitable, non-int initializer.
1948 return true; // we found end of string, success!
1949 Str += (char)CI->getZExtValue();
1952 return false; // The array isn't null terminated.
1955 /// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
1956 /// inserting the cast before IP, and return the cast.
1957 /// @brief Cast a value to a "C" string.
1958 static Value *CastToCStr(Value *V, Instruction *IP) {
1959 assert(isa<PointerType>(V->getType()) &&
1960 "Can't cast non-pointer type to C string type");
1961 const Type *SBPTy = PointerType::getUnqual(Type::Int8Ty);
1962 if (V->getType() != SBPTy)
1963 return new BitCastInst(V, SBPTy, V->getName(), IP);
1968 // Additional cases that we need to add to this file:
1971 // * cbrt(expN(X)) -> expN(x/3)
1972 // * cbrt(sqrt(x)) -> pow(x,1/6)
1973 // * cbrt(sqrt(x)) -> pow(x,1/9)
1976 // * cos(-x) -> cos(x)
1979 // * exp(log(x)) -> x
1982 // * log(exp(x)) -> x
1983 // * log(x**y) -> y*log(x)
1984 // * log(exp(y)) -> y*log(e)
1985 // * log(exp2(y)) -> y*log(2)
1986 // * log(exp10(y)) -> y*log(10)
1987 // * log(sqrt(x)) -> 0.5*log(x)
1988 // * log(pow(x,y)) -> y*log(x)
1990 // lround, lroundf, lroundl:
1991 // * lround(cnst) -> cnst'
1994 // * memcmp(x,y,l) -> cnst
1995 // (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
1998 // * memmove(d,s,l,a) -> memcpy(d,s,l,a)
1999 // (if s is a global constant array)
2002 // * pow(exp(x),y) -> exp(x*y)
2003 // * pow(sqrt(x),y) -> pow(x,y*0.5)
2004 // * pow(pow(x,y),z)-> pow(x,y*z)
2007 // * puts("") -> putchar("\n")
2009 // round, roundf, roundl:
2010 // * round(cnst) -> cnst'
2013 // * signbit(cnst) -> cnst'
2014 // * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2016 // sqrt, sqrtf, sqrtl:
2017 // * sqrt(expN(x)) -> expN(x*0.5)
2018 // * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2019 // * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2022 // * stpcpy(str, "literal") ->
2023 // llvm.memcpy(str,"literal",strlen("literal")+1,1)
2025 // * strrchr(s,c) -> reverse_offset_of_in(c,s)
2026 // (if c is a constant integer and s is a constant string)
2027 // * strrchr(s1,0) -> strchr(s1,0)
2030 // * strncat(x,y,0) -> x
2031 // * strncat(x,y,0) -> x (if strlen(y) = 0)
2032 // * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
2035 // * strncpy(d,s,0) -> d
2036 // * strncpy(d,s,l) -> memcpy(d,s,l,1)
2037 // (if s and l are constants)
2040 // * strpbrk(s,a) -> offset_in_for(s,a)
2041 // (if s and a are both constant strings)
2042 // * strpbrk(s,"") -> 0
2043 // * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
2046 // * strspn(s,a) -> const_int (if both args are constant)
2047 // * strspn("",a) -> 0
2048 // * strspn(s,"") -> 0
2049 // * strcspn(s,a) -> const_int (if both args are constant)
2050 // * strcspn("",a) -> 0
2051 // * strcspn(s,"") -> strlen(a)
2054 // * strstr(x,x) -> x
2055 // * strstr(s1,s2) -> offset_of_s2_in(s1)
2056 // (if s1 and s2 are constant strings)
2059 // * tan(atan(x)) -> x
2061 // trunc, truncf, truncl:
2062 // * trunc(cnst) -> cnst'