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llvm-6502/lib/Transforms/Utils/SimplifyLibCalls.cpp
Meador Inge 69ea027e04 instcombine: Migrate sprintf optimizations 
This patch migrates the sprintf optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168677 91177308-0d34-0410-b5e6-96231b3b80d8
2012-11-27 05:57:54 +00:00

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//===------ SimplifyLibCalls.cpp - Library calls simplifier ---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This is a utility pass used for testing the InstructionSimplify analysis.
// The analysis is applied to every instruction, and if it simplifies then the
// instruction is replaced by the simplification. If you are looking for a pass
// that performs serious instruction folding, use the instcombine pass instead.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/SimplifyLibCalls.h"
#include "llvm/DataLayout.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/Function.h"
#include "llvm/IRBuilder.h"
#include "llvm/Intrinsics.h"
#include "llvm/Module.h"
#include "llvm/LLVMContext.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
using namespace llvm;
/// This class is the abstract base class for the set of optimizations that
/// corresponds to one library call.
namespace {
class LibCallOptimization {
protected:
Function *Caller;
const DataLayout *TD;
const TargetLibraryInfo *TLI;
const LibCallSimplifier *LCS;
LLVMContext* Context;
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 DataLayout *TD,
const TargetLibraryInfo *TLI,
const LibCallSimplifier *LCS, IRBuilder<> &B) {
Caller = CI->getParent()->getParent();
this->TD = TD;
this->TLI = TLI;
this->LCS = LCS;
if (CI->getCalledFunction())
Context = &CI->getCalledFunction()->getContext();
// We never change the calling convention.
if (CI->getCallingConv() != llvm::CallingConv::C)
return NULL;
return callOptimizer(CI->getCalledFunction(), CI, B);
}
};
//===----------------------------------------------------------------------===//
// Helper Functions
//===----------------------------------------------------------------------===//
/// 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;
}
/// isOnlyUsedInEqualityComparison - Return true if it is only used in equality
/// comparisons with With.
static bool isOnlyUsedInEqualityComparison(Value *V, Value *With) {
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() && IC->getOperand(1) == With)
continue;
// Unknown instruction.
return false;
}
return true;
}
static bool callHasFloatingPointArgument(const CallInst *CI) {
for (CallInst::const_op_iterator it = CI->op_begin(), e = CI->op_end();
it != e; ++it) {
if ((*it)->getType()->isFloatingPointTy())
return true;
}
return false;
}
//===----------------------------------------------------------------------===//
// Fortified Library Call Optimizations
//===----------------------------------------------------------------------===//
struct FortifiedLibCallOptimization : public LibCallOptimization {
protected:
virtual bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp,
bool isString) const = 0;
};
struct InstFortifiedLibCallOptimization : public FortifiedLibCallOptimization {
CallInst *CI;
bool isFoldable(unsigned SizeCIOp, unsigned SizeArgOp, bool isString) const {
if (CI->getArgOperand(SizeCIOp) == CI->getArgOperand(SizeArgOp))
return true;
if (ConstantInt *SizeCI =
dyn_cast<ConstantInt>(CI->getArgOperand(SizeCIOp))) {
if (SizeCI->isAllOnesValue())
return true;
if (isString) {
uint64_t Len = GetStringLength(CI->getArgOperand(SizeArgOp));
// If the length is 0 we don't know how long it is and so we can't
// remove the check.
if (Len == 0) return false;
return SizeCI->getZExtValue() >= Len;
}
if (ConstantInt *Arg = dyn_cast<ConstantInt>(
CI->getArgOperand(SizeArgOp)))
return SizeCI->getZExtValue() >= Arg->getZExtValue();
}
return false;
}
};
struct MemCpyChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != TD->getIntPtrType(Context) ||
FT->getParamType(3) != TD->getIntPtrType(Context))
return 0;
if (isFoldable(3, 2, false)) {
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
return 0;
}
};
struct MemMoveChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != TD->getIntPtrType(Context) ||
FT->getParamType(3) != TD->getIntPtrType(Context))
return 0;
if (isFoldable(3, 2, false)) {
B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
return 0;
}
};
struct MemSetChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() ||
FT->getParamType(2) != TD->getIntPtrType(Context) ||
FT->getParamType(3) != TD->getIntPtrType(Context))
return 0;
if (isFoldable(3, 2, false)) {
Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(),
false);
B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
return 0;
}
};
struct StrCpyChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
StringRef Name = Callee->getName();
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 3 ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
FT->getParamType(2) != TD->getIntPtrType(Context))
return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) // __strcpy_chk(x,x) -> x
return Src;
// If a) we don't have any length information, or b) we know this will
// fit then just lower to a plain strcpy. Otherwise we'll keep our
// strcpy_chk call which may fail at runtime if the size is too long.
// TODO: It might be nice to get a maximum length out of the possible
// string lengths for varying.
if (isFoldable(2, 1, true)) {
Value *Ret = EmitStrCpy(Dst, Src, B, TD, TLI, Name.substr(2, 6));
return Ret;
} else {
// Maybe we can stil fold __strcpy_chk to __memcpy_chk.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
// This optimization require DataLayout.
if (!TD) return 0;
Value *Ret =
EmitMemCpyChk(Dst, Src,
ConstantInt::get(TD->getIntPtrType(Context), Len),
CI->getArgOperand(2), B, TD, TLI);
return Ret;
}
return 0;
}
};
struct StpCpyChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
StringRef Name = Callee->getName();
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 3 ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
FT->getParamType(2) != TD->getIntPtrType(FT->getParamType(0)))
return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, TD, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0;
}
// If a) we don't have any length information, or b) we know this will
// fit then just lower to a plain stpcpy. Otherwise we'll keep our
// stpcpy_chk call which may fail at runtime if the size is too long.
// TODO: It might be nice to get a maximum length out of the possible
// string lengths for varying.
if (isFoldable(2, 1, true)) {
Value *Ret = EmitStrCpy(Dst, Src, B, TD, TLI, Name.substr(2, 6));
return Ret;
} else {
// Maybe we can stil fold __stpcpy_chk to __memcpy_chk.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
// This optimization require DataLayout.
if (!TD) return 0;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(TD->getIntPtrType(PT),
Len - 1));
if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, TD, TLI))
return 0;
return DstEnd;
}
return 0;
}
};
struct StrNCpyChkOpt : public InstFortifiedLibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
this->CI = CI;
StringRef Name = Callee->getName();
FunctionType *FT = Callee->getFunctionType();
LLVMContext &Context = CI->getParent()->getContext();
// Check if this has the right signature.
if (FT->getNumParams() != 4 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != Type::getInt8PtrTy(Context) ||
!FT->getParamType(2)->isIntegerTy() ||
FT->getParamType(3) != TD->getIntPtrType(Context))
return 0;
if (isFoldable(3, 2, false)) {
Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), B, TD, TLI,
Name.substr(2, 7));
return Ret;
}
return 0;
}
};
//===----------------------------------------------------------------------===//
// String and Memory Library Call Optimizations
//===----------------------------------------------------------------------===//
struct StrCatOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strcat" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != B.getInt8PtrTy() ||
FT->getParamType(0) != FT->getReturnType() ||
FT->getParamType(1) != FT->getReturnType())
return 0;
// Extract some information from the instruction
Value *Dst = CI->getArgOperand(0);
Value *Src = CI->getArgOperand(1);
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
--Len; // Unbias length.
// Handle the simple, do-nothing case: strcat(x, "") -> x
if (Len == 0)
return Dst;
// These optimizations require DataLayout.
if (!TD) return 0;
return emitStrLenMemCpy(Src, Dst, Len, B);
}
Value *emitStrLenMemCpy(Value *Src, Value *Dst, uint64_t Len,
IRBuilder<> &B) {
// 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, TD, TLI);
if (!DstLen)
return 0;
// 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).
Value *CpyDst = 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.
B.CreateMemCpy(CpyDst, Src,
ConstantInt::get(TD->getIntPtrType(*Context), Len + 1), 1);
return Dst;
}
};
struct StrNCatOpt : public StrCatOpt {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strncat" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 ||
FT->getReturnType() != B.getInt8PtrTy() ||
FT->getParamType(0) != FT->getReturnType() ||
FT->getParamType(1) != FT->getReturnType() ||
!FT->getParamType(2)->isIntegerTy())
return 0;
// Extract some information from the instruction
Value *Dst = CI->getArgOperand(0);
Value *Src = CI->getArgOperand(1);
uint64_t Len;
// We don't do anything if length is not constant
if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(CI->getArgOperand(2)))
Len = LengthArg->getZExtValue();
else
return 0;
// See if we can get the length of the input string.
uint64_t SrcLen = GetStringLength(Src);
if (SrcLen == 0) return 0;
--SrcLen; // Unbias length.
// Handle the simple, do-nothing cases:
// strncat(x, "", c) -> x
// strncat(x, c, 0) -> x
if (SrcLen == 0 || Len == 0) return Dst;
// These optimizations require DataLayout.
if (!TD) return 0;
// We don't optimize this case
if (Len < SrcLen) return 0;
// strncat(x, s, c) -> strcat(x, s)
// s is constant so the strcat can be optimized further
return emitStrLenMemCpy(Src, Dst, SrcLen, B);
}
};
struct StrChrOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strchr" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != B.getInt8PtrTy() ||
FT->getParamType(0) != FT->getReturnType() ||
!FT->getParamType(1)->isIntegerTy(32))
return 0;
Value *SrcStr = CI->getArgOperand(0);
// 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->getArgOperand(1));
if (CharC == 0) {
// These optimizations require DataLayout.
if (!TD) return 0;
uint64_t Len = GetStringLength(SrcStr);
if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
return 0;
return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
ConstantInt::get(TD->getIntPtrType(*Context), Len),
B, TD, TLI);
}
// Otherwise, the character is a constant, see if the first argument is
// a string literal. If so, we can constant fold.
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str))
return 0;
// Compute the offset, make sure to handle the case when we're searching for
// zero (a weird way to spell strlen).
size_t I = CharC->getSExtValue() == 0 ?
Str.size() : Str.find(CharC->getSExtValue());
if (I == StringRef::npos) // Didn't find the char. strchr returns null.
return Constant::getNullValue(CI->getType());
// strchr(s+n,c) -> gep(s+n+i,c)
return B.CreateGEP(SrcStr, B.getInt64(I), "strchr");
}
};
struct StrRChrOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strrchr" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != B.getInt8PtrTy() ||
FT->getParamType(0) != FT->getReturnType() ||
!FT->getParamType(1)->isIntegerTy(32))
return 0;
Value *SrcStr = CI->getArgOperand(0);
ConstantInt *CharC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
// Cannot fold anything if we're not looking for a constant.
if (!CharC)
return 0;
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str)) {
// strrchr(s, 0) -> strchr(s, 0)
if (TD && CharC->isZero())
return EmitStrChr(SrcStr, '\0', B, TD, TLI);
return 0;
}
// Compute the offset.
size_t I = CharC->getSExtValue() == 0 ?
Str.size() : Str.rfind(CharC->getSExtValue());
if (I == StringRef::npos) // Didn't find the char. Return null.
return Constant::getNullValue(CI->getType());
// strrchr(s+n,c) -> gep(s+n+i,c)
return B.CreateGEP(SrcStr, B.getInt64(I), "strrchr");
}
};
struct StrCmpOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strcmp" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
!FT->getReturnType()->isIntegerTy(32) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
if (Str1P == Str2P) // strcmp(x,x) -> 0
return ConstantInt::get(CI->getType(), 0);
StringRef Str1, Str2;
bool HasStr1 = getConstantStringInfo(Str1P, Str1);
bool HasStr2 = getConstantStringInfo(Str2P, Str2);
// strcmp(x, y) -> cnst (if both x and y are constant strings)
if (HasStr1 && HasStr2)
return ConstantInt::get(CI->getType(), Str1.compare(Str2));
if (HasStr1 && Str1.empty()) // strcmp("", x) -> -*x
return B.CreateNeg(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(P, "x") -> memcmp(P, "x", 2)
uint64_t Len1 = GetStringLength(Str1P);
uint64_t Len2 = GetStringLength(Str2P);
if (Len1 && Len2) {
// These optimizations require DataLayout.
if (!TD) return 0;
return EmitMemCmp(Str1P, Str2P,
ConstantInt::get(TD->getIntPtrType(*Context),
std::min(Len1, Len2)), B, TD, TLI);
}
return 0;
}
};
struct StrNCmpOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strncmp" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 ||
!FT->getReturnType()->isIntegerTy(32) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getParamType(2)->isIntegerTy())
return 0;
Value *Str1P = CI->getArgOperand(0), *Str2P = CI->getArgOperand(1);
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->getArgOperand(2)))
Length = LengthArg->getZExtValue();
else
return 0;
if (Length == 0) // strncmp(x,y,0) -> 0
return ConstantInt::get(CI->getType(), 0);
if (TD && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, TD, TLI);
StringRef Str1, Str2;
bool HasStr1 = getConstantStringInfo(Str1P, Str1);
bool HasStr2 = getConstantStringInfo(Str2P, Str2);
// strncmp(x, y) -> cnst (if both x and y are constant strings)
if (HasStr1 && HasStr2) {
StringRef SubStr1 = Str1.substr(0, Length);
StringRef SubStr2 = Str2.substr(0, Length);
return ConstantInt::get(CI->getType(), SubStr1.compare(SubStr2));
}
if (HasStr1 && Str1.empty()) // strncmp("", x, n) -> -*x
return B.CreateNeg(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());
return 0;
}
};
struct StrCpyOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) // strcpy(x,x) -> x
return Src;
// These optimizations require DataLayout.
if (!TD) return 0;
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
B.CreateMemCpy(Dst, Src,
ConstantInt::get(TD->getIntPtrType(*Context), Len), 1);
return Dst;
}
};
struct StpCpyOpt: public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "stpcpy" function prototype.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
// These optimizations require DataLayout.
if (!TD) return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, TD, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0;
}
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(TD->getIntPtrType(PT),
Len - 1));
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
B.CreateMemCpy(Dst, Src, LenV, 1);
return DstEnd;
}
};
struct StrNCpyOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getParamType(2)->isIntegerTy())
return 0;
Value *Dst = CI->getArgOperand(0);
Value *Src = CI->getArgOperand(1);
Value *LenOp = CI->getArgOperand(2);
// See if we can get the length of the input string.
uint64_t SrcLen = GetStringLength(Src);
if (SrcLen == 0) return 0;
--SrcLen;
if (SrcLen == 0) {
// strncpy(x, "", y) -> memset(x, '\0', y, 1)
B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
return Dst;
}
uint64_t Len;
if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
Len = LengthArg->getZExtValue();
else
return 0;
if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
// These optimizations require DataLayout.
if (!TD) return 0;
// Let strncpy handle the zero padding
if (Len > SrcLen+1) return 0;
Type *PT = FT->getParamType(0);
// strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
B.CreateMemCpy(Dst, Src,
ConstantInt::get(TD->getIntPtrType(PT), Len), 1);
return Dst;
}
};
struct StrLenOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 1 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getReturnType()->isIntegerTy())
return 0;
Value *Src = CI->getArgOperand(0);
// Constant folding: strlen("xyz") -> 3
if (uint64_t Len = GetStringLength(Src))
return ConstantInt::get(CI->getType(), Len-1);
// strlen(x) != 0 --> *x != 0
// strlen(x) == 0 --> *x == 0
if (isOnlyUsedInZeroEqualityComparison(CI))
return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
return 0;
}
};
struct StrPBrkOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
FT->getParamType(1) != FT->getParamType(0) ||
FT->getReturnType() != FT->getParamType(0))
return 0;
StringRef S1, S2;
bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
// strpbrk(s, "") -> NULL
// strpbrk("", s) -> NULL
if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
return Constant::getNullValue(CI->getType());
// Constant folding.
if (HasS1 && HasS2) {
size_t I = S1.find_first_of(S2);
if (I == std::string::npos) // No match.
return Constant::getNullValue(CI->getType());
return B.CreateGEP(CI->getArgOperand(0), B.getInt64(I), "strpbrk");
}
// strpbrk(s, "a") -> strchr(s, 'a')
if (TD && HasS2 && S2.size() == 1)
return EmitStrChr(CI->getArgOperand(0), S2[0], B, TD, TLI);
return 0;
}
};
struct StrToOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy())
return 0;
Value *EndPtr = CI->getArgOperand(1);
if (isa<ConstantPointerNull>(EndPtr)) {
// With a null EndPtr, this function won't capture the main argument.
// It would be readonly too, except that it still may write to errno.
CI->addAttribute(1, Attributes::get(Callee->getContext(),
Attributes::NoCapture));
}
return 0;
}
};
struct StrSpnOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return 0;
StringRef S1, S2;
bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
// strspn(s, "") -> 0
// strspn("", s) -> 0
if ((HasS1 && S1.empty()) || (HasS2 && S2.empty()))
return Constant::getNullValue(CI->getType());
// Constant folding.
if (HasS1 && HasS2) {
size_t Pos = S1.find_first_not_of(S2);
if (Pos == StringRef::npos) Pos = S1.size();
return ConstantInt::get(CI->getType(), Pos);
}
return 0;
}
};
struct StrCSpnOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return 0;
StringRef S1, S2;
bool HasS1 = getConstantStringInfo(CI->getArgOperand(0), S1);
bool HasS2 = getConstantStringInfo(CI->getArgOperand(1), S2);
// strcspn("", s) -> 0
if (HasS1 && S1.empty())
return Constant::getNullValue(CI->getType());
// Constant folding.
if (HasS1 && HasS2) {
size_t Pos = S1.find_first_of(S2);
if (Pos == StringRef::npos) Pos = S1.size();
return ConstantInt::get(CI->getType(), Pos);
}
// strcspn(s, "") -> strlen(s)
if (TD && HasS2 && S2.empty())
return EmitStrLen(CI->getArgOperand(0), B, TD, TLI);
return 0;
}
};
struct StrStrOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isPointerTy())
return 0;
// fold strstr(x, x) -> x.
if (CI->getArgOperand(0) == CI->getArgOperand(1))
return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
// fold strstr(a, b) == a -> strncmp(a, b, strlen(b)) == 0
if (TD && isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, TD, TLI);
if (!StrLen)
return 0;
Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
StrLen, B, TD, TLI);
if (!StrNCmp)
return 0;
for (Value::use_iterator UI = CI->use_begin(), UE = CI->use_end();
UI != UE; ) {
ICmpInst *Old = cast<ICmpInst>(*UI++);
Value *Cmp = B.CreateICmp(Old->getPredicate(), StrNCmp,
ConstantInt::getNullValue(StrNCmp->getType()),
"cmp");
LCS->replaceAllUsesWith(Old, Cmp);
}
return CI;
}
// See if either input string is a constant string.
StringRef SearchStr, ToFindStr;
bool HasStr1 = getConstantStringInfo(CI->getArgOperand(0), SearchStr);
bool HasStr2 = getConstantStringInfo(CI->getArgOperand(1), ToFindStr);
// fold strstr(x, "") -> x.
if (HasStr2 && ToFindStr.empty())
return B.CreateBitCast(CI->getArgOperand(0), CI->getType());
// If both strings are known, constant fold it.
if (HasStr1 && HasStr2) {
std::string::size_type Offset = SearchStr.find(ToFindStr);
if (Offset == StringRef::npos) // strstr("foo", "bar") -> null
return Constant::getNullValue(CI->getType());
// strstr("abcd", "bc") -> gep((char*)"abcd", 1)
Value *Result = CastToCStr(CI->getArgOperand(0), B);
Result = B.CreateConstInBoundsGEP1_64(Result, Offset, "strstr");
return B.CreateBitCast(Result, CI->getType());
}
// fold strstr(x, "y") -> strchr(x, 'y').
if (HasStr2 && ToFindStr.size() == 1) {
Value *StrChr= EmitStrChr(CI->getArgOperand(0), ToFindStr[0], B, TD, TLI);
return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : 0;
}
return 0;
}
};
struct MemCmpOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isIntegerTy(32))
return 0;
Value *LHS = CI->getArgOperand(0), *RHS = CI->getArgOperand(1);
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->getArgOperand(2));
if (!LenC) return 0;
uint64_t Len = LenC->getZExtValue();
if (Len == 0) // memcmp(s1,s2,0) -> 0
return Constant::getNullValue(CI->getType());
// memcmp(S1,S2,1) -> *(unsigned char*)LHS - *(unsigned char*)RHS
if (Len == 1) {
Value *LHSV = B.CreateZExt(B.CreateLoad(CastToCStr(LHS, B), "lhsc"),
CI->getType(), "lhsv");
Value *RHSV = B.CreateZExt(B.CreateLoad(CastToCStr(RHS, B), "rhsc"),
CI->getType(), "rhsv");
return B.CreateSub(LHSV, RHSV, "chardiff");
}
// Constant folding: memcmp(x, y, l) -> cnst (all arguments are constant)
StringRef LHSStr, RHSStr;
if (getConstantStringInfo(LHS, LHSStr) &&
getConstantStringInfo(RHS, RHSStr)) {
// Make sure we're not reading out-of-bounds memory.
if (Len > LHSStr.size() || Len > RHSStr.size())
return 0;
// Fold the memcmp and normalize the result. This way we get consistent
// results across multiple platforms.
uint64_t Ret = 0;
int Cmp = memcmp(LHSStr.data(), RHSStr.data(), Len);
if (Cmp < 0)
Ret = -1;
else if (Cmp > 0)
Ret = 1;
return ConstantInt::get(CI->getType(), Ret);
}
return 0;
}
};
struct MemCpyOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// These optimizations require DataLayout.
if (!TD) return 0;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != TD->getIntPtrType(*Context))
return 0;
// memcpy(x, y, n) -> llvm.memcpy(x, y, n, 1)
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
};
struct MemMoveOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// These optimizations require DataLayout.
if (!TD) return 0;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != TD->getIntPtrType(*Context))
return 0;
// memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
};
struct MemSetOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// These optimizations require DataLayout.
if (!TD) return 0;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() ||
FT->getParamType(2) != TD->getIntPtrType(*Context))
return 0;
// memset(p, v, n) -> llvm.memset(p, v, n, 1)
Value *Val = B.CreateIntCast(CI->getArgOperand(1), B.getInt8Ty(), false);
B.CreateMemSet(CI->getArgOperand(0), Val, CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
};
//===----------------------------------------------------------------------===//
// Math Library Optimizations
//===----------------------------------------------------------------------===//
//===----------------------------------------------------------------------===//
// Double -> Float Shrinking Optimizations for Unary Functions like 'floor'
struct UnaryDoubleFPOpt : public LibCallOptimization {
bool CheckRetType;
UnaryDoubleFPOpt(bool CheckReturnType): CheckRetType(CheckReturnType) {}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
!FT->getParamType(0)->isDoubleTy())
return 0;
if (CheckRetType) {
// Check if all the uses for function like 'sin' are converted to float.
for (Value::use_iterator UseI = CI->use_begin(); UseI != CI->use_end();
++UseI) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(*UseI);
if (Cast == 0 || !Cast->getType()->isFloatTy())
return 0;
}
}
// If this is something like 'floor((double)floatval)', convert to floorf.
FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
if (Cast == 0 || !Cast->getOperand(0)->getType()->isFloatTy())
return 0;
// floor((double)floatval) -> (double)floorf(floatval)
Value *V = Cast->getOperand(0);
V = EmitUnaryFloatFnCall(V, Callee->getName(), B, Callee->getAttributes());
return B.CreateFPExt(V, B.getDoubleTy());
}
};
struct UnsafeFPLibCallOptimization : public LibCallOptimization {
bool UnsafeFPShrink;
UnsafeFPLibCallOptimization(bool UnsafeFPShrink) {
this->UnsafeFPShrink = UnsafeFPShrink;
}
};
struct CosOpt : public UnsafeFPLibCallOptimization {
CosOpt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
Value *Ret = NULL;
if (UnsafeFPShrink && Callee->getName() == "cos" &&
TLI->has(LibFunc::cosf)) {
UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
}
FunctionType *FT = Callee->getFunctionType();
// Just make sure this has 1 argument of FP type, which matches the
// result type.
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isFloatingPointTy())
return Ret;
// cos(-x) -> cos(x)
Value *Op1 = CI->getArgOperand(0);
if (BinaryOperator::isFNeg(Op1)) {
BinaryOperator *BinExpr = cast<BinaryOperator>(Op1);
return B.CreateCall(Callee, BinExpr->getOperand(1), "cos");
}
return Ret;
}
};
struct PowOpt : public UnsafeFPLibCallOptimization {
PowOpt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
Value *Ret = NULL;
if (UnsafeFPShrink && Callee->getName() == "pow" &&
TLI->has(LibFunc::powf)) {
UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
}
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)->isFloatingPointTy())
return Ret;
Value *Op1 = CI->getArgOperand(0), *Op2 = CI->getArgOperand(1);
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, Callee->getAttributes());
}
ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
if (Op2C == 0) return Ret;
if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
return ConstantFP::get(CI->getType(), 1.0);
if (Op2C->isExactlyValue(0.5)) {
// Expand pow(x, 0.5) to (x == -infinity ? +infinity : fabs(sqrt(x))).
// This is faster than calling pow, and still handles negative zero
// and negative infinity correctly.
// TODO: In fast-math mode, this could be just sqrt(x).
// TODO: In finite-only mode, this could be just fabs(sqrt(x)).
Value *Inf = ConstantFP::getInfinity(CI->getType());
Value *NegInf = ConstantFP::getInfinity(CI->getType(), true);
Value *Sqrt = EmitUnaryFloatFnCall(Op1, "sqrt", B,
Callee->getAttributes());
Value *FAbs = EmitUnaryFloatFnCall(Sqrt, "fabs", B,
Callee->getAttributes());
Value *FCmp = B.CreateFCmpOEQ(Op1, NegInf);
Value *Sel = B.CreateSelect(FCmp, Inf, FAbs);
return Sel;
}
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.CreateFMul(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;
}
};
struct Exp2Opt : public UnsafeFPLibCallOptimization {
Exp2Opt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
Value *Ret = NULL;
if (UnsafeFPShrink && Callee->getName() == "exp2" &&
TLI->has(LibFunc::exp2)) {
UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
Ret = UnsafeUnaryDoubleFP.callOptimizer(Callee, CI, B);
}
FunctionType *FT = Callee->getFunctionType();
// Just make sure this has 1 argument of FP type, which matches the
// result type.
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isFloatingPointTy())
return Ret;
Value *Op = CI->getArgOperand(0);
// Turn exp2(sitofp(x)) -> ldexp(1.0, sext(x)) if sizeof(x) <= 32
// Turn exp2(uitofp(x)) -> ldexp(1.0, zext(x)) if sizeof(x) < 32
Value *LdExpArg = 0;
if (SIToFPInst *OpC = dyn_cast<SIToFPInst>(Op)) {
if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() <= 32)
LdExpArg = B.CreateSExt(OpC->getOperand(0), B.getInt32Ty());
} else if (UIToFPInst *OpC = dyn_cast<UIToFPInst>(Op)) {
if (OpC->getOperand(0)->getType()->getPrimitiveSizeInBits() < 32)
LdExpArg = B.CreateZExt(OpC->getOperand(0), B.getInt32Ty());
}
if (LdExpArg) {
const char *Name;
if (Op->getType()->isFloatTy())
Name = "ldexpf";
else if (Op->getType()->isDoubleTy())
Name = "ldexp";
else
Name = "ldexpl";
Constant *One = ConstantFP::get(*Context, APFloat(1.0f));
if (!Op->getType()->isFloatTy())
One = ConstantExpr::getFPExtend(One, Op->getType());
Module *M = Caller->getParent();
Value *Callee = M->getOrInsertFunction(Name, Op->getType(),
Op->getType(),
B.getInt32Ty(), NULL);
CallInst *CI = B.CreateCall2(Callee, One, LdExpArg);
if (const Function *F = dyn_cast<Function>(Callee->stripPointerCasts()))
CI->setCallingConv(F->getCallingConv());
return CI;
}
return Ret;
}
};
//===----------------------------------------------------------------------===//
// Integer Library Call Optimizations
//===----------------------------------------------------------------------===//
struct FFSOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
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()->isIntegerTy(32) ||
!FT->getParamType(0)->isIntegerTy())
return 0;
Value *Op = CI->getArgOperand(0);
// Constant fold.
if (ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
if (CI->isZero()) // ffs(0) -> 0.
return B.getInt32(0);
// ffs(c) -> cttz(c)+1
return B.getInt32(CI->getValue().countTrailingZeros() + 1);
}
// ffs(x) -> x != 0 ? (i32)llvm.cttz(x)+1 : 0
Type *ArgType = Op->getType();
Value *F = Intrinsic::getDeclaration(Callee->getParent(),
Intrinsic::cttz, ArgType);
Value *V = B.CreateCall2(F, Op, B.getFalse(), "cttz");
V = B.CreateAdd(V, ConstantInt::get(V->getType(), 1));
V = B.CreateIntCast(V, B.getInt32Ty(), false);
Value *Cond = B.CreateICmpNE(Op, Constant::getNullValue(ArgType));
return B.CreateSelect(Cond, V, B.getInt32(0));
}
};
struct AbsOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
// We require integer(integer) where the types agree.
if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
FT->getParamType(0) != FT->getReturnType())
return 0;
// abs(x) -> x >s -1 ? x : -x
Value *Op = CI->getArgOperand(0);
Value *Pos = B.CreateICmpSGT(Op, Constant::getAllOnesValue(Op->getType()),
"ispos");
Value *Neg = B.CreateNeg(Op, "neg");
return B.CreateSelect(Pos, Op, Neg);
}
};
struct IsDigitOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
// We require integer(i32)
if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
!FT->getParamType(0)->isIntegerTy(32))
return 0;
// isdigit(c) -> (c-'0') <u 10
Value *Op = CI->getArgOperand(0);
Op = B.CreateSub(Op, B.getInt32('0'), "isdigittmp");
Op = B.CreateICmpULT(Op, B.getInt32(10), "isdigit");
return B.CreateZExt(Op, CI->getType());
}
};
struct IsAsciiOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
// We require integer(i32)
if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
!FT->getParamType(0)->isIntegerTy(32))
return 0;
// isascii(c) -> c <u 128
Value *Op = CI->getArgOperand(0);
Op = B.CreateICmpULT(Op, B.getInt32(128), "isascii");
return B.CreateZExt(Op, CI->getType());
}
};
struct ToAsciiOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
// We require i32(i32)
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isIntegerTy(32))
return 0;
// toascii(c) -> c & 0x7f
return B.CreateAnd(CI->getArgOperand(0),
ConstantInt::get(CI->getType(),0x7F));
}
};
//===----------------------------------------------------------------------===//
// Formatting and IO Library Call Optimizations
//===----------------------------------------------------------------------===//
struct PrintFOpt : public LibCallOptimization {
Value *optimizeFixedFormatString(Function *Callee, CallInst *CI,
IRBuilder<> &B) {
// Check for a fixed format string.
StringRef FormatStr;
if (!getConstantStringInfo(CI->getArgOperand(0), FormatStr))
return 0;
// Empty format string -> noop.
if (FormatStr.empty()) // Tolerate printf's declared void.
return CI->use_empty() ? (Value*)CI :
ConstantInt::get(CI->getType(), 0);
// Do not do any of the following transformations if the printf return value
// is used, in general the printf return value is not compatible with either
// putchar() or puts().
if (!CI->use_empty())
return 0;
// printf("x") -> putchar('x'), even for '%'.
if (FormatStr.size() == 1) {
Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, TD, TLI);
if (CI->use_empty() || !Res) return Res;
return B.CreateIntCast(Res, CI->getType(), true);
}
// 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 = FormatStr.drop_back();
Value *GV = B.CreateGlobalString(FormatStr, "str");
Value *NewCI = EmitPutS(GV, B, TD, TLI);
return (CI->use_empty() || !NewCI) ?
NewCI :
ConstantInt::get(CI->getType(), FormatStr.size()+1);
}
// Optimize specific format strings.
// printf("%c", chr) --> putchar(chr)
if (FormatStr == "%c" && CI->getNumArgOperands() > 1 &&
CI->getArgOperand(1)->getType()->isIntegerTy()) {
Value *Res = EmitPutChar(CI->getArgOperand(1), B, TD, TLI);
if (CI->use_empty() || !Res) return Res;
return B.CreateIntCast(Res, CI->getType(), true);
}
// printf("%s\n", str) --> puts(str)
if (FormatStr == "%s\n" && CI->getNumArgOperands() > 1 &&
CI->getArgOperand(1)->getType()->isPointerTy()) {
return EmitPutS(CI->getArgOperand(1), B, TD, TLI);
}
return 0;
}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Require one fixed pointer argument and an integer/void result.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
!(FT->getReturnType()->isIntegerTy() ||
FT->getReturnType()->isVoidTy()))
return 0;
if (Value *V = optimizeFixedFormatString(Callee, CI, B)) {
return V;
}
// printf(format, ...) -> iprintf(format, ...) if no floating point
// arguments.
if (TLI->has(LibFunc::iprintf) && !callHasFloatingPointArgument(CI)) {
Module *M = B.GetInsertBlock()->getParent()->getParent();
Constant *IPrintFFn =
M->getOrInsertFunction("iprintf", FT, Callee->getAttributes());
CallInst *New = cast<CallInst>(CI->clone());
New->setCalledFunction(IPrintFFn);
B.Insert(New);
return New;
}
return 0;
}
};
struct SPrintFOpt : public LibCallOptimization {
Value *OptimizeFixedFormatString(Function *Callee, CallInst *CI,
IRBuilder<> &B) {
// Check for a fixed format string.
StringRef FormatStr;
if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
return 0;
// If we just have a format string (nothing else crazy) transform it.
if (CI->getNumArgOperands() == 2) {
// 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.
// These optimizations require DataLayout.
if (!TD) return 0;
// sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
ConstantInt::get(TD->getIntPtrType(*Context), // Copy the
FormatStr.size() + 1), 1); // nul byte.
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->getNumArgOperands() < 3)
return 0;
// Decode the second character of the format string.
if (FormatStr[1] == 'c') {
// sprintf(dst, "%c", chr) --> *(i8*)dst = chr; *((i8*)dst+1) = 0
if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return 0;
Value *V = B.CreateTrunc(CI->getArgOperand(2), B.getInt8Ty(), "char");
Value *Ptr = CastToCStr(CI->getArgOperand(0), B);
B.CreateStore(V, Ptr);
Ptr = B.CreateGEP(Ptr, B.getInt32(1), "nul");
B.CreateStore(B.getInt8(0), Ptr);
return ConstantInt::get(CI->getType(), 1);
}
if (FormatStr[1] == 's') {
// These optimizations require DataLayout.
if (!TD) return 0;
// sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
if (!CI->getArgOperand(2)->getType()->isPointerTy()) return 0;
Value *Len = EmitStrLen(CI->getArgOperand(2), B, TD, TLI);
if (!Len)
return 0;
Value *IncLen = B.CreateAdd(Len,
ConstantInt::get(Len->getType(), 1),
"leninc");
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(2), IncLen, 1);
// The sprintf result is the unincremented number of bytes in the string.
return B.CreateIntCast(Len, CI->getType(), false);
}
return 0;
}
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Require two fixed pointer arguments and an integer result.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isIntegerTy())
return 0;
if (Value *V = OptimizeFixedFormatString(Callee, CI, B)) {
return V;
}
// sprintf(str, format, ...) -> siprintf(str, format, ...) if no floating
// point arguments.
if (TLI->has(LibFunc::siprintf) && !callHasFloatingPointArgument(CI)) {
Module *M = B.GetInsertBlock()->getParent()->getParent();
Constant *SIPrintFFn =
M->getOrInsertFunction("siprintf", FT, Callee->getAttributes());
CallInst *New = cast<CallInst>(CI->clone());
New->setCalledFunction(SIPrintFFn);
B.Insert(New);
return New;
}
return 0;
}
};
} // End anonymous namespace.
namespace llvm {
class LibCallSimplifierImpl {
const DataLayout *TD;
const TargetLibraryInfo *TLI;
const LibCallSimplifier *LCS;
bool UnsafeFPShrink;
StringMap<LibCallOptimization*> Optimizations;
// Fortified library call optimizations.
MemCpyChkOpt MemCpyChk;
MemMoveChkOpt MemMoveChk;
MemSetChkOpt MemSetChk;
StrCpyChkOpt StrCpyChk;
StpCpyChkOpt StpCpyChk;
StrNCpyChkOpt StrNCpyChk;
// String library call optimizations.
StrCatOpt StrCat;
StrNCatOpt StrNCat;
StrChrOpt StrChr;
StrRChrOpt StrRChr;
StrCmpOpt StrCmp;
StrNCmpOpt StrNCmp;
StrCpyOpt StrCpy;
StpCpyOpt StpCpy;
StrNCpyOpt StrNCpy;
StrLenOpt StrLen;
StrPBrkOpt StrPBrk;
StrToOpt StrTo;
StrSpnOpt StrSpn;
StrCSpnOpt StrCSpn;
StrStrOpt StrStr;
// Memory library call optimizations.
MemCmpOpt MemCmp;
MemCpyOpt MemCpy;
MemMoveOpt MemMove;
MemSetOpt MemSet;
// Math library call optimizations.
UnaryDoubleFPOpt UnaryDoubleFP, UnsafeUnaryDoubleFP;
CosOpt Cos; PowOpt Pow; Exp2Opt Exp2;
// Integer library call optimizations.
FFSOpt FFS;
AbsOpt Abs;
IsDigitOpt IsDigit;
IsAsciiOpt IsAscii;
ToAsciiOpt ToAscii;
// Formatting and IO library call optimizations.
PrintFOpt PrintF;
SPrintFOpt SPrintF;
void initOptimizations();
void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
void addOpt(LibFunc::Func F1, LibFunc::Func F2, LibCallOptimization* Opt);
public:
LibCallSimplifierImpl(const DataLayout *TD, const TargetLibraryInfo *TLI,
const LibCallSimplifier *LCS,
bool UnsafeFPShrink = false)
: UnaryDoubleFP(false), UnsafeUnaryDoubleFP(true),
Cos(UnsafeFPShrink), Pow(UnsafeFPShrink), Exp2(UnsafeFPShrink) {
this->TD = TD;
this->TLI = TLI;
this->LCS = LCS;
this->UnsafeFPShrink = UnsafeFPShrink;
}
Value *optimizeCall(CallInst *CI);
};
void LibCallSimplifierImpl::initOptimizations() {
// Fortified library call optimizations.
Optimizations["__memcpy_chk"] = &MemCpyChk;
Optimizations["__memmove_chk"] = &MemMoveChk;
Optimizations["__memset_chk"] = &MemSetChk;
Optimizations["__strcpy_chk"] = &StrCpyChk;
Optimizations["__stpcpy_chk"] = &StpCpyChk;
Optimizations["__strncpy_chk"] = &StrNCpyChk;
Optimizations["__stpncpy_chk"] = &StrNCpyChk;
// String library call optimizations.
addOpt(LibFunc::strcat, &StrCat);
addOpt(LibFunc::strncat, &StrNCat);
addOpt(LibFunc::strchr, &StrChr);
addOpt(LibFunc::strrchr, &StrRChr);
addOpt(LibFunc::strcmp, &StrCmp);
addOpt(LibFunc::strncmp, &StrNCmp);
addOpt(LibFunc::strcpy, &StrCpy);
addOpt(LibFunc::stpcpy, &StpCpy);
addOpt(LibFunc::strncpy, &StrNCpy);
addOpt(LibFunc::strlen, &StrLen);
addOpt(LibFunc::strpbrk, &StrPBrk);
addOpt(LibFunc::strtol, &StrTo);
addOpt(LibFunc::strtod, &StrTo);
addOpt(LibFunc::strtof, &StrTo);
addOpt(LibFunc::strtoul, &StrTo);
addOpt(LibFunc::strtoll, &StrTo);
addOpt(LibFunc::strtold, &StrTo);
addOpt(LibFunc::strtoull, &StrTo);
addOpt(LibFunc::strspn, &StrSpn);
addOpt(LibFunc::strcspn, &StrCSpn);
addOpt(LibFunc::strstr, &StrStr);
// Memory library call optimizations.
addOpt(LibFunc::memcmp, &MemCmp);
addOpt(LibFunc::memcpy, &MemCpy);
addOpt(LibFunc::memmove, &MemMove);
addOpt(LibFunc::memset, &MemSet);
// Math library call optimizations.
addOpt(LibFunc::ceil, LibFunc::ceilf, &UnaryDoubleFP);
addOpt(LibFunc::fabs, LibFunc::fabsf, &UnaryDoubleFP);
addOpt(LibFunc::floor, LibFunc::floorf, &UnaryDoubleFP);
addOpt(LibFunc::rint, LibFunc::rintf, &UnaryDoubleFP);
addOpt(LibFunc::round, LibFunc::roundf, &UnaryDoubleFP);
addOpt(LibFunc::nearbyint, LibFunc::nearbyintf, &UnaryDoubleFP);
addOpt(LibFunc::trunc, LibFunc::truncf, &UnaryDoubleFP);
if(UnsafeFPShrink) {
addOpt(LibFunc::acos, LibFunc::acosf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::acosh, LibFunc::acoshf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::asin, LibFunc::asinf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::asinh, LibFunc::asinhf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::atan, LibFunc::atanf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::atanh, LibFunc::atanhf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::cbrt, LibFunc::cbrtf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::cosh, LibFunc::coshf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::exp, LibFunc::expf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::exp10, LibFunc::exp10f, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::expm1, LibFunc::expm1f, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::log, LibFunc::logf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::log10, LibFunc::log10f, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::log1p, LibFunc::log1pf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::log2, LibFunc::log2f, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::logb, LibFunc::logbf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::sin, LibFunc::sinf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::sinh, LibFunc::sinhf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::sqrt, LibFunc::sqrtf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::tan, LibFunc::tanf, &UnsafeUnaryDoubleFP);
addOpt(LibFunc::tanh, LibFunc::tanhf, &UnsafeUnaryDoubleFP);
}
addOpt(LibFunc::cosf, &Cos);
addOpt(LibFunc::cos, &Cos);
addOpt(LibFunc::cosl, &Cos);
addOpt(LibFunc::powf, &Pow);
addOpt(LibFunc::pow, &Pow);
addOpt(LibFunc::powl, &Pow);
Optimizations["llvm.pow.f32"] = &Pow;
Optimizations["llvm.pow.f64"] = &Pow;
Optimizations["llvm.pow.f80"] = &Pow;
Optimizations["llvm.pow.f128"] = &Pow;
Optimizations["llvm.pow.ppcf128"] = &Pow;
addOpt(LibFunc::exp2l, &Exp2);
addOpt(LibFunc::exp2, &Exp2);
addOpt(LibFunc::exp2f, &Exp2);
Optimizations["llvm.exp2.ppcf128"] = &Exp2;
Optimizations["llvm.exp2.f128"] = &Exp2;
Optimizations["llvm.exp2.f80"] = &Exp2;
Optimizations["llvm.exp2.f64"] = &Exp2;
Optimizations["llvm.exp2.f32"] = &Exp2;
// Integer library call optimizations.
addOpt(LibFunc::ffs, &FFS);
addOpt(LibFunc::ffsl, &FFS);
addOpt(LibFunc::ffsll, &FFS);
addOpt(LibFunc::abs, &Abs);
addOpt(LibFunc::labs, &Abs);
addOpt(LibFunc::llabs, &Abs);
addOpt(LibFunc::isdigit, &IsDigit);
addOpt(LibFunc::isascii, &IsAscii);
addOpt(LibFunc::toascii, &ToAscii);
// Formatting and IO library call optimizations.
addOpt(LibFunc::printf, &PrintF);
addOpt(LibFunc::sprintf, &SPrintF);
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {
if (Optimizations.empty())
initOptimizations();
Function *Callee = CI->getCalledFunction();
LibCallOptimization *LCO = Optimizations.lookup(Callee->getName());
if (LCO) {
IRBuilder<> Builder(CI);
return LCO->optimizeCall(CI, TD, TLI, LCS, Builder);
}
return 0;
}
void LibCallSimplifierImpl::addOpt(LibFunc::Func F, LibCallOptimization* Opt) {
if (TLI->has(F))
Optimizations[TLI->getName(F)] = Opt;
}
void LibCallSimplifierImpl::addOpt(LibFunc::Func F1, LibFunc::Func F2,
LibCallOptimization* Opt) {
if (TLI->has(F1) && TLI->has(F2))
Optimizations[TLI->getName(F1)] = Opt;
}
LibCallSimplifier::LibCallSimplifier(const DataLayout *TD,
const TargetLibraryInfo *TLI,
bool UnsafeFPShrink) {
Impl = new LibCallSimplifierImpl(TD, TLI, this, UnsafeFPShrink);
}
LibCallSimplifier::~LibCallSimplifier() {
delete Impl;
}
Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
return Impl->optimizeCall(CI);
}
void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
I->replaceAllUsesWith(With);
I->eraseFromParent();
}
}
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