1 //===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
3 // The LLVM Compiler Infrastructure
5 // This file was developed by Reid Spencer and is distributed under the
6 // University of Illinois Open Source 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/hash_map"
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"
35 /// This statistic keeps track of the total number of library calls that have
36 /// been simplified regardless of which call it is.
37 STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
40 // Forward declarations
41 class LibCallOptimization;
42 class SimplifyLibCalls;
44 /// This list is populated by the constructor for LibCallOptimization class.
45 /// Therefore all subclasses are registered here at static initialization time
46 /// and this list is what the SimplifyLibCalls pass uses to apply the individual
47 /// optimizations to the call sites.
48 /// @brief The list of optimizations deriving from LibCallOptimization
49 static LibCallOptimization *OptList = 0;
51 /// This class is the abstract base class for the set of optimizations that
52 /// corresponds to one library call. The SimplifyLibCalls pass will call the
53 /// ValidateCalledFunction method to ask the optimization if a given Function
54 /// is the kind that the optimization can handle. If the subclass returns true,
55 /// then SImplifyLibCalls will also call the OptimizeCall method to perform,
56 /// or attempt to perform, the optimization(s) for the library call. Otherwise,
57 /// OptimizeCall won't be called. Subclasses are responsible for providing the
58 /// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
59 /// constructor. This is used to efficiently select which call instructions to
60 /// optimize. The criteria for a "lib call" is "anything with well known
61 /// semantics", typically a library function that is defined by an international
62 /// standard. Because the semantics are well known, the optimizations can
63 /// generally short-circuit actually calling the function if there's a simpler
64 /// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
65 /// @brief Base class for library call optimizations
66 class VISIBILITY_HIDDEN LibCallOptimization {
67 LibCallOptimization **Prev, *Next;
68 const char *FunctionName; ///< Name of the library call we optimize
70 Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
73 /// The \p fname argument must be the name of the library function being
74 /// optimized by the subclass.
75 /// @brief Constructor that registers the optimization.
76 LibCallOptimization(const char *FName, const char *Description)
77 : FunctionName(FName) {
80 occurrences.construct("simplify-libcalls", Description);
82 // Register this optimizer in the list of optimizations.
86 if (Next) Next->Prev = &Next;
89 /// getNext - All libcall optimizations are chained together into a list,
90 /// return the next one in the list.
91 LibCallOptimization *getNext() { return Next; }
93 /// @brief Deregister from the optlist
94 virtual ~LibCallOptimization() {
96 if (Next) Next->Prev = Prev;
99 /// The implementation of this function in subclasses should determine if
100 /// \p F is suitable for the optimization. This method is called by
101 /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
102 /// sites of such a function if that function is not suitable in the first
103 /// place. If the called function is suitabe, this method should return true;
104 /// false, otherwise. This function should also perform any lazy
105 /// initialization that the LibCallOptimization needs to do, if its to return
106 /// true. This avoids doing initialization until the optimizer is actually
107 /// going to be called upon to do some optimization.
108 /// @brief Determine if the function is suitable for optimization
109 virtual bool ValidateCalledFunction(
110 const Function* F, ///< The function that is the target of call sites
111 SimplifyLibCalls& SLC ///< The pass object invoking us
114 /// The implementations of this function in subclasses is the heart of the
115 /// SimplifyLibCalls algorithm. Sublcasses of this class implement
116 /// OptimizeCall to determine if (a) the conditions are right for optimizing
117 /// the call and (b) to perform the optimization. If an action is taken
118 /// against ci, the subclass is responsible for returning true and ensuring
119 /// that ci is erased from its parent.
120 /// @brief Optimize a call, if possible.
121 virtual bool OptimizeCall(
122 CallInst* ci, ///< The call instruction that should be optimized.
123 SimplifyLibCalls& SLC ///< The pass object invoking us
126 /// @brief Get the name of the library call being optimized
127 const char *getFunctionName() const { return FunctionName; }
129 /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
132 DEBUG(++occurrences);
137 /// This class is an LLVM Pass that applies each of the LibCallOptimization
138 /// instances to all the call sites in a module, relatively efficiently. The
139 /// purpose of this pass is to provide optimizations for calls to well-known
140 /// functions with well-known semantics, such as those in the c library. The
141 /// class provides the basic infrastructure for handling runOnModule. Whenever
142 /// this pass finds a function call, it asks the appropriate optimizer to
143 /// validate the call (ValidateLibraryCall). If it is validated, then
144 /// the OptimizeCall method is also called.
145 /// @brief A ModulePass for optimizing well-known function calls.
146 class VISIBILITY_HIDDEN SimplifyLibCalls : public ModulePass {
148 /// We need some target data for accurate signature details that are
149 /// target dependent. So we require target data in our AnalysisUsage.
150 /// @brief Require TargetData from AnalysisUsage.
151 virtual void getAnalysisUsage(AnalysisUsage& Info) const {
152 // Ask that the TargetData analysis be performed before us so we can use
154 Info.addRequired<TargetData>();
157 /// For this pass, process all of the function calls in the module, calling
158 /// ValidateLibraryCall and OptimizeCall as appropriate.
159 /// @brief Run all the lib call optimizations on a Module.
160 virtual bool runOnModule(Module &M) {
164 hash_map<std::string, LibCallOptimization*> OptznMap;
165 for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
166 OptznMap[Optzn->getFunctionName()] = Optzn;
168 // The call optimizations can be recursive. That is, the optimization might
169 // generate a call to another function which can also be optimized. This way
170 // we make the LibCallOptimization instances very specific to the case they
171 // handle. It also means we need to keep running over the function calls in
172 // the module until we don't get any more optimizations possible.
173 bool found_optimization = false;
175 found_optimization = false;
176 for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
177 // All the "well-known" functions are external and have external linkage
178 // because they live in a runtime library somewhere and were (probably)
179 // not compiled by LLVM. So, we only act on external functions that
180 // have external or dllimport linkage and non-empty uses.
181 if (!FI->isDeclaration() ||
182 !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
186 // Get the optimization class that pertains to this function
187 hash_map<std::string, LibCallOptimization*>::iterator OMI =
188 OptznMap.find(FI->getName());
189 if (OMI == OptznMap.end()) continue;
191 LibCallOptimization *CO = OMI->second;
193 // Make sure the called function is suitable for the optimization
194 if (!CO->ValidateCalledFunction(FI, *this))
197 // Loop over each of the uses of the function
198 for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
200 // If the use of the function is a call instruction
201 if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
202 // Do the optimization on the LibCallOptimization.
203 if (CO->OptimizeCall(CI, *this)) {
204 ++SimplifiedLibCalls;
205 found_optimization = result = true;
211 } while (found_optimization);
216 /// @brief Return the *current* module we're working on.
217 Module* getModule() const { return M; }
219 /// @brief Return the *current* target data for the module we're working on.
220 TargetData* getTargetData() const { return TD; }
222 /// @brief Return the size_t type -- syntactic shortcut
223 const Type* getIntPtrType() const { return TD->getIntPtrType(); }
225 /// @brief Return a Function* for the putchar libcall
226 Constant *get_putchar() {
229 M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
233 /// @brief Return a Function* for the puts libcall
234 Constant *get_puts() {
236 puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
237 PointerType::get(Type::Int8Ty),
242 /// @brief Return a Function* for the fputc libcall
243 Constant *get_fputc(const Type* FILEptr_type) {
245 fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
250 /// @brief Return a Function* for the fputs libcall
251 Constant *get_fputs(const Type* FILEptr_type) {
253 fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
254 PointerType::get(Type::Int8Ty),
259 /// @brief Return a Function* for the fwrite libcall
260 Constant *get_fwrite(const Type* FILEptr_type) {
262 fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
263 PointerType::get(Type::Int8Ty),
270 /// @brief Return a Function* for the sqrt libcall
271 Constant *get_sqrt() {
273 sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
274 Type::DoubleTy, NULL);
278 /// @brief Return a Function* for the strcpy libcall
279 Constant *get_strcpy() {
281 strcpy_func = M->getOrInsertFunction("strcpy",
282 PointerType::get(Type::Int8Ty),
283 PointerType::get(Type::Int8Ty),
284 PointerType::get(Type::Int8Ty),
289 /// @brief Return a Function* for the strlen libcall
290 Constant *get_strlen() {
292 strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
293 PointerType::get(Type::Int8Ty),
298 /// @brief Return a Function* for the memchr libcall
299 Constant *get_memchr() {
301 memchr_func = M->getOrInsertFunction("memchr",
302 PointerType::get(Type::Int8Ty),
303 PointerType::get(Type::Int8Ty),
304 Type::Int32Ty, TD->getIntPtrType(),
309 /// @brief Return a Function* for the memcpy libcall
310 Constant *get_memcpy() {
312 const Type *SBP = PointerType::get(Type::Int8Ty);
313 const char *N = TD->getIntPtrType() == Type::Int32Ty ?
314 "llvm.memcpy.i32" : "llvm.memcpy.i64";
315 memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
316 TD->getIntPtrType(), Type::Int32Ty,
322 Constant *getUnaryFloatFunction(const char *Name, Constant *&Cache) {
324 Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
328 Constant *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
329 Constant *get_ceilf() { return getUnaryFloatFunction( "ceilf", ceilf_func);}
330 Constant *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
331 Constant *get_rintf() { return getUnaryFloatFunction( "rintf", rintf_func);}
332 Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
335 /// @brief Reset our cached data for a new Module
336 void reset(Module& mod) {
338 TD = &getAnalysis<TargetData>();
357 /// Caches for function pointers.
358 Constant *putchar_func, *puts_func;
359 Constant *fputc_func, *fputs_func, *fwrite_func;
360 Constant *memcpy_func, *memchr_func;
362 Constant *strcpy_func, *strlen_func;
363 Constant *floorf_func, *ceilf_func, *roundf_func;
364 Constant *rintf_func, *nearbyintf_func;
365 Module *M; ///< Cached Module
366 TargetData *TD; ///< Cached TargetData
370 RegisterPass<SimplifyLibCalls>
371 X("simplify-libcalls", "Simplify well-known library calls");
373 } // anonymous namespace
375 // The only public symbol in this file which just instantiates the pass object
376 ModulePass *llvm::createSimplifyLibCallsPass() {
377 return new SimplifyLibCalls();
380 // Classes below here, in the anonymous namespace, are all subclasses of the
381 // LibCallOptimization class, each implementing all optimizations possible for a
382 // single well-known library call. Each has a static singleton instance that
383 // auto registers it into the "optlist" global above.
386 // Forward declare utility functions.
387 static bool GetConstantStringInfo(Value *V, ConstantArray *&Array,
388 uint64_t &Length, uint64_t &StartIdx);
389 static Value *CastToCStr(Value *V, Instruction &IP);
391 /// This LibCallOptimization will find instances of a call to "exit" that occurs
392 /// within the "main" function and change it to a simple "ret" instruction with
393 /// the same value passed to the exit function. When this is done, it splits the
394 /// basic block at the exit(3) call and deletes the call instruction.
395 /// @brief Replace calls to exit in main with a simple return
396 struct VISIBILITY_HIDDEN ExitInMainOptimization : public LibCallOptimization {
397 ExitInMainOptimization() : LibCallOptimization("exit",
398 "Number of 'exit' calls simplified") {}
400 // Make sure the called function looks like exit (int argument, int return
401 // type, external linkage, not varargs).
402 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
403 return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
406 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
407 // To be careful, we check that the call to exit is coming from "main", that
408 // main has external linkage, and the return type of main and the argument
409 // to exit have the same type.
410 Function *from = ci->getParent()->getParent();
411 if (from->hasExternalLinkage())
412 if (from->getReturnType() == ci->getOperand(1)->getType())
413 if (from->getName() == "main") {
414 // Okay, time to actually do the optimization. First, get the basic
415 // block of the call instruction
416 BasicBlock* bb = ci->getParent();
418 // Create a return instruction that we'll replace the call with.
419 // Note that the argument of the return is the argument of the call
421 new ReturnInst(ci->getOperand(1), ci);
423 // Split the block at the call instruction which places it in a new
425 bb->splitBasicBlock(ci);
427 // The block split caused a branch instruction to be inserted into
428 // the end of the original block, right after the return instruction
429 // that we put there. That's not a valid block, so delete the branch
431 bb->getInstList().pop_back();
433 // Now we can finally get rid of the call instruction which now lives
434 // in the new basic block.
435 ci->eraseFromParent();
437 // Optimization succeeded, return true.
440 // We didn't pass the criteria for this optimization so return false
443 } ExitInMainOptimizer;
445 /// This LibCallOptimization will simplify a call to the strcat library
446 /// function. The simplification is possible only if the string being
447 /// concatenated is a constant array or a constant expression that results in
448 /// a constant string. In this case we can replace it with strlen + llvm.memcpy
449 /// of the constant string. Both of these calls are further reduced, if possible
450 /// on subsequent passes.
451 /// @brief Simplify the strcat library function.
452 struct VISIBILITY_HIDDEN StrCatOptimization : public LibCallOptimization {
454 /// @brief Default constructor
455 StrCatOptimization() : LibCallOptimization("strcat",
456 "Number of 'strcat' calls simplified") {}
460 /// @brief Make sure that the "strcat" function has the right prototype
461 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
462 if (f->getReturnType() == PointerType::get(Type::Int8Ty))
463 if (f->arg_size() == 2)
465 Function::const_arg_iterator AI = f->arg_begin();
466 if (AI++->getType() == PointerType::get(Type::Int8Ty))
467 if (AI->getType() == PointerType::get(Type::Int8Ty))
469 // Indicate this is a suitable call type.
476 /// @brief Optimize the strcat library function
477 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
478 // Extract some information from the instruction
479 Value *Dst = CI->getOperand(1);
480 Value *Src = CI->getOperand(2);
482 // Extract the initializer (while making numerous checks) from the
483 // source operand of the call to strcat.
484 uint64_t SrcLength, StartIdx;
486 if (!GetConstantStringInfo(Src, Arr, SrcLength, StartIdx))
489 // Handle the simple, do-nothing case
490 if (SrcLength == 0) {
491 CI->replaceAllUsesWith(Dst);
492 CI->eraseFromParent();
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 (further
498 // optimized in another pass).
499 CallInst *DstLen = new CallInst(SLC.get_strlen(), Dst,
500 Dst->getName()+".len", CI);
502 // Now that we have the destination's length, we must index into the
503 // destination's pointer to get the actual memcpy destination (end of
504 // the string .. we're concatenating).
505 Dst = new GetElementPtrInst(Dst, DstLen, Dst->getName()+".indexed", CI);
507 // We have enough information to now generate the memcpy call to
508 // do the concatenation for us.
511 ConstantInt::get(SLC.getIntPtrType(), SrcLength+1), // copy nul term.
512 ConstantInt::get(Type::Int32Ty, 1) // alignment
514 new CallInst(SLC.get_memcpy(), Vals, 4, "", CI);
516 // Finally, substitute the first operand of the strcat call for the
517 // strcat call itself since strcat returns its first operand; and,
518 // kill the strcat CallInst.
519 CI->replaceAllUsesWith(Dst);
520 CI->eraseFromParent();
525 /// This LibCallOptimization will simplify a call to the strchr library
526 /// function. It optimizes out cases where the arguments are both constant
527 /// and the result can be determined statically.
528 /// @brief Simplify the strcmp library function.
529 struct VISIBILITY_HIDDEN StrChrOptimization : public LibCallOptimization {
531 StrChrOptimization() : LibCallOptimization("strchr",
532 "Number of 'strchr' calls simplified") {}
534 /// @brief Make sure that the "strchr" function has the right prototype
535 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
536 const FunctionType *FT = F->getFunctionType();
537 return FT->getNumParams() == 2 &&
538 FT->getReturnType() == PointerType::get(Type::Int8Ty) &&
539 FT->getParamType(0) == FT->getReturnType() &&
540 isa<IntegerType>(FT->getParamType(1));
543 /// @brief Perform the strchr optimizations
544 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
545 // Check that the first argument to strchr is a constant array of sbyte.
546 // If it is, get the length and data, otherwise return false.
547 uint64_t StrLength, StartIdx;
548 ConstantArray *CA = 0;
549 if (!GetConstantStringInfo(CI->getOperand(1), CA, StrLength, StartIdx))
552 // If the second operand is not constant, just lower this to memchr since we
553 // know the length of the input string.
554 ConstantInt *CSI = dyn_cast<ConstantInt>(CI->getOperand(2));
559 ConstantInt::get(SLC.getIntPtrType(), StrLength+1)
561 CI->replaceAllUsesWith(new CallInst(SLC.get_memchr(), Args, 3,
563 CI->eraseFromParent();
567 // Get the character we're looking for
568 int64_t CharValue = CSI->getSExtValue();
570 if (StrLength == 0) {
571 // If the length of the string is zero, and we are searching for zero,
572 // return the input pointer.
573 if (CharValue == 0) {
574 CI->replaceAllUsesWith(CI->getOperand(1));
576 // Otherwise, char wasn't found.
577 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
579 CI->eraseFromParent();
583 // Compute the offset
586 assert(i <= StrLength && "Didn't find null terminator?");
587 if (ConstantInt *C = dyn_cast<ConstantInt>(CA->getOperand(i+StartIdx))) {
588 // Did we find our match?
589 if (C->getSExtValue() == CharValue)
592 // We found the end of the string. strchr returns null.
593 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
594 CI->eraseFromParent();
601 // strchr(s+n,c) -> gep(s+n+i,c)
602 // (if c is a constant integer and s is a constant string)
603 Value *Idx = ConstantInt::get(Type::Int64Ty, i);
604 Value *GEP = new GetElementPtrInst(CI->getOperand(1), Idx,
605 CI->getOperand(1)->getName() +
607 CI->replaceAllUsesWith(GEP);
608 CI->eraseFromParent();
613 /// This LibCallOptimization will simplify a call to the strcmp library
614 /// function. It optimizes out cases where one or both arguments are constant
615 /// and the result can be determined statically.
616 /// @brief Simplify the strcmp library function.
617 struct VISIBILITY_HIDDEN StrCmpOptimization : public LibCallOptimization {
619 StrCmpOptimization() : LibCallOptimization("strcmp",
620 "Number of 'strcmp' calls simplified") {}
622 /// @brief Make sure that the "strcmp" function has the right prototype
623 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
624 const FunctionType *FT = F->getFunctionType();
625 return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 2 &&
626 FT->getParamType(0) == FT->getParamType(1) &&
627 FT->getParamType(0) == PointerType::get(Type::Int8Ty);
630 /// @brief Perform the strcmp optimization
631 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
632 // First, check to see if src and destination are the same. If they are,
633 // then the optimization is to replace the CallInst with a constant 0
634 // because the call is a no-op.
635 Value *Str1P = CI->getOperand(1);
636 Value *Str2P = CI->getOperand(2);
637 if (Str1P == Str2P) {
639 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), 0));
640 CI->eraseFromParent();
644 uint64_t Str1Len, Str1StartIdx;
646 bool Str1IsCst = GetConstantStringInfo(Str1P, A1, Str1Len, Str1StartIdx);
647 if (Str1IsCst && Str1Len == 0) {
648 // strcmp("", x) -> *x
649 Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
650 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
651 CI->replaceAllUsesWith(V);
652 CI->eraseFromParent();
656 uint64_t Str2Len, Str2StartIdx;
658 bool Str2IsCst = GetConstantStringInfo(Str2P, A2, Str2Len, Str2StartIdx);
659 if (Str2IsCst && Str2Len == 0) {
660 // strcmp(x,"") -> *x
661 Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
662 V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
663 CI->replaceAllUsesWith(V);
664 CI->eraseFromParent();
668 if (Str1IsCst && Str2IsCst && A1->isCString() && A2->isCString()) {
669 // strcmp(x, y) -> cnst (if both x and y are constant strings)
670 std::string S1 = A1->getAsString();
671 std::string S2 = A2->getAsString();
672 int R = strcmp(S1.c_str()+Str1StartIdx, S2.c_str()+Str2StartIdx);
673 CI->replaceAllUsesWith(ConstantInt::get(CI->getType(), R));
674 CI->eraseFromParent();
681 /// This LibCallOptimization will simplify a call to the strncmp library
682 /// function. It optimizes out cases where one or both arguments are constant
683 /// and the result can be determined statically.
684 /// @brief Simplify the strncmp library function.
685 struct VISIBILITY_HIDDEN StrNCmpOptimization : public LibCallOptimization {
687 StrNCmpOptimization() : LibCallOptimization("strncmp",
688 "Number of 'strncmp' calls simplified") {}
690 /// @brief Make sure that the "strncmp" function has the right prototype
691 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
692 if (f->getReturnType() == Type::Int32Ty && f->arg_size() == 3)
697 /// @brief Perform the strncpy optimization
698 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
699 // First, check to see if src and destination are the same. If they are,
700 // then the optimization is to replace the CallInst with a constant 0
701 // because the call is a no-op.
702 Value* s1 = ci->getOperand(1);
703 Value* s2 = ci->getOperand(2);
705 // strncmp(x,x,l) -> 0
706 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
707 ci->eraseFromParent();
711 // Check the length argument, if it is Constant zero then the strings are
713 uint64_t len_arg = 0;
714 bool len_arg_is_const = false;
715 if (ConstantInt* len_CI = dyn_cast<ConstantInt>(ci->getOperand(3))) {
716 len_arg_is_const = true;
717 len_arg = len_CI->getZExtValue();
719 // strncmp(x,y,0) -> 0
720 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
721 ci->eraseFromParent();
726 bool isstr_1 = false;
727 uint64_t len_1 = 0, StartIdx;
729 if (GetConstantStringInfo(s1, A1, len_1, StartIdx)) {
732 // strncmp("",x) -> *x
733 LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
735 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
736 ci->getName()+".int", ci);
737 ci->replaceAllUsesWith(cast);
738 ci->eraseFromParent();
743 bool isstr_2 = false;
746 if (GetConstantStringInfo(s2, A2, len_2, StartIdx)) {
749 // strncmp(x,"") -> *x
750 LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
752 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
753 ci->getName()+".int", ci);
754 ci->replaceAllUsesWith(cast);
755 ci->eraseFromParent();
760 if (isstr_1 && isstr_2 && len_arg_is_const) {
761 // strncmp(x,y,const) -> constant
762 std::string str1 = A1->getAsString();
763 std::string str2 = A2->getAsString();
764 int result = strncmp(str1.c_str(), str2.c_str(), len_arg);
765 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,result));
766 ci->eraseFromParent();
773 /// This LibCallOptimization will simplify a call to the strcpy library
774 /// function. Two optimizations are possible:
775 /// (1) If src and dest are the same and not volatile, just return dest
776 /// (2) If the src is a constant then we can convert to llvm.memmove
777 /// @brief Simplify the strcpy library function.
778 struct VISIBILITY_HIDDEN StrCpyOptimization : public LibCallOptimization {
780 StrCpyOptimization() : LibCallOptimization("strcpy",
781 "Number of 'strcpy' calls simplified") {}
783 /// @brief Make sure that the "strcpy" function has the right prototype
784 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
785 if (f->getReturnType() == PointerType::get(Type::Int8Ty))
786 if (f->arg_size() == 2) {
787 Function::const_arg_iterator AI = f->arg_begin();
788 if (AI++->getType() == PointerType::get(Type::Int8Ty))
789 if (AI->getType() == PointerType::get(Type::Int8Ty)) {
790 // Indicate this is a suitable call type.
797 /// @brief Perform the strcpy optimization
798 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
799 // First, check to see if src and destination are the same. If they are,
800 // then the optimization is to replace the CallInst with the destination
801 // because the call is a no-op. Note that this corresponds to the
802 // degenerate strcpy(X,X) case which should have "undefined" results
803 // according to the C specification. However, it occurs sometimes and
804 // we optimize it as a no-op.
805 Value* dest = ci->getOperand(1);
806 Value* src = ci->getOperand(2);
808 ci->replaceAllUsesWith(dest);
809 ci->eraseFromParent();
813 // Get the length of the constant string referenced by the second operand,
814 // the "src" parameter. Fail the optimization if we can't get the length
815 // (note that GetConstantStringInfo does lots of checks to make sure this
817 uint64_t len, StartIdx;
819 if (!GetConstantStringInfo(ci->getOperand(2), A, len, StartIdx))
822 // If the constant string's length is zero we can optimize this by just
823 // doing a store of 0 at the first byte of the destination
825 new StoreInst(ConstantInt::get(Type::Int8Ty,0),ci->getOperand(1),ci);
826 ci->replaceAllUsesWith(dest);
827 ci->eraseFromParent();
831 // Increment the length because we actually want to memcpy the null
832 // terminator as well.
835 // We have enough information to now generate the memcpy call to
836 // do the concatenation for us.
839 ConstantInt::get(SLC.getIntPtrType(),len), // length
840 ConstantInt::get(Type::Int32Ty, 1) // alignment
842 new CallInst(SLC.get_memcpy(), vals, 4, "", ci);
844 // Finally, substitute the first operand of the strcat call for the
845 // strcat call itself since strcat returns its first operand; and,
846 // kill the strcat CallInst.
847 ci->replaceAllUsesWith(dest);
848 ci->eraseFromParent();
853 /// This LibCallOptimization will simplify a call to the strlen library
854 /// function by replacing it with a constant value if the string provided to
855 /// it is a constant array.
856 /// @brief Simplify the strlen library function.
857 struct VISIBILITY_HIDDEN StrLenOptimization : public LibCallOptimization {
858 StrLenOptimization() : LibCallOptimization("strlen",
859 "Number of 'strlen' calls simplified") {}
861 /// @brief Make sure that the "strlen" function has the right prototype
862 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
864 if (f->getReturnType() == SLC.getTargetData()->getIntPtrType())
865 if (f->arg_size() == 1)
866 if (Function::const_arg_iterator AI = f->arg_begin())
867 if (AI->getType() == PointerType::get(Type::Int8Ty))
872 /// @brief Perform the strlen optimization
873 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
875 // Make sure we're dealing with an sbyte* here.
876 Value* str = ci->getOperand(1);
877 if (str->getType() != PointerType::get(Type::Int8Ty))
880 // Does the call to strlen have exactly one use?
882 // Is that single use a icmp operator?
883 if (ICmpInst* bop = dyn_cast<ICmpInst>(ci->use_back()))
884 // Is it compared against a constant integer?
885 if (ConstantInt* CI = dyn_cast<ConstantInt>(bop->getOperand(1)))
887 // Get the value the strlen result is compared to
888 uint64_t val = CI->getZExtValue();
890 // If its compared against length 0 with == or !=
892 (bop->getPredicate() == ICmpInst::ICMP_EQ ||
893 bop->getPredicate() == ICmpInst::ICMP_NE))
895 // strlen(x) != 0 -> *x != 0
896 // strlen(x) == 0 -> *x == 0
897 LoadInst* load = new LoadInst(str,str->getName()+".first",ci);
898 ICmpInst* rbop = new ICmpInst(bop->getPredicate(), load,
899 ConstantInt::get(Type::Int8Ty,0),
900 bop->getName()+".strlen", ci);
901 bop->replaceAllUsesWith(rbop);
902 bop->eraseFromParent();
903 ci->eraseFromParent();
908 // Get the length of the constant string operand
909 uint64_t len = 0, StartIdx;
911 if (!GetConstantStringInfo(ci->getOperand(1), A, len, StartIdx))
914 // strlen("xyz") -> 3 (for example)
915 const Type *Ty = SLC.getTargetData()->getIntPtrType();
916 ci->replaceAllUsesWith(ConstantInt::get(Ty, len));
918 ci->eraseFromParent();
923 /// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
924 /// is equal or not-equal to zero.
925 static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
926 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
928 Instruction *User = cast<Instruction>(*UI);
929 if (ICmpInst *IC = dyn_cast<ICmpInst>(User)) {
930 if ((IC->getPredicate() == ICmpInst::ICMP_NE ||
931 IC->getPredicate() == ICmpInst::ICMP_EQ) &&
932 isa<Constant>(IC->getOperand(1)) &&
933 cast<Constant>(IC->getOperand(1))->isNullValue())
935 } else if (CastInst *CI = dyn_cast<CastInst>(User))
936 if (CI->getType() == Type::Int1Ty)
938 // Unknown instruction.
944 /// This memcmpOptimization will simplify a call to the memcmp library
946 struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
947 /// @brief Default Constructor
949 : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
951 /// @brief Make sure that the "memcmp" function has the right prototype
952 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
953 Function::const_arg_iterator AI = F->arg_begin();
954 if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
955 if (!isa<PointerType>((++AI)->getType())) return false;
956 if (!(++AI)->getType()->isInteger()) return false;
957 if (!F->getReturnType()->isInteger()) return false;
961 /// Because of alignment and instruction information that we don't have, we
962 /// leave the bulk of this to the code generators.
964 /// Note that we could do much more if we could force alignment on otherwise
965 /// small aligned allocas, or if we could indicate that loads have a small
967 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
968 Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
970 // If the two operands are the same, return zero.
972 // memcmp(s,s,x) -> 0
973 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
974 CI->eraseFromParent();
978 // Make sure we have a constant length.
979 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
980 if (!LenC) return false;
981 uint64_t Len = LenC->getZExtValue();
983 // If the length is zero, this returns 0.
986 // memcmp(s1,s2,0) -> 0
987 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
988 CI->eraseFromParent();
991 // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
992 const Type *UCharPtr = PointerType::get(Type::Int8Ty);
993 CastInst *Op1Cast = CastInst::create(
994 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
995 CastInst *Op2Cast = CastInst::create(
996 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
997 Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
998 Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
999 Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
1000 if (RV->getType() != CI->getType())
1001 RV = CastInst::createIntegerCast(RV, CI->getType(), false,
1003 CI->replaceAllUsesWith(RV);
1004 CI->eraseFromParent();
1008 if (IsOnlyUsedInEqualsZeroComparison(CI)) {
1009 // TODO: IF both are aligned, use a short load/compare.
1011 // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
1012 const Type *UCharPtr = PointerType::get(Type::Int8Ty);
1013 CastInst *Op1Cast = CastInst::create(
1014 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
1015 CastInst *Op2Cast = CastInst::create(
1016 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
1017 Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
1018 Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
1019 Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
1020 CI->getName()+".d1", CI);
1021 Constant *One = ConstantInt::get(Type::Int32Ty, 1);
1022 Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
1023 Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
1024 Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
1025 Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
1026 Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
1027 CI->getName()+".d1", CI);
1028 Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
1029 if (Or->getType() != CI->getType())
1030 Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
1032 CI->replaceAllUsesWith(Or);
1033 CI->eraseFromParent();
1046 /// This LibCallOptimization will simplify a call to the memcpy library
1047 /// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
1048 /// bytes depending on the length of the string and the alignment. Additional
1049 /// optimizations are possible in code generation (sequence of immediate store)
1050 /// @brief Simplify the memcpy library function.
1051 struct VISIBILITY_HIDDEN LLVMMemCpyMoveOptzn : public LibCallOptimization {
1052 LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
1053 : LibCallOptimization(fname, desc) {}
1055 /// @brief Make sure that the "memcpy" function has the right prototype
1056 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
1057 // Just make sure this has 4 arguments per LLVM spec.
1058 return (f->arg_size() == 4);
1061 /// Because of alignment and instruction information that we don't have, we
1062 /// leave the bulk of this to the code generators. The optimization here just
1063 /// deals with a few degenerate cases where the length of the string and the
1064 /// alignment match the sizes of our intrinsic types so we can do a load and
1065 /// store instead of the memcpy call.
1066 /// @brief Perform the memcpy optimization.
1067 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
1068 // Make sure we have constant int values to work with
1069 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
1072 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
1076 // If the length is larger than the alignment, we can't optimize
1077 uint64_t len = LEN->getZExtValue();
1078 uint64_t alignment = ALIGN->getZExtValue();
1080 alignment = 1; // Alignment 0 is identity for alignment 1
1081 if (len > alignment)
1084 // Get the type we will cast to, based on size of the string
1085 Value* dest = ci->getOperand(1);
1086 Value* src = ci->getOperand(2);
1087 const Type* castType = 0;
1091 // memcpy(d,s,0,a) -> noop
1092 ci->eraseFromParent();
1094 case 1: castType = Type::Int8Ty; break;
1095 case 2: castType = Type::Int16Ty; break;
1096 case 4: castType = Type::Int32Ty; break;
1097 case 8: castType = Type::Int64Ty; break;
1102 // Cast source and dest to the right sized primitive and then load/store
1103 CastInst* SrcCast = CastInst::create(Instruction::BitCast,
1104 src, PointerType::get(castType), src->getName()+".cast", ci);
1105 CastInst* DestCast = CastInst::create(Instruction::BitCast,
1106 dest, PointerType::get(castType),dest->getName()+".cast", ci);
1107 LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
1108 new StoreInst(LI, DestCast, ci);
1109 ci->eraseFromParent();
1114 /// This LibCallOptimization will simplify a call to the memcpy/memmove library
1116 LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
1117 "Number of 'llvm.memcpy' calls simplified");
1118 LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
1119 "Number of 'llvm.memcpy' calls simplified");
1120 LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
1121 "Number of 'llvm.memmove' calls simplified");
1122 LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
1123 "Number of 'llvm.memmove' calls simplified");
1125 /// This LibCallOptimization will simplify a call to the memset library
1126 /// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
1127 /// bytes depending on the length argument.
1128 struct VISIBILITY_HIDDEN LLVMMemSetOptimization : public LibCallOptimization {
1129 /// @brief Default Constructor
1130 LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
1131 "Number of 'llvm.memset' calls simplified") {}
1133 /// @brief Make sure that the "memset" function has the right prototype
1134 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
1135 // Just make sure this has 3 arguments per LLVM spec.
1136 return F->arg_size() == 4;
1139 /// Because of alignment and instruction information that we don't have, we
1140 /// leave the bulk of this to the code generators. The optimization here just
1141 /// deals with a few degenerate cases where the length parameter is constant
1142 /// and the alignment matches the sizes of our intrinsic types so we can do
1143 /// store instead of the memcpy call. Other calls are transformed into the
1144 /// llvm.memset intrinsic.
1145 /// @brief Perform the memset optimization.
1146 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
1147 // Make sure we have constant int values to work with
1148 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
1151 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
1155 // Extract the length and alignment
1156 uint64_t len = LEN->getZExtValue();
1157 uint64_t alignment = ALIGN->getZExtValue();
1159 // Alignment 0 is identity for alignment 1
1163 // If the length is zero, this is a no-op
1165 // memset(d,c,0,a) -> noop
1166 ci->eraseFromParent();
1170 // If the length is larger than the alignment, we can't optimize
1171 if (len > alignment)
1174 // Make sure we have a constant ubyte to work with so we can extract
1175 // the value to be filled.
1176 ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
1179 if (FILL->getType() != Type::Int8Ty)
1182 // memset(s,c,n) -> store s, c (for n=1,2,4,8)
1184 // Extract the fill character
1185 uint64_t fill_char = FILL->getZExtValue();
1186 uint64_t fill_value = fill_char;
1188 // Get the type we will cast to, based on size of memory area to fill, and
1189 // and the value we will store there.
1190 Value* dest = ci->getOperand(1);
1191 const Type* castType = 0;
1194 castType = Type::Int8Ty;
1197 castType = Type::Int16Ty;
1198 fill_value |= fill_char << 8;
1201 castType = Type::Int32Ty;
1202 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1205 castType = Type::Int64Ty;
1206 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1207 fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
1208 fill_value |= fill_char << 56;
1214 // Cast dest to the right sized primitive and then load/store
1215 CastInst* DestCast = new BitCastInst(dest, PointerType::get(castType),
1216 dest->getName()+".cast", ci);
1217 new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
1218 ci->eraseFromParent();
1223 LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
1224 LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
1227 /// This LibCallOptimization will simplify calls to the "pow" library
1228 /// function. It looks for cases where the result of pow is well known and
1229 /// substitutes the appropriate value.
1230 /// @brief Simplify the pow library function.
1231 struct VISIBILITY_HIDDEN PowOptimization : public LibCallOptimization {
1233 /// @brief Default Constructor
1234 PowOptimization() : LibCallOptimization("pow",
1235 "Number of 'pow' calls simplified") {}
1237 /// @brief Make sure that the "pow" function has the right prototype
1238 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1239 // Just make sure this has 2 arguments
1240 return (f->arg_size() == 2);
1243 /// @brief Perform the pow optimization.
1244 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1245 const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
1246 Value* base = ci->getOperand(1);
1247 Value* expn = ci->getOperand(2);
1248 if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
1249 double Op1V = Op1->getValue();
1251 // pow(1.0,x) -> 1.0
1252 ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
1253 ci->eraseFromParent();
1256 } else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
1257 double Op2V = Op2->getValue();
1259 // pow(x,0.0) -> 1.0
1260 ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
1261 ci->eraseFromParent();
1263 } else if (Op2V == 0.5) {
1264 // pow(x,0.5) -> sqrt(x)
1265 CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
1266 ci->getName()+".pow",ci);
1267 ci->replaceAllUsesWith(sqrt_inst);
1268 ci->eraseFromParent();
1270 } else if (Op2V == 1.0) {
1272 ci->replaceAllUsesWith(base);
1273 ci->eraseFromParent();
1275 } else if (Op2V == -1.0) {
1276 // pow(x,-1.0) -> 1.0/x
1277 BinaryOperator* div_inst= BinaryOperator::createFDiv(
1278 ConstantFP::get(Ty,1.0), base, ci->getName()+".pow", ci);
1279 ci->replaceAllUsesWith(div_inst);
1280 ci->eraseFromParent();
1284 return false; // opt failed
1288 /// This LibCallOptimization will simplify calls to the "printf" library
1289 /// function. It looks for cases where the result of printf is not used and the
1290 /// operation can be reduced to something simpler.
1291 /// @brief Simplify the printf library function.
1292 struct VISIBILITY_HIDDEN PrintfOptimization : public LibCallOptimization {
1294 /// @brief Default Constructor
1295 PrintfOptimization() : LibCallOptimization("printf",
1296 "Number of 'printf' calls simplified") {}
1298 /// @brief Make sure that the "printf" function has the right prototype
1299 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1300 // Just make sure this has at least 1 arguments
1301 return (f->arg_size() >= 1);
1304 /// @brief Perform the printf optimization.
1305 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
1306 // If the call has more than 2 operands, we can't optimize it
1307 if (ci->getNumOperands() > 3 || ci->getNumOperands() <= 2)
1310 // If the result of the printf call is used, none of these optimizations
1312 if (!ci->use_empty())
1315 // All the optimizations depend on the length of the first argument and the
1316 // fact that it is a constant string array. Check that now
1317 uint64_t len, StartIdx;
1318 ConstantArray* CA = 0;
1319 if (!GetConstantStringInfo(ci->getOperand(1), CA, len, StartIdx))
1322 if (len != 2 && len != 3)
1325 // The first character has to be a %
1326 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
1327 if (CI->getZExtValue() != '%')
1330 // Get the second character and switch on its value
1331 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
1332 switch (CI->getZExtValue()) {
1336 dyn_cast<ConstantInt>(CA->getOperand(2))->getZExtValue() != '\n')
1339 // printf("%s\n",str) -> puts(str)
1340 std::vector<Value*> args;
1341 new CallInst(SLC.get_puts(), CastToCStr(ci->getOperand(2), *ci),
1343 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, len));
1348 // printf("%c",c) -> putchar(c)
1352 CastInst *Char = CastInst::createSExtOrBitCast(
1353 ci->getOperand(2), Type::Int32Ty, CI->getName()+".int", ci);
1354 new CallInst(SLC.get_putchar(), Char, "", ci);
1355 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, 1));
1361 ci->eraseFromParent();
1366 /// This LibCallOptimization will simplify calls to the "fprintf" library
1367 /// function. It looks for cases where the result of fprintf is not used and the
1368 /// operation can be reduced to something simpler.
1369 /// @brief Simplify the fprintf library function.
1370 struct VISIBILITY_HIDDEN FPrintFOptimization : public LibCallOptimization {
1372 /// @brief Default Constructor
1373 FPrintFOptimization() : LibCallOptimization("fprintf",
1374 "Number of 'fprintf' calls simplified") {}
1376 /// @brief Make sure that the "fprintf" function has the right prototype
1377 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1378 // Just make sure this has at least 2 arguments
1379 return (f->arg_size() >= 2);
1382 /// @brief Perform the fprintf optimization.
1383 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
1384 // If the call has more than 3 operands, we can't optimize it
1385 if (ci->getNumOperands() > 4 || ci->getNumOperands() <= 2)
1388 // If the result of the fprintf call is used, none of these optimizations
1390 if (!ci->use_empty())
1393 // All the optimizations depend on the length of the second argument and the
1394 // fact that it is a constant string array. Check that now
1395 uint64_t len, StartIdx;
1396 ConstantArray* CA = 0;
1397 if (!GetConstantStringInfo(ci->getOperand(2), CA, len, StartIdx))
1400 if (ci->getNumOperands() == 3) {
1401 // Make sure there's no % in the constant array
1402 for (unsigned i = 0; i < len; ++i) {
1403 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
1404 // Check for the null terminator
1405 if (CI->getZExtValue() == '%')
1406 return false; // we found end of string
1412 // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
1413 const Type* FILEptr_type = ci->getOperand(1)->getType();
1415 // Make sure that the fprintf() and fwrite() functions both take the
1416 // same type of char pointer.
1417 if (ci->getOperand(2)->getType() != PointerType::get(Type::Int8Ty))
1422 ConstantInt::get(SLC.getIntPtrType(),len),
1423 ConstantInt::get(SLC.getIntPtrType(),1),
1426 new CallInst(SLC.get_fwrite(FILEptr_type), args, 4, ci->getName(), ci);
1427 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
1428 ci->eraseFromParent();
1432 // The remaining optimizations require the format string to be length 2
1437 // The first character has to be a %
1438 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
1439 if (CI->getZExtValue() != '%')
1442 // Get the second character and switch on its value
1443 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
1444 switch (CI->getZExtValue()) {
1447 uint64_t len, StartIdx;
1448 ConstantArray* CA = 0;
1449 if (GetConstantStringInfo(ci->getOperand(3), CA, len, StartIdx)) {
1450 // fprintf(file,"%s",str) -> fwrite(str,strlen(str),1,file)
1451 const Type* FILEptr_type = ci->getOperand(1)->getType();
1453 CastToCStr(ci->getOperand(3), *ci),
1454 ConstantInt::get(SLC.getIntPtrType(), len),
1455 ConstantInt::get(SLC.getIntPtrType(), 1),
1458 new CallInst(SLC.get_fwrite(FILEptr_type), args, 4,ci->getName(), ci);
1459 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, len));
1461 // fprintf(file,"%s",str) -> fputs(str,file)
1462 const Type* FILEptr_type = ci->getOperand(1)->getType();
1463 new CallInst(SLC.get_fputs(FILEptr_type),
1464 CastToCStr(ci->getOperand(3), *ci),
1465 ci->getOperand(1), ci->getName(),ci);
1466 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
1472 // fprintf(file,"%c",c) -> fputc(c,file)
1473 const Type* FILEptr_type = ci->getOperand(1)->getType();
1474 CastInst* cast = CastInst::createSExtOrBitCast(
1475 ci->getOperand(3), Type::Int32Ty, CI->getName()+".int", ci);
1476 new CallInst(SLC.get_fputc(FILEptr_type), cast,ci->getOperand(1),"",ci);
1477 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
1483 ci->eraseFromParent();
1488 /// This LibCallOptimization will simplify calls to the "sprintf" library
1489 /// function. It looks for cases where the result of sprintf is not used and the
1490 /// operation can be reduced to something simpler.
1491 /// @brief Simplify the sprintf library function.
1492 struct VISIBILITY_HIDDEN SPrintFOptimization : public LibCallOptimization {
1494 /// @brief Default Constructor
1495 SPrintFOptimization() : LibCallOptimization("sprintf",
1496 "Number of 'sprintf' calls simplified") {}
1498 /// @brief Make sure that the "fprintf" function has the right prototype
1499 virtual bool ValidateCalledFunction(const Function *f, SimplifyLibCalls &SLC){
1500 // Just make sure this has at least 2 arguments
1501 return (f->getReturnType() == Type::Int32Ty && f->arg_size() >= 2);
1504 /// @brief Perform the sprintf optimization.
1505 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1506 // If the call has more than 3 operands, we can't optimize it
1507 if (ci->getNumOperands() > 4 || ci->getNumOperands() < 3)
1510 // All the optimizations depend on the length of the second argument and the
1511 // fact that it is a constant string array. Check that now
1512 uint64_t len, StartIdx;
1513 ConstantArray* CA = 0;
1514 if (!GetConstantStringInfo(ci->getOperand(2), CA, len, StartIdx))
1517 if (ci->getNumOperands() == 3) {
1519 // If the length is 0, we just need to store a null byte
1520 new StoreInst(ConstantInt::get(Type::Int8Ty,0),ci->getOperand(1),ci);
1521 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
1522 ci->eraseFromParent();
1526 // Make sure there's no % in the constant array
1527 for (unsigned i = 0; i < len; ++i) {
1528 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
1529 // Check for the null terminator
1530 if (CI->getZExtValue() == '%')
1531 return false; // we found a %, can't optimize
1533 return false; // initializer is not constant int, can't optimize
1537 // Increment length because we want to copy the null byte too
1540 // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
1544 ConstantInt::get(SLC.getIntPtrType(),len),
1545 ConstantInt::get(Type::Int32Ty, 1)
1547 new CallInst(SLC.get_memcpy(), args, 4, "", ci);
1548 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
1549 ci->eraseFromParent();
1553 // The remaining optimizations require the format string to be length 2
1558 // The first character has to be a %
1559 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
1560 if (CI->getZExtValue() != '%')
1563 // Get the second character and switch on its value
1564 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
1565 switch (CI->getZExtValue()) {
1567 // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
1568 Value *Len = new CallInst(SLC.get_strlen(),
1569 CastToCStr(ci->getOperand(3), *ci),
1570 ci->getOperand(3)->getName()+".len", ci);
1571 Value *Len1 = BinaryOperator::createAdd(Len,
1572 ConstantInt::get(Len->getType(), 1),
1573 Len->getName()+"1", ci);
1574 if (Len1->getType() != SLC.getIntPtrType())
1575 Len1 = CastInst::createIntegerCast(Len1, SLC.getIntPtrType(), false,
1576 Len1->getName(), ci);
1578 CastToCStr(ci->getOperand(1), *ci),
1579 CastToCStr(ci->getOperand(3), *ci),
1581 ConstantInt::get(Type::Int32Ty,1)
1583 new CallInst(SLC.get_memcpy(), args, 4, "", ci);
1585 // The strlen result is the unincremented number of bytes in the string.
1586 if (!ci->use_empty()) {
1587 if (Len->getType() != ci->getType())
1588 Len = CastInst::createIntegerCast(Len, ci->getType(), false,
1589 Len->getName(), ci);
1590 ci->replaceAllUsesWith(Len);
1592 ci->eraseFromParent();
1596 // sprintf(dest,"%c",chr) -> store chr, dest
1597 CastInst* cast = CastInst::createTruncOrBitCast(
1598 ci->getOperand(3), Type::Int8Ty, "char", ci);
1599 new StoreInst(cast, ci->getOperand(1), ci);
1600 GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
1601 ConstantInt::get(Type::Int32Ty,1),ci->getOperand(1)->getName()+".end",
1603 new StoreInst(ConstantInt::get(Type::Int8Ty,0),gep,ci);
1604 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
1605 ci->eraseFromParent();
1613 /// This LibCallOptimization will simplify calls to the "fputs" library
1614 /// function. It looks for cases where the result of fputs is not used and the
1615 /// operation can be reduced to something simpler.
1616 /// @brief Simplify the puts library function.
1617 struct VISIBILITY_HIDDEN PutsOptimization : public LibCallOptimization {
1619 /// @brief Default Constructor
1620 PutsOptimization() : LibCallOptimization("fputs",
1621 "Number of 'fputs' calls simplified") {}
1623 /// @brief Make sure that the "fputs" function has the right prototype
1624 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1625 // Just make sure this has 2 arguments
1626 return F->arg_size() == 2;
1629 /// @brief Perform the fputs optimization.
1630 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
1631 // If the result is used, none of these optimizations work
1632 if (!ci->use_empty())
1635 // All the optimizations depend on the length of the first argument and the
1636 // fact that it is a constant string array. Check that now
1637 uint64_t len, StartIdx;
1639 if (!GetConstantStringInfo(ci->getOperand(1), CA, len, StartIdx))
1644 // fputs("",F) -> noop
1648 // fputs(s,F) -> fputc(s[0],F) (if s is constant and strlen(s) == 1)
1649 const Type* FILEptr_type = ci->getOperand(2)->getType();
1650 LoadInst* loadi = new LoadInst(ci->getOperand(1),
1651 ci->getOperand(1)->getName()+".byte",ci);
1652 CastInst* casti = new SExtInst(loadi, Type::Int32Ty,
1653 loadi->getName()+".int", ci);
1654 new CallInst(SLC.get_fputc(FILEptr_type), casti,
1655 ci->getOperand(2), "", ci);
1660 // fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
1661 const Type* FILEptr_type = ci->getOperand(2)->getType();
1664 ConstantInt::get(SLC.getIntPtrType(),len),
1665 ConstantInt::get(SLC.getIntPtrType(),1),
1668 new CallInst(SLC.get_fwrite(FILEptr_type), parms, 4, "", ci);
1672 ci->eraseFromParent();
1673 return true; // success
1677 /// This LibCallOptimization will simplify calls to the "isdigit" library
1678 /// function. It simply does range checks the parameter explicitly.
1679 /// @brief Simplify the isdigit library function.
1680 struct VISIBILITY_HIDDEN isdigitOptimization : public LibCallOptimization {
1682 isdigitOptimization() : LibCallOptimization("isdigit",
1683 "Number of 'isdigit' calls simplified") {}
1685 /// @brief Make sure that the "isdigit" function has the right prototype
1686 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1687 // Just make sure this has 1 argument
1688 return (f->arg_size() == 1);
1691 /// @brief Perform the toascii optimization.
1692 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1693 if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
1694 // isdigit(c) -> 0 or 1, if 'c' is constant
1695 uint64_t val = CI->getZExtValue();
1696 if (val >= '0' && val <='9')
1697 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
1699 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
1700 ci->eraseFromParent();
1704 // isdigit(c) -> (unsigned)c - '0' <= 9
1705 CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
1706 Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
1707 BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
1708 ConstantInt::get(Type::Int32Ty,0x30),
1709 ci->getOperand(1)->getName()+".sub",ci);
1710 ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
1711 ConstantInt::get(Type::Int32Ty,9),
1712 ci->getOperand(1)->getName()+".cmp",ci);
1713 CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
1714 ci->getOperand(1)->getName()+".isdigit", ci);
1715 ci->replaceAllUsesWith(c2);
1716 ci->eraseFromParent();
1721 struct VISIBILITY_HIDDEN isasciiOptimization : public LibCallOptimization {
1723 isasciiOptimization()
1724 : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
1726 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1727 return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
1728 F->getReturnType()->isInteger();
1731 /// @brief Perform the isascii optimization.
1732 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1733 // isascii(c) -> (unsigned)c < 128
1734 Value *V = CI->getOperand(1);
1735 Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
1736 ConstantInt::get(V->getType(), 128),
1737 V->getName()+".isascii", CI);
1738 if (Cmp->getType() != CI->getType())
1739 Cmp = new BitCastInst(Cmp, CI->getType(), Cmp->getName(), CI);
1740 CI->replaceAllUsesWith(Cmp);
1741 CI->eraseFromParent();
1747 /// This LibCallOptimization will simplify calls to the "toascii" library
1748 /// function. It simply does the corresponding and operation to restrict the
1749 /// range of values to the ASCII character set (0-127).
1750 /// @brief Simplify the toascii library function.
1751 struct VISIBILITY_HIDDEN ToAsciiOptimization : public LibCallOptimization {
1753 /// @brief Default Constructor
1754 ToAsciiOptimization() : LibCallOptimization("toascii",
1755 "Number of 'toascii' calls simplified") {}
1757 /// @brief Make sure that the "fputs" function has the right prototype
1758 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1759 // Just make sure this has 2 arguments
1760 return (f->arg_size() == 1);
1763 /// @brief Perform the toascii optimization.
1764 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1765 // toascii(c) -> (c & 0x7f)
1766 Value* chr = ci->getOperand(1);
1767 BinaryOperator* and_inst = BinaryOperator::createAnd(chr,
1768 ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
1769 ci->replaceAllUsesWith(and_inst);
1770 ci->eraseFromParent();
1775 /// This LibCallOptimization will simplify calls to the "ffs" library
1776 /// calls which find the first set bit in an int, long, or long long. The
1777 /// optimization is to compute the result at compile time if the argument is
1779 /// @brief Simplify the ffs library function.
1780 struct VISIBILITY_HIDDEN FFSOptimization : public LibCallOptimization {
1782 /// @brief Subclass Constructor
1783 FFSOptimization(const char* funcName, const char* description)
1784 : LibCallOptimization(funcName, description) {}
1787 /// @brief Default Constructor
1788 FFSOptimization() : LibCallOptimization("ffs",
1789 "Number of 'ffs' calls simplified") {}
1791 /// @brief Make sure that the "ffs" function has the right prototype
1792 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1793 // Just make sure this has 2 arguments
1794 return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
1797 /// @brief Perform the ffs optimization.
1798 virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
1799 if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
1800 // ffs(cnst) -> bit#
1801 // ffsl(cnst) -> bit#
1802 // ffsll(cnst) -> bit#
1803 uint64_t val = CI->getZExtValue();
1807 while ((val & 1) == 0) {
1812 TheCall->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, result));
1813 TheCall->eraseFromParent();
1817 // ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1818 // ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1819 // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1820 const Type *ArgType = TheCall->getOperand(1)->getType();
1821 const char *CTTZName;
1822 assert(ArgType->getTypeID() == Type::IntegerTyID &&
1823 "llvm.cttz argument is not an integer?");
1824 unsigned BitWidth = cast<IntegerType>(ArgType)->getBitWidth();
1826 CTTZName = "llvm.cttz.i8";
1827 else if (BitWidth == 16)
1828 CTTZName = "llvm.cttz.i16";
1829 else if (BitWidth == 32)
1830 CTTZName = "llvm.cttz.i32";
1832 assert(BitWidth == 64 && "Unknown bitwidth");
1833 CTTZName = "llvm.cttz.i64";
1836 Constant *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
1838 Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
1839 false/*ZExt*/, "tmp", TheCall);
1840 Value *V2 = new CallInst(F, V, "tmp", TheCall);
1841 V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
1843 V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
1845 Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
1846 Constant::getNullValue(V->getType()), "tmp",
1848 V2 = new SelectInst(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
1849 TheCall->getName(), TheCall);
1850 TheCall->replaceAllUsesWith(V2);
1851 TheCall->eraseFromParent();
1856 /// This LibCallOptimization will simplify calls to the "ffsl" library
1857 /// calls. It simply uses FFSOptimization for which the transformation is
1859 /// @brief Simplify the ffsl library function.
1860 struct VISIBILITY_HIDDEN FFSLOptimization : public FFSOptimization {
1862 /// @brief Default Constructor
1863 FFSLOptimization() : FFSOptimization("ffsl",
1864 "Number of 'ffsl' calls simplified") {}
1868 /// This LibCallOptimization will simplify calls to the "ffsll" library
1869 /// calls. It simply uses FFSOptimization for which the transformation is
1871 /// @brief Simplify the ffsl library function.
1872 struct VISIBILITY_HIDDEN FFSLLOptimization : public FFSOptimization {
1874 /// @brief Default Constructor
1875 FFSLLOptimization() : FFSOptimization("ffsll",
1876 "Number of 'ffsll' calls simplified") {}
1880 /// This optimizes unary functions that take and return doubles.
1881 struct UnaryDoubleFPOptimizer : public LibCallOptimization {
1882 UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
1883 : LibCallOptimization(Fn, Desc) {}
1885 // Make sure that this function has the right prototype
1886 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1887 return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
1888 F->getReturnType() == Type::DoubleTy;
1891 /// ShrinkFunctionToFloatVersion - If the input to this function is really a
1892 /// float, strength reduce this to a float version of the function,
1893 /// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
1894 /// when the target supports the destination function and where there can be
1895 /// no precision loss.
1896 static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
1897 Constant *(SimplifyLibCalls::*FP)()){
1898 if (CastInst *Cast = dyn_cast<CastInst>(CI->getOperand(1)))
1899 if (Cast->getOperand(0)->getType() == Type::FloatTy) {
1900 Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
1902 New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
1903 CI->replaceAllUsesWith(New);
1904 CI->eraseFromParent();
1905 if (Cast->use_empty())
1906 Cast->eraseFromParent();
1914 struct VISIBILITY_HIDDEN FloorOptimization : public UnaryDoubleFPOptimizer {
1916 : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
1918 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1920 // If this is a float argument passed in, convert to floorf.
1921 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
1924 return false; // opt failed
1928 struct VISIBILITY_HIDDEN CeilOptimization : public UnaryDoubleFPOptimizer {
1930 : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
1932 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1934 // If this is a float argument passed in, convert to ceilf.
1935 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
1938 return false; // opt failed
1942 struct VISIBILITY_HIDDEN RoundOptimization : public UnaryDoubleFPOptimizer {
1944 : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
1946 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1948 // If this is a float argument passed in, convert to roundf.
1949 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
1952 return false; // opt failed
1956 struct VISIBILITY_HIDDEN RintOptimization : public UnaryDoubleFPOptimizer {
1958 : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
1960 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1962 // If this is a float argument passed in, convert to rintf.
1963 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
1966 return false; // opt failed
1970 struct VISIBILITY_HIDDEN NearByIntOptimization : public UnaryDoubleFPOptimizer {
1971 NearByIntOptimization()
1972 : UnaryDoubleFPOptimizer("nearbyint",
1973 "Number of 'nearbyint' calls simplified") {}
1975 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1976 #ifdef HAVE_NEARBYINTF
1977 // If this is a float argument passed in, convert to nearbyintf.
1978 if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
1981 return false; // opt failed
1983 } NearByIntOptimizer;
1985 /// GetConstantStringInfo - This function computes the length of a
1986 /// null-terminated constant array of integers. This function can't rely on the
1987 /// size of the constant array because there could be a null terminator in the
1988 /// middle of the array.
1990 /// We also have to bail out if we find a non-integer constant initializer
1991 /// of one of the elements or if there is no null-terminator. The logic
1992 /// below checks each of these conditions and will return true only if all
1993 /// conditions are met. If the conditions aren't met, this returns false.
1995 /// If successful, the \p Array param is set to the constant array being
1996 /// indexed, the \p Length parameter is set to the length of the null-terminated
1997 /// string pointed to by V, the \p StartIdx value is set to the first
1998 /// element of the Array that V points to, and true is returned.
1999 static bool GetConstantStringInfo(Value *V, ConstantArray *&Array,
2000 uint64_t &Length, uint64_t &StartIdx) {
2001 assert(V != 0 && "Invalid args to GetConstantStringInfo");
2002 // Initialize results.
2008 // If the value is not a GEP instruction nor a constant expression with a
2009 // GEP instruction, then return false because ConstantArray can't occur
2011 if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
2013 } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
2014 if (CE->getOpcode() != Instruction::GetElementPtr)
2021 // Make sure the GEP has exactly three arguments.
2022 if (GEP->getNumOperands() != 3)
2025 // Check to make sure that the first operand of the GEP is an integer and
2026 // has value 0 so that we are sure we're indexing into the initializer.
2027 if (ConstantInt* op1 = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
2033 // If the second index isn't a ConstantInt, then this is a variable index
2034 // into the array. If this occurs, we can't say anything meaningful about
2037 if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
2038 StartIdx = CI->getZExtValue();
2042 // The GEP instruction, constant or instruction, must reference a global
2043 // variable that is a constant and is initialized. The referenced constant
2044 // initializer is the array that we'll use for optimization.
2045 GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
2046 if (!GV || !GV->isConstant() || !GV->hasInitializer())
2048 Constant *GlobalInit = GV->getInitializer();
2050 // Handle the ConstantAggregateZero case
2051 if (isa<ConstantAggregateZero>(GlobalInit)) {
2052 // This is a degenerate case. The initializer is constant zero so the
2053 // length of the string must be zero.
2058 // Must be a Constant Array
2059 Array = dyn_cast<ConstantArray>(GlobalInit);
2060 if (!Array) return false;
2062 // Get the number of elements in the array
2063 uint64_t NumElts = Array->getType()->getNumElements();
2065 // Traverse the constant array from start_idx (derived above) which is
2066 // the place the GEP refers to in the array.
2069 if (Length >= NumElts)
2070 return false; // The array isn't null terminated.
2072 Constant *Elt = Array->getOperand(Length);
2073 if (ConstantInt *CI = dyn_cast<ConstantInt>(Elt)) {
2074 // Check for the null terminator.
2076 break; // we found end of string
2078 return false; // This array isn't suitable, non-int initializer
2082 // Subtract out the initial value from the length
2084 return true; // success!
2087 /// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
2088 /// inserting the cast before IP, and return the cast.
2089 /// @brief Cast a value to a "C" string.
2090 static Value *CastToCStr(Value *V, Instruction &IP) {
2091 assert(isa<PointerType>(V->getType()) &&
2092 "Can't cast non-pointer type to C string type");
2093 const Type *SBPTy = PointerType::get(Type::Int8Ty);
2094 if (V->getType() != SBPTy)
2095 return new BitCastInst(V, SBPTy, V->getName(), &IP);
2100 // Additional cases that we need to add to this file:
2103 // * cbrt(expN(X)) -> expN(x/3)
2104 // * cbrt(sqrt(x)) -> pow(x,1/6)
2105 // * cbrt(sqrt(x)) -> pow(x,1/9)
2108 // * cos(-x) -> cos(x)
2111 // * exp(log(x)) -> x
2114 // * log(exp(x)) -> x
2115 // * log(x**y) -> y*log(x)
2116 // * log(exp(y)) -> y*log(e)
2117 // * log(exp2(y)) -> y*log(2)
2118 // * log(exp10(y)) -> y*log(10)
2119 // * log(sqrt(x)) -> 0.5*log(x)
2120 // * log(pow(x,y)) -> y*log(x)
2122 // lround, lroundf, lroundl:
2123 // * lround(cnst) -> cnst'
2126 // * memcmp(x,y,l) -> cnst
2127 // (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
2130 // * memmove(d,s,l,a) -> memcpy(d,s,l,a)
2131 // (if s is a global constant array)
2134 // * pow(exp(x),y) -> exp(x*y)
2135 // * pow(sqrt(x),y) -> pow(x,y*0.5)
2136 // * pow(pow(x,y),z)-> pow(x,y*z)
2139 // * puts("") -> fputc("\n",stdout) (how do we get "stdout"?)
2141 // round, roundf, roundl:
2142 // * round(cnst) -> cnst'
2145 // * signbit(cnst) -> cnst'
2146 // * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2148 // sqrt, sqrtf, sqrtl:
2149 // * sqrt(expN(x)) -> expN(x*0.5)
2150 // * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2151 // * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2154 // * stpcpy(str, "literal") ->
2155 // llvm.memcpy(str,"literal",strlen("literal")+1,1)
2157 // * strrchr(s,c) -> reverse_offset_of_in(c,s)
2158 // (if c is a constant integer and s is a constant string)
2159 // * strrchr(s1,0) -> strchr(s1,0)
2162 // * strncat(x,y,0) -> x
2163 // * strncat(x,y,0) -> x (if strlen(y) = 0)
2164 // * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
2167 // * strncpy(d,s,0) -> d
2168 // * strncpy(d,s,l) -> memcpy(d,s,l,1)
2169 // (if s and l are constants)
2172 // * strpbrk(s,a) -> offset_in_for(s,a)
2173 // (if s and a are both constant strings)
2174 // * strpbrk(s,"") -> 0
2175 // * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
2178 // * strspn(s,a) -> const_int (if both args are constant)
2179 // * strspn("",a) -> 0
2180 // * strspn(s,"") -> 0
2181 // * strcspn(s,a) -> const_int (if both args are constant)
2182 // * strcspn("",a) -> 0
2183 // * strcspn(s,"") -> strlen(a)
2186 // * strstr(x,x) -> x
2187 // * strstr(s1,s2) -> offset_of_s2_in(s1)
2188 // (if s1 and s2 are constant strings)
2191 // * tan(atan(x)) -> x
2193 // trunc, truncf, truncl:
2194 // * trunc(cnst) -> cnst'