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Reid Spencer9bbaa2a2005-04-25 03:59:26 +00001//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
Reid Spencer39a762d2005-04-25 02:53:12 +00002//
3// The LLVM Compiler Infrastructure
4//
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00005// This file was developed by Reid Spencer and is distributed under the
Reid Spencer9bbaa2a2005-04-25 03:59:26 +00006// University of Illinois Open Source License. See LICENSE.TXT for details.
Reid Spencer39a762d2005-04-25 02:53:12 +00007//
8//===----------------------------------------------------------------------===//
9//
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000010// 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
Reid Spencer0b13cda2005-05-21 00:57:44 +000013// occurs within the main() function can be transformed into a simple "return 3"
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000014// instruction. Any optimization that takes this form (replace call to library
15// function with simpler code that provides the same result) belongs in this
16// file.
Reid Spencer39a762d2005-04-25 02:53:12 +000017//
18//===----------------------------------------------------------------------===//
19
Reid Spencer18b99812005-04-26 23:05:17 +000020#define DEBUG_TYPE "simplify-libcalls"
Reid Spencer2bc7a4f2005-04-26 23:02:16 +000021#include "llvm/Constants.h"
22#include "llvm/DerivedTypes.h"
23#include "llvm/Instructions.h"
Reid Spencer39a762d2005-04-25 02:53:12 +000024#include "llvm/Module.h"
25#include "llvm/Pass.h"
Reid Spencer9bbaa2a2005-04-25 03:59:26 +000026#include "llvm/ADT/hash_map"
Reid Spencer2bc7a4f2005-04-26 23:02:16 +000027#include "llvm/ADT/Statistic.h"
Reid Spencerade18212006-01-19 08:36:56 +000028#include "llvm/Config/config.h"
Reid Spencer2bc7a4f2005-04-26 23:02:16 +000029#include "llvm/Support/Debug.h"
Reid Spencerbb92b4f2005-04-26 19:13:17 +000030#include "llvm/Target/TargetData.h"
Reid Spencer2bc7a4f2005-04-26 23:02:16 +000031#include "llvm/Transforms/IPO.h"
Reid Spencer39a762d2005-04-25 02:53:12 +000032using namespace llvm;
33
Reid Spencere249a822005-04-27 07:54:40 +000034/// This statistic keeps track of the total number of library calls that have
35/// been simplified regardless of which call it is.
Chris Lattner1631bcb2006-12-19 22:09:18 +000036STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
Reid Spencer39a762d2005-04-25 02:53:12 +000037
Chris Lattner1631bcb2006-12-19 22:09:18 +000038namespace {
39 // Forward declarations
40 class LibCallOptimization;
41 class SimplifyLibCalls;
42
Chris Lattner33081b42006-01-22 23:10:26 +000043/// This list is populated by the constructor for LibCallOptimization class.
Reid Spencer9fbad132005-05-21 01:27:04 +000044/// Therefore all subclasses are registered here at static initialization time
45/// and this list is what the SimplifyLibCalls pass uses to apply the individual
46/// optimizations to the call sites.
Reid Spencer7ddcfb32005-04-27 21:29:20 +000047/// @brief The list of optimizations deriving from LibCallOptimization
Chris Lattner33081b42006-01-22 23:10:26 +000048static LibCallOptimization *OptList = 0;
Reid Spencer39a762d2005-04-25 02:53:12 +000049
Reid Spencere249a822005-04-27 07:54:40 +000050/// This class is the abstract base class for the set of optimizations that
Reid Spencer7ddcfb32005-04-27 21:29:20 +000051/// corresponds to one library call. The SimplifyLibCalls pass will call the
Reid Spencere249a822005-04-27 07:54:40 +000052/// ValidateCalledFunction method to ask the optimization if a given Function
Reid Spencer7ddcfb32005-04-27 21:29:20 +000053/// is the kind that the optimization can handle. If the subclass returns true,
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000054/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
Reid Spencer7ddcfb32005-04-27 21:29:20 +000055/// or attempt to perform, the optimization(s) for the library call. Otherwise,
56/// OptimizeCall won't be called. Subclasses are responsible for providing the
57/// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
58/// constructor. This is used to efficiently select which call instructions to
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000059/// optimize. The criteria for a "lib call" is "anything with well known
Reid Spencer7ddcfb32005-04-27 21:29:20 +000060/// semantics", typically a library function that is defined by an international
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000061/// standard. Because the semantics are well known, the optimizations can
Reid Spencer7ddcfb32005-04-27 21:29:20 +000062/// generally short-circuit actually calling the function if there's a simpler
63/// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
Reid Spencere249a822005-04-27 07:54:40 +000064/// @brief Base class for library call optimizations
Chris Lattner0d4ebfc2006-01-22 22:35:08 +000065class LibCallOptimization {
Chris Lattner33081b42006-01-22 23:10:26 +000066 LibCallOptimization **Prev, *Next;
67 const char *FunctionName; ///< Name of the library call we optimize
68#ifndef NDEBUG
Chris Lattner700b8732006-12-06 17:46:33 +000069 Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
Chris Lattner33081b42006-01-22 23:10:26 +000070#endif
Jeff Cohen4bc952f2005-04-29 03:05:44 +000071public:
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000072 /// The \p fname argument must be the name of the library function being
Reid Spencer7ddcfb32005-04-27 21:29:20 +000073 /// optimized by the subclass.
74 /// @brief Constructor that registers the optimization.
Chris Lattner33081b42006-01-22 23:10:26 +000075 LibCallOptimization(const char *FName, const char *Description)
Chris Lattner575d3212006-12-19 23:16:47 +000076 : FunctionName(FName) {
77
Reid Spencere95a6472005-04-27 00:05:45 +000078#ifndef NDEBUG
Chris Lattner575d3212006-12-19 23:16:47 +000079 occurrences.construct("simplify-libcalls", Description);
Reid Spencere95a6472005-04-27 00:05:45 +000080#endif
Chris Lattner33081b42006-01-22 23:10:26 +000081 // Register this optimizer in the list of optimizations.
82 Next = OptList;
83 OptList = this;
84 Prev = &OptList;
85 if (Next) Next->Prev = &Next;
Reid Spencer39a762d2005-04-25 02:53:12 +000086 }
Chris Lattner33081b42006-01-22 23:10:26 +000087
88 /// getNext - All libcall optimizations are chained together into a list,
89 /// return the next one in the list.
90 LibCallOptimization *getNext() { return Next; }
Reid Spencer39a762d2005-04-25 02:53:12 +000091
Reid Spencer7ddcfb32005-04-27 21:29:20 +000092 /// @brief Deregister from the optlist
Chris Lattner33081b42006-01-22 23:10:26 +000093 virtual ~LibCallOptimization() {
94 *Prev = Next;
95 if (Next) Next->Prev = Prev;
96 }
Reid Spencer8ee5aac2005-04-26 03:26:15 +000097
Reid Spencere249a822005-04-27 07:54:40 +000098 /// The implementation of this function in subclasses should determine if
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +000099 /// \p F is suitable for the optimization. This method is called by
100 /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
101 /// sites of such a function if that function is not suitable in the first
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000102 /// place. If the called function is suitabe, this method should return true;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000103 /// false, otherwise. This function should also perform any lazy
104 /// initialization that the LibCallOptimization needs to do, if its to return
Reid Spencere249a822005-04-27 07:54:40 +0000105 /// true. This avoids doing initialization until the optimizer is actually
106 /// going to be called upon to do some optimization.
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000107 /// @brief Determine if the function is suitable for optimization
Reid Spencere249a822005-04-27 07:54:40 +0000108 virtual bool ValidateCalledFunction(
109 const Function* F, ///< The function that is the target of call sites
110 SimplifyLibCalls& SLC ///< The pass object invoking us
111 ) = 0;
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000112
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000113 /// The implementations of this function in subclasses is the heart of the
114 /// SimplifyLibCalls algorithm. Sublcasses of this class implement
Reid Spencere249a822005-04-27 07:54:40 +0000115 /// OptimizeCall to determine if (a) the conditions are right for optimizing
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000116 /// the call and (b) to perform the optimization. If an action is taken
Reid Spencere249a822005-04-27 07:54:40 +0000117 /// against ci, the subclass is responsible for returning true and ensuring
118 /// that ci is erased from its parent.
Reid Spencere249a822005-04-27 07:54:40 +0000119 /// @brief Optimize a call, if possible.
120 virtual bool OptimizeCall(
121 CallInst* ci, ///< The call instruction that should be optimized.
122 SimplifyLibCalls& SLC ///< The pass object invoking us
123 ) = 0;
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000124
Reid Spencere249a822005-04-27 07:54:40 +0000125 /// @brief Get the name of the library call being optimized
Chris Lattner33081b42006-01-22 23:10:26 +0000126 const char *getFunctionName() const { return FunctionName; }
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000127
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000128 /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
Chris Lattner33081b42006-01-22 23:10:26 +0000129 void succeeded() {
Reid Spencere249a822005-04-27 07:54:40 +0000130#ifndef NDEBUG
Chris Lattner33081b42006-01-22 23:10:26 +0000131 DEBUG(++occurrences);
Reid Spencere249a822005-04-27 07:54:40 +0000132#endif
Chris Lattner33081b42006-01-22 23:10:26 +0000133 }
Reid Spencere249a822005-04-27 07:54:40 +0000134};
135
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000136/// This class is an LLVM Pass that applies each of the LibCallOptimization
Reid Spencere249a822005-04-27 07:54:40 +0000137/// instances to all the call sites in a module, relatively efficiently. The
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000138/// purpose of this pass is to provide optimizations for calls to well-known
Reid Spencere249a822005-04-27 07:54:40 +0000139/// functions with well-known semantics, such as those in the c library. The
Chris Lattner4201cd12005-08-24 17:22:17 +0000140/// class provides the basic infrastructure for handling runOnModule. Whenever
141/// this pass finds a function call, it asks the appropriate optimizer to
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000142/// validate the call (ValidateLibraryCall). If it is validated, then
143/// the OptimizeCall method is also called.
Reid Spencere249a822005-04-27 07:54:40 +0000144/// @brief A ModulePass for optimizing well-known function calls.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000145class SimplifyLibCalls : public ModulePass {
Jeff Cohen4bc952f2005-04-29 03:05:44 +0000146public:
Reid Spencere249a822005-04-27 07:54:40 +0000147 /// We need some target data for accurate signature details that are
148 /// target dependent. So we require target data in our AnalysisUsage.
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000149 /// @brief Require TargetData from AnalysisUsage.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000150 virtual void getAnalysisUsage(AnalysisUsage& Info) const {
Reid Spencere249a822005-04-27 07:54:40 +0000151 // Ask that the TargetData analysis be performed before us so we can use
152 // the target data.
153 Info.addRequired<TargetData>();
154 }
155
156 /// For this pass, process all of the function calls in the module, calling
157 /// ValidateLibraryCall and OptimizeCall as appropriate.
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000158 /// @brief Run all the lib call optimizations on a Module.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000159 virtual bool runOnModule(Module &M) {
Reid Spencere249a822005-04-27 07:54:40 +0000160 reset(M);
161
162 bool result = false;
Chris Lattner33081b42006-01-22 23:10:26 +0000163 hash_map<std::string, LibCallOptimization*> OptznMap;
164 for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
165 OptznMap[Optzn->getFunctionName()] = Optzn;
Reid Spencere249a822005-04-27 07:54:40 +0000166
167 // The call optimizations can be recursive. That is, the optimization might
168 // generate a call to another function which can also be optimized. This way
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000169 // we make the LibCallOptimization instances very specific to the case they
170 // handle. It also means we need to keep running over the function calls in
Reid Spencere249a822005-04-27 07:54:40 +0000171 // the module until we don't get any more optimizations possible.
172 bool found_optimization = false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000173 do {
Reid Spencere249a822005-04-27 07:54:40 +0000174 found_optimization = false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000175 for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
Reid Spencere249a822005-04-27 07:54:40 +0000176 // All the "well-known" functions are external and have external linkage
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000177 // because they live in a runtime library somewhere and were (probably)
178 // not compiled by LLVM. So, we only act on external functions that
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000179 // have external or dllimport linkage and non-empty uses.
Reid Spencer5301e7c2007-01-30 20:08:39 +0000180 if (!FI->isDeclaration() ||
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000181 !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
182 FI->use_empty())
Reid Spencere249a822005-04-27 07:54:40 +0000183 continue;
184
185 // Get the optimization class that pertains to this function
Chris Lattner33081b42006-01-22 23:10:26 +0000186 hash_map<std::string, LibCallOptimization*>::iterator OMI =
187 OptznMap.find(FI->getName());
188 if (OMI == OptznMap.end()) continue;
189
190 LibCallOptimization *CO = OMI->second;
Reid Spencere249a822005-04-27 07:54:40 +0000191
192 // Make sure the called function is suitable for the optimization
Chris Lattner33081b42006-01-22 23:10:26 +0000193 if (!CO->ValidateCalledFunction(FI, *this))
Reid Spencere249a822005-04-27 07:54:40 +0000194 continue;
195
196 // Loop over each of the uses of the function
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000197 for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000198 UI != UE ; ) {
Reid Spencere249a822005-04-27 07:54:40 +0000199 // If the use of the function is a call instruction
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000200 if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
Reid Spencere249a822005-04-27 07:54:40 +0000201 // Do the optimization on the LibCallOptimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000202 if (CO->OptimizeCall(CI, *this)) {
Reid Spencere249a822005-04-27 07:54:40 +0000203 ++SimplifiedLibCalls;
204 found_optimization = result = true;
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000205 CO->succeeded();
Reid Spencere249a822005-04-27 07:54:40 +0000206 }
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000207 }
208 }
209 }
Reid Spencere249a822005-04-27 07:54:40 +0000210 } while (found_optimization);
Chris Lattner33081b42006-01-22 23:10:26 +0000211
Reid Spencere249a822005-04-27 07:54:40 +0000212 return result;
213 }
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000214
Reid Spencere249a822005-04-27 07:54:40 +0000215 /// @brief Return the *current* module we're working on.
Reid Spencer93616972005-04-29 09:39:47 +0000216 Module* getModule() const { return M; }
Reid Spencerbb92b4f2005-04-26 19:13:17 +0000217
Reid Spencere249a822005-04-27 07:54:40 +0000218 /// @brief Return the *current* target data for the module we're working on.
Reid Spencer93616972005-04-29 09:39:47 +0000219 TargetData* getTargetData() const { return TD; }
220
221 /// @brief Return the size_t type -- syntactic shortcut
222 const Type* getIntPtrType() const { return TD->getIntPtrType(); }
223
Evan Cheng1fc40252006-06-16 08:36:35 +0000224 /// @brief Return a Function* for the putchar libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000225 Constant *get_putchar() {
Evan Cheng1fc40252006-06-16 08:36:35 +0000226 if (!putchar_func)
Reid Spencerc635f472006-12-31 05:48:39 +0000227 putchar_func =
228 M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
Evan Cheng1fc40252006-06-16 08:36:35 +0000229 return putchar_func;
230 }
231
232 /// @brief Return a Function* for the puts libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000233 Constant *get_puts() {
Evan Cheng1fc40252006-06-16 08:36:35 +0000234 if (!puts_func)
Reid Spencerc635f472006-12-31 05:48:39 +0000235 puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
236 PointerType::get(Type::Int8Ty),
Evan Cheng1fc40252006-06-16 08:36:35 +0000237 NULL);
238 return puts_func;
239 }
240
Reid Spencer93616972005-04-29 09:39:47 +0000241 /// @brief Return a Function* for the fputc libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000242 Constant *get_fputc(const Type* FILEptr_type) {
Reid Spencer93616972005-04-29 09:39:47 +0000243 if (!fputc_func)
Reid Spencerc635f472006-12-31 05:48:39 +0000244 fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000245 FILEptr_type, NULL);
Reid Spencer93616972005-04-29 09:39:47 +0000246 return fputc_func;
247 }
248
Evan Chengf2ea5872006-06-16 04:52:30 +0000249 /// @brief Return a Function* for the fputs libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000250 Constant *get_fputs(const Type* FILEptr_type) {
Evan Chengf2ea5872006-06-16 04:52:30 +0000251 if (!fputs_func)
Reid Spencerc635f472006-12-31 05:48:39 +0000252 fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
253 PointerType::get(Type::Int8Ty),
Evan Chengf2ea5872006-06-16 04:52:30 +0000254 FILEptr_type, NULL);
255 return fputs_func;
256 }
257
Reid Spencer93616972005-04-29 09:39:47 +0000258 /// @brief Return a Function* for the fwrite libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000259 Constant *get_fwrite(const Type* FILEptr_type) {
Reid Spencer93616972005-04-29 09:39:47 +0000260 if (!fwrite_func)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000261 fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
Reid Spencerc635f472006-12-31 05:48:39 +0000262 PointerType::get(Type::Int8Ty),
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000263 TD->getIntPtrType(),
264 TD->getIntPtrType(),
265 FILEptr_type, NULL);
Reid Spencer93616972005-04-29 09:39:47 +0000266 return fwrite_func;
267 }
268
269 /// @brief Return a Function* for the sqrt libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000270 Constant *get_sqrt() {
Reid Spencer93616972005-04-29 09:39:47 +0000271 if (!sqrt_func)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000272 sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
273 Type::DoubleTy, NULL);
Reid Spencer93616972005-04-29 09:39:47 +0000274 return sqrt_func;
275 }
Reid Spencere249a822005-04-27 07:54:40 +0000276
Owen Andersondfd79ad2007-01-20 10:07:23 +0000277 /// @brief Return a Function* for the strcpy libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000278 Constant *get_strcpy() {
Reid Spencer1e520fd2005-05-04 03:20:21 +0000279 if (!strcpy_func)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000280 strcpy_func = M->getOrInsertFunction("strcpy",
Reid Spencerc635f472006-12-31 05:48:39 +0000281 PointerType::get(Type::Int8Ty),
282 PointerType::get(Type::Int8Ty),
283 PointerType::get(Type::Int8Ty),
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000284 NULL);
Reid Spencer1e520fd2005-05-04 03:20:21 +0000285 return strcpy_func;
286 }
287
288 /// @brief Return a Function* for the strlen libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000289 Constant *get_strlen() {
Reid Spencere249a822005-04-27 07:54:40 +0000290 if (!strlen_func)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000291 strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
Reid Spencerc635f472006-12-31 05:48:39 +0000292 PointerType::get(Type::Int8Ty),
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000293 NULL);
Reid Spencere249a822005-04-27 07:54:40 +0000294 return strlen_func;
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000295 }
296
Reid Spencer38cabd72005-05-03 07:23:44 +0000297 /// @brief Return a Function* for the memchr libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000298 Constant *get_memchr() {
Reid Spencer38cabd72005-05-03 07:23:44 +0000299 if (!memchr_func)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000300 memchr_func = M->getOrInsertFunction("memchr",
Reid Spencerc635f472006-12-31 05:48:39 +0000301 PointerType::get(Type::Int8Ty),
302 PointerType::get(Type::Int8Ty),
303 Type::Int32Ty, TD->getIntPtrType(),
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000304 NULL);
Reid Spencer38cabd72005-05-03 07:23:44 +0000305 return memchr_func;
306 }
307
Reid Spencere249a822005-04-27 07:54:40 +0000308 /// @brief Return a Function* for the memcpy libcall
Chris Lattner34acba42007-01-07 08:12:01 +0000309 Constant *get_memcpy() {
Chris Lattner4201cd12005-08-24 17:22:17 +0000310 if (!memcpy_func) {
Reid Spencerc635f472006-12-31 05:48:39 +0000311 const Type *SBP = PointerType::get(Type::Int8Ty);
312 const char *N = TD->getIntPtrType() == Type::Int32Ty ?
Chris Lattnerea7986a2006-03-03 01:30:23 +0000313 "llvm.memcpy.i32" : "llvm.memcpy.i64";
314 memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
Reid Spencerc635f472006-12-31 05:48:39 +0000315 TD->getIntPtrType(), Type::Int32Ty,
Chris Lattnerea7986a2006-03-03 01:30:23 +0000316 NULL);
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000317 }
Reid Spencere249a822005-04-27 07:54:40 +0000318 return memcpy_func;
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000319 }
Reid Spencer76dab9a2005-04-26 05:24:00 +0000320
Chris Lattner34acba42007-01-07 08:12:01 +0000321 Constant *getUnaryFloatFunction(const char *Name, Constant *&Cache) {
Chris Lattner57740402006-01-23 06:24:46 +0000322 if (!Cache)
323 Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
324 return Cache;
Chris Lattner4201cd12005-08-24 17:22:17 +0000325 }
326
Chris Lattner34acba42007-01-07 08:12:01 +0000327 Constant *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
328 Constant *get_ceilf() { return getUnaryFloatFunction( "ceilf", ceilf_func);}
329 Constant *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
330 Constant *get_rintf() { return getUnaryFloatFunction( "rintf", rintf_func);}
331 Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
Chris Lattner57740402006-01-23 06:24:46 +0000332 nearbyintf_func); }
Reid Spencere249a822005-04-27 07:54:40 +0000333private:
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000334 /// @brief Reset our cached data for a new Module
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000335 void reset(Module& mod) {
Reid Spencere249a822005-04-27 07:54:40 +0000336 M = &mod;
337 TD = &getAnalysis<TargetData>();
Evan Cheng1fc40252006-06-16 08:36:35 +0000338 putchar_func = 0;
339 puts_func = 0;
Reid Spencer93616972005-04-29 09:39:47 +0000340 fputc_func = 0;
Evan Chengf2ea5872006-06-16 04:52:30 +0000341 fputs_func = 0;
Reid Spencer93616972005-04-29 09:39:47 +0000342 fwrite_func = 0;
Reid Spencere249a822005-04-27 07:54:40 +0000343 memcpy_func = 0;
Reid Spencer38cabd72005-05-03 07:23:44 +0000344 memchr_func = 0;
Reid Spencer93616972005-04-29 09:39:47 +0000345 sqrt_func = 0;
Reid Spencer1e520fd2005-05-04 03:20:21 +0000346 strcpy_func = 0;
Reid Spencere249a822005-04-27 07:54:40 +0000347 strlen_func = 0;
Chris Lattner4201cd12005-08-24 17:22:17 +0000348 floorf_func = 0;
Chris Lattner57740402006-01-23 06:24:46 +0000349 ceilf_func = 0;
350 roundf_func = 0;
351 rintf_func = 0;
352 nearbyintf_func = 0;
Reid Spencer76dab9a2005-04-26 05:24:00 +0000353 }
Reid Spencer39a762d2005-04-25 02:53:12 +0000354
Reid Spencere249a822005-04-27 07:54:40 +0000355private:
Chris Lattner57740402006-01-23 06:24:46 +0000356 /// Caches for function pointers.
Chris Lattner34acba42007-01-07 08:12:01 +0000357 Constant *putchar_func, *puts_func;
358 Constant *fputc_func, *fputs_func, *fwrite_func;
359 Constant *memcpy_func, *memchr_func;
360 Constant *sqrt_func;
361 Constant *strcpy_func, *strlen_func;
362 Constant *floorf_func, *ceilf_func, *roundf_func;
363 Constant *rintf_func, *nearbyintf_func;
Chris Lattner57740402006-01-23 06:24:46 +0000364 Module *M; ///< Cached Module
365 TargetData *TD; ///< Cached TargetData
Reid Spencere249a822005-04-27 07:54:40 +0000366};
367
368// Register the pass
Chris Lattnerc2d3d312006-08-27 22:42:52 +0000369RegisterPass<SimplifyLibCalls>
370X("simplify-libcalls", "Simplify well-known library calls");
Reid Spencere249a822005-04-27 07:54:40 +0000371
372} // anonymous namespace
373
374// The only public symbol in this file which just instantiates the pass object
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000375ModulePass *llvm::createSimplifyLibCallsPass() {
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000376 return new SimplifyLibCalls();
Reid Spencere249a822005-04-27 07:54:40 +0000377}
378
379// Classes below here, in the anonymous namespace, are all subclasses of the
380// LibCallOptimization class, each implementing all optimizations possible for a
381// single well-known library call. Each has a static singleton instance that
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000382// auto registers it into the "optlist" global above.
Reid Spencere249a822005-04-27 07:54:40 +0000383namespace {
384
Reid Spencera7828ba2005-06-18 17:46:28 +0000385// Forward declare utility functions.
Reid Spencer4c444fe2005-04-30 03:17:54 +0000386bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** A = 0 );
Reid Spencera7828ba2005-06-18 17:46:28 +0000387Value *CastToCStr(Value *V, Instruction &IP);
Reid Spencere249a822005-04-27 07:54:40 +0000388
389/// This LibCallOptimization will find instances of a call to "exit" that occurs
Reid Spencer39a762d2005-04-25 02:53:12 +0000390/// within the "main" function and change it to a simple "ret" instruction with
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000391/// the same value passed to the exit function. When this is done, it splits the
392/// basic block at the exit(3) call and deletes the call instruction.
Reid Spencer39a762d2005-04-25 02:53:12 +0000393/// @brief Replace calls to exit in main with a simple return
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000394struct ExitInMainOptimization : public LibCallOptimization {
Reid Spencer95d8efd2005-05-03 02:54:54 +0000395 ExitInMainOptimization() : LibCallOptimization("exit",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000396 "Number of 'exit' calls simplified") {}
Reid Spencerf2534c72005-04-25 21:11:48 +0000397
398 // Make sure the called function looks like exit (int argument, int return
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000399 // type, external linkage, not varargs).
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000400 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
Chris Lattner03c49532007-01-15 02:27:26 +0000401 return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
Reid Spencerf2534c72005-04-25 21:11:48 +0000402 }
403
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000404 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencerf2534c72005-04-25 21:11:48 +0000405 // To be careful, we check that the call to exit is coming from "main", that
406 // main has external linkage, and the return type of main and the argument
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000407 // to exit have the same type.
Reid Spencerf2534c72005-04-25 21:11:48 +0000408 Function *from = ci->getParent()->getParent();
409 if (from->hasExternalLinkage())
410 if (from->getReturnType() == ci->getOperand(1)->getType())
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000411 if (from->getName() == "main") {
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000412 // Okay, time to actually do the optimization. First, get the basic
Reid Spencerf2534c72005-04-25 21:11:48 +0000413 // block of the call instruction
414 BasicBlock* bb = ci->getParent();
Reid Spencer39a762d2005-04-25 02:53:12 +0000415
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000416 // Create a return instruction that we'll replace the call with.
417 // Note that the argument of the return is the argument of the call
Reid Spencerf2534c72005-04-25 21:11:48 +0000418 // instruction.
Chris Lattnercd60d382006-05-12 23:35:26 +0000419 new ReturnInst(ci->getOperand(1), ci);
Reid Spencer39a762d2005-04-25 02:53:12 +0000420
Reid Spencerf2534c72005-04-25 21:11:48 +0000421 // Split the block at the call instruction which places it in a new
422 // basic block.
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000423 bb->splitBasicBlock(ci);
Reid Spencer39a762d2005-04-25 02:53:12 +0000424
Reid Spencerf2534c72005-04-25 21:11:48 +0000425 // The block split caused a branch instruction to be inserted into
426 // the end of the original block, right after the return instruction
427 // that we put there. That's not a valid block, so delete the branch
428 // instruction.
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000429 bb->getInstList().pop_back();
Reid Spencer39a762d2005-04-25 02:53:12 +0000430
Reid Spencerf2534c72005-04-25 21:11:48 +0000431 // Now we can finally get rid of the call instruction which now lives
432 // in the new basic block.
433 ci->eraseFromParent();
434
435 // Optimization succeeded, return true.
436 return true;
437 }
438 // We didn't pass the criteria for this optimization so return false
439 return false;
Reid Spencer9bbaa2a2005-04-25 03:59:26 +0000440 }
Reid Spencer39a762d2005-04-25 02:53:12 +0000441} ExitInMainOptimizer;
442
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000443/// This LibCallOptimization will simplify a call to the strcat library
444/// function. The simplification is possible only if the string being
445/// concatenated is a constant array or a constant expression that results in
446/// a constant string. In this case we can replace it with strlen + llvm.memcpy
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000447/// of the constant string. Both of these calls are further reduced, if possible
448/// on subsequent passes.
Reid Spencerf2534c72005-04-25 21:11:48 +0000449/// @brief Simplify the strcat library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000450struct StrCatOptimization : public LibCallOptimization {
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000451public:
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000452 /// @brief Default constructor
Reid Spencer95d8efd2005-05-03 02:54:54 +0000453 StrCatOptimization() : LibCallOptimization("strcat",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000454 "Number of 'strcat' calls simplified") {}
Reid Spencere249a822005-04-27 07:54:40 +0000455
456public:
Reid Spencerf2534c72005-04-25 21:11:48 +0000457
458 /// @brief Make sure that the "strcat" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000459 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencerc635f472006-12-31 05:48:39 +0000460 if (f->getReturnType() == PointerType::get(Type::Int8Ty))
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000461 if (f->arg_size() == 2)
Reid Spencerf2534c72005-04-25 21:11:48 +0000462 {
463 Function::const_arg_iterator AI = f->arg_begin();
Reid Spencerc635f472006-12-31 05:48:39 +0000464 if (AI++->getType() == PointerType::get(Type::Int8Ty))
465 if (AI->getType() == PointerType::get(Type::Int8Ty))
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000466 {
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000467 // Indicate this is a suitable call type.
Reid Spencerf2534c72005-04-25 21:11:48 +0000468 return true;
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000469 }
Reid Spencerf2534c72005-04-25 21:11:48 +0000470 }
471 return false;
472 }
473
Reid Spencere249a822005-04-27 07:54:40 +0000474 /// @brief Optimize the strcat library function
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000475 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencer08b49402005-04-27 17:46:54 +0000476 // Extract some information from the instruction
Reid Spencer08b49402005-04-27 17:46:54 +0000477 Value* dest = ci->getOperand(1);
478 Value* src = ci->getOperand(2);
479
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000480 // Extract the initializer (while making numerous checks) from the
Reid Spencer76dab9a2005-04-26 05:24:00 +0000481 // source operand of the call to strcat. If we get null back, one of
482 // a variety of checks in get_GVInitializer failed
Reid Spencerb4f7b832005-04-26 07:45:18 +0000483 uint64_t len = 0;
Reid Spencer08b49402005-04-27 17:46:54 +0000484 if (!getConstantStringLength(src,len))
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000485 return false;
486
Reid Spencerb4f7b832005-04-26 07:45:18 +0000487 // Handle the simple, do-nothing case
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000488 if (len == 0) {
Reid Spencer08b49402005-04-27 17:46:54 +0000489 ci->replaceAllUsesWith(dest);
Reid Spencer8ee5aac2005-04-26 03:26:15 +0000490 ci->eraseFromParent();
491 return true;
492 }
493
Reid Spencerb4f7b832005-04-26 07:45:18 +0000494 // Increment the length because we actually want to memcpy the null
495 // terminator as well.
496 len++;
Reid Spencerf2534c72005-04-25 21:11:48 +0000497
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000498 // We need to find the end of the destination string. That's where the
499 // memory is to be moved to. We just generate a call to strlen (further
500 // optimized in another pass). Note that the SLC.get_strlen() call
Reid Spencerb4f7b832005-04-26 07:45:18 +0000501 // caches the Function* for us.
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000502 CallInst* strlen_inst =
Reid Spencer08b49402005-04-27 17:46:54 +0000503 new CallInst(SLC.get_strlen(), dest, dest->getName()+".len",ci);
Reid Spencerb4f7b832005-04-26 07:45:18 +0000504
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000505 // Now that we have the destination's length, we must index into the
Reid Spencerb4f7b832005-04-26 07:45:18 +0000506 // destination's pointer to get the actual memcpy destination (end of
507 // the string .. we're concatenating).
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000508 GetElementPtrInst* gep =
Chris Lattner927653f2007-01-31 19:59:55 +0000509 new GetElementPtrInst(dest, strlen_inst, dest->getName()+".indexed", ci);
Reid Spencerb4f7b832005-04-26 07:45:18 +0000510
511 // We have enough information to now generate the memcpy call to
512 // do the concatenation for us.
513 std::vector<Value*> vals;
514 vals.push_back(gep); // destination
515 vals.push_back(ci->getOperand(2)); // source
Reid Spencere0fc4df2006-10-20 07:07:24 +0000516 vals.push_back(ConstantInt::get(SLC.getIntPtrType(),len)); // length
Reid Spencerc635f472006-12-31 05:48:39 +0000517 vals.push_back(ConstantInt::get(Type::Int32Ty,1)); // alignment
Reid Spencer08b49402005-04-27 17:46:54 +0000518 new CallInst(SLC.get_memcpy(), vals, "", ci);
Reid Spencerb4f7b832005-04-26 07:45:18 +0000519
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000520 // Finally, substitute the first operand of the strcat call for the
521 // strcat call itself since strcat returns its first operand; and,
Reid Spencerb4f7b832005-04-26 07:45:18 +0000522 // kill the strcat CallInst.
Reid Spencer08b49402005-04-27 17:46:54 +0000523 ci->replaceAllUsesWith(dest);
Reid Spencerb4f7b832005-04-26 07:45:18 +0000524 ci->eraseFromParent();
525 return true;
Reid Spencer9bbaa2a2005-04-25 03:59:26 +0000526 }
527} StrCatOptimizer;
528
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000529/// This LibCallOptimization will simplify a call to the strchr library
Reid Spencer38cabd72005-05-03 07:23:44 +0000530/// function. It optimizes out cases where the arguments are both constant
531/// and the result can be determined statically.
532/// @brief Simplify the strcmp library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000533struct StrChrOptimization : public LibCallOptimization {
Reid Spencer38cabd72005-05-03 07:23:44 +0000534public:
535 StrChrOptimization() : LibCallOptimization("strchr",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000536 "Number of 'strchr' calls simplified") {}
Reid Spencer38cabd72005-05-03 07:23:44 +0000537
538 /// @brief Make sure that the "strchr" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000539 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencerc635f472006-12-31 05:48:39 +0000540 if (f->getReturnType() == PointerType::get(Type::Int8Ty) &&
Reid Spencer38cabd72005-05-03 07:23:44 +0000541 f->arg_size() == 2)
542 return true;
543 return false;
544 }
545
Chris Lattnerf8053ce2005-05-20 22:22:25 +0000546 /// @brief Perform the strchr optimizations
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000547 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
Reid Spencer38cabd72005-05-03 07:23:44 +0000548 // If there aren't three operands, bail
549 if (ci->getNumOperands() != 3)
550 return false;
551
552 // Check that the first argument to strchr is a constant array of sbyte.
553 // If it is, get the length and data, otherwise return false.
554 uint64_t len = 0;
Reid Spencere0fc4df2006-10-20 07:07:24 +0000555 ConstantArray* CA = 0;
Reid Spencerc635f472006-12-31 05:48:39 +0000556 if (!getConstantStringLength(ci->getOperand(1), len, &CA))
Reid Spencer38cabd72005-05-03 07:23:44 +0000557 return false;
558
Reid Spencere0fc4df2006-10-20 07:07:24 +0000559 // Check that the second argument to strchr is a constant int. If it isn't
560 // a constant signed integer, we can try an alternate optimization
561 ConstantInt* CSI = dyn_cast<ConstantInt>(ci->getOperand(2));
Reid Spencerc635f472006-12-31 05:48:39 +0000562 if (!CSI) {
Reid Spencere0fc4df2006-10-20 07:07:24 +0000563 // The second operand is not constant, or not signed. Just lower this to
564 // memchr since we know the length of the string since it is constant.
Chris Lattner34acba42007-01-07 08:12:01 +0000565 Constant *f = SLC.get_memchr();
Reid Spencer38cabd72005-05-03 07:23:44 +0000566 std::vector<Value*> args;
567 args.push_back(ci->getOperand(1));
568 args.push_back(ci->getOperand(2));
Reid Spencerc635f472006-12-31 05:48:39 +0000569 args.push_back(ConstantInt::get(SLC.getIntPtrType(), len));
Chris Lattner34acba42007-01-07 08:12:01 +0000570 ci->replaceAllUsesWith(new CallInst(f, args, ci->getName(), ci));
Reid Spencer38cabd72005-05-03 07:23:44 +0000571 ci->eraseFromParent();
572 return true;
573 }
574
575 // Get the character we're looking for
Reid Spencere0fc4df2006-10-20 07:07:24 +0000576 int64_t chr = CSI->getSExtValue();
Reid Spencer38cabd72005-05-03 07:23:44 +0000577
578 // Compute the offset
579 uint64_t offset = 0;
580 bool char_found = false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000581 for (uint64_t i = 0; i < len; ++i) {
Reid Spencere0fc4df2006-10-20 07:07:24 +0000582 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
Reid Spencer38cabd72005-05-03 07:23:44 +0000583 // Check for the null terminator
584 if (CI->isNullValue())
585 break; // we found end of string
Reid Spencere0fc4df2006-10-20 07:07:24 +0000586 else if (CI->getSExtValue() == chr) {
Reid Spencer38cabd72005-05-03 07:23:44 +0000587 char_found = true;
588 offset = i;
589 break;
590 }
591 }
592 }
593
594 // strchr(s,c) -> offset_of_in(c,s)
595 // (if c is a constant integer and s is a constant string)
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000596 if (char_found) {
Chris Lattner927653f2007-01-31 19:59:55 +0000597 Value* Idx = ConstantInt::get(Type::Int64Ty,offset);
598 GetElementPtrInst* GEP = new GetElementPtrInst(ci->getOperand(1), Idx,
Reid Spencer38cabd72005-05-03 07:23:44 +0000599 ci->getOperand(1)->getName()+".strchr",ci);
600 ci->replaceAllUsesWith(GEP);
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000601 } else {
Reid Spencer38cabd72005-05-03 07:23:44 +0000602 ci->replaceAllUsesWith(
Reid Spencerc635f472006-12-31 05:48:39 +0000603 ConstantPointerNull::get(PointerType::get(Type::Int8Ty)));
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000604 }
Reid Spencer38cabd72005-05-03 07:23:44 +0000605 ci->eraseFromParent();
606 return true;
607 }
608} StrChrOptimizer;
609
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000610/// This LibCallOptimization will simplify a call to the strcmp library
Reid Spencer4c444fe2005-04-30 03:17:54 +0000611/// function. It optimizes out cases where one or both arguments are constant
612/// and the result can be determined statically.
613/// @brief Simplify the strcmp library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000614struct StrCmpOptimization : public LibCallOptimization {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000615public:
Reid Spencer95d8efd2005-05-03 02:54:54 +0000616 StrCmpOptimization() : LibCallOptimization("strcmp",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000617 "Number of 'strcmp' calls simplified") {}
Reid Spencer4c444fe2005-04-30 03:17:54 +0000618
Chris Lattnerf8053ce2005-05-20 22:22:25 +0000619 /// @brief Make sure that the "strcmp" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000620 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
Reid Spencerc635f472006-12-31 05:48:39 +0000621 return F->getReturnType() == Type::Int32Ty && F->arg_size() == 2;
Reid Spencer4c444fe2005-04-30 03:17:54 +0000622 }
623
Chris Lattnerf8053ce2005-05-20 22:22:25 +0000624 /// @brief Perform the strcmp optimization
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000625 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000626 // First, check to see if src and destination are the same. If they are,
Reid Spencer16449a92005-04-30 06:45:47 +0000627 // then the optimization is to replace the CallInst with a constant 0
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000628 // because the call is a no-op.
Reid Spencer4c444fe2005-04-30 03:17:54 +0000629 Value* s1 = ci->getOperand(1);
630 Value* s2 = ci->getOperand(2);
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000631 if (s1 == s2) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000632 // strcmp(x,x) -> 0
Reid Spencerc635f472006-12-31 05:48:39 +0000633 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
Reid Spencer4c444fe2005-04-30 03:17:54 +0000634 ci->eraseFromParent();
635 return true;
636 }
637
638 bool isstr_1 = false;
639 uint64_t len_1 = 0;
640 ConstantArray* A1;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000641 if (getConstantStringLength(s1,len_1,&A1)) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000642 isstr_1 = true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000643 if (len_1 == 0) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000644 // strcmp("",x) -> *x
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000645 LoadInst* load =
Reid Spencera7828ba2005-06-18 17:46:28 +0000646 new LoadInst(CastToCStr(s2,*ci), ci->getName()+".load",ci);
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000647 CastInst* cast =
Reid Spencerc635f472006-12-31 05:48:39 +0000648 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
Reid Spencer6c38f0b2006-11-27 01:05:10 +0000649 ci->getName()+".int", ci);
Reid Spencer4c444fe2005-04-30 03:17:54 +0000650 ci->replaceAllUsesWith(cast);
651 ci->eraseFromParent();
652 return true;
653 }
654 }
655
656 bool isstr_2 = false;
657 uint64_t len_2 = 0;
658 ConstantArray* A2;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000659 if (getConstantStringLength(s2, len_2, &A2)) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000660 isstr_2 = true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000661 if (len_2 == 0) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000662 // strcmp(x,"") -> *x
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000663 LoadInst* load =
Reid Spencera7828ba2005-06-18 17:46:28 +0000664 new LoadInst(CastToCStr(s1,*ci),ci->getName()+".val",ci);
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000665 CastInst* cast =
Reid Spencerc635f472006-12-31 05:48:39 +0000666 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
Reid Spencer6c38f0b2006-11-27 01:05:10 +0000667 ci->getName()+".int", ci);
Reid Spencer4c444fe2005-04-30 03:17:54 +0000668 ci->replaceAllUsesWith(cast);
669 ci->eraseFromParent();
670 return true;
671 }
672 }
673
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000674 if (isstr_1 && isstr_2) {
Reid Spencer4c444fe2005-04-30 03:17:54 +0000675 // strcmp(x,y) -> cnst (if both x and y are constant strings)
676 std::string str1 = A1->getAsString();
677 std::string str2 = A2->getAsString();
678 int result = strcmp(str1.c_str(), str2.c_str());
Reid Spencerc635f472006-12-31 05:48:39 +0000679 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,result));
Reid Spencer4c444fe2005-04-30 03:17:54 +0000680 ci->eraseFromParent();
681 return true;
682 }
683 return false;
684 }
685} StrCmpOptimizer;
686
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000687/// This LibCallOptimization will simplify a call to the strncmp library
Reid Spencer49fa07042005-05-03 01:43:45 +0000688/// function. It optimizes out cases where one or both arguments are constant
689/// and the result can be determined statically.
690/// @brief Simplify the strncmp library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000691struct StrNCmpOptimization : public LibCallOptimization {
Reid Spencer49fa07042005-05-03 01:43:45 +0000692public:
Reid Spencer95d8efd2005-05-03 02:54:54 +0000693 StrNCmpOptimization() : LibCallOptimization("strncmp",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000694 "Number of 'strncmp' calls simplified") {}
Reid Spencer49fa07042005-05-03 01:43:45 +0000695
Chris Lattnerf8053ce2005-05-20 22:22:25 +0000696 /// @brief Make sure that the "strncmp" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000697 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencerc635f472006-12-31 05:48:39 +0000698 if (f->getReturnType() == Type::Int32Ty && f->arg_size() == 3)
Reid Spencer49fa07042005-05-03 01:43:45 +0000699 return true;
700 return false;
701 }
702
703 /// @brief Perform the strncpy optimization
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000704 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000705 // First, check to see if src and destination are the same. If they are,
706 // then the optimization is to replace the CallInst with a constant 0
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000707 // because the call is a no-op.
Reid Spencer49fa07042005-05-03 01:43:45 +0000708 Value* s1 = ci->getOperand(1);
709 Value* s2 = ci->getOperand(2);
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000710 if (s1 == s2) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000711 // strncmp(x,x,l) -> 0
Reid Spencerc635f472006-12-31 05:48:39 +0000712 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
Reid Spencer49fa07042005-05-03 01:43:45 +0000713 ci->eraseFromParent();
714 return true;
715 }
716
717 // Check the length argument, if it is Constant zero then the strings are
718 // considered equal.
719 uint64_t len_arg = 0;
720 bool len_arg_is_const = false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000721 if (ConstantInt* len_CI = dyn_cast<ConstantInt>(ci->getOperand(3))) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000722 len_arg_is_const = true;
Reid Spencere0fc4df2006-10-20 07:07:24 +0000723 len_arg = len_CI->getZExtValue();
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000724 if (len_arg == 0) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000725 // strncmp(x,y,0) -> 0
Reid Spencerc635f472006-12-31 05:48:39 +0000726 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
Reid Spencer49fa07042005-05-03 01:43:45 +0000727 ci->eraseFromParent();
728 return true;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000729 }
Reid Spencer49fa07042005-05-03 01:43:45 +0000730 }
731
732 bool isstr_1 = false;
733 uint64_t len_1 = 0;
734 ConstantArray* A1;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000735 if (getConstantStringLength(s1, len_1, &A1)) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000736 isstr_1 = true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000737 if (len_1 == 0) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000738 // strncmp("",x) -> *x
739 LoadInst* load = new LoadInst(s1,ci->getName()+".load",ci);
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000740 CastInst* cast =
Reid Spencerc635f472006-12-31 05:48:39 +0000741 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
Reid Spencer6c38f0b2006-11-27 01:05:10 +0000742 ci->getName()+".int", ci);
Reid Spencer49fa07042005-05-03 01:43:45 +0000743 ci->replaceAllUsesWith(cast);
744 ci->eraseFromParent();
745 return true;
746 }
747 }
748
749 bool isstr_2 = false;
750 uint64_t len_2 = 0;
751 ConstantArray* A2;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000752 if (getConstantStringLength(s2,len_2,&A2)) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000753 isstr_2 = true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000754 if (len_2 == 0) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000755 // strncmp(x,"") -> *x
756 LoadInst* load = new LoadInst(s2,ci->getName()+".val",ci);
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000757 CastInst* cast =
Reid Spencerc635f472006-12-31 05:48:39 +0000758 CastInst::create(Instruction::SExt, load, Type::Int32Ty,
Reid Spencer6c38f0b2006-11-27 01:05:10 +0000759 ci->getName()+".int", ci);
Reid Spencer49fa07042005-05-03 01:43:45 +0000760 ci->replaceAllUsesWith(cast);
761 ci->eraseFromParent();
762 return true;
763 }
764 }
765
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000766 if (isstr_1 && isstr_2 && len_arg_is_const) {
Reid Spencer49fa07042005-05-03 01:43:45 +0000767 // strncmp(x,y,const) -> constant
768 std::string str1 = A1->getAsString();
769 std::string str2 = A2->getAsString();
770 int result = strncmp(str1.c_str(), str2.c_str(), len_arg);
Reid Spencerc635f472006-12-31 05:48:39 +0000771 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,result));
Reid Spencer49fa07042005-05-03 01:43:45 +0000772 ci->eraseFromParent();
773 return true;
774 }
775 return false;
776 }
777} StrNCmpOptimizer;
778
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000779/// This LibCallOptimization will simplify a call to the strcpy library
780/// function. Two optimizations are possible:
Reid Spencere249a822005-04-27 07:54:40 +0000781/// (1) If src and dest are the same and not volatile, just return dest
782/// (2) If the src is a constant then we can convert to llvm.memmove
783/// @brief Simplify the strcpy library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000784struct StrCpyOptimization : public LibCallOptimization {
Reid Spencere249a822005-04-27 07:54:40 +0000785public:
Reid Spencer95d8efd2005-05-03 02:54:54 +0000786 StrCpyOptimization() : LibCallOptimization("strcpy",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000787 "Number of 'strcpy' calls simplified") {}
Reid Spencere249a822005-04-27 07:54:40 +0000788
789 /// @brief Make sure that the "strcpy" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000790 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencerc635f472006-12-31 05:48:39 +0000791 if (f->getReturnType() == PointerType::get(Type::Int8Ty))
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000792 if (f->arg_size() == 2) {
Reid Spencere249a822005-04-27 07:54:40 +0000793 Function::const_arg_iterator AI = f->arg_begin();
Reid Spencerc635f472006-12-31 05:48:39 +0000794 if (AI++->getType() == PointerType::get(Type::Int8Ty))
795 if (AI->getType() == PointerType::get(Type::Int8Ty)) {
Reid Spencere249a822005-04-27 07:54:40 +0000796 // Indicate this is a suitable call type.
797 return true;
798 }
799 }
800 return false;
801 }
802
803 /// @brief Perform the strcpy optimization
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000804 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencere249a822005-04-27 07:54:40 +0000805 // First, check to see if src and destination are the same. If they are,
806 // then the optimization is to replace the CallInst with the destination
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000807 // because the call is a no-op. Note that this corresponds to the
Reid Spencere249a822005-04-27 07:54:40 +0000808 // degenerate strcpy(X,X) case which should have "undefined" results
809 // according to the C specification. However, it occurs sometimes and
810 // we optimize it as a no-op.
811 Value* dest = ci->getOperand(1);
812 Value* src = ci->getOperand(2);
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000813 if (dest == src) {
Reid Spencere249a822005-04-27 07:54:40 +0000814 ci->replaceAllUsesWith(dest);
815 ci->eraseFromParent();
816 return true;
817 }
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000818
Reid Spencere249a822005-04-27 07:54:40 +0000819 // Get the length of the constant string referenced by the second operand,
820 // the "src" parameter. Fail the optimization if we can't get the length
821 // (note that getConstantStringLength does lots of checks to make sure this
822 // is valid).
823 uint64_t len = 0;
824 if (!getConstantStringLength(ci->getOperand(2),len))
825 return false;
826
827 // If the constant string's length is zero we can optimize this by just
828 // doing a store of 0 at the first byte of the destination
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000829 if (len == 0) {
Reid Spencerc635f472006-12-31 05:48:39 +0000830 new StoreInst(ConstantInt::get(Type::Int8Ty,0),ci->getOperand(1),ci);
Reid Spencere249a822005-04-27 07:54:40 +0000831 ci->replaceAllUsesWith(dest);
832 ci->eraseFromParent();
833 return true;
834 }
835
836 // Increment the length because we actually want to memcpy the null
837 // terminator as well.
838 len++;
839
Reid Spencere249a822005-04-27 07:54:40 +0000840 // We have enough information to now generate the memcpy call to
841 // do the concatenation for us.
842 std::vector<Value*> vals;
843 vals.push_back(dest); // destination
844 vals.push_back(src); // source
Reid Spencere0fc4df2006-10-20 07:07:24 +0000845 vals.push_back(ConstantInt::get(SLC.getIntPtrType(),len)); // length
Reid Spencerc635f472006-12-31 05:48:39 +0000846 vals.push_back(ConstantInt::get(Type::Int32Ty,1)); // alignment
Reid Spencer08b49402005-04-27 17:46:54 +0000847 new CallInst(SLC.get_memcpy(), vals, "", ci);
Reid Spencere249a822005-04-27 07:54:40 +0000848
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000849 // Finally, substitute the first operand of the strcat call for the
850 // strcat call itself since strcat returns its first operand; and,
Reid Spencere249a822005-04-27 07:54:40 +0000851 // kill the strcat CallInst.
852 ci->replaceAllUsesWith(dest);
853 ci->eraseFromParent();
854 return true;
855 }
856} StrCpyOptimizer;
857
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000858/// This LibCallOptimization will simplify a call to the strlen library
859/// function by replacing it with a constant value if the string provided to
Reid Spencer7ddcfb32005-04-27 21:29:20 +0000860/// it is a constant array.
Reid Spencer76dab9a2005-04-26 05:24:00 +0000861/// @brief Simplify the strlen library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +0000862struct StrLenOptimization : public LibCallOptimization {
Reid Spencer95d8efd2005-05-03 02:54:54 +0000863 StrLenOptimization() : LibCallOptimization("strlen",
Reid Spencer170ae7f2005-05-07 20:15:59 +0000864 "Number of 'strlen' calls simplified") {}
Reid Spencer76dab9a2005-04-26 05:24:00 +0000865
866 /// @brief Make sure that the "strlen" function has the right prototype
Reid Spencere249a822005-04-27 07:54:40 +0000867 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
Reid Spencer76dab9a2005-04-26 05:24:00 +0000868 {
Reid Spencere249a822005-04-27 07:54:40 +0000869 if (f->getReturnType() == SLC.getTargetData()->getIntPtrType())
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000870 if (f->arg_size() == 1)
Reid Spencer76dab9a2005-04-26 05:24:00 +0000871 if (Function::const_arg_iterator AI = f->arg_begin())
Reid Spencerc635f472006-12-31 05:48:39 +0000872 if (AI->getType() == PointerType::get(Type::Int8Ty))
Reid Spencer76dab9a2005-04-26 05:24:00 +0000873 return true;
874 return false;
875 }
876
877 /// @brief Perform the strlen optimization
Reid Spencere249a822005-04-27 07:54:40 +0000878 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
Reid Spencer76dab9a2005-04-26 05:24:00 +0000879 {
Reid Spencer170ae7f2005-05-07 20:15:59 +0000880 // Make sure we're dealing with an sbyte* here.
881 Value* str = ci->getOperand(1);
Reid Spencerc635f472006-12-31 05:48:39 +0000882 if (str->getType() != PointerType::get(Type::Int8Ty))
Reid Spencer170ae7f2005-05-07 20:15:59 +0000883 return false;
884
885 // Does the call to strlen have exactly one use?
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +0000886 if (ci->hasOneUse())
Reid Spencer266e42b2006-12-23 06:05:41 +0000887 // Is that single use a icmp operator?
888 if (ICmpInst* bop = dyn_cast<ICmpInst>(ci->use_back()))
Reid Spencer170ae7f2005-05-07 20:15:59 +0000889 // Is it compared against a constant integer?
890 if (ConstantInt* CI = dyn_cast<ConstantInt>(bop->getOperand(1)))
891 {
892 // Get the value the strlen result is compared to
Reid Spencere0fc4df2006-10-20 07:07:24 +0000893 uint64_t val = CI->getZExtValue();
Reid Spencer170ae7f2005-05-07 20:15:59 +0000894
895 // If its compared against length 0 with == or !=
896 if (val == 0 &&
Reid Spencer266e42b2006-12-23 06:05:41 +0000897 (bop->getPredicate() == ICmpInst::ICMP_EQ ||
898 bop->getPredicate() == ICmpInst::ICMP_NE))
Reid Spencer170ae7f2005-05-07 20:15:59 +0000899 {
900 // strlen(x) != 0 -> *x != 0
901 // strlen(x) == 0 -> *x == 0
902 LoadInst* load = new LoadInst(str,str->getName()+".first",ci);
Reid Spencer266e42b2006-12-23 06:05:41 +0000903 ICmpInst* rbop = new ICmpInst(bop->getPredicate(), load,
Reid Spencerc635f472006-12-31 05:48:39 +0000904 ConstantInt::get(Type::Int8Ty,0),
Reid Spencer266e42b2006-12-23 06:05:41 +0000905 bop->getName()+".strlen", ci);
Reid Spencer170ae7f2005-05-07 20:15:59 +0000906 bop->replaceAllUsesWith(rbop);
907 bop->eraseFromParent();
908 ci->eraseFromParent();
909 return true;
910 }
911 }
912
913 // Get the length of the constant string operand
Reid Spencerb4f7b832005-04-26 07:45:18 +0000914 uint64_t len = 0;
915 if (!getConstantStringLength(ci->getOperand(1),len))
Reid Spencer76dab9a2005-04-26 05:24:00 +0000916 return false;
917
Reid Spencer170ae7f2005-05-07 20:15:59 +0000918 // strlen("xyz") -> 3 (for example)
Chris Lattnere17c5d02005-08-01 16:52:50 +0000919 const Type *Ty = SLC.getTargetData()->getIntPtrType();
Reid Spencer4720d4d2006-12-21 07:15:54 +0000920 ci->replaceAllUsesWith(ConstantInt::get(Ty, len));
Chris Lattnere17c5d02005-08-01 16:52:50 +0000921
Reid Spencerb4f7b832005-04-26 07:45:18 +0000922 ci->eraseFromParent();
923 return true;
Reid Spencer76dab9a2005-04-26 05:24:00 +0000924 }
925} StrLenOptimizer;
926
Chris Lattnerc244e7c2005-09-29 04:54:20 +0000927/// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
928/// is equal or not-equal to zero.
929static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
930 for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
931 UI != E; ++UI) {
932 Instruction *User = cast<Instruction>(*UI);
Reid Spencer266e42b2006-12-23 06:05:41 +0000933 if (ICmpInst *IC = dyn_cast<ICmpInst>(User)) {
934 if ((IC->getPredicate() == ICmpInst::ICMP_NE ||
935 IC->getPredicate() == ICmpInst::ICMP_EQ) &&
936 isa<Constant>(IC->getOperand(1)) &&
937 cast<Constant>(IC->getOperand(1))->isNullValue())
Chris Lattnerc244e7c2005-09-29 04:54:20 +0000938 continue;
939 } else if (CastInst *CI = dyn_cast<CastInst>(User))
Reid Spencer542964f2007-01-11 18:21:29 +0000940 if (CI->getType() == Type::Int1Ty)
Chris Lattnerc244e7c2005-09-29 04:54:20 +0000941 continue;
942 // Unknown instruction.
943 return false;
944 }
945 return true;
946}
947
948/// This memcmpOptimization will simplify a call to the memcmp library
949/// function.
950struct memcmpOptimization : public LibCallOptimization {
951 /// @brief Default Constructor
952 memcmpOptimization()
953 : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
954
955 /// @brief Make sure that the "memcmp" function has the right prototype
956 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
957 Function::const_arg_iterator AI = F->arg_begin();
958 if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
959 if (!isa<PointerType>((++AI)->getType())) return false;
Chris Lattner03c49532007-01-15 02:27:26 +0000960 if (!(++AI)->getType()->isInteger()) return false;
961 if (!F->getReturnType()->isInteger()) return false;
Chris Lattnerc244e7c2005-09-29 04:54:20 +0000962 return true;
963 }
964
965 /// Because of alignment and instruction information that we don't have, we
966 /// leave the bulk of this to the code generators.
967 ///
968 /// Note that we could do much more if we could force alignment on otherwise
969 /// small aligned allocas, or if we could indicate that loads have a small
970 /// alignment.
971 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
972 Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
973
974 // If the two operands are the same, return zero.
975 if (LHS == RHS) {
976 // memcmp(s,s,x) -> 0
977 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
978 CI->eraseFromParent();
979 return true;
980 }
981
982 // Make sure we have a constant length.
983 ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
984 if (!LenC) return false;
Reid Spencere0fc4df2006-10-20 07:07:24 +0000985 uint64_t Len = LenC->getZExtValue();
Chris Lattnerc244e7c2005-09-29 04:54:20 +0000986
987 // If the length is zero, this returns 0.
988 switch (Len) {
989 case 0:
990 // memcmp(s1,s2,0) -> 0
991 CI->replaceAllUsesWith(Constant::getNullValue(CI->getType()));
992 CI->eraseFromParent();
993 return true;
994 case 1: {
995 // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
Reid Spencerc635f472006-12-31 05:48:39 +0000996 const Type *UCharPtr = PointerType::get(Type::Int8Ty);
Reid Spencer6c38f0b2006-11-27 01:05:10 +0000997 CastInst *Op1Cast = CastInst::create(
998 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
999 CastInst *Op2Cast = CastInst::create(
1000 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001001 Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
1002 Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
1003 Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
1004 if (RV->getType() != CI->getType())
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001005 RV = CastInst::createIntegerCast(RV, CI->getType(), false,
1006 RV->getName(), CI);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001007 CI->replaceAllUsesWith(RV);
1008 CI->eraseFromParent();
1009 return true;
1010 }
1011 case 2:
1012 if (IsOnlyUsedInEqualsZeroComparison(CI)) {
1013 // TODO: IF both are aligned, use a short load/compare.
1014
1015 // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
Reid Spencerc635f472006-12-31 05:48:39 +00001016 const Type *UCharPtr = PointerType::get(Type::Int8Ty);
Reid Spencer6c38f0b2006-11-27 01:05:10 +00001017 CastInst *Op1Cast = CastInst::create(
1018 Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
1019 CastInst *Op2Cast = CastInst::create(
1020 Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001021 Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
1022 Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
1023 Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
1024 CI->getName()+".d1", CI);
Reid Spencerc635f472006-12-31 05:48:39 +00001025 Constant *One = ConstantInt::get(Type::Int32Ty, 1);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001026 Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
1027 Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
1028 Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
Chris Lattnercd60d382006-05-12 23:35:26 +00001029 Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001030 Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
1031 CI->getName()+".d1", CI);
1032 Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
1033 if (Or->getType() != CI->getType())
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001034 Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
1035 Or->getName(), CI);
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001036 CI->replaceAllUsesWith(Or);
1037 CI->eraseFromParent();
1038 return true;
1039 }
1040 break;
1041 default:
1042 break;
1043 }
1044
Chris Lattnerc244e7c2005-09-29 04:54:20 +00001045 return false;
1046 }
1047} memcmpOptimizer;
1048
1049
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001050/// This LibCallOptimization will simplify a call to the memcpy library
1051/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
Reid Spencer7ddcfb32005-04-27 21:29:20 +00001052/// bytes depending on the length of the string and the alignment. Additional
1053/// optimizations are possible in code generation (sequence of immediate store)
Reid Spencerf2534c72005-04-25 21:11:48 +00001054/// @brief Simplify the memcpy library function.
Chris Lattnerea7986a2006-03-03 01:30:23 +00001055struct LLVMMemCpyMoveOptzn : public LibCallOptimization {
1056 LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
1057 : LibCallOptimization(fname, desc) {}
Reid Spencerf2534c72005-04-25 21:11:48 +00001058
1059 /// @brief Make sure that the "memcpy" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001060 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001061 // Just make sure this has 4 arguments per LLVM spec.
Reid Spencer2bc7a4f2005-04-26 23:02:16 +00001062 return (f->arg_size() == 4);
Reid Spencerf2534c72005-04-25 21:11:48 +00001063 }
1064
Reid Spencerb4f7b832005-04-26 07:45:18 +00001065 /// Because of alignment and instruction information that we don't have, we
1066 /// leave the bulk of this to the code generators. The optimization here just
1067 /// deals with a few degenerate cases where the length of the string and the
1068 /// alignment match the sizes of our intrinsic types so we can do a load and
1069 /// store instead of the memcpy call.
1070 /// @brief Perform the memcpy optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001071 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
Reid Spencer4855ebf2005-04-26 19:55:57 +00001072 // Make sure we have constant int values to work with
1073 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
1074 if (!LEN)
1075 return false;
1076 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
1077 if (!ALIGN)
1078 return false;
1079
1080 // If the length is larger than the alignment, we can't optimize
Reid Spencere0fc4df2006-10-20 07:07:24 +00001081 uint64_t len = LEN->getZExtValue();
1082 uint64_t alignment = ALIGN->getZExtValue();
Reid Spencer38cabd72005-05-03 07:23:44 +00001083 if (alignment == 0)
1084 alignment = 1; // Alignment 0 is identity for alignment 1
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001085 if (len > alignment)
Reid Spencerb4f7b832005-04-26 07:45:18 +00001086 return false;
1087
Reid Spencer08b49402005-04-27 17:46:54 +00001088 // Get the type we will cast to, based on size of the string
Reid Spencerb4f7b832005-04-26 07:45:18 +00001089 Value* dest = ci->getOperand(1);
1090 Value* src = ci->getOperand(2);
Reid Spencer4f98e622007-01-07 21:45:41 +00001091 const Type* castType = 0;
Reid Spencerb4f7b832005-04-26 07:45:18 +00001092 switch (len)
1093 {
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001094 case 0:
Reid Spencer93616972005-04-29 09:39:47 +00001095 // memcpy(d,s,0,a) -> noop
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001096 ci->eraseFromParent();
1097 return true;
Reid Spencerc635f472006-12-31 05:48:39 +00001098 case 1: castType = Type::Int8Ty; break;
1099 case 2: castType = Type::Int16Ty; break;
1100 case 4: castType = Type::Int32Ty; break;
1101 case 8: castType = Type::Int64Ty; break;
Reid Spencerb4f7b832005-04-26 07:45:18 +00001102 default:
1103 return false;
1104 }
Reid Spencer08b49402005-04-27 17:46:54 +00001105
1106 // Cast source and dest to the right sized primitive and then load/store
Reid Spencer6c38f0b2006-11-27 01:05:10 +00001107 CastInst* SrcCast = CastInst::create(Instruction::BitCast,
1108 src, PointerType::get(castType), src->getName()+".cast", ci);
1109 CastInst* DestCast = CastInst::create(Instruction::BitCast,
1110 dest, PointerType::get(castType),dest->getName()+".cast", ci);
Reid Spencer08b49402005-04-27 17:46:54 +00001111 LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
Reid Spencerde46e482006-11-02 20:25:50 +00001112 new StoreInst(LI, DestCast, ci);
Reid Spencerb4f7b832005-04-26 07:45:18 +00001113 ci->eraseFromParent();
1114 return true;
Reid Spencerf2534c72005-04-25 21:11:48 +00001115 }
Chris Lattnerea7986a2006-03-03 01:30:23 +00001116};
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001117
Chris Lattnerea7986a2006-03-03 01:30:23 +00001118/// This LibCallOptimization will simplify a call to the memcpy/memmove library
1119/// functions.
1120LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
1121 "Number of 'llvm.memcpy' calls simplified");
1122LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
1123 "Number of 'llvm.memcpy' calls simplified");
1124LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
1125 "Number of 'llvm.memmove' calls simplified");
1126LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
1127 "Number of 'llvm.memmove' calls simplified");
Reid Spencer38cabd72005-05-03 07:23:44 +00001128
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001129/// This LibCallOptimization will simplify a call to the memset library
1130/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
1131/// bytes depending on the length argument.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001132struct LLVMMemSetOptimization : public LibCallOptimization {
Reid Spencer38cabd72005-05-03 07:23:44 +00001133 /// @brief Default Constructor
Chris Lattnerea7986a2006-03-03 01:30:23 +00001134 LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
Reid Spencer38cabd72005-05-03 07:23:44 +00001135 "Number of 'llvm.memset' calls simplified") {}
Reid Spencer38cabd72005-05-03 07:23:44 +00001136
1137 /// @brief Make sure that the "memset" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001138 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
Reid Spencer38cabd72005-05-03 07:23:44 +00001139 // Just make sure this has 3 arguments per LLVM spec.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001140 return F->arg_size() == 4;
Reid Spencer38cabd72005-05-03 07:23:44 +00001141 }
1142
1143 /// Because of alignment and instruction information that we don't have, we
1144 /// leave the bulk of this to the code generators. The optimization here just
1145 /// deals with a few degenerate cases where the length parameter is constant
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001146 /// and the alignment matches the sizes of our intrinsic types so we can do
Reid Spencer38cabd72005-05-03 07:23:44 +00001147 /// store instead of the memcpy call. Other calls are transformed into the
1148 /// llvm.memset intrinsic.
1149 /// @brief Perform the memset optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001150 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
Reid Spencer38cabd72005-05-03 07:23:44 +00001151 // Make sure we have constant int values to work with
1152 ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
1153 if (!LEN)
1154 return false;
1155 ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
1156 if (!ALIGN)
1157 return false;
1158
1159 // Extract the length and alignment
Reid Spencere0fc4df2006-10-20 07:07:24 +00001160 uint64_t len = LEN->getZExtValue();
1161 uint64_t alignment = ALIGN->getZExtValue();
Reid Spencer38cabd72005-05-03 07:23:44 +00001162
1163 // Alignment 0 is identity for alignment 1
1164 if (alignment == 0)
1165 alignment = 1;
1166
1167 // If the length is zero, this is a no-op
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001168 if (len == 0) {
Reid Spencer38cabd72005-05-03 07:23:44 +00001169 // memset(d,c,0,a) -> noop
1170 ci->eraseFromParent();
1171 return true;
1172 }
1173
1174 // If the length is larger than the alignment, we can't optimize
1175 if (len > alignment)
1176 return false;
1177
1178 // Make sure we have a constant ubyte to work with so we can extract
1179 // the value to be filled.
Reid Spencere0fc4df2006-10-20 07:07:24 +00001180 ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
Reid Spencer38cabd72005-05-03 07:23:44 +00001181 if (!FILL)
1182 return false;
Reid Spencerc635f472006-12-31 05:48:39 +00001183 if (FILL->getType() != Type::Int8Ty)
Reid Spencer38cabd72005-05-03 07:23:44 +00001184 return false;
1185
1186 // memset(s,c,n) -> store s, c (for n=1,2,4,8)
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001187
Reid Spencer38cabd72005-05-03 07:23:44 +00001188 // Extract the fill character
Reid Spencere0fc4df2006-10-20 07:07:24 +00001189 uint64_t fill_char = FILL->getZExtValue();
Reid Spencer38cabd72005-05-03 07:23:44 +00001190 uint64_t fill_value = fill_char;
1191
1192 // Get the type we will cast to, based on size of memory area to fill, and
1193 // and the value we will store there.
1194 Value* dest = ci->getOperand(1);
Reid Spencer4f98e622007-01-07 21:45:41 +00001195 const Type* castType = 0;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001196 switch (len) {
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001197 case 1:
Reid Spencerc635f472006-12-31 05:48:39 +00001198 castType = Type::Int8Ty;
Reid Spencer38cabd72005-05-03 07:23:44 +00001199 break;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001200 case 2:
Reid Spencerc635f472006-12-31 05:48:39 +00001201 castType = Type::Int16Ty;
Reid Spencer38cabd72005-05-03 07:23:44 +00001202 fill_value |= fill_char << 8;
1203 break;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001204 case 4:
Reid Spencerc635f472006-12-31 05:48:39 +00001205 castType = Type::Int32Ty;
Reid Spencer38cabd72005-05-03 07:23:44 +00001206 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1207 break;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001208 case 8:
Reid Spencerc635f472006-12-31 05:48:39 +00001209 castType = Type::Int64Ty;
Reid Spencer38cabd72005-05-03 07:23:44 +00001210 fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
1211 fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
1212 fill_value |= fill_char << 56;
1213 break;
1214 default:
1215 return false;
1216 }
1217
1218 // Cast dest to the right sized primitive and then load/store
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001219 CastInst* DestCast = new BitCastInst(dest, PointerType::get(castType),
1220 dest->getName()+".cast", ci);
Reid Spencere0fc4df2006-10-20 07:07:24 +00001221 new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
Reid Spencer38cabd72005-05-03 07:23:44 +00001222 ci->eraseFromParent();
1223 return true;
1224 }
Chris Lattnerea7986a2006-03-03 01:30:23 +00001225};
1226
1227LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
1228LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
1229
Reid Spencerbb92b4f2005-04-26 19:13:17 +00001230
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001231/// This LibCallOptimization will simplify calls to the "pow" library
1232/// function. It looks for cases where the result of pow is well known and
Reid Spencer93616972005-04-29 09:39:47 +00001233/// substitutes the appropriate value.
1234/// @brief Simplify the pow library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001235struct PowOptimization : public LibCallOptimization {
Reid Spencer93616972005-04-29 09:39:47 +00001236public:
1237 /// @brief Default Constructor
Reid Spencer95d8efd2005-05-03 02:54:54 +00001238 PowOptimization() : LibCallOptimization("pow",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001239 "Number of 'pow' calls simplified") {}
Reid Spencer95d8efd2005-05-03 02:54:54 +00001240
Reid Spencer93616972005-04-29 09:39:47 +00001241 /// @brief Make sure that the "pow" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001242 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencer93616972005-04-29 09:39:47 +00001243 // Just make sure this has 2 arguments
1244 return (f->arg_size() == 2);
1245 }
1246
1247 /// @brief Perform the pow optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001248 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
Reid Spencer93616972005-04-29 09:39:47 +00001249 const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
1250 Value* base = ci->getOperand(1);
1251 Value* expn = ci->getOperand(2);
1252 if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
1253 double Op1V = Op1->getValue();
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001254 if (Op1V == 1.0) {
Reid Spencer93616972005-04-29 09:39:47 +00001255 // pow(1.0,x) -> 1.0
1256 ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
1257 ci->eraseFromParent();
1258 return true;
1259 }
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001260 } else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
Reid Spencer93616972005-04-29 09:39:47 +00001261 double Op2V = Op2->getValue();
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001262 if (Op2V == 0.0) {
Reid Spencer93616972005-04-29 09:39:47 +00001263 // pow(x,0.0) -> 1.0
1264 ci->replaceAllUsesWith(ConstantFP::get(Ty,1.0));
1265 ci->eraseFromParent();
1266 return true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001267 } else if (Op2V == 0.5) {
Reid Spencer93616972005-04-29 09:39:47 +00001268 // pow(x,0.5) -> sqrt(x)
1269 CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
1270 ci->getName()+".pow",ci);
1271 ci->replaceAllUsesWith(sqrt_inst);
1272 ci->eraseFromParent();
1273 return true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001274 } else if (Op2V == 1.0) {
Reid Spencer93616972005-04-29 09:39:47 +00001275 // pow(x,1.0) -> x
1276 ci->replaceAllUsesWith(base);
1277 ci->eraseFromParent();
1278 return true;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001279 } else if (Op2V == -1.0) {
Reid Spencer93616972005-04-29 09:39:47 +00001280 // pow(x,-1.0) -> 1.0/x
Reid Spencer7e80b0b2006-10-26 06:15:43 +00001281 BinaryOperator* div_inst= BinaryOperator::createFDiv(
Reid Spencer93616972005-04-29 09:39:47 +00001282 ConstantFP::get(Ty,1.0), base, ci->getName()+".pow", ci);
1283 ci->replaceAllUsesWith(div_inst);
1284 ci->eraseFromParent();
1285 return true;
1286 }
1287 }
1288 return false; // opt failed
1289 }
1290} PowOptimizer;
1291
Evan Cheng1fc40252006-06-16 08:36:35 +00001292/// This LibCallOptimization will simplify calls to the "printf" library
1293/// function. It looks for cases where the result of printf is not used and the
1294/// operation can be reduced to something simpler.
1295/// @brief Simplify the printf library function.
1296struct PrintfOptimization : public LibCallOptimization {
1297public:
1298 /// @brief Default Constructor
1299 PrintfOptimization() : LibCallOptimization("printf",
1300 "Number of 'printf' calls simplified") {}
1301
1302 /// @brief Make sure that the "printf" function has the right prototype
1303 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
1304 // Just make sure this has at least 1 arguments
1305 return (f->arg_size() >= 1);
1306 }
1307
1308 /// @brief Perform the printf optimization.
1309 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
1310 // If the call has more than 2 operands, we can't optimize it
1311 if (ci->getNumOperands() > 3 || ci->getNumOperands() <= 2)
1312 return false;
1313
1314 // If the result of the printf call is used, none of these optimizations
1315 // can be made.
1316 if (!ci->use_empty())
1317 return false;
1318
1319 // All the optimizations depend on the length of the first argument and the
1320 // fact that it is a constant string array. Check that now
1321 uint64_t len = 0;
1322 ConstantArray* CA = 0;
1323 if (!getConstantStringLength(ci->getOperand(1), len, &CA))
1324 return false;
1325
1326 if (len != 2 && len != 3)
1327 return false;
1328
1329 // The first character has to be a %
1330 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
Reid Spencere0fc4df2006-10-20 07:07:24 +00001331 if (CI->getZExtValue() != '%')
Evan Cheng1fc40252006-06-16 08:36:35 +00001332 return false;
1333
1334 // Get the second character and switch on its value
1335 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001336 switch (CI->getZExtValue()) {
Evan Cheng1fc40252006-06-16 08:36:35 +00001337 case 's':
1338 {
1339 if (len != 3 ||
Reid Spencere0fc4df2006-10-20 07:07:24 +00001340 dyn_cast<ConstantInt>(CA->getOperand(2))->getZExtValue() != '\n')
Evan Cheng1fc40252006-06-16 08:36:35 +00001341 return false;
1342
1343 // printf("%s\n",str) -> puts(str)
Evan Cheng1fc40252006-06-16 08:36:35 +00001344 std::vector<Value*> args;
Chris Lattner34acba42007-01-07 08:12:01 +00001345 new CallInst(SLC.get_puts(), CastToCStr(ci->getOperand(2), *ci),
1346 ci->getName(), ci);
1347 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, len));
Evan Cheng1fc40252006-06-16 08:36:35 +00001348 break;
1349 }
1350 case 'c':
1351 {
1352 // printf("%c",c) -> putchar(c)
1353 if (len != 2)
1354 return false;
1355
Chris Lattner34acba42007-01-07 08:12:01 +00001356 CastInst *Char = CastInst::createSExtOrBitCast(
Reid Spencerc635f472006-12-31 05:48:39 +00001357 ci->getOperand(2), Type::Int32Ty, CI->getName()+".int", ci);
Chris Lattner34acba42007-01-07 08:12:01 +00001358 new CallInst(SLC.get_putchar(), Char, "", ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001359 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, 1));
Evan Cheng1fc40252006-06-16 08:36:35 +00001360 break;
1361 }
1362 default:
1363 return false;
1364 }
1365 ci->eraseFromParent();
1366 return true;
1367 }
1368} PrintfOptimizer;
1369
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001370/// This LibCallOptimization will simplify calls to the "fprintf" library
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001371/// function. It looks for cases where the result of fprintf is not used and the
1372/// operation can be reduced to something simpler.
Evan Cheng1fc40252006-06-16 08:36:35 +00001373/// @brief Simplify the fprintf library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001374struct FPrintFOptimization : public LibCallOptimization {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001375public:
1376 /// @brief Default Constructor
Reid Spencer95d8efd2005-05-03 02:54:54 +00001377 FPrintFOptimization() : LibCallOptimization("fprintf",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001378 "Number of 'fprintf' calls simplified") {}
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001379
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001380 /// @brief Make sure that the "fprintf" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001381 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001382 // Just make sure this has at least 2 arguments
1383 return (f->arg_size() >= 2);
1384 }
1385
1386 /// @brief Perform the fprintf optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001387 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001388 // If the call has more than 3 operands, we can't optimize it
1389 if (ci->getNumOperands() > 4 || ci->getNumOperands() <= 2)
1390 return false;
1391
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001392 // If the result of the fprintf call is used, none of these optimizations
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001393 // can be made.
Chris Lattner175463a2005-09-24 22:17:06 +00001394 if (!ci->use_empty())
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001395 return false;
1396
1397 // All the optimizations depend on the length of the second argument and the
1398 // fact that it is a constant string array. Check that now
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001399 uint64_t len = 0;
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001400 ConstantArray* CA = 0;
1401 if (!getConstantStringLength(ci->getOperand(2), len, &CA))
1402 return false;
1403
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001404 if (ci->getNumOperands() == 3) {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001405 // Make sure there's no % in the constant array
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001406 for (unsigned i = 0; i < len; ++i) {
1407 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001408 // Check for the null terminator
Reid Spencere0fc4df2006-10-20 07:07:24 +00001409 if (CI->getZExtValue() == '%')
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001410 return false; // we found end of string
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001411 } else {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001412 return false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001413 }
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001414 }
1415
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001416 // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001417 const Type* FILEptr_type = ci->getOperand(1)->getType();
John Criswell4642afd2005-06-29 15:03:18 +00001418
1419 // Make sure that the fprintf() and fwrite() functions both take the
1420 // same type of char pointer.
Chris Lattner34acba42007-01-07 08:12:01 +00001421 if (ci->getOperand(2)->getType() != PointerType::get(Type::Int8Ty))
John Criswell4642afd2005-06-29 15:03:18 +00001422 return false;
John Criswell4642afd2005-06-29 15:03:18 +00001423
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001424 std::vector<Value*> args;
1425 args.push_back(ci->getOperand(2));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001426 args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
1427 args.push_back(ConstantInt::get(SLC.getIntPtrType(),1));
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001428 args.push_back(ci->getOperand(1));
Chris Lattner34acba42007-01-07 08:12:01 +00001429 new CallInst(SLC.get_fwrite(FILEptr_type), args, ci->getName(), ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001430 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001431 ci->eraseFromParent();
1432 return true;
1433 }
1434
1435 // The remaining optimizations require the format string to be length 2
1436 // "%s" or "%c".
1437 if (len != 2)
1438 return false;
1439
1440 // The first character has to be a %
1441 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
Reid Spencere0fc4df2006-10-20 07:07:24 +00001442 if (CI->getZExtValue() != '%')
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001443 return false;
1444
1445 // Get the second character and switch on its value
1446 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001447 switch (CI->getZExtValue()) {
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001448 case 's':
1449 {
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001450 uint64_t len = 0;
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001451 ConstantArray* CA = 0;
Evan Chengf2ea5872006-06-16 04:52:30 +00001452 if (getConstantStringLength(ci->getOperand(3), len, &CA)) {
1453 // fprintf(file,"%s",str) -> fwrite(str,strlen(str),1,file)
1454 const Type* FILEptr_type = ci->getOperand(1)->getType();
Evan Chengf2ea5872006-06-16 04:52:30 +00001455 std::vector<Value*> args;
1456 args.push_back(CastToCStr(ci->getOperand(3), *ci));
Chris Lattner34acba42007-01-07 08:12:01 +00001457 args.push_back(ConstantInt::get(SLC.getIntPtrType(), len));
1458 args.push_back(ConstantInt::get(SLC.getIntPtrType(), 1));
Evan Chengf2ea5872006-06-16 04:52:30 +00001459 args.push_back(ci->getOperand(1));
Chris Lattner34acba42007-01-07 08:12:01 +00001460 new CallInst(SLC.get_fwrite(FILEptr_type), args, ci->getName(), ci);
1461 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, len));
Evan Chengf2ea5872006-06-16 04:52:30 +00001462 } else {
1463 // fprintf(file,"%s",str) -> fputs(str,file)
1464 const Type* FILEptr_type = ci->getOperand(1)->getType();
Chris Lattner34acba42007-01-07 08:12:01 +00001465 new CallInst(SLC.get_fputs(FILEptr_type),
1466 CastToCStr(ci->getOperand(3), *ci),
1467 ci->getOperand(1), ci->getName(),ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001468 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
Evan Chengf2ea5872006-06-16 04:52:30 +00001469 }
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001470 break;
1471 }
1472 case 'c':
1473 {
Evan Cheng1fc40252006-06-16 08:36:35 +00001474 // fprintf(file,"%c",c) -> fputc(c,file)
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001475 const Type* FILEptr_type = ci->getOperand(1)->getType();
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001476 CastInst* cast = CastInst::createSExtOrBitCast(
Reid Spencerc635f472006-12-31 05:48:39 +00001477 ci->getOperand(3), Type::Int32Ty, CI->getName()+".int", ci);
Chris Lattner34acba42007-01-07 08:12:01 +00001478 new CallInst(SLC.get_fputc(FILEptr_type), cast,ci->getOperand(1),"",ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001479 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
Reid Spencer2d5c7be2005-05-02 23:59:26 +00001480 break;
1481 }
1482 default:
1483 return false;
1484 }
1485 ci->eraseFromParent();
1486 return true;
1487 }
1488} FPrintFOptimizer;
1489
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001490/// This LibCallOptimization will simplify calls to the "sprintf" library
Reid Spencer1e520fd2005-05-04 03:20:21 +00001491/// function. It looks for cases where the result of sprintf is not used and the
1492/// operation can be reduced to something simpler.
Evan Cheng1fc40252006-06-16 08:36:35 +00001493/// @brief Simplify the sprintf library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001494struct SPrintFOptimization : public LibCallOptimization {
Reid Spencer1e520fd2005-05-04 03:20:21 +00001495public:
1496 /// @brief Default Constructor
1497 SPrintFOptimization() : LibCallOptimization("sprintf",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001498 "Number of 'sprintf' calls simplified") {}
Reid Spencer1e520fd2005-05-04 03:20:21 +00001499
Reid Spencer1e520fd2005-05-04 03:20:21 +00001500 /// @brief Make sure that the "fprintf" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001501 virtual bool ValidateCalledFunction(const Function *f, SimplifyLibCalls &SLC){
Reid Spencer1e520fd2005-05-04 03:20:21 +00001502 // Just make sure this has at least 2 arguments
Reid Spencerc635f472006-12-31 05:48:39 +00001503 return (f->getReturnType() == Type::Int32Ty && f->arg_size() >= 2);
Reid Spencer1e520fd2005-05-04 03:20:21 +00001504 }
1505
1506 /// @brief Perform the sprintf optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001507 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
Reid Spencer1e520fd2005-05-04 03:20:21 +00001508 // If the call has more than 3 operands, we can't optimize it
1509 if (ci->getNumOperands() > 4 || ci->getNumOperands() < 3)
1510 return false;
1511
1512 // All the optimizations depend on the length of the second argument and the
1513 // fact that it is a constant string array. Check that now
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001514 uint64_t len = 0;
Reid Spencer1e520fd2005-05-04 03:20:21 +00001515 ConstantArray* CA = 0;
1516 if (!getConstantStringLength(ci->getOperand(2), len, &CA))
1517 return false;
1518
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001519 if (ci->getNumOperands() == 3) {
1520 if (len == 0) {
Reid Spencer1e520fd2005-05-04 03:20:21 +00001521 // If the length is 0, we just need to store a null byte
Reid Spencerc635f472006-12-31 05:48:39 +00001522 new StoreInst(ConstantInt::get(Type::Int8Ty,0),ci->getOperand(1),ci);
1523 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
Reid Spencer1e520fd2005-05-04 03:20:21 +00001524 ci->eraseFromParent();
1525 return true;
1526 }
1527
1528 // Make sure there's no % in the constant array
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001529 for (unsigned i = 0; i < len; ++i) {
1530 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i))) {
Reid Spencer1e520fd2005-05-04 03:20:21 +00001531 // Check for the null terminator
Reid Spencere0fc4df2006-10-20 07:07:24 +00001532 if (CI->getZExtValue() == '%')
Reid Spencer1e520fd2005-05-04 03:20:21 +00001533 return false; // we found a %, can't optimize
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001534 } else {
Reid Spencer1e520fd2005-05-04 03:20:21 +00001535 return false; // initializer is not constant int, can't optimize
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001536 }
Reid Spencer1e520fd2005-05-04 03:20:21 +00001537 }
1538
1539 // Increment length because we want to copy the null byte too
1540 len++;
1541
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001542 // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
Reid Spencer1e520fd2005-05-04 03:20:21 +00001543 std::vector<Value*> args;
1544 args.push_back(ci->getOperand(1));
1545 args.push_back(ci->getOperand(2));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001546 args.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
Reid Spencerc635f472006-12-31 05:48:39 +00001547 args.push_back(ConstantInt::get(Type::Int32Ty,1));
Chris Lattner34acba42007-01-07 08:12:01 +00001548 new CallInst(SLC.get_memcpy(), args, "", ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001549 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,len));
Reid Spencer1e520fd2005-05-04 03:20:21 +00001550 ci->eraseFromParent();
1551 return true;
1552 }
1553
1554 // The remaining optimizations require the format string to be length 2
1555 // "%s" or "%c".
1556 if (len != 2)
1557 return false;
1558
1559 // The first character has to be a %
1560 if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
Reid Spencere0fc4df2006-10-20 07:07:24 +00001561 if (CI->getZExtValue() != '%')
Reid Spencer1e520fd2005-05-04 03:20:21 +00001562 return false;
1563
1564 // Get the second character and switch on its value
1565 ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001566 switch (CI->getZExtValue()) {
Chris Lattner175463a2005-09-24 22:17:06 +00001567 case 's': {
1568 // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
Chris Lattner34acba42007-01-07 08:12:01 +00001569 Value *Len = new CallInst(SLC.get_strlen(),
1570 CastToCStr(ci->getOperand(3), *ci),
Chris Lattner175463a2005-09-24 22:17:06 +00001571 ci->getOperand(3)->getName()+".len", ci);
1572 Value *Len1 = BinaryOperator::createAdd(Len,
1573 ConstantInt::get(Len->getType(), 1),
1574 Len->getName()+"1", ci);
Andrew Lenharth47da6012006-02-15 21:13:37 +00001575 if (Len1->getType() != SLC.getIntPtrType())
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001576 Len1 = CastInst::createIntegerCast(Len1, SLC.getIntPtrType(), false,
1577 Len1->getName(), ci);
Chris Lattner175463a2005-09-24 22:17:06 +00001578 std::vector<Value*> args;
1579 args.push_back(CastToCStr(ci->getOperand(1), *ci));
1580 args.push_back(CastToCStr(ci->getOperand(3), *ci));
1581 args.push_back(Len1);
Reid Spencerc635f472006-12-31 05:48:39 +00001582 args.push_back(ConstantInt::get(Type::Int32Ty,1));
Chris Lattner34acba42007-01-07 08:12:01 +00001583 new CallInst(SLC.get_memcpy(), args, "", ci);
Chris Lattner175463a2005-09-24 22:17:06 +00001584
1585 // The strlen result is the unincremented number of bytes in the string.
Chris Lattnerf4877682005-09-25 07:06:48 +00001586 if (!ci->use_empty()) {
1587 if (Len->getType() != ci->getType())
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001588 Len = CastInst::createIntegerCast(Len, ci->getType(), false,
1589 Len->getName(), ci);
Chris Lattnerf4877682005-09-25 07:06:48 +00001590 ci->replaceAllUsesWith(Len);
1591 }
Chris Lattner175463a2005-09-24 22:17:06 +00001592 ci->eraseFromParent();
1593 return true;
Reid Spencer1e520fd2005-05-04 03:20:21 +00001594 }
Chris Lattner175463a2005-09-24 22:17:06 +00001595 case 'c': {
1596 // sprintf(dest,"%c",chr) -> store chr, dest
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001597 CastInst* cast = CastInst::createTruncOrBitCast(
Reid Spencerc635f472006-12-31 05:48:39 +00001598 ci->getOperand(3), Type::Int8Ty, "char", ci);
Chris Lattner175463a2005-09-24 22:17:06 +00001599 new StoreInst(cast, ci->getOperand(1), ci);
1600 GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
Reid Spencerc635f472006-12-31 05:48:39 +00001601 ConstantInt::get(Type::Int32Ty,1),ci->getOperand(1)->getName()+".end",
Chris Lattner175463a2005-09-24 22:17:06 +00001602 ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001603 new StoreInst(ConstantInt::get(Type::Int8Ty,0),gep,ci);
1604 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
Chris Lattner175463a2005-09-24 22:17:06 +00001605 ci->eraseFromParent();
1606 return true;
1607 }
1608 }
1609 return false;
Reid Spencer1e520fd2005-05-04 03:20:21 +00001610 }
1611} SPrintFOptimizer;
1612
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001613/// This LibCallOptimization will simplify calls to the "fputs" library
Reid Spencer93616972005-04-29 09:39:47 +00001614/// function. It looks for cases where the result of fputs is not used and the
1615/// operation can be reduced to something simpler.
Evan Cheng1fc40252006-06-16 08:36:35 +00001616/// @brief Simplify the puts library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001617struct PutsOptimization : public LibCallOptimization {
Reid Spencer93616972005-04-29 09:39:47 +00001618public:
1619 /// @brief Default Constructor
Reid Spencer95d8efd2005-05-03 02:54:54 +00001620 PutsOptimization() : LibCallOptimization("fputs",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001621 "Number of 'fputs' calls simplified") {}
Reid Spencer93616972005-04-29 09:39:47 +00001622
Reid Spencer93616972005-04-29 09:39:47 +00001623 /// @brief Make sure that the "fputs" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001624 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
Reid Spencer93616972005-04-29 09:39:47 +00001625 // Just make sure this has 2 arguments
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001626 return F->arg_size() == 2;
Reid Spencer93616972005-04-29 09:39:47 +00001627 }
1628
1629 /// @brief Perform the fputs optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001630 virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
Reid Spencer93616972005-04-29 09:39:47 +00001631 // If the result is used, none of these optimizations work
Chris Lattner175463a2005-09-24 22:17:06 +00001632 if (!ci->use_empty())
Reid Spencer93616972005-04-29 09:39:47 +00001633 return false;
1634
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
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001637 uint64_t len = 0;
Reid Spencer93616972005-04-29 09:39:47 +00001638 if (!getConstantStringLength(ci->getOperand(1), len))
1639 return false;
1640
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001641 switch (len) {
Reid Spencer93616972005-04-29 09:39:47 +00001642 case 0:
1643 // fputs("",F) -> noop
1644 break;
1645 case 1:
1646 {
1647 // fputs(s,F) -> fputc(s[0],F) (if s is constant and strlen(s) == 1)
Reid Spencer4c444fe2005-04-30 03:17:54 +00001648 const Type* FILEptr_type = ci->getOperand(2)->getType();
Reid Spencer93616972005-04-29 09:39:47 +00001649 LoadInst* loadi = new LoadInst(ci->getOperand(1),
1650 ci->getOperand(1)->getName()+".byte",ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001651 CastInst* casti = new SExtInst(loadi, Type::Int32Ty,
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001652 loadi->getName()+".int", ci);
Chris Lattner34acba42007-01-07 08:12:01 +00001653 new CallInst(SLC.get_fputc(FILEptr_type), casti,
1654 ci->getOperand(2), "", ci);
Reid Spencer93616972005-04-29 09:39:47 +00001655 break;
1656 }
1657 default:
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001658 {
Reid Spencer93616972005-04-29 09:39:47 +00001659 // fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
Reid Spencer4c444fe2005-04-30 03:17:54 +00001660 const Type* FILEptr_type = ci->getOperand(2)->getType();
Reid Spencer93616972005-04-29 09:39:47 +00001661 std::vector<Value*> parms;
1662 parms.push_back(ci->getOperand(1));
Reid Spencere0fc4df2006-10-20 07:07:24 +00001663 parms.push_back(ConstantInt::get(SLC.getIntPtrType(),len));
1664 parms.push_back(ConstantInt::get(SLC.getIntPtrType(),1));
Reid Spencer93616972005-04-29 09:39:47 +00001665 parms.push_back(ci->getOperand(2));
Chris Lattner34acba42007-01-07 08:12:01 +00001666 new CallInst(SLC.get_fwrite(FILEptr_type), parms, "", ci);
Reid Spencer93616972005-04-29 09:39:47 +00001667 break;
1668 }
1669 }
1670 ci->eraseFromParent();
1671 return true; // success
1672 }
1673} PutsOptimizer;
1674
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001675/// This LibCallOptimization will simplify calls to the "isdigit" library
Reid Spencer282d0572005-05-04 18:58:28 +00001676/// function. It simply does range checks the parameter explicitly.
1677/// @brief Simplify the isdigit library function.
Chris Lattner5f6035f2005-09-29 06:16:11 +00001678struct isdigitOptimization : public LibCallOptimization {
Reid Spencer282d0572005-05-04 18:58:28 +00001679public:
Chris Lattner5f6035f2005-09-29 06:16:11 +00001680 isdigitOptimization() : LibCallOptimization("isdigit",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001681 "Number of 'isdigit' calls simplified") {}
Reid Spencer282d0572005-05-04 18:58:28 +00001682
Chris Lattner5f6035f2005-09-29 06:16:11 +00001683 /// @brief Make sure that the "isdigit" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001684 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencer282d0572005-05-04 18:58:28 +00001685 // Just make sure this has 1 argument
1686 return (f->arg_size() == 1);
1687 }
1688
1689 /// @brief Perform the toascii optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001690 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
1691 if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
Reid Spencer282d0572005-05-04 18:58:28 +00001692 // isdigit(c) -> 0 or 1, if 'c' is constant
Reid Spencere0fc4df2006-10-20 07:07:24 +00001693 uint64_t val = CI->getZExtValue();
Reid Spencer282d0572005-05-04 18:58:28 +00001694 if (val >= '0' && val <='9')
Reid Spencerc635f472006-12-31 05:48:39 +00001695 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,1));
Reid Spencer282d0572005-05-04 18:58:28 +00001696 else
Reid Spencerc635f472006-12-31 05:48:39 +00001697 ci->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty,0));
Reid Spencer282d0572005-05-04 18:58:28 +00001698 ci->eraseFromParent();
1699 return true;
1700 }
1701
1702 // isdigit(c) -> (unsigned)c - '0' <= 9
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001703 CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
Reid Spencerc635f472006-12-31 05:48:39 +00001704 Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
Chris Lattner4201cd12005-08-24 17:22:17 +00001705 BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
Reid Spencerc635f472006-12-31 05:48:39 +00001706 ConstantInt::get(Type::Int32Ty,0x30),
Reid Spencer282d0572005-05-04 18:58:28 +00001707 ci->getOperand(1)->getName()+".sub",ci);
Reid Spencer266e42b2006-12-23 06:05:41 +00001708 ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
Reid Spencerc635f472006-12-31 05:48:39 +00001709 ConstantInt::get(Type::Int32Ty,9),
Reid Spencer282d0572005-05-04 18:58:28 +00001710 ci->getOperand(1)->getName()+".cmp",ci);
Reid Spencerc635f472006-12-31 05:48:39 +00001711 CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001712 ci->getOperand(1)->getName()+".isdigit", ci);
Reid Spencer282d0572005-05-04 18:58:28 +00001713 ci->replaceAllUsesWith(c2);
1714 ci->eraseFromParent();
1715 return true;
1716 }
Chris Lattner5f6035f2005-09-29 06:16:11 +00001717} isdigitOptimizer;
1718
Chris Lattner87ef9432005-09-29 06:17:27 +00001719struct isasciiOptimization : public LibCallOptimization {
1720public:
1721 isasciiOptimization()
1722 : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
1723
1724 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
Chris Lattner03c49532007-01-15 02:27:26 +00001725 return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
1726 F->getReturnType()->isInteger();
Chris Lattner87ef9432005-09-29 06:17:27 +00001727 }
1728
1729 /// @brief Perform the isascii optimization.
1730 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1731 // isascii(c) -> (unsigned)c < 128
1732 Value *V = CI->getOperand(1);
Reid Spencer266e42b2006-12-23 06:05:41 +00001733 Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
1734 ConstantInt::get(V->getType(), 128),
1735 V->getName()+".isascii", CI);
Chris Lattner87ef9432005-09-29 06:17:27 +00001736 if (Cmp->getType() != CI->getType())
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001737 Cmp = new BitCastInst(Cmp, CI->getType(), Cmp->getName(), CI);
Chris Lattner87ef9432005-09-29 06:17:27 +00001738 CI->replaceAllUsesWith(Cmp);
1739 CI->eraseFromParent();
1740 return true;
1741 }
1742} isasciiOptimizer;
Chris Lattner5f6035f2005-09-29 06:16:11 +00001743
Reid Spencer282d0572005-05-04 18:58:28 +00001744
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001745/// This LibCallOptimization will simplify calls to the "toascii" library
Reid Spencer4c444fe2005-04-30 03:17:54 +00001746/// function. It simply does the corresponding and operation to restrict the
1747/// range of values to the ASCII character set (0-127).
1748/// @brief Simplify the toascii library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001749struct ToAsciiOptimization : public LibCallOptimization {
Reid Spencer4c444fe2005-04-30 03:17:54 +00001750public:
1751 /// @brief Default Constructor
Reid Spencer95d8efd2005-05-03 02:54:54 +00001752 ToAsciiOptimization() : LibCallOptimization("toascii",
Reid Spencer170ae7f2005-05-07 20:15:59 +00001753 "Number of 'toascii' calls simplified") {}
Reid Spencer4c444fe2005-04-30 03:17:54 +00001754
Reid Spencer4c444fe2005-04-30 03:17:54 +00001755 /// @brief Make sure that the "fputs" function has the right prototype
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001756 virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
Reid Spencer4c444fe2005-04-30 03:17:54 +00001757 // Just make sure this has 2 arguments
1758 return (f->arg_size() == 1);
1759 }
1760
1761 /// @brief Perform the toascii optimization.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001762 virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
Reid Spencer4c444fe2005-04-30 03:17:54 +00001763 // toascii(c) -> (c & 0x7f)
1764 Value* chr = ci->getOperand(1);
Chris Lattner4201cd12005-08-24 17:22:17 +00001765 BinaryOperator* and_inst = BinaryOperator::createAnd(chr,
Reid Spencer4c444fe2005-04-30 03:17:54 +00001766 ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
1767 ci->replaceAllUsesWith(and_inst);
1768 ci->eraseFromParent();
1769 return true;
1770 }
1771} ToAsciiOptimizer;
1772
Reid Spencerb195fcd2005-05-14 16:42:52 +00001773/// This LibCallOptimization will simplify calls to the "ffs" library
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001774/// calls which find the first set bit in an int, long, or long long. The
Reid Spencerb195fcd2005-05-14 16:42:52 +00001775/// optimization is to compute the result at compile time if the argument is
1776/// a constant.
1777/// @brief Simplify the ffs library function.
Chris Lattner801f4752006-01-17 18:27:17 +00001778struct FFSOptimization : public LibCallOptimization {
Reid Spencerb195fcd2005-05-14 16:42:52 +00001779protected:
1780 /// @brief Subclass Constructor
1781 FFSOptimization(const char* funcName, const char* description)
Chris Lattner801f4752006-01-17 18:27:17 +00001782 : LibCallOptimization(funcName, description) {}
Reid Spencerb195fcd2005-05-14 16:42:52 +00001783
1784public:
1785 /// @brief Default Constructor
1786 FFSOptimization() : LibCallOptimization("ffs",
1787 "Number of 'ffs' calls simplified") {}
1788
Chris Lattner801f4752006-01-17 18:27:17 +00001789 /// @brief Make sure that the "ffs" function has the right prototype
1790 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
Reid Spencerb195fcd2005-05-14 16:42:52 +00001791 // Just make sure this has 2 arguments
Reid Spencerc635f472006-12-31 05:48:39 +00001792 return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
Reid Spencerb195fcd2005-05-14 16:42:52 +00001793 }
1794
1795 /// @brief Perform the ffs optimization.
Chris Lattner801f4752006-01-17 18:27:17 +00001796 virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
1797 if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
Reid Spencerb195fcd2005-05-14 16:42:52 +00001798 // ffs(cnst) -> bit#
1799 // ffsl(cnst) -> bit#
Reid Spencer17f77842005-05-15 21:19:45 +00001800 // ffsll(cnst) -> bit#
Reid Spencere0fc4df2006-10-20 07:07:24 +00001801 uint64_t val = CI->getZExtValue();
Reid Spencer17f77842005-05-15 21:19:45 +00001802 int result = 0;
Chris Lattner801f4752006-01-17 18:27:17 +00001803 if (val) {
1804 ++result;
1805 while ((val & 1) == 0) {
1806 ++result;
1807 val >>= 1;
1808 }
Reid Spencer17f77842005-05-15 21:19:45 +00001809 }
Reid Spencerc635f472006-12-31 05:48:39 +00001810 TheCall->replaceAllUsesWith(ConstantInt::get(Type::Int32Ty, result));
Chris Lattner801f4752006-01-17 18:27:17 +00001811 TheCall->eraseFromParent();
Reid Spencerb195fcd2005-05-14 16:42:52 +00001812 return true;
1813 }
Reid Spencer17f77842005-05-15 21:19:45 +00001814
Chris Lattner801f4752006-01-17 18:27:17 +00001815 // ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1816 // ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1817 // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
1818 const Type *ArgType = TheCall->getOperand(1)->getType();
Chris Lattner801f4752006-01-17 18:27:17 +00001819 const char *CTTZName;
Reid Spencer7a9c62b2007-01-12 07:05:14 +00001820 assert(ArgType->getTypeID() == Type::IntegerTyID &&
1821 "llvm.cttz argument is not an integer?");
1822 unsigned BitWidth = cast<IntegerType>(ArgType)->getBitWidth();
Chris Lattner3b6058c2007-01-12 22:49:11 +00001823 if (BitWidth == 8)
Reid Spencer7a9c62b2007-01-12 07:05:14 +00001824 CTTZName = "llvm.cttz.i8";
Chris Lattner3b6058c2007-01-12 22:49:11 +00001825 else if (BitWidth == 16)
Reid Spencer7a9c62b2007-01-12 07:05:14 +00001826 CTTZName = "llvm.cttz.i16";
Chris Lattner3b6058c2007-01-12 22:49:11 +00001827 else if (BitWidth == 32)
Reid Spencer7a9c62b2007-01-12 07:05:14 +00001828 CTTZName = "llvm.cttz.i32";
Chris Lattner3b6058c2007-01-12 22:49:11 +00001829 else {
1830 assert(BitWidth == 64 && "Unknown bitwidth");
Reid Spencer7a9c62b2007-01-12 07:05:14 +00001831 CTTZName = "llvm.cttz.i64";
Chris Lattner3b6058c2007-01-12 22:49:11 +00001832 }
Chris Lattner801f4752006-01-17 18:27:17 +00001833
Chris Lattner34acba42007-01-07 08:12:01 +00001834 Constant *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
Chris Lattner801f4752006-01-17 18:27:17 +00001835 ArgType, NULL);
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001836 Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
1837 false/*ZExt*/, "tmp", TheCall);
Chris Lattner801f4752006-01-17 18:27:17 +00001838 Value *V2 = new CallInst(F, V, "tmp", TheCall);
Reid Spencerc635f472006-12-31 05:48:39 +00001839 V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
Reid Spencerbfe26ff2006-12-13 00:50:17 +00001840 "tmp", TheCall);
Reid Spencerc635f472006-12-31 05:48:39 +00001841 V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
Chris Lattner801f4752006-01-17 18:27:17 +00001842 "tmp", TheCall);
Reid Spencer266e42b2006-12-23 06:05:41 +00001843 Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
1844 Constant::getNullValue(V->getType()), "tmp",
1845 TheCall);
Reid Spencerc635f472006-12-31 05:48:39 +00001846 V2 = new SelectInst(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
Chris Lattner801f4752006-01-17 18:27:17 +00001847 TheCall->getName(), TheCall);
1848 TheCall->replaceAllUsesWith(V2);
1849 TheCall->eraseFromParent();
Reid Spencer17f77842005-05-15 21:19:45 +00001850 return true;
Reid Spencerb195fcd2005-05-14 16:42:52 +00001851 }
1852} FFSOptimizer;
1853
1854/// This LibCallOptimization will simplify calls to the "ffsl" library
1855/// calls. It simply uses FFSOptimization for which the transformation is
1856/// identical.
1857/// @brief Simplify the ffsl library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001858struct FFSLOptimization : public FFSOptimization {
Reid Spencerb195fcd2005-05-14 16:42:52 +00001859public:
1860 /// @brief Default Constructor
1861 FFSLOptimization() : FFSOptimization("ffsl",
1862 "Number of 'ffsl' calls simplified") {}
1863
1864} FFSLOptimizer;
1865
1866/// This LibCallOptimization will simplify calls to the "ffsll" library
1867/// calls. It simply uses FFSOptimization for which the transformation is
1868/// identical.
1869/// @brief Simplify the ffsl library function.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001870struct FFSLLOptimization : public FFSOptimization {
Reid Spencerb195fcd2005-05-14 16:42:52 +00001871public:
1872 /// @brief Default Constructor
1873 FFSLLOptimization() : FFSOptimization("ffsll",
1874 "Number of 'ffsll' calls simplified") {}
1875
1876} FFSLLOptimizer;
1877
Chris Lattner57a28632006-01-23 05:57:36 +00001878/// This optimizes unary functions that take and return doubles.
1879struct UnaryDoubleFPOptimizer : public LibCallOptimization {
1880 UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
1881 : LibCallOptimization(Fn, Desc) {}
Chris Lattner4201cd12005-08-24 17:22:17 +00001882
Chris Lattner57a28632006-01-23 05:57:36 +00001883 // Make sure that this function has the right prototype
Chris Lattner4201cd12005-08-24 17:22:17 +00001884 virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
1885 return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
1886 F->getReturnType() == Type::DoubleTy;
1887 }
Chris Lattner57a28632006-01-23 05:57:36 +00001888
1889 /// ShrinkFunctionToFloatVersion - If the input to this function is really a
1890 /// float, strength reduce this to a float version of the function,
1891 /// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
1892 /// when the target supports the destination function and where there can be
1893 /// no precision loss.
1894 static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
Chris Lattner34acba42007-01-07 08:12:01 +00001895 Constant *(SimplifyLibCalls::*FP)()){
Chris Lattner4201cd12005-08-24 17:22:17 +00001896 if (CastInst *Cast = dyn_cast<CastInst>(CI->getOperand(1)))
1897 if (Cast->getOperand(0)->getType() == Type::FloatTy) {
Chris Lattner57a28632006-01-23 05:57:36 +00001898 Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
Chris Lattner4201cd12005-08-24 17:22:17 +00001899 CI->getName(), CI);
Reid Spencer6c38f0b2006-11-27 01:05:10 +00001900 New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
Chris Lattner4201cd12005-08-24 17:22:17 +00001901 CI->replaceAllUsesWith(New);
1902 CI->eraseFromParent();
1903 if (Cast->use_empty())
1904 Cast->eraseFromParent();
1905 return true;
1906 }
Chris Lattner57a28632006-01-23 05:57:36 +00001907 return false;
Chris Lattner4201cd12005-08-24 17:22:17 +00001908 }
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001909};
1910
Chris Lattner57a28632006-01-23 05:57:36 +00001911
Chris Lattner57a28632006-01-23 05:57:36 +00001912struct FloorOptimization : public UnaryDoubleFPOptimizer {
1913 FloorOptimization()
1914 : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
1915
1916 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001917#ifdef HAVE_FLOORF
Chris Lattner57a28632006-01-23 05:57:36 +00001918 // If this is a float argument passed in, convert to floorf.
1919 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
1920 return true;
Reid Spencerade18212006-01-19 08:36:56 +00001921#endif
Chris Lattner57a28632006-01-23 05:57:36 +00001922 return false; // opt failed
1923 }
1924} FloorOptimizer;
Chris Lattner4201cd12005-08-24 17:22:17 +00001925
Chris Lattner57740402006-01-23 06:24:46 +00001926struct CeilOptimization : public UnaryDoubleFPOptimizer {
1927 CeilOptimization()
1928 : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
1929
1930 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1931#ifdef HAVE_CEILF
1932 // If this is a float argument passed in, convert to ceilf.
1933 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
1934 return true;
1935#endif
1936 return false; // opt failed
1937 }
1938} CeilOptimizer;
Chris Lattner4201cd12005-08-24 17:22:17 +00001939
Chris Lattner57740402006-01-23 06:24:46 +00001940struct RoundOptimization : public UnaryDoubleFPOptimizer {
1941 RoundOptimization()
1942 : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
1943
1944 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1945#ifdef HAVE_ROUNDF
1946 // If this is a float argument passed in, convert to roundf.
1947 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
1948 return true;
1949#endif
1950 return false; // opt failed
1951 }
1952} RoundOptimizer;
1953
1954struct RintOptimization : public UnaryDoubleFPOptimizer {
1955 RintOptimization()
1956 : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
1957
1958 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1959#ifdef HAVE_RINTF
1960 // If this is a float argument passed in, convert to rintf.
1961 if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
1962 return true;
1963#endif
1964 return false; // opt failed
1965 }
1966} RintOptimizer;
1967
1968struct NearByIntOptimization : public UnaryDoubleFPOptimizer {
1969 NearByIntOptimization()
1970 : UnaryDoubleFPOptimizer("nearbyint",
1971 "Number of 'nearbyint' calls simplified") {}
1972
1973 virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
1974#ifdef HAVE_NEARBYINTF
1975 // If this is a float argument passed in, convert to nearbyintf.
1976 if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
1977 return true;
1978#endif
1979 return false; // opt failed
1980 }
1981} NearByIntOptimizer;
Chris Lattner4201cd12005-08-24 17:22:17 +00001982
Reid Spencer7ddcfb32005-04-27 21:29:20 +00001983/// A function to compute the length of a null-terminated constant array of
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001984/// integers. This function can't rely on the size of the constant array
1985/// because there could be a null terminator in the middle of the array.
1986/// We also have to bail out if we find a non-integer constant initializer
1987/// of one of the elements or if there is no null-terminator. The logic
Reid Spencer7ddcfb32005-04-27 21:29:20 +00001988/// below checks each of these conditions and will return true only if all
1989/// conditions are met. In that case, the \p len parameter is set to the length
1990/// of the null-terminated string. If false is returned, the conditions were
1991/// not met and len is set to 0.
1992/// @brief Get the length of a constant string (null-terminated array).
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00001993bool getConstantStringLength(Value *V, uint64_t &len, ConstantArray **CA) {
Reid Spencere249a822005-04-27 07:54:40 +00001994 assert(V != 0 && "Invalid args to getConstantStringLength");
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001995 len = 0; // make sure we initialize this
Reid Spencere249a822005-04-27 07:54:40 +00001996 User* GEP = 0;
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00001997 // If the value is not a GEP instruction nor a constant expression with a
1998 // GEP instruction, then return false because ConstantArray can't occur
Reid Spencere249a822005-04-27 07:54:40 +00001999 // any other way
2000 if (GetElementPtrInst* GEPI = dyn_cast<GetElementPtrInst>(V))
2001 GEP = GEPI;
2002 else if (ConstantExpr* CE = dyn_cast<ConstantExpr>(V))
2003 if (CE->getOpcode() == Instruction::GetElementPtr)
2004 GEP = CE;
2005 else
2006 return false;
2007 else
2008 return false;
2009
2010 // Make sure the GEP has exactly three arguments.
2011 if (GEP->getNumOperands() != 3)
2012 return false;
2013
2014 // Check to make sure that the first operand of the GEP is an integer and
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002015 // has value 0 so that we are sure we're indexing into the initializer.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00002016 if (ConstantInt* op1 = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
Reid Spencere249a822005-04-27 07:54:40 +00002017 if (!op1->isNullValue())
2018 return false;
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00002019 } else
Reid Spencere249a822005-04-27 07:54:40 +00002020 return false;
2021
2022 // Ensure that the second operand is a ConstantInt. If it isn't then this
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002023 // GEP is wonky and we're not really sure what were referencing into and
Reid Spencere249a822005-04-27 07:54:40 +00002024 // better of not optimizing it. While we're at it, get the second index
2025 // value. We'll need this later for indexing the ConstantArray.
2026 uint64_t start_idx = 0;
2027 if (ConstantInt* CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
Reid Spencere0fc4df2006-10-20 07:07:24 +00002028 start_idx = CI->getZExtValue();
Reid Spencere249a822005-04-27 07:54:40 +00002029 else
2030 return false;
2031
2032 // The GEP instruction, constant or instruction, must reference a global
2033 // variable that is a constant and is initialized. The referenced constant
2034 // initializer is the array that we'll use for optimization.
2035 GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
2036 if (!GV || !GV->isConstant() || !GV->hasInitializer())
2037 return false;
2038
2039 // Get the initializer.
2040 Constant* INTLZR = GV->getInitializer();
2041
2042 // Handle the ConstantAggregateZero case
Reid Spencerde46e482006-11-02 20:25:50 +00002043 if (isa<ConstantAggregateZero>(INTLZR)) {
Reid Spencere249a822005-04-27 07:54:40 +00002044 // This is a degenerate case. The initializer is constant zero so the
2045 // length of the string must be zero.
2046 len = 0;
2047 return true;
2048 }
2049
2050 // Must be a Constant Array
2051 ConstantArray* A = dyn_cast<ConstantArray>(INTLZR);
2052 if (!A)
2053 return false;
2054
2055 // Get the number of elements in the array
2056 uint64_t max_elems = A->getType()->getNumElements();
2057
2058 // Traverse the constant array from start_idx (derived above) which is
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002059 // the place the GEP refers to in the array.
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00002060 for (len = start_idx; len < max_elems; len++) {
2061 if (ConstantInt *CI = dyn_cast<ConstantInt>(A->getOperand(len))) {
Reid Spencere249a822005-04-27 07:54:40 +00002062 // Check for the null terminator
2063 if (CI->isNullValue())
2064 break; // we found end of string
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00002065 } else
Reid Spencere249a822005-04-27 07:54:40 +00002066 return false; // This array isn't suitable, non-int initializer
2067 }
Chris Lattner0d4ebfc2006-01-22 22:35:08 +00002068
Reid Spencere249a822005-04-27 07:54:40 +00002069 if (len >= max_elems)
2070 return false; // This array isn't null terminated
2071
2072 // Subtract out the initial value from the length
2073 len -= start_idx;
Reid Spencer4c444fe2005-04-30 03:17:54 +00002074 if (CA)
2075 *CA = A;
Reid Spencere249a822005-04-27 07:54:40 +00002076 return true; // success!
2077}
2078
Reid Spencera7828ba2005-06-18 17:46:28 +00002079/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
2080/// inserting the cast before IP, and return the cast.
2081/// @brief Cast a value to a "C" string.
2082Value *CastToCStr(Value *V, Instruction &IP) {
Reid Spencera730cf82006-12-13 08:04:32 +00002083 assert(isa<PointerType>(V->getType()) &&
Reid Spencerbfe26ff2006-12-13 00:50:17 +00002084 "Can't cast non-pointer type to C string type");
Reid Spencerc635f472006-12-31 05:48:39 +00002085 const Type *SBPTy = PointerType::get(Type::Int8Ty);
Reid Spencera7828ba2005-06-18 17:46:28 +00002086 if (V->getType() != SBPTy)
Reid Spencerbfe26ff2006-12-13 00:50:17 +00002087 return new BitCastInst(V, SBPTy, V->getName(), &IP);
Reid Spencera7828ba2005-06-18 17:46:28 +00002088 return V;
2089}
2090
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002091// TODO:
Reid Spencer649ac282005-04-28 04:40:06 +00002092// Additional cases that we need to add to this file:
2093//
Reid Spencer649ac282005-04-28 04:40:06 +00002094// cbrt:
Reid Spencer649ac282005-04-28 04:40:06 +00002095// * cbrt(expN(X)) -> expN(x/3)
2096// * cbrt(sqrt(x)) -> pow(x,1/6)
2097// * cbrt(sqrt(x)) -> pow(x,1/9)
2098//
Reid Spencer649ac282005-04-28 04:40:06 +00002099// cos, cosf, cosl:
Reid Spencer16983ca2005-04-28 18:05:16 +00002100// * cos(-x) -> cos(x)
Reid Spencer649ac282005-04-28 04:40:06 +00002101//
2102// exp, expf, expl:
Reid Spencer649ac282005-04-28 04:40:06 +00002103// * exp(log(x)) -> x
2104//
Reid Spencer649ac282005-04-28 04:40:06 +00002105// log, logf, logl:
Reid Spencer649ac282005-04-28 04:40:06 +00002106// * log(exp(x)) -> x
2107// * log(x**y) -> y*log(x)
2108// * log(exp(y)) -> y*log(e)
2109// * log(exp2(y)) -> y*log(2)
2110// * log(exp10(y)) -> y*log(10)
2111// * log(sqrt(x)) -> 0.5*log(x)
2112// * log(pow(x,y)) -> y*log(x)
2113//
2114// lround, lroundf, lroundl:
2115// * lround(cnst) -> cnst'
2116//
2117// memcmp:
Reid Spencer649ac282005-04-28 04:40:06 +00002118// * memcmp(x,y,l) -> cnst
2119// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
Reid Spencer649ac282005-04-28 04:40:06 +00002120//
Reid Spencer649ac282005-04-28 04:40:06 +00002121// memmove:
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002122// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
Reid Spencer649ac282005-04-28 04:40:06 +00002123// (if s is a global constant array)
2124//
Reid Spencer649ac282005-04-28 04:40:06 +00002125// pow, powf, powl:
Reid Spencer649ac282005-04-28 04:40:06 +00002126// * pow(exp(x),y) -> exp(x*y)
2127// * pow(sqrt(x),y) -> pow(x,y*0.5)
2128// * pow(pow(x,y),z)-> pow(x,y*z)
2129//
2130// puts:
2131// * puts("") -> fputc("\n",stdout) (how do we get "stdout"?)
2132//
2133// round, roundf, roundl:
2134// * round(cnst) -> cnst'
2135//
2136// signbit:
2137// * signbit(cnst) -> cnst'
2138// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
2139//
Reid Spencer649ac282005-04-28 04:40:06 +00002140// sqrt, sqrtf, sqrtl:
Reid Spencer649ac282005-04-28 04:40:06 +00002141// * sqrt(expN(x)) -> expN(x*0.5)
2142// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
2143// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
2144//
Reid Spencer170ae7f2005-05-07 20:15:59 +00002145// stpcpy:
2146// * stpcpy(str, "literal") ->
2147// llvm.memcpy(str,"literal",strlen("literal")+1,1)
Reid Spencer38cabd72005-05-03 07:23:44 +00002148// strrchr:
Reid Spencer649ac282005-04-28 04:40:06 +00002149// * strrchr(s,c) -> reverse_offset_of_in(c,s)
2150// (if c is a constant integer and s is a constant string)
2151// * strrchr(s1,0) -> strchr(s1,0)
2152//
Reid Spencer649ac282005-04-28 04:40:06 +00002153// strncat:
2154// * strncat(x,y,0) -> x
2155// * strncat(x,y,0) -> x (if strlen(y) = 0)
2156// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
2157//
Reid Spencer649ac282005-04-28 04:40:06 +00002158// strncpy:
2159// * strncpy(d,s,0) -> d
2160// * strncpy(d,s,l) -> memcpy(d,s,l,1)
2161// (if s and l are constants)
2162//
2163// strpbrk:
2164// * strpbrk(s,a) -> offset_in_for(s,a)
2165// (if s and a are both constant strings)
2166// * strpbrk(s,"") -> 0
2167// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
2168//
2169// strspn, strcspn:
2170// * strspn(s,a) -> const_int (if both args are constant)
2171// * strspn("",a) -> 0
2172// * strspn(s,"") -> 0
2173// * strcspn(s,a) -> const_int (if both args are constant)
2174// * strcspn("",a) -> 0
2175// * strcspn(s,"") -> strlen(a)
2176//
2177// strstr:
2178// * strstr(x,x) -> x
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002179// * strstr(s1,s2) -> offset_of_s2_in(s1)
Reid Spencer649ac282005-04-28 04:40:06 +00002180// (if s1 and s2 are constant strings)
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002181//
Reid Spencer649ac282005-04-28 04:40:06 +00002182// tan, tanf, tanl:
Reid Spencer649ac282005-04-28 04:40:06 +00002183// * tan(atan(x)) -> x
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002184//
Reid Spencer649ac282005-04-28 04:40:06 +00002185// trunc, truncf, truncl:
2186// * trunc(cnst) -> cnst'
2187//
Jeff Cohen5f4ef3c2005-07-27 06:12:32 +00002188//
Reid Spencer39a762d2005-04-25 02:53:12 +00002189}