Delete the IPO simplify-libcalls and completely reimplement it as
a FunctionPass. This makes it simpler, fixes dozens of bugs, adds
a couple of minor features, and shrinks is considerably: from
2214 to 1437 lines.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50520 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
new file mode 100644
index 0000000..a03bc7e
--- /dev/null
+++ b/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -0,0 +1,1437 @@
+//===- SimplifyLibCalls.cpp - Optimize specific well-known library calls --===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a simple 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/Transforms/Scalar.h"
+#include "llvm/Intrinsics.h"
+#include "llvm/Module.h"
+#include "llvm/Pass.h"
+#include "llvm/Support/IRBuilder.h"
+#include "llvm/Target/TargetData.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/StringMap.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Support/Compiler.h"
+#include "llvm/Config/config.h"
+using namespace llvm;
+
+STATISTIC(NumSimplified, "Number of library calls simplified");
+
+//===----------------------------------------------------------------------===//
+// Optimizer Base Class
+//===----------------------------------------------------------------------===//
+
+/// This class is the abstract base class for the set of optimizations that
+/// corresponds to one library call.
+namespace {
+class VISIBILITY_HIDDEN LibCallOptimization {
+protected:
+ Function *Caller;
+ const TargetData *TD;
+public:
+ LibCallOptimization() { }
+ virtual ~LibCallOptimization() {}
+
+ /// CallOptimizer - This pure virtual method is implemented by base classes to
+ /// do various optimizations. If this returns null then no transformation was
+ /// performed. If it returns CI, then it transformed the call and CI is to be
+ /// deleted. If it returns something else, replace CI with the new value and
+ /// delete CI.
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) =0;
+
+ Value *OptimizeCall(CallInst *CI, const TargetData &TD, IRBuilder &B) {
+ Caller = CI->getParent()->getParent();
+ this->TD = &TD;
+ return CallOptimizer(CI->getCalledFunction(), CI, B);
+ }
+
+ /// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
+ Value *CastToCStr(Value *V, IRBuilder &B);
+
+ /// EmitStrLen - Emit a call to the strlen function to the builder, for the
+ /// specified pointer. Ptr is required to be some pointer type, and the
+ /// return value has 'intptr_t' type.
+ Value *EmitStrLen(Value *Ptr, IRBuilder &B);
+
+ /// EmitMemCpy - Emit a call to the memcpy function to the builder. This
+ /// always expects that the size has type 'intptr_t' and Dst/Src are pointers.
+ Value *EmitMemCpy(Value *Dst, Value *Src, Value *Len,
+ unsigned Align, IRBuilder &B);
+
+ /// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
+ /// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
+ Value *EmitMemChr(Value *Ptr, Value *Val, Value *Len, IRBuilder &B);
+
+ /// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
+ /// 'floor'). This function is known to take a single of type matching 'Op'
+ /// and returns one value with the same type. If 'Op' is a long double, 'l'
+ /// is added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
+ Value *EmitUnaryFloatFnCall(Value *Op, const char *Name, IRBuilder &B);
+
+ /// EmitPutChar - Emit a call to the putchar function. This assumes that Char
+ /// is an integer.
+ void EmitPutChar(Value *Char, IRBuilder &B);
+
+ /// EmitPutS - Emit a call to the puts function. This assumes that Str is
+ /// some pointer.
+ void EmitPutS(Value *Str, IRBuilder &B);
+
+ /// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
+ /// an i32, and File is a pointer to FILE.
+ void EmitFPutC(Value *Char, Value *File, IRBuilder &B);
+
+ /// EmitFPutS - Emit a call to the puts function. Str is required to be a
+ /// pointer and File is a pointer to FILE.
+ void EmitFPutS(Value *Str, Value *File, IRBuilder &B);
+
+ /// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
+ /// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
+ void EmitFWrite(Value *Ptr, Value *Size, Value *File, IRBuilder &B);
+
+};
+} // End anonymous namespace.
+
+/// CastToCStr - Return V if it is an i8*, otherwise cast it to i8*.
+Value *LibCallOptimization::CastToCStr(Value *V, IRBuilder &B) {
+ return B.CreateBitCast(V, PointerType::getUnqual(Type::Int8Ty), "cstr");
+}
+
+/// EmitStrLen - Emit a call to the strlen function to the builder, for the
+/// specified pointer. This always returns an integer value of size intptr_t.
+Value *LibCallOptimization::EmitStrLen(Value *Ptr, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *StrLen =M->getOrInsertFunction("strlen", TD->getIntPtrType(),
+ PointerType::getUnqual(Type::Int8Ty),
+ NULL);
+ return B.CreateCall(StrLen, CastToCStr(Ptr, B), "strlen");
+}
+
+/// EmitMemCpy - Emit a call to the memcpy function to the builder. This always
+/// expects that the size has type 'intptr_t' and Dst/Src are pointers.
+Value *LibCallOptimization::EmitMemCpy(Value *Dst, Value *Src, Value *Len,
+ unsigned Align, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Intrinsic::ID IID = TD->getIntPtrType() == Type::Int32Ty ?
+ Intrinsic::memcpy_i32 : Intrinsic::memcpy_i64;
+ Value *MemCpy = Intrinsic::getDeclaration(M, IID);
+ return B.CreateCall4(MemCpy, CastToCStr(Dst, B), CastToCStr(Src, B), Len,
+ ConstantInt::get(Type::Int32Ty, Align));
+}
+
+/// EmitMemChr - Emit a call to the memchr function. This assumes that Ptr is
+/// a pointer, Val is an i32 value, and Len is an 'intptr_t' value.
+Value *LibCallOptimization::EmitMemChr(Value *Ptr, Value *Val,
+ Value *Len, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *MemChr = M->getOrInsertFunction("memchr",
+ PointerType::getUnqual(Type::Int8Ty),
+ PointerType::getUnqual(Type::Int8Ty),
+ Type::Int32Ty, TD->getIntPtrType(),
+ NULL);
+ return B.CreateCall3(MemChr, CastToCStr(Ptr, B), Val, Len, "memchr");
+}
+
+/// EmitUnaryFloatFnCall - Emit a call to the unary function named 'Name' (e.g.
+/// 'floor'). This function is known to take a single of type matching 'Op' and
+/// returns one value with the same type. If 'Op' is a long double, 'l' is
+/// added as the suffix of name, if 'Op' is a float, we add a 'f' suffix.
+Value *LibCallOptimization::EmitUnaryFloatFnCall(Value *Op, const char *Name,
+ IRBuilder &B) {
+ char NameBuffer[20];
+ if (Op->getType() != Type::DoubleTy) {
+ // If we need to add a suffix, copy into NameBuffer.
+ unsigned NameLen = strlen(Name);
+ assert(NameLen < sizeof(NameBuffer)-2);
+ memcpy(NameBuffer, Name, NameLen);
+ if (Op->getType() == Type::FloatTy)
+ NameBuffer[NameLen] = 'f'; // floorf
+ else
+ NameBuffer[NameLen] = 'l'; // floorl
+ NameBuffer[NameLen+1] = 0;
+ Name = NameBuffer;
+ }
+
+ Module *M = Caller->getParent();
+ Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
+ Op->getType(), NULL);
+ return B.CreateCall(Callee, Op, Name);
+}
+
+/// EmitPutChar - Emit a call to the putchar function. This assumes that Char
+/// is an integer.
+void LibCallOptimization::EmitPutChar(Value *Char, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *F = M->getOrInsertFunction("putchar", Type::Int32Ty,
+ Type::Int32Ty, NULL);
+ B.CreateCall(F, B.CreateIntCast(Char, Type::Int32Ty, "chari"), "putchar");
+}
+
+/// EmitPutS - Emit a call to the puts function. This assumes that Str is
+/// some pointer.
+void LibCallOptimization::EmitPutS(Value *Str, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Value *F = M->getOrInsertFunction("puts", Type::Int32Ty,
+ PointerType::getUnqual(Type::Int8Ty), NULL);
+ B.CreateCall(F, CastToCStr(Str, B), "puts");
+}
+
+/// EmitFPutC - Emit a call to the fputc function. This assumes that Char is
+/// an integer and File is a pointer to FILE.
+void LibCallOptimization::EmitFPutC(Value *Char, Value *File, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fputc", Type::Int32Ty, Type::Int32Ty,
+ File->getType(), NULL);
+ Char = B.CreateIntCast(Char, Type::Int32Ty, "chari");
+ B.CreateCall2(F, Char, File, "fputc");
+}
+
+/// EmitFPutS - Emit a call to the puts function. Str is required to be a
+/// pointer and File is a pointer to FILE.
+void LibCallOptimization::EmitFPutS(Value *Str, Value *File, IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fputs", Type::Int32Ty,
+ PointerType::getUnqual(Type::Int8Ty),
+ File->getType(), NULL);
+ B.CreateCall2(F, CastToCStr(Str, B), File, "fputs");
+}
+
+/// EmitFWrite - Emit a call to the fwrite function. This assumes that Ptr is
+/// a pointer, Size is an 'intptr_t', and File is a pointer to FILE.
+void LibCallOptimization::EmitFWrite(Value *Ptr, Value *Size, Value *File,
+ IRBuilder &B) {
+ Module *M = Caller->getParent();
+ Constant *F = M->getOrInsertFunction("fwrite", TD->getIntPtrType(),
+ PointerType::getUnqual(Type::Int8Ty),
+ TD->getIntPtrType(), TD->getIntPtrType(),
+ File->getType(), NULL);
+ B.CreateCall4(F, CastToCStr(Ptr, B), Size,
+ ConstantInt::get(TD->getIntPtrType(), 1), File);
+}
+
+//===----------------------------------------------------------------------===//
+// Helper Functions
+//===----------------------------------------------------------------------===//
+
+/// GetConstantStringInfo - This function computes the length of a
+/// null-terminated C string pointed to by V. If successful, it returns true
+/// and returns the string in Str. If unsuccessful, it returns false.
+static bool GetConstantStringInfo(Value *V, std::string &Str) {
+ // Look bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ return GetConstantStringInfo(BCI->getOperand(0), Str);
+
+ // 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 == 0 || Array->getType()->getElementType() != Type::Int8Ty)
+ 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.
+}
+
+/// GetStringLengthH - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
+ // Look through noop bitcast instructions.
+ if (BitCastInst *BCI = dyn_cast<BitCastInst>(V))
+ return GetStringLengthH(BCI->getOperand(0), PHIs);
+
+ // If this is a PHI node, there are two cases: either we have already seen it
+ // or we haven't.
+ if (PHINode *PN = dyn_cast<PHINode>(V)) {
+ if (!PHIs.insert(PN))
+ return ~0ULL; // already in the set.
+
+ // If it was new, see if all the input strings are the same length.
+ uint64_t LenSoFar = ~0ULL;
+ for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
+ uint64_t Len = GetStringLengthH(PN->getIncomingValue(i), PHIs);
+ if (Len == 0) return 0; // Unknown length -> unknown.
+
+ if (Len == ~0ULL) continue;
+
+ if (Len != LenSoFar && LenSoFar != ~0ULL)
+ return 0; // Disagree -> unknown.
+ LenSoFar = Len;
+ }
+
+ // Success, all agree.
+ return LenSoFar;
+ }
+
+ // strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
+ if (SelectInst *SI = dyn_cast<SelectInst>(V)) {
+ uint64_t Len1 = GetStringLengthH(SI->getTrueValue(), PHIs);
+ if (Len1 == 0) return 0;
+ uint64_t Len2 = GetStringLengthH(SI->getFalseValue(), PHIs);
+ if (Len2 == 0) return 0;
+ if (Len1 == ~0ULL) return Len2;
+ if (Len2 == ~0ULL) return Len1;
+ if (Len1 != Len2) return 0;
+ return Len1;
+ }
+
+ // If the value is not a GEP instruction nor a constant expression with a
+ // GEP instruction, then return unknown.
+ 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 0;
+ GEP = CE;
+ } else {
+ return 0;
+ }
+
+ // Make sure the GEP has exactly three arguments.
+ if (GEP->getNumOperands() != 3)
+ return 0;
+
+ // 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 0;
+ } else
+ return 0;
+
+ // 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 0;
+
+ // 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 0;
+ Constant *GlobalInit = GV->getInitializer();
+
+ // Handle the ConstantAggregateZero case, which is a degenerate case. The
+ // initializer is constant zero so the length of the string must be zero.
+ if (isa<ConstantAggregateZero>(GlobalInit))
+ return 1; // Len = 0 offset by 1.
+
+ // Must be a Constant Array
+ ConstantArray *Array = dyn_cast<ConstantArray>(GlobalInit);
+ if (!Array || Array->getType()->getElementType() != Type::Int8Ty)
+ 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 0;
+ if (CI->isZero())
+ return i-StartIdx+1; // We found end of string, success!
+ }
+
+ return 0; // The array isn't null terminated, conservatively return 'unknown'.
+}
+
+/// GetStringLength - If we can compute the length of the string pointed to by
+/// the specified pointer, return 'len+1'. If we can't, return 0.
+static uint64_t GetStringLength(Value *V) {
+ if (!isa<PointerType>(V->getType())) return 0;
+
+ SmallPtrSet<PHINode*, 32> PHIs;
+ uint64_t Len = GetStringLengthH(V, PHIs);
+ // If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
+ // an empty string as a length.
+ return Len == ~0ULL ? 1 : Len;
+}
+
+/// IsOnlyUsedInZeroEqualityComparison - Return true if it only matters that the
+/// value is equal or not-equal to zero.
+static bool IsOnlyUsedInZeroEqualityComparison(Value *V) {
+ for (Value::use_iterator UI = V->use_begin(), E = V->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;
+}
+
+//===----------------------------------------------------------------------===//
+// Miscellaneous LibCall Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'exit' Optimizations
+
+/// ExitOpt - int main() { exit(4); } --> int main() { return 4; }
+struct VISIBILITY_HIDDEN ExitOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify we have a reasonable prototype for exit.
+ if (Callee->arg_size() == 0 || !CI->use_empty())
+ return 0;
+
+ // Verify the caller is main, and that the result type of main matches the
+ // argument type of exit.
+ if (!Caller->isName("main") || !Caller->hasExternalLinkage() ||
+ Caller->getReturnType() != CI->getOperand(1)->getType())
+ return 0;
+
+ TerminatorInst *OldTI = CI->getParent()->getTerminator();
+
+ // Create the return after the call.
+ ReturnInst *RI = B.CreateRet(CI->getOperand(1));
+
+ // Drop all successor phi node entries.
+ for (unsigned i = 0, e = OldTI->getNumSuccessors(); i != e; ++i)
+ OldTI->getSuccessor(i)->removePredecessor(CI->getParent());
+
+ // Erase all instructions from after our return instruction until the end of
+ // the block.
+ BasicBlock::iterator FirstDead = RI; ++FirstDead;
+ CI->getParent()->getInstList().erase(FirstDead, CI->getParent()->end());
+ return CI;
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// String and Memory LibCall Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'strcat' Optimizations
+
+struct VISIBILITY_HIDDEN StrCatOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcat" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
+ FT->getParamType(0) != FT->getReturnType() ||
+ FT->getParamType(1) != FT->getReturnType())
+ return 0;
+
+ // Extract some information from the instruction
+ Value *Dst = CI->getOperand(1);
+ Value *Src = CI->getOperand(2);
+
+ // See if we can get the length of the input string.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return false;
+ --Len; // Unbias length.
+
+ // Handle the simple, do-nothing case: strcat(x, "") -> x
+ if (Len == 0)
+ return 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.
+ Value *DstLen = EmitStrLen(Dst, B);
+
+ // 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 = B.CreateGEP(Dst, DstLen, "endptr");
+
+ // We have enough information to now generate the memcpy call to do the
+ // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
+ EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len+1), 1, B);
+ return Dst;
+ }
+};
+
+//===---------------------------------------===//
+// 'strchr' Optimizations
+
+struct VISIBILITY_HIDDEN StrChrOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strchr" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 ||
+ FT->getReturnType() != PointerType::getUnqual(Type::Int8Ty) ||
+ FT->getParamType(0) != FT->getReturnType())
+ return 0;
+
+ Value *SrcStr = CI->getOperand(1);
+
+ // If the second operand is non-constant, see if we can compute the length
+ // of the input string and turn this into memchr.
+ ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getOperand(2));
+ if (CharC == 0) {
+ uint64_t Len = GetStringLength(SrcStr);
+ if (Len == 0 || FT->getParamType(1) != Type::Int32Ty) // memchr needs i32.
+ return 0;
+
+ return EmitMemChr(SrcStr, CI->getOperand(2), // include nul.
+ ConstantInt::get(TD->getIntPtrType(), Len), B);
+ }
+
+ // Otherwise, the character is a constant, see if the first argument is
+ // a string literal. If so, we can constant fold.
+ std::string Str;
+ if (!GetConstantStringInfo(SrcStr, Str))
+ return false;
+
+ // strchr can find the nul character.
+ Str += '\0';
+ char CharValue = CharC->getSExtValue();
+
+ // Compute the offset.
+ uint64_t i = 0;
+ while (1) {
+ if (i == Str.size()) // Didn't find the char. strchr returns null.
+ return Constant::getNullValue(CI->getType());
+ // Did we find our match?
+ if (Str[i] == CharValue)
+ break;
+ ++i;
+ }
+
+ // strchr(s+n,c) -> gep(s+n+i,c)
+ Value *Idx = ConstantInt::get(Type::Int64Ty, i);
+ return B.CreateGEP(SrcStr, Idx, "strchr");
+ }
+};
+
+//===---------------------------------------===//
+// 'strcmp' Optimizations
+
+struct VISIBILITY_HIDDEN StrCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcmp" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || FT->getReturnType() != Type::Int32Ty ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strcmp(x,x) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strcmp("", x) -> *x
+ return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
+
+ if (HasStr2 && Str2.empty()) // strcmp(x,"") -> *x
+ return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+
+ // strcmp(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(), strcmp(Str1.c_str(),Str2.c_str()));
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'strncmp' Optimizations
+
+struct VISIBILITY_HIDDEN StrNCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strncmp" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != Type::Int32Ty ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
+ !isa<IntegerType>(FT->getParamType(2)))
+ return 0;
+
+ Value *Str1P = CI->getOperand(1), *Str2P = CI->getOperand(2);
+ if (Str1P == Str2P) // strncmp(x,x,n) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ // Get the length argument if it is constant.
+ uint64_t Length;
+ if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getOperand(3)))
+ Length = LengthArg->getZExtValue();
+ else
+ return 0;
+
+ if (Length == 0) // strncmp(x,y,0) -> 0
+ return ConstantInt::get(CI->getType(), 0);
+
+ std::string Str1, Str2;
+ bool HasStr1 = GetConstantStringInfo(Str1P, Str1);
+ bool HasStr2 = GetConstantStringInfo(Str2P, Str2);
+
+ if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> *x
+ return B.CreateZExt(B.CreateLoad(Str2P, "strcmpload"), CI->getType());
+
+ if (HasStr2 && Str2.empty()) // strncmp(x, "", n) -> *x
+ return B.CreateZExt(B.CreateLoad(Str1P, "strcmpload"), CI->getType());
+
+ // strncmp(x, y) -> cnst (if both x and y are constant strings)
+ if (HasStr1 && HasStr2)
+ return ConstantInt::get(CI->getType(),
+ strncmp(Str1.c_str(), Str2.c_str(), Length));
+ return 0;
+ }
+};
+
+
+//===---------------------------------------===//
+// 'strcpy' Optimizations
+
+struct VISIBILITY_HIDDEN StrCpyOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Verify the "strcpy" function prototype.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty))
+ return 0;
+
+ Value *Dst = CI->getOperand(1), *Src = CI->getOperand(2);
+ if (Dst == Src) // strcpy(x,x) -> x
+ return Src;
+
+ // See if we can get the length of the input string.
+ uint64_t Len = GetStringLength(Src);
+ if (Len == 0) return false;
+
+ // We have enough information to now generate the memcpy call to do the
+ // concatenation for us. Make a memcpy to copy the nul byte with align = 1.
+ EmitMemCpy(Dst, Src, ConstantInt::get(TD->getIntPtrType(), Len), 1, B);
+ return Dst;
+ }
+};
+
+
+
+//===---------------------------------------===//
+// 'strlen' Optimizations
+
+struct VISIBILITY_HIDDEN StrLenOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 1 ||
+ FT->getParamType(0) != PointerType::getUnqual(Type::Int8Ty) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ Value *Src = CI->getOperand(1);
+
+ // Constant folding: strlen("xyz") -> 3
+ if (uint64_t Len = GetStringLength(Src))
+ return ConstantInt::get(CI->getType(), Len-1);
+
+ // Handle strlen(p) != 0.
+ if (!IsOnlyUsedInZeroEqualityComparison(CI)) return 0;
+
+ // strlen(x) != 0 --> *x != 0
+ // strlen(x) == 0 --> *x == 0
+ return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'memcmp' Optimizations
+
+struct VISIBILITY_HIDDEN MemCmpOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ FT->getReturnType() != Type::Int32Ty)
+ return 0;
+
+ Value *LHS = CI->getOperand(1), *RHS = CI->getOperand(2);
+
+ if (LHS == RHS) // memcmp(s,s,x) -> 0
+ return 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 (Len == 0) // memcmp(s1,s2,0) -> 0
+ return Constant::getNullValue(CI->getType());
+
+ if (Len == 1) { // memcmp(S1,S2,1) -> *LHS - *RHS
+ Value *LHSV = B.CreateLoad(CastToCStr(LHS, B), "lhsv");
+ Value *RHSV = B.CreateLoad(CastToCStr(RHS, B), "rhsv");
+ return B.CreateZExt(B.CreateSub(LHSV, RHSV, "chardiff"), CI->getType());
+ }
+
+ // memcmp(S1,S2,2) != 0 -> (*(short*)LHS ^ *(short*)RHS) != 0
+ // memcmp(S1,S2,4) != 0 -> (*(int*)LHS ^ *(int*)RHS) != 0
+ if ((Len == 2 || Len == 4) && IsOnlyUsedInZeroEqualityComparison(CI)) {
+ LHS = B.CreateBitCast(LHS, PointerType::getUnqual(Type::Int16Ty), "tmp");
+ RHS = B.CreateBitCast(RHS, LHS->getType(), "tmp");
+ LoadInst *LHSV = B.CreateLoad(LHS, "lhsv");
+ LoadInst *RHSV = B.CreateLoad(RHS, "rhsv");
+ LHSV->setAlignment(1); RHSV->setAlignment(1); // Unaligned loads.
+ return B.CreateZExt(B.CreateXor(LHSV, RHSV, "shortdiff"), CI->getType());
+ }
+
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'memcpy' Optimizations
+
+struct VISIBILITY_HIDDEN MemCpyOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
+ !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ FT->getParamType(2) != TD->getIntPtrType())
+ return 0;
+
+ // memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2), CI->getOperand(3), 1, B);
+ return CI->getOperand(1);
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Math Library Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'pow*' Optimizations
+
+struct VISIBILITY_HIDDEN PowOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // Just make sure this has 2 arguments of the same FP type, which match the
+ // result type.
+ if (FT->getNumParams() != 2 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != FT->getParamType(1) ||
+ !FT->getParamType(0)->isFloatingPoint())
+ return 0;
+
+ Value *Op1 = CI->getOperand(1), *Op2 = CI->getOperand(2);
+ if (ConstantFP *Op1C = dyn_cast<ConstantFP>(Op1)) {
+ if (Op1C->isExactlyValue(1.0)) // pow(1.0, x) -> 1.0
+ return Op1C;
+ if (Op1C->isExactlyValue(2.0)) // pow(2.0, x) -> exp2(x)
+ return EmitUnaryFloatFnCall(Op2, "exp2", B);
+ }
+
+ ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
+ if (Op2C == 0) return 0;
+
+ if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
+ return ConstantFP::get(CI->getType(), 1.0);
+
+ if (Op2C->isExactlyValue(0.5)) {
+ // FIXME: This is not safe for -0.0 and -inf. This can only be done when
+ // 'unsafe' math optimizations are allowed.
+ // x pow(x, 0.5) sqrt(x)
+ // ---------------------------------------------
+ // -0.0 +0.0 -0.0
+ // -inf +inf NaN
+#if 0
+ // pow(x, 0.5) -> sqrt(x)
+ return B.CreateCall(get_sqrt(), Op1, "sqrt");
+#endif
+ }
+
+ if (Op2C->isExactlyValue(1.0)) // pow(x, 1.0) -> x
+ return Op1;
+ if (Op2C->isExactlyValue(2.0)) // pow(x, 2.0) -> x*x
+ return B.CreateMul(Op1, Op1, "pow2");
+ if (Op2C->isExactlyValue(-1.0)) // pow(x, -1.0) -> 1.0/x
+ return B.CreateFDiv(ConstantFP::get(CI->getType(), 1.0), Op1, "powrecip");
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
+
+struct VISIBILITY_HIDDEN UnaryDoubleFPOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 1 || FT->getReturnType() != Type::DoubleTy ||
+ FT->getParamType(0) != Type::DoubleTy)
+ return 0;
+
+ // If this is something like 'floor((double)floatval)', convert to floorf.
+ FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getOperand(1));
+ if (Cast == 0 || Cast->getOperand(0)->getType() != Type::FloatTy)
+ return 0;
+
+ // floor((double)floatval) -> (double)floorf(floatval)
+ Value *V = Cast->getOperand(0);
+ V = EmitUnaryFloatFnCall(V, Callee->getNameStart(), B);
+ return B.CreateFPExt(V, Type::DoubleTy);
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Integer Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'ffs*' Optimizations
+
+struct VISIBILITY_HIDDEN FFSOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // Just make sure this has 2 arguments of the same FP type, which match the
+ // result type.
+ if (FT->getNumParams() != 1 || FT->getReturnType() != Type::Int32Ty ||
+ !isa<IntegerType>(FT->getParamType(0)))
+ return 0;
+
+ Value *Op = CI->getOperand(1);
+
+ // Constant fold.
+ if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
+ if (CI->getValue() == 0) // ffs(0) -> 0.
+ return Constant::getNullValue(CI->getType());
+ return ConstantInt::get(Type::Int32Ty, // ffs(c) -> cttz(c)+1
+ CI->getValue().countTrailingZeros()+1);
+ }
+
+ // ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
+ const Type *ArgType = Op->getType();
+ Value *F = Intrinsic::getDeclaration(Callee->getParent(),
+ Intrinsic::cttz, &ArgType, 1);
+ Value *V = B.CreateCall(F, Op, "cttz");
+ V = B.CreateAdd(V, ConstantInt::get(Type::Int32Ty, 1), "tmp");
+ V = B.CreateIntCast(V, Type::Int32Ty, false, "tmp");
+
+ Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType), "tmp");
+ return B.CreateSelect(Cond, V, ConstantInt::get(Type::Int32Ty, 0));
+ }
+};
+
+//===---------------------------------------===//
+// 'isdigit' Optimizations
+
+struct VISIBILITY_HIDDEN IsDigitOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require integer(i32)
+ if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isdigit(c) -> (c-'0') <u 10
+ Value *Op = CI->getOperand(1);
+ Op = B.CreateSub(Op, ConstantInt::get(Type::Int32Ty, '0'), "isdigittmp");
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 10), "isdigit");
+ return B.CreateZExt(Op, CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'isascii' Optimizations
+
+struct VISIBILITY_HIDDEN IsAsciiOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require integer(i32)
+ if (FT->getNumParams() != 1 || !isa<IntegerType>(FT->getReturnType()) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isascii(c) -> c <u 128
+ Value *Op = CI->getOperand(1);
+ Op = B.CreateICmpULT(Op, ConstantInt::get(Type::Int32Ty, 128), "isascii");
+ return B.CreateZExt(Op, CI->getType());
+ }
+};
+
+//===---------------------------------------===//
+// 'toascii' Optimizations
+
+struct VISIBILITY_HIDDEN ToAsciiOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ const FunctionType *FT = Callee->getFunctionType();
+ // We require i32(i32)
+ if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
+ FT->getParamType(0) != Type::Int32Ty)
+ return 0;
+
+ // isascii(c) -> c & 0x7f
+ return B.CreateAnd(CI->getOperand(1), ConstantInt::get(CI->getType(),0x7F));
+ }
+};
+
+//===----------------------------------------------------------------------===//
+// Formatting and IO Optimizations
+//===----------------------------------------------------------------------===//
+
+//===---------------------------------------===//
+// 'printf' Optimizations
+
+struct VISIBILITY_HIDDEN PrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require one fixed pointer argument and an integer/void result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() < 1 || !isa<PointerType>(FT->getParamType(0)) ||
+ !(isa<IntegerType>(FT->getReturnType()) ||
+ FT->getReturnType() == Type::VoidTy))
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(1), FormatStr))
+ return false;
+
+ // Empty format string -> noop.
+ if (FormatStr.empty()) // Tolerate printf's declared void.
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 0);
+
+ // printf("x") -> putchar('x'), even for '%'.
+ if (FormatStr.size() == 1) {
+ EmitPutChar(ConstantInt::get(Type::Int32Ty, FormatStr[0]), B);
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
+ }
+
+ // printf("foo\n") --> puts("foo")
+ if (FormatStr[FormatStr.size()-1] == '\n' &&
+ FormatStr.find('%') == std::string::npos) { // no format characters.
+ // 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 *C = ConstantArray::get(FormatStr, true);
+ C = new GlobalVariable(C->getType(), true,GlobalVariable::InternalLinkage,
+ C, "str", Callee->getParent());
+ EmitPutS(C, B);
+ return CI->use_empty() ? (Value*)CI :
+ ConstantInt::get(CI->getType(), FormatStr.size()+1);
+ }
+
+ // Optimize specific format strings.
+ // printf("%c", chr) --> putchar(*(i8*)dst)
+ if (FormatStr == "%c" && CI->getNumOperands() > 2 &&
+ isa<IntegerType>(CI->getOperand(2)->getType())) {
+ EmitPutChar(CI->getOperand(2), B);
+ return CI->use_empty() ? (Value*)CI : ConstantInt::get(CI->getType(), 1);
+ }
+
+ // printf("%s\n", str) --> puts(str)
+ if (FormatStr == "%s\n" && CI->getNumOperands() > 2 &&
+ isa<PointerType>(CI->getOperand(2)->getType()) &&
+ CI->use_empty()) {
+ EmitPutS(CI->getOperand(2), B);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'sprintf' Optimizations
+
+struct VISIBILITY_HIDDEN SPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two fixed pointer arguments and an integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // Check for a fixed format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ // If we just have a format string (nothing else crazy) transform it.
+ if (CI->getNumOperands() == 3) {
+ // Make sure there's no % in the constant array. We could try to handle
+ // %% -> % in the future if we cared.
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%')
+ return 0; // we found a format specifier, bail out.
+
+ // sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(2), // Copy the nul byte.
+ ConstantInt::get(TD->getIntPtrType(), FormatStr.size()+1),1,B);
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c"
+ // and have an extra operand.
+ if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
+ return 0;
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ // sprintf(dst, "%c", chr) --> *(i8*)dst = chr
+ if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
+ Value *V = B.CreateTrunc(CI->getOperand(3), Type::Int8Ty, "char");
+ B.CreateStore(V, CastToCStr(CI->getOperand(1), B));
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
+ if (!isa<PointerType>(CI->getOperand(3)->getType())) return 0;
+
+ Value *Len = EmitStrLen(CI->getOperand(3), B);
+ Value *IncLen = B.CreateAdd(Len, ConstantInt::get(Len->getType(), 1),
+ "leninc");
+ EmitMemCpy(CI->getOperand(1), CI->getOperand(3), IncLen, 1, B);
+
+ // The sprintf result is the unincremented number of bytes in the string.
+ return B.CreateIntCast(Len, CI->getType(), false);
+ }
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'fwrite' Optimizations
+
+struct VISIBILITY_HIDDEN FWriteOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require a pointer, an integer, an integer, a pointer, returning integer.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 4 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<IntegerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getParamType(2)) ||
+ !isa<PointerType>(FT->getParamType(3)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // Get the element size and count.
+ ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getOperand(2));
+ ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getOperand(3));
+ if (!SizeC || !CountC) return 0;
+ uint64_t Bytes = SizeC->getZExtValue()*CountC->getZExtValue();
+
+ // If this is writing zero records, remove the call (it's a noop).
+ if (Bytes == 0)
+ return ConstantInt::get(CI->getType(), 0);
+
+ // If this is writing one byte, turn it into fputc.
+ if (Bytes == 1) { // fwrite(S,1,1,F) -> fputc(S[0],F)
+ Value *Char = B.CreateLoad(CastToCStr(CI->getOperand(1), B), "char");
+ EmitFPutC(Char, CI->getOperand(4), B);
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ return 0;
+ }
+};
+
+//===---------------------------------------===//
+// 'fputs' Optimizations
+
+struct VISIBILITY_HIDDEN FPutsOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two pointers. Also, we can't optimize if return value is used.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !CI->use_empty())
+ return 0;
+
+ // fputs(s,F) --> fwrite(s,1,strlen(s),F)
+ uint64_t Len = GetStringLength(CI->getOperand(1));
+ if (!Len) return false;
+ EmitFWrite(CI->getOperand(1), ConstantInt::get(TD->getIntPtrType(), Len-1),
+ CI->getOperand(2), B);
+ return CI; // Known to have no uses (see above).
+ }
+};
+
+//===---------------------------------------===//
+// 'fprintf' Optimizations
+
+struct VISIBILITY_HIDDEN FPrintFOpt : public LibCallOptimization {
+ virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder &B) {
+ // Require two fixed paramters as pointers and integer result.
+ const FunctionType *FT = Callee->getFunctionType();
+ if (FT->getNumParams() != 2 || !isa<PointerType>(FT->getParamType(0)) ||
+ !isa<PointerType>(FT->getParamType(1)) ||
+ !isa<IntegerType>(FT->getReturnType()))
+ return 0;
+
+ // All the optimizations depend on the format string.
+ std::string FormatStr;
+ if (!GetConstantStringInfo(CI->getOperand(2), FormatStr))
+ return false;
+
+ // fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
+ if (CI->getNumOperands() == 3) {
+ for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
+ if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
+ return false; // We found a format specifier.
+
+ EmitFWrite(CI->getOperand(2), ConstantInt::get(TD->getIntPtrType(),
+ FormatStr.size()),
+ CI->getOperand(1), B);
+ return ConstantInt::get(CI->getType(), FormatStr.size());
+ }
+
+ // The remaining optimizations require the format string to be "%s" or "%c"
+ // and have an extra operand.
+ if (FormatStr.size() != 2 || FormatStr[0] != '%' || CI->getNumOperands() <4)
+ return 0;
+
+ // Decode the second character of the format string.
+ if (FormatStr[1] == 'c') {
+ // fprintf(F, "%c", chr) --> *(i8*)dst = chr
+ if (!isa<IntegerType>(CI->getOperand(3)->getType())) return 0;
+ EmitFPutC(CI->getOperand(3), CI->getOperand(1), B);
+ return ConstantInt::get(CI->getType(), 1);
+ }
+
+ if (FormatStr[1] == 's') {
+ // fprintf(F, "%s", str) -> fputs(str, F)
+ if (!isa<PointerType>(CI->getOperand(3)->getType()) || !CI->use_empty())
+ return 0;
+ EmitFPutS(CI->getOperand(3), CI->getOperand(1), B);
+ return CI;
+ }
+ return 0;
+ }
+};
+
+
+//===----------------------------------------------------------------------===//
+// SimplifyLibCalls Pass Implementation
+//===----------------------------------------------------------------------===//
+
+namespace {
+ /// This pass optimizes well known library functions from libc and libm.
+ ///
+ class VISIBILITY_HIDDEN SimplifyLibCalls : public FunctionPass {
+ StringMap<LibCallOptimization*> Optimizations;
+ // Miscellaneous LibCall Optimizations
+ ExitOpt Exit;
+ // String and Memory LibCall Optimizations
+ StrCatOpt StrCat; StrChrOpt StrChr; StrCmpOpt StrCmp; StrNCmpOpt StrNCmp;
+ StrCpyOpt StrCpy; StrLenOpt StrLen; MemCmpOpt MemCmp; MemCpyOpt MemCpy;
+ // Math Library Optimizations
+ PowOpt Pow; UnaryDoubleFPOpt UnaryDoubleFP;
+ // Integer Optimizations
+ FFSOpt FFS; IsDigitOpt IsDigit; IsAsciiOpt IsAscii; ToAsciiOpt ToAscii;
+ // Formatting and IO Optimizations
+ SPrintFOpt SPrintF; PrintFOpt PrintF;
+ FWriteOpt FWrite; FPutsOpt FPuts; FPrintFOpt FPrintF;
+ public:
+ static char ID; // Pass identification
+ SimplifyLibCalls() : FunctionPass((intptr_t)&ID) {}
+
+ void InitOptimizations();
+ bool runOnFunction(Function &F);
+
+ virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+ AU.addRequired<TargetData>();
+ }
+ };
+ char SimplifyLibCalls::ID = 0;
+} // end anonymous namespace.
+
+static RegisterPass<SimplifyLibCalls>
+X("simplify-libcalls", "Simplify well-known library calls");
+
+// Public interface to the Simplify LibCalls pass.
+FunctionPass *llvm::createSimplifyLibCallsPass() {
+ return new SimplifyLibCalls();
+}
+
+/// Optimizations - Populate the Optimizations map with all the optimizations
+/// we know.
+void SimplifyLibCalls::InitOptimizations() {
+ // Miscellaneous LibCall Optimizations
+ Optimizations["exit"] = &Exit;
+
+ // String and Memory LibCall Optimizations
+ Optimizations["strcat"] = &StrCat;
+ Optimizations["strchr"] = &StrChr;
+ Optimizations["strcmp"] = &StrCmp;
+ Optimizations["strncmp"] = &StrNCmp;
+ Optimizations["strcpy"] = &StrCpy;
+ Optimizations["strlen"] = &StrLen;
+ Optimizations["memcmp"] = &MemCmp;
+ Optimizations["memcpy"] = &MemCpy;
+
+ // Math Library Optimizations
+ Optimizations["powf"] = &Pow;
+ Optimizations["pow"] = &Pow;
+ Optimizations["powl"] = &Pow;
+#ifdef HAVE_FLOORF
+ Optimizations["floor"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_CEILF
+ Optimizations["ceil"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_ROUNDF
+ Optimizations["round"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_RINTF
+ Optimizations["rint"] = &UnaryDoubleFP;
+#endif
+#ifdef HAVE_NEARBYINTF
+ Optimizations["nearbyint"] = &UnaryDoubleFP;
+#endif
+
+ // Integer Optimizations
+ Optimizations["ffs"] = &FFS;
+ Optimizations["ffsl"] = &FFS;
+ Optimizations["ffsll"] = &FFS;
+ Optimizations["isdigit"] = &IsDigit;
+ Optimizations["isascii"] = &IsAscii;
+ Optimizations["toascii"] = &ToAscii;
+
+ // Formatting and IO Optimizations
+ Optimizations["sprintf"] = &SPrintF;
+ Optimizations["printf"] = &PrintF;
+ Optimizations["fwrite"] = &FWrite;
+ Optimizations["fputs"] = &FPuts;
+ Optimizations["fprintf"] = &FPrintF;
+}
+
+
+/// runOnFunction - Top level algorithm.
+///
+bool SimplifyLibCalls::runOnFunction(Function &F) {
+ if (Optimizations.empty())
+ InitOptimizations();
+
+ const TargetData &TD = getAnalysis<TargetData>();
+
+ IRBuilder Builder;
+
+ bool Changed = false;
+ for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB) {
+ for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ) {
+ // Ignore non-calls.
+ CallInst *CI = dyn_cast<CallInst>(I++);
+ if (!CI) continue;
+
+ // Ignore indirect calls and calls to non-external functions.
+ Function *Callee = CI->getCalledFunction();
+ if (Callee == 0 || !Callee->isDeclaration() ||
+ !(Callee->hasExternalLinkage() || Callee->hasDLLImportLinkage()))
+ continue;
+
+ // Ignore unknown calls.
+ const char *CalleeName = Callee->getNameStart();
+ StringMap<LibCallOptimization*>::iterator OMI =
+ Optimizations.find(CalleeName, CalleeName+Callee->getNameLen());
+ if (OMI == Optimizations.end()) continue;
+
+ // Set the builder to the instruction after the call.
+ Builder.SetInsertPoint(BB, I);
+
+ // Try to optimize this call.
+ Value *Result = OMI->second->OptimizeCall(CI, TD, Builder);
+ if (Result == 0) continue;
+
+ // Something changed!
+ Changed = true;
+ ++NumSimplified;
+
+ // Inspect the instruction after the call (which was potentially just
+ // added) next.
+ I = CI; ++I;
+
+ if (CI != Result && !CI->use_empty()) {
+ CI->replaceAllUsesWith(Result);
+ if (!Result->hasName())
+ Result->takeName(CI);
+ }
+ CI->eraseFromParent();
+ }
+ }
+ return Changed;
+}
+
+
+// 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'
+//
+//