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implement a fixme: move optimizations for fwrite out of fputs into a new

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fwrite optimizer.

llvm-svn: 35758
This commit is contained in:
Chris Lattner 2007-04-08 07:00:35 +00:00
parent 71592d1ef2
commit 34464bdf2b
1 changed files with 58 additions and 28 deletions
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86
lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -1388,7 +1388,7 @@ public:
/// This LibCallOptimization will simplify calls to the "fputs" library
/// function. It looks for cases where the result of fputs is not used and the
/// operation can be reduced to something simpler.
/// @brief Simplify the puts library function.
/// @brief Simplify the fputs library function.
struct VISIBILITY_HIDDEN FPutsOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor
@ -1413,36 +1413,66 @@ public:
if (!GetConstantStringInfo(CI->getOperand(1), Str))
return false;
Value *Ptr = CI->getOperand(1);
const Type *FILETy = CI->getOperand(2)->getType();
// FIXME: Remove these optimizations and fold fwrite with 0/1 length
// instead.
switch (Str.size()) {
case 0:
// fputs("",F) -> noop
break;
case 1: {
// fputs(s,F) -> fputc(s[0],F) (if s is constant and strlen(s) == 1)
Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
Val = new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI);
new CallInst(SLC.get_fputc(FILETy), Val, CI->getOperand(2), "", CI);
break;
}
default: {
// fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
Value *FWriteParms[4] = {
CI->getOperand(1),
ConstantInt::get(SLC.getIntPtrType(), Str.size()),
ConstantInt::get(SLC.getIntPtrType(), 1),
CI->getOperand(2)
};
new CallInst(SLC.get_fwrite(FILETy), FWriteParms, 4, "", CI);
break;
}
}
// fputs(s,F) -> fwrite(s,1,len,F) (if s is constant and strlen(s) > 1)
Value *FWriteParms[4] = {
CI->getOperand(1),
ConstantInt::get(SLC.getIntPtrType(), Str.size()),
ConstantInt::get(SLC.getIntPtrType(), 1),
CI->getOperand(2)
};
new CallInst(SLC.get_fwrite(FILETy), FWriteParms, 4, "", CI);
return ReplaceCallWith(CI, 0); // Known to have no uses (see above).
}
} PutsOptimizer;
} FPutsOptimizer;
/// This LibCallOptimization will simplify calls to the "fwrite" function.
struct VISIBILITY_HIDDEN FWriteOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor
FWriteOptimization() : LibCallOptimization("fwrite",
"Number of 'fwrite' calls simplified") {}
/// @brief Make sure that the "fputs" function has the right prototype
virtual bool ValidateCalledFunction(const Function *F, SimplifyLibCalls &SLC){
const FunctionType *FT = F->getFunctionType();
return FT->getNumParams() == 4 &&
FT->getParamType(0) == PointerType::get(Type::Int8Ty) &&
FT->getParamType(1) == FT->getParamType(2) &&
isa<IntegerType>(FT->getParamType(1)) &&
isa<PointerType>(FT->getParamType(3)) &&
isa<IntegerType>(FT->getReturnType());
}
virtual bool OptimizeCall(CallInst *CI, SimplifyLibCalls &SLC) {
// Get the element size and count.
uint64_t EltSize, EltCount;
if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(2)))
EltSize = C->getZExtValue();
else
return false;
if (ConstantInt *C = dyn_cast<ConstantInt>(CI->getOperand(3)))
EltCount = C->getZExtValue();
else
return false;
// If this is writing zero records, remove the call (it's a noop).
if (EltSize * EltCount == 0)
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 0));
// If this is writing one byte, turn it into fputc.
if (EltSize == 1 && EltCount == 1) {
// fwrite(s,1,1,F) -> fputc(s[0],F)
Value *Ptr = CI->getOperand(1);
Value *Val = new LoadInst(Ptr, Ptr->getName()+".byte", CI);
Val = new ZExtInst(Val, Type::Int32Ty, Val->getName()+".int", CI);
const Type *FILETy = CI->getOperand(4)->getType();
new CallInst(SLC.get_fputc(FILETy), Val, CI->getOperand(4), "", CI);
return ReplaceCallWith(CI, ConstantInt::get(CI->getType(), 1));
}
return false;
}
} FWriteOptimizer;
/// This LibCallOptimization will simplify calls to the "isdigit" library
/// function. It simply does range checks the parameter explicitly.