//===------ 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/ADT/SmallString.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/Triple.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DiagnosticInfo.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Intrinsics.h"
#include "llvm/IR/LLVMContext.h"
#include "llvm/IR/Module.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Target/TargetLibraryInfo.h"
#include "llvm/Transforms/Utils/BuildLibCalls.h"
using namespace llvm;
static cl::opt<bool>
ColdErrorCalls("error-reporting-is-cold", cl::init(true),
cl::Hidden, cl::desc("Treat error-reporting calls as cold"));
/// 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 *DL;
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;
/// ignoreCallingConv - Returns false if this transformation could possibly
/// change the calling convention.
virtual bool ignoreCallingConv() { return false; }
Value *optimizeCall(CallInst *CI, const DataLayout *DL,
const TargetLibraryInfo *TLI,
const LibCallSimplifier *LCS, IRBuilder<> &B) {
Caller = CI->getParent()->getParent();
this->DL = DL;
this->TLI = TLI;
this->LCS = LCS;
if (CI->getCalledFunction())
Context = &CI->getCalledFunction()->getContext();
// We never change the calling convention.
if (!ignoreCallingConv() && CI->getCallingConv() != llvm::CallingConv::C)
return nullptr;
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 (User *U : V->users()) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
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 (User *U : V->users()) {
if (ICmpInst *IC = dyn_cast<ICmpInst>(U))
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;
}
/// \brief Check whether the overloaded unary floating point function
/// corresponing to \a Ty is available.
static bool hasUnaryFloatFn(const TargetLibraryInfo *TLI, Type *Ty,
LibFunc::Func DoubleFn, LibFunc::Func FloatFn,
LibFunc::Func LongDoubleFn) {
switch (Ty->getTypeID()) {
case Type::FloatTyID:
return TLI->has(FloatFn);
case Type::DoubleTyID:
return TLI->has(DoubleFn);
default:
return TLI->has(LongDoubleFn);
}
}
//===----------------------------------------------------------------------===//
// 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 override {
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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(Context) ||
FT->getParamType(3) != DL->getIntPtrType(Context))
return nullptr;
if (isFoldable(3, 2, false)) {
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
return nullptr;
}
};
struct MemMoveChkOpt : public InstFortifiedLibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(Context) ||
FT->getParamType(3) != DL->getIntPtrType(Context))
return nullptr;
if (isFoldable(3, 2, false)) {
B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), 1);
return CI->getArgOperand(0);
}
return nullptr;
}
};
struct MemSetChkOpt : public InstFortifiedLibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(Context) ||
FT->getParamType(3) != DL->getIntPtrType(Context))
return nullptr;
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 nullptr;
}
};
struct StrCpyChkOpt : public InstFortifiedLibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(Context))
return nullptr;
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, DL, 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 nullptr;
// This optimization require DataLayout.
if (!DL) return nullptr;
Value *Ret =
EmitMemCpyChk(Dst, Src,
ConstantInt::get(DL->getIntPtrType(Context), Len),
CI->getArgOperand(2), B, DL, TLI);
return Ret;
}
return nullptr;
}
};
struct StpCpyChkOpt : public InstFortifiedLibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(FT->getParamType(0)))
return nullptr;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, DL, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
}
// 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, DL, 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 nullptr;
// This optimization require DataLayout.
if (!DL) return nullptr;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(DL->getIntPtrType(PT),
Len - 1));
if (!EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B, DL, TLI))
return nullptr;
return DstEnd;
}
return nullptr;
}
};
struct StrNCpyChkOpt : public InstFortifiedLibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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) != DL->getIntPtrType(Context))
return nullptr;
if (isFoldable(3, 2, false)) {
Value *Ret = EmitStrNCpy(CI->getArgOperand(0), CI->getArgOperand(1),
CI->getArgOperand(2), B, DL, TLI,
Name.substr(2, 7));
return Ret;
}
return nullptr;
}
};
//===----------------------------------------------------------------------===//
// String and Memory Library Call Optimizations
//===----------------------------------------------------------------------===//
struct StrCatOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
// 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 nullptr;
--Len; // Unbias length.
// Handle the simple, do-nothing case: strcat(x, "") -> x
if (Len == 0)
return Dst;
// These optimizations require DataLayout.
if (!DL) return nullptr;
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, DL, TLI);
if (!DstLen)
return nullptr;
// 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(DL->getIntPtrType(*Context), Len + 1), 1);
return Dst;
}
};
struct StrNCatOpt : public StrCatOpt {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
// 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 nullptr;
// See if we can get the length of the input string.
uint64_t SrcLen = GetStringLength(Src);
if (SrcLen == 0) return nullptr;
--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 (!DL) return nullptr;
// We don't optimize this case
if (Len < SrcLen) return nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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) {
// These optimizations require DataLayout.
if (!DL) return nullptr;
uint64_t Len = GetStringLength(SrcStr);
if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
return nullptr;
return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
ConstantInt::get(DL->getIntPtrType(*Context), Len),
B, DL, 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)) {
if (DL && CharC->isZero()) // strchr(p, 0) -> p + strlen(p)
return B.CreateGEP(SrcStr, EmitStrLen(SrcStr, B, DL, TLI), "strchr");
return nullptr;
}
// Compute the offset, make sure to handle the case when we're searching for
// zero (a weird way to spell strlen).
size_t I = (0xFF & 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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 nullptr;
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str)) {
// strrchr(s, 0) -> strchr(s, 0)
if (DL && CharC->isZero())
return EmitStrChr(SrcStr, '\0', B, DL, TLI);
return nullptr;
}
// Compute the offset.
size_t I = (0xFF & 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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 (!DL) return nullptr;
return EmitMemCmp(Str1P, Str2P,
ConstantInt::get(DL->getIntPtrType(*Context),
std::min(Len1, Len2)), B, DL, TLI);
}
return nullptr;
}
};
struct StrNCmpOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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 nullptr;
if (Length == 0) // strncmp(x,y,0) -> 0
return ConstantInt::get(CI->getType(), 0);
if (DL && Length == 1) // strncmp(x,y,1) -> memcmp(x,y,1)
return EmitMemCmp(Str1P, Str2P, CI->getArgOperand(2), B, DL, 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 nullptr;
}
};
struct StrCpyOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) // strcpy(x,x) -> x
return Src;
// These optimizations require DataLayout.
if (!DL) return nullptr;
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return nullptr;
// 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(DL->getIntPtrType(*Context), Len), 1);
return Dst;
}
};
struct StpCpyOpt: public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
// These optimizations require DataLayout.
if (!DL) return nullptr;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, DL, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : nullptr;
}
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return nullptr;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(DL->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(DL->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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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 nullptr;
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 nullptr;
--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 nullptr;
if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
// These optimizations require DataLayout.
if (!DL) return nullptr;
// Let strncpy handle the zero padding
if (Len > SrcLen+1) return nullptr;
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(DL->getIntPtrType(PT), Len), 1);
return Dst;
}
};
struct StrLenOpt : public LibCallOptimization {
bool ignoreCallingConv() override { return true; }
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 1 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getReturnType()->isIntegerTy())
return nullptr;
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?"foo":"bars") --> x ? 3 : 4
if (SelectInst *SI = dyn_cast<SelectInst>(Src)) {
uint64_t LenTrue = GetStringLength(SI->getTrueValue());
uint64_t LenFalse = GetStringLength(SI->getFalseValue());
if (LenTrue && LenFalse) {
emitOptimizationRemark(*Context, "simplify-libcalls", *Caller,
SI->getDebugLoc(),
"folded strlen(select) to select of constants");
return B.CreateSelect(SI->getCondition(),
ConstantInt::get(CI->getType(), LenTrue-1),
ConstantInt::get(CI->getType(), LenFalse-1));
}
}
// strlen(x) != 0 --> *x != 0
// strlen(x) == 0 --> *x == 0
if (isOnlyUsedInZeroEqualityComparison(CI))
return B.CreateZExt(B.CreateLoad(Src, "strlenfirst"), CI->getType());
return nullptr;
}
};
struct StrPBrkOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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 nullptr;
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 == StringRef::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 (DL && HasS2 && S2.size() == 1)
return EmitStrChr(CI->getArgOperand(0), S2[0], B, DL, TLI);
return nullptr;
}
};
struct StrToOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if ((FT->getNumParams() != 2 && FT->getNumParams() != 3) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy())
return nullptr;
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, Attribute::NoCapture);
}
return nullptr;
}
};
struct StrSpnOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return nullptr;
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 nullptr;
}
};
struct StrCSpnOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
FT->getParamType(0) != B.getInt8PtrTy() ||
FT->getParamType(1) != FT->getParamType(0) ||
!FT->getReturnType()->isIntegerTy())
return nullptr;
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 (DL && HasS2 && S2.empty())
return EmitStrLen(CI->getArgOperand(0), B, DL, TLI);
return nullptr;
}
};
struct StrStrOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isPointerTy())
return nullptr;
// 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 (DL && isOnlyUsedInEqualityComparison(CI, CI->getArgOperand(0))) {
Value *StrLen = EmitStrLen(CI->getArgOperand(1), B, DL, TLI);
if (!StrLen)
return nullptr;
Value *StrNCmp = EmitStrNCmp(CI->getArgOperand(0), CI->getArgOperand(1),
StrLen, B, DL, TLI);
if (!StrNCmp)
return nullptr;
for (auto UI = CI->user_begin(), UE = CI->user_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) {
size_t 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, DL, TLI);
return StrChr ? B.CreateBitCast(StrChr, CI->getType()) : nullptr;
}
return nullptr;
}
};
struct MemCmpOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isIntegerTy(32))
return nullptr;
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 nullptr;
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 nullptr;
// 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 nullptr;
}
};
struct MemCpyOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// These optimizations require DataLayout.
if (!DL) return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != DL->getIntPtrType(*Context))
return nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// These optimizations require DataLayout.
if (!DL) return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
FT->getParamType(2) != DL->getIntPtrType(*Context))
return nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// These optimizations require DataLayout.
if (!DL) return nullptr;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() ||
FT->getParamType(2) != DL->getIntPtrType(FT->getParamType(0)))
return nullptr;
// 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) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 1 || !FT->getReturnType()->isDoubleTy() ||
!FT->getParamType(0)->isDoubleTy())
return nullptr;
if (CheckRetType) {
// Check if all the uses for function like 'sin' are converted to float.
for (User *U : CI->users()) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
if (!Cast || !Cast->getType()->isFloatTy())
return nullptr;
}
}
// If this is something like 'floor((double)floatval)', convert to floorf.
FPExtInst *Cast = dyn_cast<FPExtInst>(CI->getArgOperand(0));
if (!Cast || !Cast->getOperand(0)->getType()->isFloatTy())
return nullptr;
// 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());
}
};
// Double -> Float Shrinking Optimizations for Binary Functions like 'fmin/fmax'
struct BinaryDoubleFPOpt : public LibCallOptimization {
bool CheckRetType;
BinaryDoubleFPOpt(bool CheckReturnType): CheckRetType(CheckReturnType) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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 nullptr;
if (CheckRetType) {
// Check if all the uses for function like 'fmin/fmax' are converted to
// float.
for (User *U : CI->users()) {
FPTruncInst *Cast = dyn_cast<FPTruncInst>(U);
if (!Cast || !Cast->getType()->isFloatTy())
return nullptr;
}
}
// If this is something like 'fmin((double)floatval1, (double)floatval2)',
// we convert it to fminf.
FPExtInst *Cast1 = dyn_cast<FPExtInst>(CI->getArgOperand(0));
FPExtInst *Cast2 = dyn_cast<FPExtInst>(CI->getArgOperand(1));
if (!Cast1 || !Cast1->getOperand(0)->getType()->isFloatTy() ||
!Cast2 || !Cast2->getOperand(0)->getType()->isFloatTy())
return nullptr;
// fmin((double)floatval1, (double)floatval2)
// -> (double)fmin(floatval1, floatval2)
Value *V = nullptr;
Value *V1 = Cast1->getOperand(0);
Value *V2 = Cast2->getOperand(0);
V = EmitBinaryFloatFnCall(V1, V2, 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) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
Value *Ret = nullptr;
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) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
Value *Ret = nullptr;
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)) {
// pow(1.0, x) -> 1.0
if (Op1C->isExactlyValue(1.0))
return Op1C;
// pow(2.0, x) -> exp2(x)
if (Op1C->isExactlyValue(2.0) &&
hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp2, LibFunc::exp2f,
LibFunc::exp2l))
return EmitUnaryFloatFnCall(Op2, "exp2", B, Callee->getAttributes());
// pow(10.0, x) -> exp10(x)
if (Op1C->isExactlyValue(10.0) &&
hasUnaryFloatFn(TLI, Op1->getType(), LibFunc::exp10, LibFunc::exp10f,
LibFunc::exp10l))
return EmitUnaryFloatFnCall(Op2, TLI->getName(LibFunc::exp10), B,
Callee->getAttributes());
}
ConstantFP *Op2C = dyn_cast<ConstantFP>(Op2);
if (!Op2C) return Ret;
if (Op2C->getValueAPF().isZero()) // pow(x, 0.0) -> 1.0
return ConstantFP::get(CI->getType(), 1.0);
if (Op2C->isExactlyValue(0.5) &&
hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::sqrt, LibFunc::sqrtf,
LibFunc::sqrtl) &&
hasUnaryFloatFn(TLI, Op2->getType(), LibFunc::fabs, LibFunc::fabsf,
LibFunc::fabsl)) {
// 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 nullptr;
}
};
struct Exp2Opt : public UnsafeFPLibCallOptimization {
Exp2Opt(bool UnsafeFPShrink) : UnsafeFPLibCallOptimization(UnsafeFPShrink) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
Value *Ret = nullptr;
if (UnsafeFPShrink && Callee->getName() == "exp2" &&
TLI->has(LibFunc::exp2f)) {
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
LibFunc::Func LdExp = LibFunc::ldexpl;
if (Op->getType()->isFloatTy())
LdExp = LibFunc::ldexpf;
else if (Op->getType()->isDoubleTy())
LdExp = LibFunc::ldexp;
if (TLI->has(LdExp)) {
Value *LdExpArg = nullptr;
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) {
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(TLI->getName(LdExp), 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;
}
};
struct SinCosPiOpt : public LibCallOptimization {
SinCosPiOpt() {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// Make sure the prototype is as expected, otherwise the rest of the
// function is probably invalid and likely to abort.
if (!isTrigLibCall(CI))
return nullptr;
Value *Arg = CI->getArgOperand(0);
SmallVector<CallInst *, 1> SinCalls;
SmallVector<CallInst *, 1> CosCalls;
SmallVector<CallInst *, 1> SinCosCalls;
bool IsFloat = Arg->getType()->isFloatTy();
// Look for all compatible sinpi, cospi and sincospi calls with the same
// argument. If there are enough (in some sense) we can make the
// substitution.
for (User *U : Arg->users())
classifyArgUse(U, CI->getParent(), IsFloat, SinCalls, CosCalls,
SinCosCalls);
// It's only worthwhile if both sinpi and cospi are actually used.
if (SinCosCalls.empty() && (SinCalls.empty() || CosCalls.empty()))
return nullptr;
Value *Sin, *Cos, *SinCos;
insertSinCosCall(B, CI->getCalledFunction(), Arg, IsFloat, Sin, Cos,
SinCos);
replaceTrigInsts(SinCalls, Sin);
replaceTrigInsts(CosCalls, Cos);
replaceTrigInsts(SinCosCalls, SinCos);
return nullptr;
}
bool isTrigLibCall(CallInst *CI) {
Function *Callee = CI->getCalledFunction();
FunctionType *FT = Callee->getFunctionType();
// We can only hope to do anything useful if we can ignore things like errno
// and floating-point exceptions.
bool AttributesSafe = CI->hasFnAttr(Attribute::NoUnwind) &&
CI->hasFnAttr(Attribute::ReadNone);
// Other than that we need float(float) or double(double)
return AttributesSafe && FT->getNumParams() == 1 &&
FT->getReturnType() == FT->getParamType(0) &&
(FT->getParamType(0)->isFloatTy() ||
FT->getParamType(0)->isDoubleTy());
}
void classifyArgUse(Value *Val, BasicBlock *BB, bool IsFloat,
SmallVectorImpl<CallInst *> &SinCalls,
SmallVectorImpl<CallInst *> &CosCalls,
SmallVectorImpl<CallInst *> &SinCosCalls) {
CallInst *CI = dyn_cast<CallInst>(Val);
if (!CI)
return;
Function *Callee = CI->getCalledFunction();
StringRef FuncName = Callee->getName();
LibFunc::Func Func;
if (!TLI->getLibFunc(FuncName, Func) || !TLI->has(Func) ||
!isTrigLibCall(CI))
return;
if (IsFloat) {
if (Func == LibFunc::sinpif)
SinCalls.push_back(CI);
else if (Func == LibFunc::cospif)
CosCalls.push_back(CI);
else if (Func == LibFunc::sincospif_stret)
SinCosCalls.push_back(CI);
} else {
if (Func == LibFunc::sinpi)
SinCalls.push_back(CI);
else if (Func == LibFunc::cospi)
CosCalls.push_back(CI);
else if (Func == LibFunc::sincospi_stret)
SinCosCalls.push_back(CI);
}
}
void replaceTrigInsts(SmallVectorImpl<CallInst*> &Calls, Value *Res) {
for (SmallVectorImpl<CallInst*>::iterator I = Calls.begin(),
E = Calls.end();
I != E; ++I) {
LCS->replaceAllUsesWith(*I, Res);
}
}
void insertSinCosCall(IRBuilder<> &B, Function *OrigCallee, Value *Arg,
bool UseFloat, Value *&Sin, Value *&Cos,
Value *&SinCos) {
Type *ArgTy = Arg->getType();
Type *ResTy;
StringRef Name;
Triple T(OrigCallee->getParent()->getTargetTriple());
if (UseFloat) {
Name = "__sincospif_stret";
assert(T.getArch() != Triple::x86 && "x86 messy and unsupported for now");
// x86_64 can't use {float, float} since that would be returned in both
// xmm0 and xmm1, which isn't what a real struct would do.
ResTy = T.getArch() == Triple::x86_64
? static_cast<Type *>(VectorType::get(ArgTy, 2))
: static_cast<Type *>(StructType::get(ArgTy, ArgTy, NULL));
} else {
Name = "__sincospi_stret";
ResTy = StructType::get(ArgTy, ArgTy, NULL);
}
Module *M = OrigCallee->getParent();
Value *Callee = M->getOrInsertFunction(Name, OrigCallee->getAttributes(),
ResTy, ArgTy, NULL);
if (Instruction *ArgInst = dyn_cast<Instruction>(Arg)) {
// If the argument is an instruction, it must dominate all uses so put our
// sincos call there.
BasicBlock::iterator Loc = ArgInst;
B.SetInsertPoint(ArgInst->getParent(), ++Loc);
} else {
// Otherwise (e.g. for a constant) the beginning of the function is as
// good a place as any.
BasicBlock &EntryBB = B.GetInsertBlock()->getParent()->getEntryBlock();
B.SetInsertPoint(&EntryBB, EntryBB.begin());
}
SinCos = B.CreateCall(Callee, Arg, "sincospi");
if (SinCos->getType()->isStructTy()) {
Sin = B.CreateExtractValue(SinCos, 0, "sinpi");
Cos = B.CreateExtractValue(SinCos, 1, "cospi");
} else {
Sin = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 0),
"sinpi");
Cos = B.CreateExtractElement(SinCos, ConstantInt::get(B.getInt32Ty(), 1),
"cospi");
}
}
};
//===----------------------------------------------------------------------===//
// Integer Library Call Optimizations
//===----------------------------------------------------------------------===//
struct FFSOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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 nullptr;
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 {
bool ignoreCallingConv() override { return true; }
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
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 nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
// We require integer(i32)
if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
!FT->getParamType(0)->isIntegerTy(32))
return nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
// We require integer(i32)
if (FT->getNumParams() != 1 || !FT->getReturnType()->isIntegerTy() ||
!FT->getParamType(0)->isIntegerTy(32))
return nullptr;
// 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 {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
FunctionType *FT = Callee->getFunctionType();
// We require i32(i32)
if (FT->getNumParams() != 1 || FT->getReturnType() != FT->getParamType(0) ||
!FT->getParamType(0)->isIntegerTy(32))
return nullptr;
// toascii(c) -> c & 0x7f
return B.CreateAnd(CI->getArgOperand(0),
ConstantInt::get(CI->getType(),0x7F));
}
};
//===----------------------------------------------------------------------===//
// Formatting and IO Library Call Optimizations
//===----------------------------------------------------------------------===//
struct ErrorReportingOpt : public LibCallOptimization {
ErrorReportingOpt(int S = -1) : StreamArg(S) {}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &) override {
// Error reporting calls should be cold, mark them as such.
// This applies even to non-builtin calls: it is only a hint and applies to
// functions that the frontend might not understand as builtins.
// This heuristic was suggested in:
// Improving Static Branch Prediction in a Compiler
// Brian L. Deitrich, Ben-Chung Cheng, Wen-mei W. Hwu
// Proceedings of PACT'98, Oct. 1998, IEEE
if (!CI->hasFnAttr(Attribute::Cold) && isReportingError(Callee, CI)) {
CI->addAttribute(AttributeSet::FunctionIndex, Attribute::Cold);
}
return nullptr;
}
protected:
bool isReportingError(Function *Callee, CallInst *CI) {
if (!ColdErrorCalls)
return false;
if (!Callee || !Callee->isDeclaration())
return false;
if (StreamArg < 0)
return true;
// These functions might be considered cold, but only if their stream
// argument is stderr.
if (StreamArg >= (int) CI->getNumArgOperands())
return false;
LoadInst *LI = dyn_cast<LoadInst>(CI->getArgOperand(StreamArg));
if (!LI)
return false;
GlobalVariable *GV = dyn_cast<GlobalVariable>(LI->getPointerOperand());
if (!GV || !GV->isDeclaration())
return false;
return GV->getName() == "stderr";
}
int StreamArg;
};
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 nullptr;
// 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 nullptr;
// printf("x") -> putchar('x'), even for '%'.
if (FormatStr.size() == 1) {
Value *Res = EmitPutChar(B.getInt32(FormatStr[0]), B, DL, 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('%') == StringRef::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, DL, 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, DL, 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, DL, TLI);
}
return nullptr;
}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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 nullptr;
}
};
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 nullptr;
// 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 nullptr; // we found a format specifier, bail out.
// These optimizations require DataLayout.
if (!DL) return nullptr;
// sprintf(str, fmt) -> llvm.memcpy(str, fmt, strlen(fmt)+1, 1)
B.CreateMemCpy(CI->getArgOperand(0), CI->getArgOperand(1),
ConstantInt::get(DL->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 nullptr;
// 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 nullptr;
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 (!DL) return nullptr;
// sprintf(dest, "%s", str) -> llvm.memcpy(dest, str, strlen(str)+1, 1)
if (!CI->getArgOperand(2)->getType()->isPointerTy()) return nullptr;
Value *Len = EmitStrLen(CI->getArgOperand(2), B, DL, TLI);
if (!Len)
return nullptr;
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 nullptr;
}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
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 nullptr;
}
};
struct FPrintFOpt : public LibCallOptimization {
Value *optimizeFixedFormatString(Function *Callee, CallInst *CI,
IRBuilder<> &B) {
ErrorReportingOpt ER(/* StreamArg = */ 0);
(void) ER.callOptimizer(Callee, CI, B);
// All the optimizations depend on the format string.
StringRef FormatStr;
if (!getConstantStringInfo(CI->getArgOperand(1), FormatStr))
return nullptr;
// Do not do any of the following transformations if the fprintf return
// value is used, in general the fprintf return value is not compatible
// with fwrite(), fputc() or fputs().
if (!CI->use_empty())
return nullptr;
// fprintf(F, "foo") --> fwrite("foo", 3, 1, F)
if (CI->getNumArgOperands() == 2) {
for (unsigned i = 0, e = FormatStr.size(); i != e; ++i)
if (FormatStr[i] == '%') // Could handle %% -> % if we cared.
return nullptr; // We found a format specifier.
// These optimizations require DataLayout.
if (!DL) return nullptr;
return EmitFWrite(CI->getArgOperand(1),
ConstantInt::get(DL->getIntPtrType(*Context),
FormatStr.size()),
CI->getArgOperand(0), B, DL, TLI);
}
// 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 nullptr;
// Decode the second character of the format string.
if (FormatStr[1] == 'c') {
// fprintf(F, "%c", chr) --> fputc(chr, F)
if (!CI->getArgOperand(2)->getType()->isIntegerTy()) return nullptr;
return EmitFPutC(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
}
if (FormatStr[1] == 's') {
// fprintf(F, "%s", str) --> fputs(str, F)
if (!CI->getArgOperand(2)->getType()->isPointerTy())
return nullptr;
return EmitFPutS(CI->getArgOperand(2), CI->getArgOperand(0), B, DL, TLI);
}
return nullptr;
}
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// Require two fixed paramters as pointers and integer result.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!FT->getReturnType()->isIntegerTy())
return nullptr;
if (Value *V = optimizeFixedFormatString(Callee, CI, B)) {
return V;
}
// fprintf(stream, format, ...) -> fiprintf(stream, format, ...) if no
// floating point arguments.
if (TLI->has(LibFunc::fiprintf) && !callHasFloatingPointArgument(CI)) {
Module *M = B.GetInsertBlock()->getParent()->getParent();
Constant *FIPrintFFn =
M->getOrInsertFunction("fiprintf", FT, Callee->getAttributes());
CallInst *New = cast<CallInst>(CI->clone());
New->setCalledFunction(FIPrintFFn);
B.Insert(New);
return New;
}
return nullptr;
}
};
struct FWriteOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
ErrorReportingOpt ER(/* StreamArg = */ 3);
(void) ER.callOptimizer(Callee, CI, B);
// Require a pointer, an integer, an integer, a pointer, returning integer.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 4 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isIntegerTy() ||
!FT->getParamType(2)->isIntegerTy() ||
!FT->getParamType(3)->isPointerTy() ||
!FT->getReturnType()->isIntegerTy())
return nullptr;
// Get the element size and count.
ConstantInt *SizeC = dyn_cast<ConstantInt>(CI->getArgOperand(1));
ConstantInt *CountC = dyn_cast<ConstantInt>(CI->getArgOperand(2));
if (!SizeC || !CountC) return nullptr;
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.
// This optimisation is only valid, if the return value is unused.
if (Bytes == 1 && CI->use_empty()) { // fwrite(S,1,1,F) -> fputc(S[0],F)
Value *Char = B.CreateLoad(CastToCStr(CI->getArgOperand(0), B), "char");
Value *NewCI = EmitFPutC(Char, CI->getArgOperand(3), B, DL, TLI);
return NewCI ? ConstantInt::get(CI->getType(), 1) : nullptr;
}
return nullptr;
}
};
struct FPutsOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
ErrorReportingOpt ER(/* StreamArg = */ 1);
(void) ER.callOptimizer(Callee, CI, B);
// These optimizations require DataLayout.
if (!DL) return nullptr;
// Require two pointers. Also, we can't optimize if return value is used.
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
!FT->getParamType(1)->isPointerTy() ||
!CI->use_empty())
return nullptr;
// fputs(s,F) --> fwrite(s,1,strlen(s),F)
uint64_t Len = GetStringLength(CI->getArgOperand(0));
if (!Len) return nullptr;
// Known to have no uses (see above).
return EmitFWrite(CI->getArgOperand(0),
ConstantInt::get(DL->getIntPtrType(*Context), Len-1),
CI->getArgOperand(1), B, DL, TLI);
}
};
struct PutsOpt : public LibCallOptimization {
Value *callOptimizer(Function *Callee, CallInst *CI,
IRBuilder<> &B) override {
// 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 nullptr;
// Check for a constant string.
StringRef Str;
if (!getConstantStringInfo(CI->getArgOperand(0), Str))
return nullptr;
if (Str.empty() && CI->use_empty()) {
// puts("") -> putchar('\n')
Value *Res = EmitPutChar(B.getInt32('\n'), B, DL, TLI);
if (CI->use_empty() || !Res) return Res;
return B.CreateIntCast(Res, CI->getType(), true);
}
return nullptr;
}
};
} // End anonymous namespace.
namespace llvm {
class LibCallSimplifierImpl {
const DataLayout *DL;
const TargetLibraryInfo *TLI;
const LibCallSimplifier *LCS;
bool UnsafeFPShrink;
// Math library call optimizations.
CosOpt Cos;
PowOpt Pow;
Exp2Opt Exp2;
public:
LibCallSimplifierImpl(const DataLayout *DL, const TargetLibraryInfo *TLI,
const LibCallSimplifier *LCS,
bool UnsafeFPShrink = false)
: Cos(UnsafeFPShrink), Pow(UnsafeFPShrink), Exp2(UnsafeFPShrink) {
this->DL = DL;
this->TLI = TLI;
this->LCS = LCS;
this->UnsafeFPShrink = UnsafeFPShrink;
}
Value *optimizeCall(CallInst *CI);
LibCallOptimization *lookupOptimization(CallInst *CI);
bool hasFloatVersion(StringRef FuncName);
};
bool LibCallSimplifierImpl::hasFloatVersion(StringRef FuncName) {
LibFunc::Func Func;
SmallString<20> FloatFuncName = FuncName;
FloatFuncName += 'f';
if (TLI->getLibFunc(FloatFuncName, Func))
return TLI->has(Func);
return false;
}
// Fortified library call optimizations.
static MemCpyChkOpt MemCpyChk;
static MemMoveChkOpt MemMoveChk;
static MemSetChkOpt MemSetChk;
static StrCpyChkOpt StrCpyChk;
static StpCpyChkOpt StpCpyChk;
static StrNCpyChkOpt StrNCpyChk;
// String library call optimizations.
static StrCatOpt StrCat;
static StrNCatOpt StrNCat;
static StrChrOpt StrChr;
static StrRChrOpt StrRChr;
static StrCmpOpt StrCmp;
static StrNCmpOpt StrNCmp;
static StrCpyOpt StrCpy;
static StpCpyOpt StpCpy;
static StrNCpyOpt StrNCpy;
static StrLenOpt StrLen;
static StrPBrkOpt StrPBrk;
static StrToOpt StrTo;
static StrSpnOpt StrSpn;
static StrCSpnOpt StrCSpn;
static StrStrOpt StrStr;
// Memory library call optimizations.
static MemCmpOpt MemCmp;
static MemCpyOpt MemCpy;
static MemMoveOpt MemMove;
static MemSetOpt MemSet;
// Math library call optimizations.
static UnaryDoubleFPOpt UnaryDoubleFP(false);
static BinaryDoubleFPOpt BinaryDoubleFP(false);
static UnaryDoubleFPOpt UnsafeUnaryDoubleFP(true);
static SinCosPiOpt SinCosPi;
// Integer library call optimizations.
static FFSOpt FFS;
static AbsOpt Abs;
static IsDigitOpt IsDigit;
static IsAsciiOpt IsAscii;
static ToAsciiOpt ToAscii;
// Formatting and IO library call optimizations.
static ErrorReportingOpt ErrorReporting;
static ErrorReportingOpt ErrorReporting0(0);
static ErrorReportingOpt ErrorReporting1(1);
static PrintFOpt PrintF;
static SPrintFOpt SPrintF;
static FPrintFOpt FPrintF;
static FWriteOpt FWrite;
static FPutsOpt FPuts;
static PutsOpt Puts;
LibCallOptimization *LibCallSimplifierImpl::lookupOptimization(CallInst *CI) {
LibFunc::Func Func;
Function *Callee = CI->getCalledFunction();
StringRef FuncName = Callee->getName();
// Next check for intrinsics.
if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(CI)) {
switch (II->getIntrinsicID()) {
case Intrinsic::pow:
return &Pow;
case Intrinsic::exp2:
return &Exp2;
default:
return nullptr;
}
}
// Then check for known library functions.
if (TLI->getLibFunc(FuncName, Func) && TLI->has(Func)) {
switch (Func) {
case LibFunc::strcat:
return &StrCat;
case LibFunc::strncat:
return &StrNCat;
case LibFunc::strchr:
return &StrChr;
case LibFunc::strrchr:
return &StrRChr;
case LibFunc::strcmp:
return &StrCmp;
case LibFunc::strncmp:
return &StrNCmp;
case LibFunc::strcpy:
return &StrCpy;
case LibFunc::stpcpy:
return &StpCpy;
case LibFunc::strncpy:
return &StrNCpy;
case LibFunc::strlen:
return &StrLen;
case LibFunc::strpbrk:
return &StrPBrk;
case LibFunc::strtol:
case LibFunc::strtod:
case LibFunc::strtof:
case LibFunc::strtoul:
case LibFunc::strtoll:
case LibFunc::strtold:
case LibFunc::strtoull:
return &StrTo;
case LibFunc::strspn:
return &StrSpn;
case LibFunc::strcspn:
return &StrCSpn;
case LibFunc::strstr:
return &StrStr;
case LibFunc::memcmp:
return &MemCmp;
case LibFunc::memcpy:
return &MemCpy;
case LibFunc::memmove:
return &MemMove;
case LibFunc::memset:
return &MemSet;
case LibFunc::cosf:
case LibFunc::cos:
case LibFunc::cosl:
return &Cos;
case LibFunc::sinpif:
case LibFunc::sinpi:
case LibFunc::cospif:
case LibFunc::cospi:
return &SinCosPi;
case LibFunc::powf:
case LibFunc::pow:
case LibFunc::powl:
return &Pow;
case LibFunc::exp2l:
case LibFunc::exp2:
case LibFunc::exp2f:
return &Exp2;
case LibFunc::ffs:
case LibFunc::ffsl:
case LibFunc::ffsll:
return &FFS;
case LibFunc::abs:
case LibFunc::labs:
case LibFunc::llabs:
return &Abs;
case LibFunc::isdigit:
return &IsDigit;
case LibFunc::isascii:
return &IsAscii;
case LibFunc::toascii:
return &ToAscii;
case LibFunc::printf:
return &PrintF;
case LibFunc::sprintf:
return &SPrintF;
case LibFunc::fprintf:
return &FPrintF;
case LibFunc::fwrite:
return &FWrite;
case LibFunc::fputs:
return &FPuts;
case LibFunc::puts:
return &Puts;
case LibFunc::perror:
return &ErrorReporting;
case LibFunc::vfprintf:
case LibFunc::fiprintf:
return &ErrorReporting0;
case LibFunc::fputc:
return &ErrorReporting1;
case LibFunc::ceil:
case LibFunc::fabs:
case LibFunc::floor:
case LibFunc::rint:
case LibFunc::round:
case LibFunc::nearbyint:
case LibFunc::trunc:
if (hasFloatVersion(FuncName))
return &UnaryDoubleFP;
return nullptr;
case LibFunc::acos:
case LibFunc::acosh:
case LibFunc::asin:
case LibFunc::asinh:
case LibFunc::atan:
case LibFunc::atanh:
case LibFunc::cbrt:
case LibFunc::cosh:
case LibFunc::exp:
case LibFunc::exp10:
case LibFunc::expm1:
case LibFunc::log:
case LibFunc::log10:
case LibFunc::log1p:
case LibFunc::log2:
case LibFunc::logb:
case LibFunc::sin:
case LibFunc::sinh:
case LibFunc::sqrt:
case LibFunc::tan:
case LibFunc::tanh:
if (UnsafeFPShrink && hasFloatVersion(FuncName))
return &UnsafeUnaryDoubleFP;
return nullptr;
case LibFunc::fmin:
case LibFunc::fmax:
if (hasFloatVersion(FuncName))
return &BinaryDoubleFP;
return nullptr;
case LibFunc::memcpy_chk:
return &MemCpyChk;
default:
return nullptr;
}
}
// Finally check for fortified library calls.
if (FuncName.endswith("_chk")) {
if (FuncName == "__memmove_chk")
return &MemMoveChk;
else if (FuncName == "__memset_chk")
return &MemSetChk;
else if (FuncName == "__strcpy_chk")
return &StrCpyChk;
else if (FuncName == "__stpcpy_chk")
return &StpCpyChk;
else if (FuncName == "__strncpy_chk")
return &StrNCpyChk;
else if (FuncName == "__stpncpy_chk")
return &StrNCpyChk;
}
return nullptr;
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {
LibCallOptimization *LCO = lookupOptimization(CI);
if (LCO) {
IRBuilder<> Builder(CI);
return LCO->optimizeCall(CI, DL, TLI, LCS, Builder);
}
return nullptr;
}
LibCallSimplifier::LibCallSimplifier(const DataLayout *DL,
const TargetLibraryInfo *TLI,
bool UnsafeFPShrink) {
Impl = new LibCallSimplifierImpl(DL, TLI, this, UnsafeFPShrink);
}
LibCallSimplifier::~LibCallSimplifier() {
delete Impl;
}
Value *LibCallSimplifier::optimizeCall(CallInst *CI) {
if (CI->isNoBuiltin()) return nullptr;
return Impl->optimizeCall(CI);
}
void LibCallSimplifier::replaceAllUsesWith(Instruction *I, Value *With) const {
I->replaceAllUsesWith(With);
I->eraseFromParent();
}
}
// 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)
//
// 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'
//
// 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)
//
// 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)
//
// tan, tanf, tanl:
// * tan(atan(x)) -> x
//
// trunc, truncf, truncl:
// * trunc(cnst) -> cnst'
//
//