It's not necessary to do rounding for alloca operations when the requested
alignment is equal to the stack alignment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40004 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/SimplifyLibCalls.cpp b/lib/Transforms/IPO/SimplifyLibCalls.cpp
new file mode 100644
index 0000000..b0f9128
--- /dev/null
+++ b/lib/Transforms/IPO/SimplifyLibCalls.cpp
@@ -0,0 +1,2021 @@
+//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file was developed by Reid Spencer and is distributed under the
+// University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a module pass that applies a variety of small
+// optimizations for calls to specific well-known function calls (e.g. runtime
+// library functions). For example, a call to the function "exit(3)" that
+// occurs within the main() function can be transformed into a simple "return 3"
+// instruction. Any optimization that takes this form (replace call to library
+// function with simpler code that provides the same result) belongs in this
+// file.
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "simplify-libcalls"
+#include "llvm/Constants.h"
+#include "llvm/DerivedTypes.h"
+#include "llvm/Instructions.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/ADT/hash_map"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Config/config.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Support/Debug.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/Transforms/IPO.h"
+using namespace llvm;
+
+/// This statistic keeps track of the total number of library calls that have
+/// been simplified regardless of which call it is.
+STATISTIC(SimplifiedLibCalls, "Number of library calls simplified");
+
+namespace {
+ // Forward declarations
+ class LibCallOptimization;
+ class SimplifyLibCalls;
+
+/// This list is populated by the constructor for LibCallOptimization class.
+/// Therefore all subclasses are registered here at static initialization time
+/// and this list is what the SimplifyLibCalls pass uses to apply the individual
+/// optimizations to the call sites.
+/// @brief The list of optimizations deriving from LibCallOptimization
+static LibCallOptimization *OptList = 0;
+
+/// This class is the abstract base class for the set of optimizations that
+/// corresponds to one library call. The SimplifyLibCalls pass will call the
+/// ValidateCalledFunction method to ask the optimization if a given Function
+/// is the kind that the optimization can handle. If the subclass returns true,
+/// then SImplifyLibCalls will also call the OptimizeCall method to perform,
+/// or attempt to perform, the optimization(s) for the library call. Otherwise,
+/// OptimizeCall won't be called. Subclasses are responsible for providing the
+/// name of the library call (strlen, strcpy, etc.) to the LibCallOptimization
+/// constructor. This is used to efficiently select which call instructions to
+/// optimize. The criteria for a "lib call" is "anything with well known
+/// semantics", typically a library function that is defined by an international
+/// standard. Because the semantics are well known, the optimizations can
+/// generally short-circuit actually calling the function if there's a simpler
+/// way (e.g. strlen(X) can be reduced to a constant if X is a constant global).
+/// @brief Base class for library call optimizations
+class VISIBILITY_HIDDEN LibCallOptimization {
+ LibCallOptimization **Prev, *Next;
+ const char *FunctionName; ///< Name of the library call we optimize
+#ifndef NDEBUG
+ Statistic occurrences; ///< debug statistic (-debug-only=simplify-libcalls)
+#endif
+public:
+ /// The \p fname argument must be the name of the library function being
+ /// optimized by the subclass.
+ /// @brief Constructor that registers the optimization.
+ LibCallOptimization(const char *FName, const char *Description)
+ : FunctionName(FName) {
+
+#ifndef NDEBUG
+ occurrences.construct("simplify-libcalls", Description);
+#endif
+ // Register this optimizer in the list of optimizations.
+ Next = OptList;
+ OptList = this;
+ Prev = &OptList;
+ if (Next) Next->Prev = &Next;
+ }
+
+ /// getNext - All libcall optimizations are chained together into a list,
+ /// return the next one in the list.
+ LibCallOptimization *getNext() { return Next; }
+
+ /// @brief Deregister from the optlist
+ virtual ~LibCallOptimization() {
+ *Prev = Next;
+ if (Next) Next->Prev = Prev;
+ }
+
+ /// The implementation of this function in subclasses should determine if
+ /// \p F is suitable for the optimization. This method is called by
+ /// SimplifyLibCalls::runOnModule to short circuit visiting all the call
+ /// sites of such a function if that function is not suitable in the first
+ /// place. If the called function is suitabe, this method should return true;
+ /// false, otherwise. This function should also perform any lazy
+ /// initialization that the LibCallOptimization needs to do, if its to return
+ /// true. This avoids doing initialization until the optimizer is actually
+ /// going to be called upon to do some optimization.
+ /// @brief Determine if the function is suitable for optimization
+ virtual bool ValidateCalledFunction(
+ const Function* F, ///< The function that is the target of call sites
+ SimplifyLibCalls& SLC ///< The pass object invoking us
+ ) = 0;
+
+ /// The implementations of this function in subclasses is the heart of the
+ /// SimplifyLibCalls algorithm. Sublcasses of this class implement
+ /// OptimizeCall to determine if (a) the conditions are right for optimizing
+ /// the call and (b) to perform the optimization. If an action is taken
+ /// against ci, the subclass is responsible for returning true and ensuring
+ /// that ci is erased from its parent.
+ /// @brief Optimize a call, if possible.
+ virtual bool OptimizeCall(
+ CallInst* ci, ///< The call instruction that should be optimized.
+ SimplifyLibCalls& SLC ///< The pass object invoking us
+ ) = 0;
+
+ /// @brief Get the name of the library call being optimized
+ const char *getFunctionName() const { return FunctionName; }
+
+ bool ReplaceCallWith(CallInst *CI, Value *V) {
+ if (!CI->use_empty())
+ CI->replaceAllUsesWith(V);
+ CI->eraseFromParent();
+ return true;
+ }
+
+ /// @brief Called by SimplifyLibCalls to update the occurrences statistic.
+ void succeeded() {
+#ifndef NDEBUG
+ DEBUG(++occurrences);
+#endif
+ }
+};
+
+/// This class is an LLVM Pass that applies each of the LibCallOptimization
+/// instances to all the call sites in a module, relatively efficiently. The
+/// purpose of this pass is to provide optimizations for calls to well-known
+/// functions with well-known semantics, such as those in the c library. The
+/// class provides the basic infrastructure for handling runOnModule. Whenever
+/// this pass finds a function call, it asks the appropriate optimizer to
+/// validate the call (ValidateLibraryCall). If it is validated, then
+/// the OptimizeCall method is also called.
+/// @brief A ModulePass for optimizing well-known function calls.
+class VISIBILITY_HIDDEN SimplifyLibCalls : public ModulePass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ SimplifyLibCalls() : ModulePass((intptr_t)&ID) {}
+
+ /// We need some target data for accurate signature details that are
+ /// target dependent. So we require target data in our AnalysisUsage.
+ /// @brief Require TargetData from AnalysisUsage.
+ virtual void getAnalysisUsage(AnalysisUsage& Info) const {
+ // Ask that the TargetData analysis be performed before us so we can use
+ // the target data.
+ Info.addRequired<TargetData>();
+ }
+
+ /// For this pass, process all of the function calls in the module, calling
+ /// ValidateLibraryCall and OptimizeCall as appropriate.
+ /// @brief Run all the lib call optimizations on a Module.
+ virtual bool runOnModule(Module &M) {
+ reset(M);
+
+ bool result = false;
+ hash_map<std::string, LibCallOptimization*> OptznMap;
+ for (LibCallOptimization *Optzn = OptList; Optzn; Optzn = Optzn->getNext())
+ OptznMap[Optzn->getFunctionName()] = Optzn;
+
+ // The call optimizations can be recursive. That is, the optimization might
+ // generate a call to another function which can also be optimized. This way
+ // we make the LibCallOptimization instances very specific to the case they
+ // handle. It also means we need to keep running over the function calls in
+ // the module until we don't get any more optimizations possible.
+ bool found_optimization = false;
+ do {
+ found_optimization = false;
+ for (Module::iterator FI = M.begin(), FE = M.end(); FI != FE; ++FI) {
+ // All the "well-known" functions are external and have external linkage
+ // because they live in a runtime library somewhere and were (probably)
+ // not compiled by LLVM. So, we only act on external functions that
+ // have external or dllimport linkage and non-empty uses.
+ if (!FI->isDeclaration() ||
+ !(FI->hasExternalLinkage() || FI->hasDLLImportLinkage()) ||
+ FI->use_empty())
+ continue;
+
+ // Get the optimization class that pertains to this function
+ hash_map<std::string, LibCallOptimization*>::iterator OMI =
+ OptznMap.find(FI->getName());
+ if (OMI == OptznMap.end()) continue;
+
+ LibCallOptimization *CO = OMI->second;
+
+ // Make sure the called function is suitable for the optimization
+ if (!CO->ValidateCalledFunction(FI, *this))
+ continue;
+
+ // Loop over each of the uses of the function
+ for (Value::use_iterator UI = FI->use_begin(), UE = FI->use_end();
+ UI != UE ; ) {
+ // If the use of the function is a call instruction
+ if (CallInst* CI = dyn_cast<CallInst>(*UI++)) {
+ // Do the optimization on the LibCallOptimization.
+ if (CO->OptimizeCall(CI, *this)) {
+ ++SimplifiedLibCalls;
+ found_optimization = result = true;
+ CO->succeeded();
+ }
+ }
+ }
+ }
+ } while (found_optimization);
+
+ return result;
+ }
+
+ /// @brief Return the *current* module we're working on.
+ Module* getModule() const { return M; }
+
+ /// @brief Return the *current* target data for the module we're working on.
+ TargetData* getTargetData() const { return TD; }
+
+ /// @brief Return the size_t type -- syntactic shortcut
+ const Type* getIntPtrType() const { return TD->getIntPtrType(); }
+
+ /// @brief Return a Function* for the putchar libcall
+ Constant *get_putchar() {
+ if (!putchar_func)
+ putchar_func =
+ M->getOrInsertFunction("putchar", Type::Int32Ty, Type::Int32Ty, NULL);
+ return putchar_func;
+ }
+
+ /// @brief Return a Function* for the puts libcall
+ Constant *get_puts() {
+ if (!puts_func)
+ puts_func = M->getOrInsertFunction("puts", Type::Int32Ty,
+ PointerType::get(Type::Int8Ty),
+ NULL);
+ return puts_func;
+ }
+
+ /// @brief Return a Function* for the fputc libcall
+ Constant *get_fputc(const Type* FILEptr_type) {
+ if (!fputc_func)
+ fputc_func = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
+ FILEptr_type, NULL);
+ return fputc_func;
+ }
+
+ /// @brief Return a Function* for the fputs libcall
+ Constant *get_fputs(const Type* FILEptr_type) {
+ if (!fputs_func)
+ fputs_func = M->getOrInsertFunction("fputs", Type::Int32Ty,
+ PointerType::get(Type::Int8Ty),
+ FILEptr_type, NULL);
+ return fputs_func;
+ }
+
+ /// @brief Return a Function* for the fwrite libcall
+ Constant *get_fwrite(const Type* FILEptr_type) {
+ if (!fwrite_func)
+ fwrite_func = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
+ PointerType::get(Type::Int8Ty),
+ TD->getIntPtrType(),
+ TD->getIntPtrType(),
+ FILEptr_type, NULL);
+ return fwrite_func;
+ }
+
+ /// @brief Return a Function* for the sqrt libcall
+ Constant *get_sqrt() {
+ if (!sqrt_func)
+ sqrt_func = M->getOrInsertFunction("sqrt", Type::DoubleTy,
+ Type::DoubleTy, NULL);
+ return sqrt_func;
+ }
+
+ /// @brief Return a Function* for the strcpy libcall
+ Constant *get_strcpy() {
+ if (!strcpy_func)
+ strcpy_func = M->getOrInsertFunction("strcpy",
+ PointerType::get(Type::Int8Ty),
+ PointerType::get(Type::Int8Ty),
+ PointerType::get(Type::Int8Ty),
+ NULL);
+ return strcpy_func;
+ }
+
+ /// @brief Return a Function* for the strlen libcall
+ Constant *get_strlen() {
+ if (!strlen_func)
+ strlen_func = M->getOrInsertFunction("strlen", TD->getIntPtrType(),
+ PointerType::get(Type::Int8Ty),
+ NULL);
+ return strlen_func;
+ }
+
+ /// @brief Return a Function* for the memchr libcall
+ Constant *get_memchr() {
+ if (!memchr_func)
+ memchr_func = M->getOrInsertFunction("memchr",
+ PointerType::get(Type::Int8Ty),
+ PointerType::get(Type::Int8Ty),
+ Type::Int32Ty, TD->getIntPtrType(),
+ NULL);
+ return memchr_func;
+ }
+
+ /// @brief Return a Function* for the memcpy libcall
+ Constant *get_memcpy() {
+ if (!memcpy_func) {
+ const Type *SBP = PointerType::get(Type::Int8Ty);
+ const char *N = TD->getIntPtrType() == Type::Int32Ty ?
+ "llvm.memcpy.i32" : "llvm.memcpy.i64";
+ memcpy_func = M->getOrInsertFunction(N, Type::VoidTy, SBP, SBP,
+ TD->getIntPtrType(), Type::Int32Ty,
+ NULL);
+ }
+ return memcpy_func;
+ }
+
+ Constant *getUnaryFloatFunction(const char *Name, Constant *&Cache) {
+ if (!Cache)
+ Cache = M->getOrInsertFunction(Name, Type::FloatTy, Type::FloatTy, NULL);
+ return Cache;
+ }
+
+ Constant *get_floorf() { return getUnaryFloatFunction("floorf", floorf_func);}
+ Constant *get_ceilf() { return getUnaryFloatFunction( "ceilf", ceilf_func);}
+ Constant *get_roundf() { return getUnaryFloatFunction("roundf", roundf_func);}
+ Constant *get_rintf() { return getUnaryFloatFunction( "rintf", rintf_func);}
+ Constant *get_nearbyintf() { return getUnaryFloatFunction("nearbyintf",
+ nearbyintf_func); }
+private:
+ /// @brief Reset our cached data for a new Module
+ void reset(Module& mod) {
+ M = &mod;
+ TD = &getAnalysis<TargetData>();
+ putchar_func = 0;
+ puts_func = 0;
+ fputc_func = 0;
+ fputs_func = 0;
+ fwrite_func = 0;
+ memcpy_func = 0;
+ memchr_func = 0;
+ sqrt_func = 0;
+ strcpy_func = 0;
+ strlen_func = 0;
+ floorf_func = 0;
+ ceilf_func = 0;
+ roundf_func = 0;
+ rintf_func = 0;
+ nearbyintf_func = 0;
+ }
+
+private:
+ /// Caches for function pointers.
+ Constant *putchar_func, *puts_func;
+ Constant *fputc_func, *fputs_func, *fwrite_func;
+ Constant *memcpy_func, *memchr_func;
+ Constant *sqrt_func;
+ Constant *strcpy_func, *strlen_func;
+ Constant *floorf_func, *ceilf_func, *roundf_func;
+ Constant *rintf_func, *nearbyintf_func;
+ Module *M; ///< Cached Module
+ TargetData *TD; ///< Cached TargetData
+};
+
+char SimplifyLibCalls::ID = 0;
+// Register the pass
+RegisterPass<SimplifyLibCalls>
+X("simplify-libcalls", "Simplify well-known library calls");
+
+} // anonymous namespace
+
+// The only public symbol in this file which just instantiates the pass object
+ModulePass *llvm::createSimplifyLibCallsPass() {
+ return new SimplifyLibCalls();
+}
+
+// Classes below here, in the anonymous namespace, are all subclasses of the
+// LibCallOptimization class, each implementing all optimizations possible for a
+// single well-known library call. Each has a static singleton instance that
+// auto registers it into the "optlist" global above.
+namespace {
+
+// Forward declare utility functions.
+static bool GetConstantStringInfo(Value *V, std::string &Str);
+static Value *CastToCStr(Value *V, Instruction *IP);
+
+/// This LibCallOptimization will find instances of a call to "exit" that occurs
+/// within the "main" function and change it to a simple "ret" instruction with
+/// the same value passed to the exit function. When this is done, it splits the
+/// basic block at the exit(3) call and deletes the call instruction.
+/// @brief Replace calls to exit in main with a simple return
+struct VISIBILITY_HIDDEN ExitInMainOptimization : public LibCallOptimization {
+ ExitInMainOptimization() : LibCallOptimization("exit",
+ "Number of 'exit' calls simplified") {}
+
+ // Make sure the called function looks like exit (int argument, int return
+ // type, external linkage, not varargs).
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ return F->arg_size() >= 1 && F->arg_begin()->getType()->isInteger();
+ }
+
+ virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
+ // To be careful, we check that the call to exit is coming from "main", that
+ // main has external linkage, and the return type of main and the argument
+ // to exit have the same type.
+ Function *from = ci->getParent()->getParent();
+ if (from->hasExternalLinkage())
+ if (from->getReturnType() == ci->getOperand(1)->getType())
+ if (from->getName() == "main") {
+ // Okay, time to actually do the optimization. First, get the basic
+ // block of the call instruction
+ BasicBlock* bb = ci->getParent();
+
+ // Create a return instruction that we'll replace the call with.
+ // Note that the argument of the return is the argument of the call
+ // instruction.
+ new ReturnInst(ci->getOperand(1), ci);
+
+ // Split the block at the call instruction which places it in a new
+ // basic block.
+ bb->splitBasicBlock(ci);
+
+ // The block split caused a branch instruction to be inserted into
+ // the end of the original block, right after the return instruction
+ // that we put there. That's not a valid block, so delete the branch
+ // instruction.
+ bb->getInstList().pop_back();
+
+ // Now we can finally get rid of the call instruction which now lives
+ // in the new basic block.
+ ci->eraseFromParent();
+
+ // Optimization succeeded, return true.
+ return true;
+ }
+ // We didn't pass the criteria for this optimization so return false
+ return false;
+ }
+} ExitInMainOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strcat library
+/// function. The simplification is possible only if the string being
+/// concatenated is a constant array or a constant expression that results in
+/// a constant string. In this case we can replace it with strlen + llvm.memcpy
+/// of the constant string. Both of these calls are further reduced, if possible
+/// on subsequent passes.
+/// @brief Simplify the strcat library function.
+struct VISIBILITY_HIDDEN StrCatOptimization : public LibCallOptimization {
+public:
+ /// @brief Default constructor
+ StrCatOptimization() : LibCallOptimization("strcat",
+ "Number of 'strcat' calls simplified") {}
+
+public:
+
+ /// @brief Make sure that the "strcat" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 2 &&
+ FT->getReturnType() == PointerType::get(Type::Int8Ty) &&
+ FT->getParamType(0) == FT->getReturnType() &&
+ FT->getParamType(1) == FT->getReturnType();
+ }
+
+ /// @brief Optimize the strcat library function
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // Extract some information from the instruction
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+
+ // Extract the initializer (while making numerous checks) from the
+ // source operand of the call to strcat.
+ std::string SrcStr;
+ if (!GetConstantStringInfo(Src, SrcStr))
+ return false;
+
+ // Handle the simple, do-nothing case
+ if (SrcStr.empty())
+ return ReplaceCallWith(CI, Dst);
+
+ // We need to find the end of the destination string. That's where the
+ // memory is to be moved to. We just generate a call to strlen.
+ CallInst *DstLen = new CallInst(SLC.get_strlen(), Dst,
+ Dst->getName()+".len", CI);
+
+ // Now that we have the destination's length, we must index into the
+ // destination's pointer to get the actual memcpy destination (end of
+ // the string .. we're concatenating).
+ Dst = new GetElementPtrInst(Dst, DstLen, Dst->getName()+".indexed", CI);
+
+ // We have enough information to now generate the memcpy call to
+ // do the concatenation for us.
+ Value *Vals[] = {
+ Dst, Src,
+ ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1), // copy nul byte.
+ ConstantInt::get(Type::Int32Ty, 1) // alignment
+ };
+ new CallInst(SLC.get_memcpy(), Vals, 4, "", CI);
+
+ return ReplaceCallWith(CI, Dst);
+ }
+} StrCatOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strchr library
+/// function. It optimizes out cases where the arguments are both constant
+/// and the result can be determined statically.
+/// @brief Simplify the strcmp library function.
+struct VISIBILITY_HIDDEN StrChrOptimization : public LibCallOptimization {
+public:
+ StrChrOptimization() : LibCallOptimization("strchr",
+ "Number of 'strchr' calls simplified") {}
+
+ /// @brief Make sure that the "strchr" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 2 &&
+ FT->getReturnType() == PointerType::get(Type::Int8Ty) &&
+ FT->getParamType(0) == FT->getReturnType() &&
+ isa<IntegerType>(FT->getParamType(1));
+ }
+
+ /// @brief Perform the strchr optimizations
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // Check that the first argument to strchr is a constant array of sbyte.
+ std::string Str;
+ if (!GetConstantStringInfo(CI->getOperand(1), Str))
+ return false;
+
+ // If the second operand is not constant, just lower this to memchr since we
+ // know the length of the input string.
+ ConstantInt *CSI = dyn_cast<ConstantInt>(CI->getOperand(2));
+ if (!CSI) {
+ Value *Args[3] = {
+ CI->getOperand(1),
+ CI->getOperand(2),
+ ConstantInt::get(SLC.getIntPtrType(), Str.size()+1)
+ };
+ return ReplaceCallWith(CI, new CallInst(SLC.get_memchr(), Args, 3,
+ CI->getName(), CI));
+ }
+
+ // strchr can find the nul character.
+ Str += '\0';
+
+ // Get the character we're looking for
+ char CharValue = CSI->getSExtValue();
+
+ // Compute the offset
+ uint64_t i = 0;
+ while (1) {
+ if (i == Str.size()) // Didn't find the char. strchr returns null.
+ return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
+ // Did we find our match?
+ if (Str[i] == CharValue)
+ break;
+ ++i;
+ }
+
+ // strchr(s+n,c) -> gep(s+n+i,c)
+ // (if c is a constant integer and s is a constant string)
+ Value *Idx = ConstantInt::get(Type::Int64Ty, i);
+ Value *GEP = new GetElementPtrInst(CI->getOperand(1), Idx,
+ CI->getOperand(1)->getName() +
+ ".strchr", CI);
+ return ReplaceCallWith(CI, GEP);
+ }
+} StrChrOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strcmp library
+/// function. It optimizes out cases where one or both arguments are constant
+/// and the result can be determined statically.
+/// @brief Simplify the strcmp library function.
+struct VISIBILITY_HIDDEN StrCmpOptimization : public LibCallOptimization {
+public:
+ StrCmpOptimization() : LibCallOptimization("strcmp",
+ "Number of 'strcmp' calls simplified") {}
+
+ /// @brief Make sure that the "strcmp" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 2 &&
+ FT->getParamType(0) == FT->getParamType(1) &&
+ FT->getParamType(0) == PointerType::get(Type::Int8Ty);
+ }
+
+ /// @brief Perform the strcmp optimization
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // First, check to see if src and destination are the same. If they are,
+ // then the optimization is to replace the CallInst with a constant 0
+ // because the call is a no-op.
+ Value *Str1P = CI->getOperand(1);
+ Value *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strcmp(x,x) -> 0
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
+
+ std::string Str1;
+ if (!GetConstantStringInfo(Str1P, Str1))
+ return false;
+ if (Str1.empty()) {
+ // strcmp("", x) -> *x
+ Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
+ V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
+ return ReplaceCallWith(CI, V);
+ }
+
+ std::string Str2;
+ if (!GetConstantStringInfo(Str2P, Str2))
+ return false;
+ if (Str2.empty()) {
+ // strcmp(x,"") -> *x
+ Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
+ V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
+ return ReplaceCallWith(CI, V);
+ }
+
+ // strcmp(x, y) -> cnst (if both x and y are constant strings)
+ int R = strcmp(Str1.c_str(), Str2.c_str());
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
+ }
+} StrCmpOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strncmp library
+/// function. It optimizes out cases where one or both arguments are constant
+/// and the result can be determined statically.
+/// @brief Simplify the strncmp library function.
+struct VISIBILITY_HIDDEN StrNCmpOptimization : public LibCallOptimization {
+public:
+ StrNCmpOptimization() : LibCallOptimization("strncmp",
+ "Number of 'strncmp' calls simplified") {}
+
+ /// @brief Make sure that the "strncmp" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getReturnType() == Type::Int32Ty && FT->getNumParams() == 3 &&
+ FT->getParamType(0) == FT->getParamType(1) &&
+ FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
+ isa<IntegerType>(FT->getParamType(2));
+ return false;
+ }
+
+ /// @brief Perform the strncmp optimization
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // First, check to see if src and destination are the same. If they are,
+ // then the optimization is to replace the CallInst with a constant 0
+ // because the call is a no-op.
+ Value *Str1P = CI->getOperand(1);
+ Value *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strncmp(x,x, n) -> 0
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
+
+ // Check the length argument, if it is Constant zero then the strings are
+ // considered equal.
+ uint64_t Length;
+ if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
+ Length = LengthArg->getZExtValue();
+ else
+ return false;
+
+ if (Length == 0) // strncmp(x,y,0) -> 0
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
+
+ std::string Str1;
+ if (!GetConstantStringInfo(Str1P, Str1))
+ return false;
+ if (Str1.empty()) {
+ // strncmp("", x, n) -> *x
+ Value *V = new LoadInst(Str2P, CI->getName()+".load", CI);
+ V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
+ return ReplaceCallWith(CI, V);
+ }
+
+ std::string Str2;
+ if (!GetConstantStringInfo(Str2P, Str2))
+ return false;
+ if (Str2.empty()) {
+ // strncmp(x, "", n) -> *x
+ Value *V = new LoadInst(Str1P, CI->getName()+".load", CI);
+ V = new ZExtInst(V, CI->getType(), CI->getName()+".int", CI);
+ return ReplaceCallWith(CI, V);
+ }
+
+ // strncmp(x, y, n) -> cnst (if both x and y are constant strings)
+ int R = strncmp(Str1.c_str(), Str2.c_str(), Length);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), R));
+ }
+} StrNCmpOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strcpy library
+/// function. Two optimizations are possible:
+/// (1) If src and dest are the same and not volatile, just return dest
+/// (2) If the src is a constant then we can convert to llvm.memmove
+/// @brief Simplify the strcpy library function.
+struct VISIBILITY_HIDDEN StrCpyOptimization : public LibCallOptimization {
+public:
+ StrCpyOptimization() : LibCallOptimization("strcpy",
+ "Number of 'strcpy' calls simplified") {}
+
+ /// @brief Make sure that the "strcpy" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 2 &&
+ FT->getParamType(0) == FT->getParamType(1) &&
+ FT->getReturnType() == FT->getParamType(0) &&
+ FT->getParamType(0) == PointerType::get(Type::Int8Ty);
+ }
+
+ /// @brief Perform the strcpy optimization
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // First, check to see if src and destination are the same. If they are,
+ // then the optimization is to replace the CallInst with the destination
+ // because the call is a no-op. Note that this corresponds to the
+ // degenerate strcpy(X,X) case which should have "undefined" results
+ // according to the C specification. However, it occurs sometimes and
+ // we optimize it as a no-op.
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+ if (Dst == Src) {
+ // strcpy(x, x) -> x
+ return ReplaceCallWith(CI, Dst);
+ }
+
+ // Get the length of the constant string referenced by the Src operand.
+ std::string SrcStr;
+ if (!GetConstantStringInfo(Src, SrcStr))
+ return false;
+
+ // If the constant string's length is zero we can optimize this by just
+ // doing a store of 0 at the first byte of the destination
+ if (SrcStr.size() == 0) {
+ new StoreInst(ConstantInt::get(Type::Int8Ty, 0), Dst, CI);
+ return ReplaceCallWith(CI, Dst);
+ }
+
+ // We have enough information to now generate the memcpy call to
+ // do the concatenation for us.
+ Value *MemcpyOps[] = {
+ Dst, Src, // Pass length including nul byte.
+ ConstantInt::get(SLC.getIntPtrType(), SrcStr.size()+1),
+ ConstantInt::get(Type::Int32Ty, 1) // alignment
+ };
+ new CallInst(SLC.get_memcpy(), MemcpyOps, 4, "", CI);
+
+ return ReplaceCallWith(CI, Dst);
+ }
+} StrCpyOptimizer;
+
+/// This LibCallOptimization will simplify a call to the strlen library
+/// function by replacing it with a constant value if the string provided to
+/// it is a constant array.
+/// @brief Simplify the strlen library function.
+struct VISIBILITY_HIDDEN StrLenOptimization : public LibCallOptimization {
+ StrLenOptimization() : LibCallOptimization("strlen",
+ "Number of 'strlen' calls simplified") {}
+
+ /// @brief Make sure that the "strlen" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 1 &&
+ FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
+ isa<IntegerType>(FT->getReturnType());
+ }
+
+ /// @brief Perform the strlen optimization
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // Make sure we're dealing with an sbyte* here.
+ Value *Src = CI->getOperand(1);
+
+ // Does the call to strlen have exactly one use?
+ if (CI->hasOneUse()) {
+ // Is that single use a icmp operator?
+ if (ICmpInst *Cmp = dyn_cast<ICmpInst>(CI->use_back()))
+ // Is it compared against a constant integer?
+ if (ConstantInt *Cst = dyn_cast<ConstantInt>(Cmp->getOperand(1))) {
+ // If its compared against length 0 with == or !=
+ if (Cst->getZExtValue() == 0 && Cmp->isEquality()) {
+ // strlen(x) != 0 -> *x != 0
+ // strlen(x) == 0 -> *x == 0
+ Value *V = new LoadInst(Src, Src->getName()+".first", CI);
+ V = new ICmpInst(Cmp->getPredicate(), V,
+ ConstantInt::get(Type::Int8Ty, 0),
+ Cmp->getName()+".strlen", CI);
+ Cmp->replaceAllUsesWith(V);
+ Cmp->eraseFromParent();
+ return ReplaceCallWith(CI, 0); // no uses.
+ }
+ }
+ }
+
+ // Get the length of the constant string operand
+ std::string Str;
+ if (!GetConstantStringInfo(Src, Str))
+ return false;
+
+ // strlen("xyz") -> 3 (for example)
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), Str.size()));
+ }
+} StrLenOptimizer;
+
+/// IsOnlyUsedInEqualsComparison - Return true if it only matters that the value
+/// is equal or not-equal to zero.
+static bool IsOnlyUsedInEqualsZeroComparison(Instruction *I) {
+ for (Value::use_iterator UI = I->use_begin(), E = I->use_end();
+ UI != E; ++UI) {
+ if (ICmpInst *IC = dyn_cast<ICmpInst>(*UI))
+ if (IC->isEquality())
+ if (Constant *C = dyn_cast<Constant>(IC->getOperand(1)))
+ if (C->isNullValue())
+ continue;
+ // Unknown instruction.
+ return false;
+ }
+ return true;
+}
+
+/// This memcmpOptimization will simplify a call to the memcmp library
+/// function.
+struct VISIBILITY_HIDDEN memcmpOptimization : public LibCallOptimization {
+ /// @brief Default Constructor
+ memcmpOptimization()
+ : LibCallOptimization("memcmp", "Number of 'memcmp' calls simplified") {}
+
+ /// @brief Make sure that the "memcmp" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
+ Function::const_arg_iterator AI = F->arg_begin();
+ if (F->arg_size() != 3 || !isa<PointerType>(AI->getType())) return false;
+ if (!isa<PointerType>((++AI)->getType())) return false;
+ if (!(++AI)->getType()->isInteger()) return false;
+ if (!F->getReturnType()->isInteger()) return false;
+ return true;
+ }
+
+ /// Because of alignment and instruction information that we don't have, we
+ /// leave the bulk of this to the code generators.
+ ///
+ /// Note that we could do much more if we could force alignment on otherwise
+ /// small aligned allocas, or if we could indicate that loads have a small
+ /// alignment.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &TD) {
+ Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
+
+ // If the two operands are the same, return zero.
+ if (LHS == RHS) {
+ // memcmp(s,s,x) -> 0
+ return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
+ }
+
+ // Make sure we have a constant length.
+ ConstantInt *LenC = dyn_cast<ConstantInt>(CI->getOperand(3));
+ if (!LenC) return false;
+ uint64_t Len = LenC->getZExtValue();
+
+ // If the length is zero, this returns 0.
+ switch (Len) {
+ case 0:
+ // memcmp(s1,s2,0) -> 0
+ return ReplaceCallWith(CI, Constant::getNullValue(CI->getType()));
+ case 1: {
+ // memcmp(S1,S2,1) -> *(ubyte*)S1 - *(ubyte*)S2
+ const Type *UCharPtr = PointerType::get(Type::Int8Ty);
+ CastInst *Op1Cast = CastInst::create(
+ Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
+ CastInst *Op2Cast = CastInst::create(
+ Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
+ Value *S1V = new LoadInst(Op1Cast, LHS->getName()+".val", CI);
+ Value *S2V = new LoadInst(Op2Cast, RHS->getName()+".val", CI);
+ Value *RV = BinaryOperator::createSub(S1V, S2V, CI->getName()+".diff",CI);
+ if (RV->getType() != CI->getType())
+ RV = CastInst::createIntegerCast(RV, CI->getType(), false,
+ RV->getName(), CI);
+ return ReplaceCallWith(CI, RV);
+ }
+ case 2:
+ if (IsOnlyUsedInEqualsZeroComparison(CI)) {
+ // TODO: IF both are aligned, use a short load/compare.
+
+ // memcmp(S1,S2,2) -> S1[0]-S2[0] | S1[1]-S2[1] iff only ==/!= 0 matters
+ const Type *UCharPtr = PointerType::get(Type::Int8Ty);
+ CastInst *Op1Cast = CastInst::create(
+ Instruction::BitCast, LHS, UCharPtr, LHS->getName(), CI);
+ CastInst *Op2Cast = CastInst::create(
+ Instruction::BitCast, RHS, UCharPtr, RHS->getName(), CI);
+ Value *S1V1 = new LoadInst(Op1Cast, LHS->getName()+".val1", CI);
+ Value *S2V1 = new LoadInst(Op2Cast, RHS->getName()+".val1", CI);
+ Value *D1 = BinaryOperator::createSub(S1V1, S2V1,
+ CI->getName()+".d1", CI);
+ Constant *One = ConstantInt::get(Type::Int32Ty, 1);
+ Value *G1 = new GetElementPtrInst(Op1Cast, One, "next1v", CI);
+ Value *G2 = new GetElementPtrInst(Op2Cast, One, "next2v", CI);
+ Value *S1V2 = new LoadInst(G1, LHS->getName()+".val2", CI);
+ Value *S2V2 = new LoadInst(G2, RHS->getName()+".val2", CI);
+ Value *D2 = BinaryOperator::createSub(S1V2, S2V2,
+ CI->getName()+".d1", CI);
+ Value *Or = BinaryOperator::createOr(D1, D2, CI->getName()+".res", CI);
+ if (Or->getType() != CI->getType())
+ Or = CastInst::createIntegerCast(Or, CI->getType(), false /*ZExt*/,
+ Or->getName(), CI);
+ return ReplaceCallWith(CI, Or);
+ }
+ break;
+ default:
+ break;
+ }
+
+ return false;
+ }
+} memcmpOptimizer;
+
+
+/// This LibCallOptimization will simplify a call to the memcpy library
+/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
+/// bytes depending on the length of the string and the alignment. Additional
+/// optimizations are possible in code generation (sequence of immediate store)
+/// @brief Simplify the memcpy library function.
+struct VISIBILITY_HIDDEN LLVMMemCpyMoveOptzn : public LibCallOptimization {
+ LLVMMemCpyMoveOptzn(const char* fname, const char* desc)
+ : LibCallOptimization(fname, desc) {}
+
+ /// @brief Make sure that the "memcpy" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& TD) {
+ // Just make sure this has 4 arguments per LLVM spec.
+ return (f->arg_size() == 4);
+ }
+
+ /// Because of alignment and instruction information that we don't have, we
+ /// leave the bulk of this to the code generators. The optimization here just
+ /// deals with a few degenerate cases where the length of the string and the
+ /// alignment match the sizes of our intrinsic types so we can do a load and
+ /// store instead of the memcpy call.
+ /// @brief Perform the memcpy optimization.
+ virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& TD) {
+ // Make sure we have constant int values to work with
+ ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
+ if (!LEN)
+ return false;
+ ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
+ if (!ALIGN)
+ return false;
+
+ // If the length is larger than the alignment, we can't optimize
+ uint64_t len = LEN->getZExtValue();
+ uint64_t alignment = ALIGN->getZExtValue();
+ if (alignment == 0)
+ alignment = 1; // Alignment 0 is identity for alignment 1
+ if (len > alignment)
+ return false;
+
+ // Get the type we will cast to, based on size of the string
+ Value* dest = ci->getOperand(1);
+ Value* src = ci->getOperand(2);
+ const Type* castType = 0;
+ switch (len) {
+ case 0:
+ // memcpy(d,s,0,a) -> d
+ return ReplaceCallWith(ci, 0);
+ case 1: castType = Type::Int8Ty; break;
+ case 2: castType = Type::Int16Ty; break;
+ case 4: castType = Type::Int32Ty; break;
+ case 8: castType = Type::Int64Ty; break;
+ default:
+ return false;
+ }
+
+ // Cast source and dest to the right sized primitive and then load/store
+ CastInst* SrcCast = CastInst::create(Instruction::BitCast,
+ src, PointerType::get(castType), src->getName()+".cast", ci);
+ CastInst* DestCast = CastInst::create(Instruction::BitCast,
+ dest, PointerType::get(castType),dest->getName()+".cast", ci);
+ LoadInst* LI = new LoadInst(SrcCast,SrcCast->getName()+".val",ci);
+ new StoreInst(LI, DestCast, ci);
+ return ReplaceCallWith(ci, 0);
+ }
+};
+
+/// This LibCallOptimization will simplify a call to the memcpy/memmove library
+/// functions.
+LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer32("llvm.memcpy.i32",
+ "Number of 'llvm.memcpy' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemCpyOptimizer64("llvm.memcpy.i64",
+ "Number of 'llvm.memcpy' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer32("llvm.memmove.i32",
+ "Number of 'llvm.memmove' calls simplified");
+LLVMMemCpyMoveOptzn LLVMMemMoveOptimizer64("llvm.memmove.i64",
+ "Number of 'llvm.memmove' calls simplified");
+
+/// This LibCallOptimization will simplify a call to the memset library
+/// function by expanding it out to a single store of size 0, 1, 2, 4, or 8
+/// bytes depending on the length argument.
+struct VISIBILITY_HIDDEN LLVMMemSetOptimization : public LibCallOptimization {
+ /// @brief Default Constructor
+ LLVMMemSetOptimization(const char *Name) : LibCallOptimization(Name,
+ "Number of 'llvm.memset' calls simplified") {}
+
+ /// @brief Make sure that the "memset" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &TD) {
+ // Just make sure this has 3 arguments per LLVM spec.
+ return F->arg_size() == 4;
+ }
+
+ /// Because of alignment and instruction information that we don't have, we
+ /// leave the bulk of this to the code generators. The optimization here just
+ /// deals with a few degenerate cases where the length parameter is constant
+ /// and the alignment matches the sizes of our intrinsic types so we can do
+ /// store instead of the memcpy call. Other calls are transformed into the
+ /// llvm.memset intrinsic.
+ /// @brief Perform the memset optimization.
+ virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &TD) {
+ // Make sure we have constant int values to work with
+ ConstantInt* LEN = dyn_cast<ConstantInt>(ci->getOperand(3));
+ if (!LEN)
+ return false;
+ ConstantInt* ALIGN = dyn_cast<ConstantInt>(ci->getOperand(4));
+ if (!ALIGN)
+ return false;
+
+ // Extract the length and alignment
+ uint64_t len = LEN->getZExtValue();
+ uint64_t alignment = ALIGN->getZExtValue();
+
+ // Alignment 0 is identity for alignment 1
+ if (alignment == 0)
+ alignment = 1;
+
+ // If the length is zero, this is a no-op
+ if (len == 0) {
+ // memset(d,c,0,a) -> noop
+ return ReplaceCallWith(ci, 0);
+ }
+
+ // If the length is larger than the alignment, we can't optimize
+ if (len > alignment)
+ return false;
+
+ // Make sure we have a constant ubyte to work with so we can extract
+ // the value to be filled.
+ ConstantInt* FILL = dyn_cast<ConstantInt>(ci->getOperand(2));
+ if (!FILL)
+ return false;
+ if (FILL->getType() != Type::Int8Ty)
+ return false;
+
+ // memset(s,c,n) -> store s, c (for n=1,2,4,8)
+
+ // Extract the fill character
+ uint64_t fill_char = FILL->getZExtValue();
+ uint64_t fill_value = fill_char;
+
+ // Get the type we will cast to, based on size of memory area to fill, and
+ // and the value we will store there.
+ Value* dest = ci->getOperand(1);
+ const Type* castType = 0;
+ switch (len) {
+ case 1:
+ castType = Type::Int8Ty;
+ break;
+ case 2:
+ castType = Type::Int16Ty;
+ fill_value |= fill_char << 8;
+ break;
+ case 4:
+ castType = Type::Int32Ty;
+ fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
+ break;
+ case 8:
+ castType = Type::Int64Ty;
+ fill_value |= fill_char << 8 | fill_char << 16 | fill_char << 24;
+ fill_value |= fill_char << 32 | fill_char << 40 | fill_char << 48;
+ fill_value |= fill_char << 56;
+ break;
+ default:
+ return false;
+ }
+
+ // Cast dest to the right sized primitive and then load/store
+ CastInst* DestCast = new BitCastInst(dest, PointerType::get(castType),
+ dest->getName()+".cast", ci);
+ new StoreInst(ConstantInt::get(castType,fill_value),DestCast, ci);
+ return ReplaceCallWith(ci, 0);
+ }
+};
+
+LLVMMemSetOptimization MemSet32Optimizer("llvm.memset.i32");
+LLVMMemSetOptimization MemSet64Optimizer("llvm.memset.i64");
+
+
+/// This LibCallOptimization will simplify calls to the "pow" library
+/// function. It looks for cases where the result of pow is well known and
+/// substitutes the appropriate value.
+/// @brief Simplify the pow library function.
+struct VISIBILITY_HIDDEN PowOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ PowOptimization() : LibCallOptimization("pow",
+ "Number of 'pow' calls simplified") {}
+
+ /// @brief Make sure that the "pow" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+ // Just make sure this has 2 arguments
+ return (f->arg_size() == 2);
+ }
+
+ /// @brief Perform the pow optimization.
+ virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+ const Type *Ty = cast<Function>(ci->getOperand(0))->getReturnType();
+ Value* base = ci->getOperand(1);
+ Value* expn = ci->getOperand(2);
+ if (ConstantFP *Op1 = dyn_cast<ConstantFP>(base)) {
+ double Op1V = Op1->getValue();
+ if (Op1V == 1.0) // pow(1.0,x) -> 1.0
+ return ReplaceCallWith(ci, ConstantFP::get(Ty, 1.0));
+ } else if (ConstantFP* Op2 = dyn_cast<ConstantFP>(expn)) {
+ double Op2V = Op2->getValue();
+ if (Op2V == 0.0) {
+ // pow(x,0.0) -> 1.0
+ return ReplaceCallWith(ci, ConstantFP::get(Ty,1.0));
+ } else if (Op2V == 0.5) {
+ // pow(x,0.5) -> sqrt(x)
+ CallInst* sqrt_inst = new CallInst(SLC.get_sqrt(), base,
+ ci->getName()+".pow",ci);
+ return ReplaceCallWith(ci, sqrt_inst);
+ } else if (Op2V == 1.0) {
+ // pow(x,1.0) -> x
+ return ReplaceCallWith(ci, base);
+ } else if (Op2V == -1.0) {
+ // pow(x,-1.0) -> 1.0/x
+ Value *div_inst =
+ BinaryOperator::createFDiv(ConstantFP::get(Ty, 1.0), base,
+ ci->getName()+".pow", ci);
+ return ReplaceCallWith(ci, div_inst);
+ }
+ }
+ return false; // opt failed
+ }
+} PowOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "printf" library
+/// function. It looks for cases where the result of printf is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the printf library function.
+struct VISIBILITY_HIDDEN PrintfOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ PrintfOptimization() : LibCallOptimization("printf",
+ "Number of 'printf' calls simplified") {}
+
+ /// @brief Make sure that the "printf" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ // Just make sure this has at least 1 argument and returns an integer or
+ // void type.
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() >= 1 &&
+ (isa<IntegerType>(FT->getReturnType()) ||
+ FT->getReturnType() == Type::VoidTy);
+ }
+
+ /// @brief Perform the printf optimization.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // All the optimizations depend on the length of the first argument and the
+ // fact that it is a constant string array. Check that now
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
+ return false;
+
+ // If this is a simple constant string with no format specifiers that ends
+ // with a \n, turn it into a puts call.
+ if (FormatStr.empty()) {
+ // Tolerate printf's declared void.
+ if (CI->use_empty()) return ReplaceCallWith(CI, 0);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
+ }
+
+ if (FormatStr.size() == 1) {
+ // Turn this into a putchar call, even if it is a %.
+ Value *V = ConstantInt::get(Type::Int32Ty, FormatStr[0]);
+ new CallInst(SLC.get_putchar(), V, "", CI);
+ if (CI->use_empty()) return ReplaceCallWith(CI, 0);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
+ }
+
+ // Check to see if the format str is something like "foo\n", in which case
+ // we convert it to a puts call. We don't allow it to contain any format
+ // characters.
+ if (FormatStr[FormatStr.size()-1] == '\n' &&
+ FormatStr.find('%') == std::string::npos) {
+ // Create a string literal with no \n on it. We expect the constant merge
+ // pass to be run after this pass, to merge duplicate strings.
+ FormatStr.erase(FormatStr.end()-1);
+ Constant *Init = ConstantArray::get(FormatStr, true);
+ Constant *GV = new GlobalVariable(Init->getType(), true,
+ GlobalVariable::InternalLinkage,
+ Init, "str",
+ CI->getParent()->getParent()->getParent());
+ // Cast GV to be a pointer to char.
+ GV = ConstantExpr::getBitCast(GV, PointerType::get(Type::Int8Ty));
+ new CallInst(SLC.get_puts(), GV, "", CI);
+
+ if (CI->use_empty()) return ReplaceCallWith(CI, 0);
+ return ReplaceCallWith(CI,
+ ConstantInt::get(CI->getType(), FormatStr.size()));
+ }
+
+
+ // Only support %c or "%s\n" for now.
+ if (FormatStr.size() < 2 || FormatStr[0] != '%')
+ return false;
+
+ // Get the second character and switch on its value
+ switch (FormatStr[1]) {
+ default: return false;
+ case 's':
+ if (FormatStr != "%s\n" || CI->getNumOperands() < 3 ||
+ // TODO: could insert strlen call to compute string length.
+ !CI->use_empty())
+ return false;
+
+ // printf("%s\n",str) -> puts(str)
+ new CallInst(SLC.get_puts(), CastToCStr(CI->getOperand(2), CI),
+ CI->getName(), CI);
+ return ReplaceCallWith(CI, 0);
+ case 'c': {
+ // printf("%c",c) -> putchar(c)
+ if (FormatStr.size() != 2 || CI->getNumOperands() < 3)
+ return false;
+
+ Value *V = CI->getOperand(2);
+ if (!isa<IntegerType>(V->getType()) ||
+ cast<IntegerType>(V->getType())->getBitWidth() > 32)
+ return false;
+
+ V = CastInst::createZExtOrBitCast(V, Type::Int32Ty, CI->getName()+".int",
+ CI);
+ new CallInst(SLC.get_putchar(), V, "", CI);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
+ }
+ }
+ }
+} PrintfOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "fprintf" library
+/// function. It looks for cases where the result of fprintf is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the fprintf library function.
+struct VISIBILITY_HIDDEN FPrintFOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ FPrintFOptimization() : LibCallOptimization("fprintf",
+ "Number of 'fprintf' calls simplified") {}
+
+ /// @brief Make sure that the "fprintf" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 2 && // two fixed arguments.
+ FT->getParamType(1) == PointerType::get(Type::Int8Ty) &&
+ isa<PointerType>(FT->getParamType(0)) &&
+ isa<IntegerType>(FT->getReturnType());
+ }
+
+ /// @brief Perform the fprintf optimization.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // If the call has more than 3 operands, we can't optimize it
+ if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
+ return false;
+
+ // All the optimizations depend on the format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ // If this is just a format string, turn it into fwrite.
+ if (CI->getNumOperands() == 3) {
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%')
+ return false; // we found a format specifier
+
+ // fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),file)
+ const Type *FILEty = CI->getOperand(1)->getType();
+
+ Value *FWriteArgs[] = {
+ CI->getOperand(2),
+ ConstantInt::get(SLC.getIntPtrType(), FormatStr.size()),
+ ConstantInt::get(SLC.getIntPtrType(), 1),
+ CI->getOperand(1)
+ };
+ new CallInst(SLC.get_fwrite(FILEty), FWriteArgs, 4, CI->getName(), CI);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
+ FormatStr.size()));
+ }
+
+ // The remaining optimizations require the format string to be length 2:
+ // "%s" or "%c".
+ if (FormatStr.size() != 2 || FormatStr[0] != '%')
+ return false;
+
+ // Get the second character and switch on its value
+ switch (FormatStr[1]) {
+ case 'c': {
+ // fprintf(file,"%c",c) -> fputc(c,file)
+ const Type *FILETy = CI->getOperand(1)->getType();
+ Value *C = CastInst::createZExtOrBitCast(CI->getOperand(3), Type::Int32Ty,
+ CI->getName()+".int", CI);
+ new CallInst(SLC.get_fputc(FILETy), C, CI->getOperand(1), "", CI);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
+ }
+ case 's': {
+ const Type *FILETy = CI->getOperand(1)->getType();
+
+ // If the result of the fprintf call is used, we can't do this.
+ // TODO: we should insert a strlen call.
+ if (!CI->use_empty())
+ return false;
+
+ // fprintf(file,"%s",str) -> fputs(str,file)
+ new CallInst(SLC.get_fputs(FILETy), CastToCStr(CI->getOperand(3), CI),
+ CI->getOperand(1), CI->getName(), CI);
+ return ReplaceCallWith(CI, 0);
+ }
+ default:
+ return false;
+ }
+ }
+} FPrintFOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "sprintf" library
+/// function. It looks for cases where the result of sprintf is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the sprintf library function.
+struct VISIBILITY_HIDDEN SPrintFOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ SPrintFOptimization() : LibCallOptimization("sprintf",
+ "Number of 'sprintf' calls simplified") {}
+
+ /// @brief Make sure that the "sprintf" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 2 && // two fixed arguments.
+ FT->getParamType(1) == PointerType::get(Type::Int8Ty) &&
+ FT->getParamType(0) == FT->getParamType(1) &&
+ isa<IntegerType>(FT->getReturnType());
+ }
+
+ /// @brief Perform the sprintf optimization.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // If the call has more than 3 operands, we can't optimize it
+ if (CI->getNumOperands() != 3 && CI->getNumOperands() != 4)
+ return false;
+
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ if (CI->getNumOperands() == 3) {
+ // Make sure there's no % in the constant array
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%')
+ return false; // we found a format specifier
+
+ // sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
+ Value *MemCpyArgs[] = {
+ CI->getOperand(1), CI->getOperand(2),
+ ConstantInt::get(SLC.getIntPtrType(),
+ FormatStr.size()+1), // Copy the nul byte.
+ ConstantInt::get(Type::Int32Ty, 1)
+ };
+ new CallInst(SLC.get_memcpy(), MemCpyArgs, 4, "", CI);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(),
+ FormatStr.size()));
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c".
+ if (FormatStr.size() != 2 || FormatStr[0] != '%')
+ return false;
+
+ // Get the second character and switch on its value
+ switch (FormatStr[1]) {
+ case 'c': {
+ // sprintf(dest,"%c",chr) -> store chr, dest
+ Value *V = CastInst::createTruncOrBitCast(CI->getOperand(3),
+ Type::Int8Ty, "char", CI);
+ new StoreInst(V, CI->getOperand(1), CI);
+ Value *Ptr = new GetElementPtrInst(CI->getOperand(1),
+ ConstantInt::get(Type::Int32Ty, 1),
+ CI->getOperand(1)->getName()+".end",
+ CI);
+ new StoreInst(ConstantInt::get(Type::Int8Ty,0), Ptr, CI);
+ return ReplaceCallWith(CI, ConstantInt::get(Type::Int32Ty, 1));
+ }
+ case 's': {
+ // sprintf(dest,"%s",str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
+ Value *Len = new CallInst(SLC.get_strlen(),
+ CastToCStr(CI->getOperand(3), CI),
+ CI->getOperand(3)->getName()+".len", CI);
+ Value *UnincLen = Len;
+ Len = BinaryOperator::createAdd(Len, ConstantInt::get(Len->getType(), 1),
+ Len->getName()+"1", CI);
+ Value *MemcpyArgs[4] = {
+ CI->getOperand(1),
+ CastToCStr(CI->getOperand(3), CI),
+ Len,
+ ConstantInt::get(Type::Int32Ty, 1)
+ };
+ new CallInst(SLC.get_memcpy(), MemcpyArgs, 4, "", CI);
+
+ // The strlen result is the unincremented number of bytes in the string.
+ if (!CI->use_empty()) {
+ if (UnincLen->getType() != CI->getType())
+ UnincLen = CastInst::createIntegerCast(UnincLen, CI->getType(), false,
+ Len->getName(), CI);
+ CI->replaceAllUsesWith(UnincLen);
+ }
+ return ReplaceCallWith(CI, 0);
+ }
+ }
+ return false;
+ }
+} SPrintFOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "fputs" library
+/// function. It looks for cases where the result of fputs is not used and the
+/// operation can be reduced to something simpler.
+/// @brief Simplify the fputs library function.
+struct VISIBILITY_HIDDEN FPutsOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ FPutsOptimization() : LibCallOptimization("fputs",
+ "Number of 'fputs' calls simplified") {}
+
+ /// @brief Make sure that the "fputs" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ // Just make sure this has 2 arguments
+ return F->arg_size() == 2;
+ }
+
+ /// @brief Perform the fputs optimization.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // If the result is used, none of these optimizations work.
+ if (!CI->use_empty())
+ return false;
+
+ // All the optimizations depend on the length of the first argument and the
+ // fact that it is a constant string array. Check that now
+ std::string Str;
+ if (!GetConstantStringInfo(CI->getOperand(1), Str))
+ return false;
+
+ const Type *FILETy = CI->getOperand(2)->getType();
+ // fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
+ Value *FWriteParms[4] = {
+ CI->getOperand(1),
+ ConstantInt::get(SLC.getIntPtrType(), Str.size()),
+ ConstantInt::get(SLC.getIntPtrType(), 1),
+ CI->getOperand(2)
+ };
+ new CallInst(SLC.get_fwrite(FILETy), FWriteParms, 4, "", CI);
+ return ReplaceCallWith(CI, 0); // Known to have no uses (see above).
+ }
+} FPutsOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "fwrite" function.
+struct VISIBILITY_HIDDEN FWriteOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ FWriteOptimization() : LibCallOptimization("fwrite",
+ "Number of 'fwrite' calls simplified") {}
+
+ /// @brief Make sure that the "fputs" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ const FunctionType *FT = F->getFunctionType();
+ return FT->getNumParams() == 4 &&
+ FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
+ FT->getParamType(1) == FT->getParamType(2) &&
+ isa<IntegerType>(FT->getParamType(1)) &&
+ isa<PointerType>(FT->getParamType(3)) &&
+ isa<IntegerType>(FT->getReturnType());
+ }
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // Get the element size and count.
+ uint64_t EltSize, EltCount;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
+ EltSize = C->getZExtValue();
+ else
+ return false;
+ if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
+ EltCount = C->getZExtValue();
+ else
+ return false;
+
+ // If this is writing zero records, remove the call (it's a noop).
+ if (EltSize * EltCount == 0)
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
+
+ // If this is writing one byte, turn it into fputc.
+ if (EltSize == 1 && EltCount == 1) {
+ // fwrite(s,1,1,F) -> fputc(s[0],F)
+ Value *Ptr = CI->getOperand(1);
+ Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
+ Val = new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI);
+ const Type *FILETy = CI->getOperand(4)->getType();
+ new CallInst(SLC.get_fputc(FILETy), Val, CI->getOperand(4), "", CI);
+ return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
+ }
+ return false;
+ }
+} FWriteOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "isdigit" library
+/// function. It simply does range checks the parameter explicitly.
+/// @brief Simplify the isdigit library function.
+struct VISIBILITY_HIDDEN isdigitOptimization : public LibCallOptimization {
+public:
+ isdigitOptimization() : LibCallOptimization("isdigit",
+ "Number of 'isdigit' calls simplified") {}
+
+ /// @brief Make sure that the "isdigit" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+ // Just make sure this has 1 argument
+ return (f->arg_size() == 1);
+ }
+
+ /// @brief Perform the toascii optimization.
+ virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+ if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1))) {
+ // isdigit(c) -> 0 or 1, if 'c' is constant
+ uint64_t val = CI->getZExtValue();
+ if (val >= '0' && val <= '9')
+ return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 1));
+ else
+ return ReplaceCallWith(ci, ConstantInt::get(Type::Int32Ty, 0));
+ }
+
+ // isdigit(c) -> (unsigned)c - '0' <= 9
+ CastInst* cast = CastInst::createIntegerCast(ci->getOperand(1),
+ Type::Int32Ty, false/*ZExt*/, ci->getOperand(1)->getName()+".uint", ci);
+ BinaryOperator* sub_inst = BinaryOperator::createSub(cast,
+ ConstantInt::get(Type::Int32Ty,0x30),
+ ci->getOperand(1)->getName()+".sub",ci);
+ ICmpInst* setcond_inst = new ICmpInst(ICmpInst::ICMP_ULE,sub_inst,
+ ConstantInt::get(Type::Int32Ty,9),
+ ci->getOperand(1)->getName()+".cmp",ci);
+ CastInst* c2 = new ZExtInst(setcond_inst, Type::Int32Ty,
+ ci->getOperand(1)->getName()+".isdigit", ci);
+ return ReplaceCallWith(ci, c2);
+ }
+} isdigitOptimizer;
+
+struct VISIBILITY_HIDDEN isasciiOptimization : public LibCallOptimization {
+public:
+ isasciiOptimization()
+ : LibCallOptimization("isascii", "Number of 'isascii' calls simplified") {}
+
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ return F->arg_size() == 1 && F->arg_begin()->getType()->isInteger() &&
+ F->getReturnType()->isInteger();
+ }
+
+ /// @brief Perform the isascii optimization.
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+ // isascii(c) -> (unsigned)c < 128
+ Value *V = CI->getOperand(1);
+ Value *Cmp = new ICmpInst(ICmpInst::ICMP_ULT, V,
+ ConstantInt::get(V->getType(), 128),
+ V->getName()+".isascii", CI);
+ if (Cmp->getType() != CI->getType())
+ Cmp = new ZExtInst(Cmp, CI->getType(), Cmp->getName(), CI);
+ return ReplaceCallWith(CI, Cmp);
+ }
+} isasciiOptimizer;
+
+
+/// This LibCallOptimization will simplify calls to the "toascii" library
+/// function. It simply does the corresponding and operation to restrict the
+/// range of values to the ASCII character set (0-127).
+/// @brief Simplify the toascii library function.
+struct VISIBILITY_HIDDEN ToAsciiOptimization : public LibCallOptimization {
+public:
+ /// @brief Default Constructor
+ ToAsciiOptimization() : LibCallOptimization("toascii",
+ "Number of 'toascii' calls simplified") {}
+
+ /// @brief Make sure that the "fputs" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
+ // Just make sure this has 2 arguments
+ return (f->arg_size() == 1);
+ }
+
+ /// @brief Perform the toascii optimization.
+ virtual bool OptimizeCall(CallInst *ci, SimplifyLibCalls &SLC) {
+ // toascii(c) -> (c & 0x7f)
+ Value *chr = ci->getOperand(1);
+ Value *and_inst = BinaryOperator::createAnd(chr,
+ ConstantInt::get(chr->getType(),0x7F),ci->getName()+".toascii",ci);
+ return ReplaceCallWith(ci, and_inst);
+ }
+} ToAsciiOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "ffs" library
+/// calls which find the first set bit in an int, long, or long long. The
+/// optimization is to compute the result at compile time if the argument is
+/// a constant.
+/// @brief Simplify the ffs library function.
+struct VISIBILITY_HIDDEN FFSOptimization : public LibCallOptimization {
+protected:
+ /// @brief Subclass Constructor
+ FFSOptimization(const char* funcName, const char* description)
+ : LibCallOptimization(funcName, description) {}
+
+public:
+ /// @brief Default Constructor
+ FFSOptimization() : LibCallOptimization("ffs",
+ "Number of 'ffs' calls simplified") {}
+
+ /// @brief Make sure that the "ffs" function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ // Just make sure this has 2 arguments
+ return F->arg_size() == 1 && F->getReturnType() == Type::Int32Ty;
+ }
+
+ /// @brief Perform the ffs optimization.
+ virtual bool OptimizeCall(CallInst *TheCall, SimplifyLibCalls &SLC) {
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(TheCall->getOperand(1))) {
+ // ffs(cnst) -> bit#
+ // ffsl(cnst) -> bit#
+ // ffsll(cnst) -> bit#
+ uint64_t val = CI->getZExtValue();
+ int result = 0;
+ if (val) {
+ ++result;
+ while ((val & 1) == 0) {
+ ++result;
+ val >>= 1;
+ }
+ }
+ return ReplaceCallWith(TheCall, ConstantInt::get(Type::Int32Ty, result));
+ }
+
+ // ffs(x) -> x == 0 ? 0 : llvm.cttz(x)+1
+ // ffsl(x) -> x == 0 ? 0 : llvm.cttz(x)+1
+ // ffsll(x) -> x == 0 ? 0 : llvm.cttz(x)+1
+ const Type *ArgType = TheCall->getOperand(1)->getType();
+ const char *CTTZName;
+ assert(ArgType->getTypeID() == Type::IntegerTyID &&
+ "llvm.cttz argument is not an integer?");
+ unsigned BitWidth = cast<IntegerType>(ArgType)->getBitWidth();
+ if (BitWidth == 8)
+ CTTZName = "llvm.cttz.i8";
+ else if (BitWidth == 16)
+ CTTZName = "llvm.cttz.i16";
+ else if (BitWidth == 32)
+ CTTZName = "llvm.cttz.i32";
+ else {
+ assert(BitWidth == 64 && "Unknown bitwidth");
+ CTTZName = "llvm.cttz.i64";
+ }
+
+ Constant *F = SLC.getModule()->getOrInsertFunction(CTTZName, ArgType,
+ ArgType, NULL);
+ Value *V = CastInst::createIntegerCast(TheCall->getOperand(1), ArgType,
+ false/*ZExt*/, "tmp", TheCall);
+ Value *V2 = new CallInst(F, V, "tmp", TheCall);
+ V2 = CastInst::createIntegerCast(V2, Type::Int32Ty, false/*ZExt*/,
+ "tmp", TheCall);
+ V2 = BinaryOperator::createAdd(V2, ConstantInt::get(Type::Int32Ty, 1),
+ "tmp", TheCall);
+ Value *Cond = new ICmpInst(ICmpInst::ICMP_EQ, V,
+ Constant::getNullValue(V->getType()), "tmp",
+ TheCall);
+ V2 = new SelectInst(Cond, ConstantInt::get(Type::Int32Ty, 0), V2,
+ TheCall->getName(), TheCall);
+ return ReplaceCallWith(TheCall, V2);
+ }
+} FFSOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "ffsl" library
+/// calls. It simply uses FFSOptimization for which the transformation is
+/// identical.
+/// @brief Simplify the ffsl library function.
+struct VISIBILITY_HIDDEN FFSLOptimization : public FFSOptimization {
+public:
+ /// @brief Default Constructor
+ FFSLOptimization() : FFSOptimization("ffsl",
+ "Number of 'ffsl' calls simplified") {}
+
+} FFSLOptimizer;
+
+/// This LibCallOptimization will simplify calls to the "ffsll" library
+/// calls. It simply uses FFSOptimization for which the transformation is
+/// identical.
+/// @brief Simplify the ffsl library function.
+struct VISIBILITY_HIDDEN FFSLLOptimization : public FFSOptimization {
+public:
+ /// @brief Default Constructor
+ FFSLLOptimization() : FFSOptimization("ffsll",
+ "Number of 'ffsll' calls simplified") {}
+
+} FFSLLOptimizer;
+
+/// This optimizes unary functions that take and return doubles.
+struct UnaryDoubleFPOptimizer : public LibCallOptimization {
+ UnaryDoubleFPOptimizer(const char *Fn, const char *Desc)
+ : LibCallOptimization(Fn, Desc) {}
+
+ // Make sure that this function has the right prototype
+ virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
+ return F->arg_size() == 1 && F->arg_begin()->getType() == Type::DoubleTy &&
+ F->getReturnType() == Type::DoubleTy;
+ }
+
+ /// ShrinkFunctionToFloatVersion - If the input to this function is really a
+ /// float, strength reduce this to a float version of the function,
+ /// e.g. floor((double)FLT) -> (double)floorf(FLT). This can only be called
+ /// when the target supports the destination function and where there can be
+ /// no precision loss.
+ static bool ShrinkFunctionToFloatVersion(CallInst *CI, SimplifyLibCalls &SLC,
+ Constant *(SimplifyLibCalls::*FP)()){
+ if (FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1)))
+ if (Cast->getOperand(0)->getType() == Type::FloatTy) {
+ Value *New = new CallInst((SLC.*FP)(), Cast->getOperand(0),
+ CI->getName(), CI);
+ New = new FPExtInst(New, Type::DoubleTy, CI->getName(), CI);
+ CI->replaceAllUsesWith(New);
+ CI->eraseFromParent();
+ if (Cast->use_empty())
+ Cast->eraseFromParent();
+ return true;
+ }
+ return false;
+ }
+};
+
+
+struct VISIBILITY_HIDDEN FloorOptimization : public UnaryDoubleFPOptimizer {
+ FloorOptimization()
+ : UnaryDoubleFPOptimizer("floor", "Number of 'floor' calls simplified") {}
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_FLOORF
+ // If this is a float argument passed in, convert to floorf.
+ if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_floorf))
+ return true;
+#endif
+ return false; // opt failed
+ }
+} FloorOptimizer;
+
+struct VISIBILITY_HIDDEN CeilOptimization : public UnaryDoubleFPOptimizer {
+ CeilOptimization()
+ : UnaryDoubleFPOptimizer("ceil", "Number of 'ceil' calls simplified") {}
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_CEILF
+ // If this is a float argument passed in, convert to ceilf.
+ if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_ceilf))
+ return true;
+#endif
+ return false; // opt failed
+ }
+} CeilOptimizer;
+
+struct VISIBILITY_HIDDEN RoundOptimization : public UnaryDoubleFPOptimizer {
+ RoundOptimization()
+ : UnaryDoubleFPOptimizer("round", "Number of 'round' calls simplified") {}
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_ROUNDF
+ // If this is a float argument passed in, convert to roundf.
+ if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_roundf))
+ return true;
+#endif
+ return false; // opt failed
+ }
+} RoundOptimizer;
+
+struct VISIBILITY_HIDDEN RintOptimization : public UnaryDoubleFPOptimizer {
+ RintOptimization()
+ : UnaryDoubleFPOptimizer("rint", "Number of 'rint' calls simplified") {}
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_RINTF
+ // If this is a float argument passed in, convert to rintf.
+ if (ShrinkFunctionToFloatVersion(CI, SLC, &SimplifyLibCalls::get_rintf))
+ return true;
+#endif
+ return false; // opt failed
+ }
+} RintOptimizer;
+
+struct VISIBILITY_HIDDEN NearByIntOptimization : public UnaryDoubleFPOptimizer {
+ NearByIntOptimization()
+ : UnaryDoubleFPOptimizer("nearbyint",
+ "Number of 'nearbyint' calls simplified") {}
+
+ virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
+#ifdef HAVE_NEARBYINTF
+ // If this is a float argument passed in, convert to nearbyintf.
+ if (ShrinkFunctionToFloatVersion(CI, SLC,&SimplifyLibCalls::get_nearbyintf))
+ return true;
+#endif
+ return false; // opt failed
+ }
+} NearByIntOptimizer;
+
+/// GetConstantStringInfo - This function computes the length of a
+/// null-terminated constant array of integers. This function can't rely on the
+/// size of the constant array because there could be a null terminator in the
+/// middle of the array.
+///
+/// We also have to bail out if we find a non-integer constant initializer
+/// of one of the elements or if there is no null-terminator. The logic
+/// below checks each of these conditions and will return true only if all
+/// conditions are met. If the conditions aren't met, this returns false.
+///
+/// If successful, the \p Array param is set to the constant array being
+/// indexed, the \p Length parameter is set to the length of the null-terminated
+/// string pointed to by V, the \p StartIdx value is set to the first
+/// element of the Array that V points to, and true is returned.
+static bool GetConstantStringInfo(Value *V, std::string &Str) {
+ // Look through noop bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V)) {
+ if (BCI->getType() == BCI->getOperand(0)->getType())
+ return GetConstantStringInfo(BCI->getOperand(0), Str);
+ return false;
+ }
+
+ // If the value is not a GEP instruction nor a constant expression with a
+ // GEP instruction, then return false because ConstantArray can't occur
+ // any other way
+ User *GEP = 0;
+ if (GetElementPtrInst *GEPI = dyn_cast<GetElementPtrInst>(V)) {
+ GEP = GEPI;
+ } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
+ if (CE->getOpcode() != Instruction::GetElementPtr)
+ return false;
+ GEP = CE;
+ } else {
+ return false;
+ }
+
+ // Make sure the GEP has exactly three arguments.
+ if (GEP->getNumOperands() != 3)
+ return false;
+
+ // Check to make sure that the first operand of the GEP is an integer and
+ // has value 0 so that we are sure we're indexing into the initializer.
+ if (ConstantInt *Idx = dyn_cast<ConstantInt>(GEP->getOperand(1))) {
+ if (!Idx->isZero())
+ return false;
+ } else
+ return false;
+
+ // If the second index isn't a ConstantInt, then this is a variable index
+ // into the array. If this occurs, we can't say anything meaningful about
+ // the string.
+ uint64_t StartIdx = 0;
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(2)))
+ StartIdx = CI->getZExtValue();
+ else
+ return false;
+
+ // The GEP instruction, constant or instruction, must reference a global
+ // variable that is a constant and is initialized. The referenced constant
+ // initializer is the array that we'll use for optimization.
+ GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
+ if (!GV || !GV->isConstant() || !GV->hasInitializer())
+ return false;
+ Constant *GlobalInit = GV->getInitializer();
+
+ // Handle the ConstantAggregateZero case
+ if (isa<ConstantAggregateZero>(GlobalInit)) {
+ // This is a degenerate case. The initializer is constant zero so the
+ // length of the string must be zero.
+ Str.clear();
+ return true;
+ }
+
+ // Must be a Constant Array
+ ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (!Array) return false;
+
+ // Get the number of elements in the array
+ uint64_t NumElts = Array->getType()->getNumElements();
+
+ // Traverse the constant array from StartIdx (derived above) which is
+ // the place the GEP refers to in the array.
+ for (unsigned i = StartIdx; i < NumElts; ++i) {
+ Constant *Elt = Array->getOperand(i);
+ ConstantInt *CI = dyn_cast<ConstantInt>(Elt);
+ if (!CI) // This array isn't suitable, non-int initializer.
+ return false;
+ if (CI->isZero())
+ return true; // we found end of string, success!
+ Str += (char)CI->getZExtValue();
+ }
+
+ return false; // The array isn't null terminated.
+}
+
+/// CastToCStr - Return V if it is an sbyte*, otherwise cast it to sbyte*,
+/// inserting the cast before IP, and return the cast.
+/// @brief Cast a value to a "C" string.
+static Value *CastToCStr(Value *V, Instruction *IP) {
+ assert(isa<PointerType>(V->getType()) &&
+ "Can't cast non-pointer type to C string type");
+ const Type *SBPTy = PointerType::get(Type::Int8Ty);
+ if (V->getType() != SBPTy)
+ return new BitCastInst(V, SBPTy, V->getName(), IP);
+ return V;
+}
+
+// TODO:
+// Additional cases that we need to add to this file:
+//
+// cbrt:
+// * cbrt(expN(X)) -> expN(x/3)
+// * cbrt(sqrt(x)) -> pow(x,1/6)
+// * cbrt(sqrt(x)) -> pow(x,1/9)
+//
+// cos, cosf, cosl:
+// * cos(-x) -> cos(x)
+//
+// exp, expf, expl:
+// * exp(log(x)) -> x
+//
+// log, logf, logl:
+// * log(exp(x)) -> x
+// * log(x**y) -> y*log(x)
+// * log(exp(y)) -> y*log(e)
+// * log(exp2(y)) -> y*log(2)
+// * log(exp10(y)) -> y*log(10)
+// * log(sqrt(x)) -> 0.5*log(x)
+// * log(pow(x,y)) -> y*log(x)
+//
+// lround, lroundf, lroundl:
+// * lround(cnst) -> cnst'
+//
+// memcmp:
+// * memcmp(x,y,l) -> cnst
+// (if all arguments are constant and strlen(x) <= l and strlen(y) <= l)
+//
+// memmove:
+// * memmove(d,s,l,a) -> memcpy(d,s,l,a)
+// (if s is a global constant array)
+//
+// pow, powf, powl:
+// * pow(exp(x),y) -> exp(x*y)
+// * pow(sqrt(x),y) -> pow(x,y*0.5)
+// * pow(pow(x,y),z)-> pow(x,y*z)
+//
+// puts:
+// * puts("") -> putchar("\n")
+//
+// round, roundf, roundl:
+// * round(cnst) -> cnst'
+//
+// signbit:
+// * signbit(cnst) -> cnst'
+// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
+//
+// sqrt, sqrtf, sqrtl:
+// * sqrt(expN(x)) -> expN(x*0.5)
+// * sqrt(Nroot(x)) -> pow(x,1/(2*N))
+// * sqrt(pow(x,y)) -> pow(|x|,y*0.5)
+//
+// stpcpy:
+// * stpcpy(str, "literal") ->
+// llvm.memcpy(str,"literal",strlen("literal")+1,1)
+// strrchr:
+// * strrchr(s,c) -> reverse_offset_of_in(c,s)
+// (if c is a constant integer and s is a constant string)
+// * strrchr(s1,0) -> strchr(s1,0)
+//
+// strncat:
+// * strncat(x,y,0) -> x
+// * strncat(x,y,0) -> x (if strlen(y) = 0)
+// * strncat(x,y,l) -> strcat(x,y) (if y and l are constants an l > strlen(y))
+//
+// strncpy:
+// * strncpy(d,s,0) -> d
+// * strncpy(d,s,l) -> memcpy(d,s,l,1)
+// (if s and l are constants)
+//
+// strpbrk:
+// * strpbrk(s,a) -> offset_in_for(s,a)
+// (if s and a are both constant strings)
+// * strpbrk(s,"") -> 0
+// * strpbrk(s,a) -> strchr(s,a[0]) (if a is constant string of length 1)
+//
+// strspn, strcspn:
+// * strspn(s,a) -> const_int (if both args are constant)
+// * strspn("",a) -> 0
+// * strspn(s,"") -> 0
+// * strcspn(s,a) -> const_int (if both args are constant)
+// * strcspn("",a) -> 0
+// * strcspn(s,"") -> strlen(a)
+//
+// strstr:
+// * strstr(x,x) -> x
+// * strstr(s1,s2) -> offset_of_s2_in(s1)
+// (if s1 and s2 are constant strings)
+//
+// tan, tanf, tanl:
+// * tan(atan(x)) -> x
+//
+// trunc, truncf, truncl:
+// * trunc(cnst) -> cnst'
+//
+//
+}