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* Correct the function prototypes for some of the functions to match the 

actual spec (int -> uint)
* Add the ability to get/cache the strlen function prototype.
* Make sure generated values are appropriately named for debugging purposes
* Add the SPrintFOptimiation for 4 casts of sprintf optimization:
    sprintf(str,cstr) -> llvm.memcpy(str,cstr) (if cstr has no %)
    sprintf(str,"")   -> store sbyte 0, str
    sprintf(str,"%s",src) -> llvm.memcpy(str,src) (if src is constant)
    sprintf(str,"%c",chr) -> store chr, str   ; store sbyte 0, str+1

The sprintf optimization didn't fire as much as I had hoped:

  2 MultiSource/Applications/SPASS
  5 MultiSource/Benchmarks/McCat/18-imp
 22 MultiSource/Benchmarks/Prolangs-C/TimberWolfMC
  1 MultiSource/Benchmarks/Prolangs-C/assembler
  6 MultiSource/Benchmarks/Prolangs-C/unix-smail
  2 MultiSource/Benchmarks/mediabench/mpeg2/mpeg2dec

llvm-svn: 21679
This commit is contained in:
Reid Spencer 2005-05-04 03:20:21 +00:00
parent 23e9f163ad
commit 1e520fd661
1 changed files with 172 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

181
llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -256,6 +256,21 @@ public:
return sqrt_func;
}
/// @brief Return a Function* for the strlen libcall
Function* get_strcpy()
{
if (!strcpy_func)
{
std::vector<const Type*> args;
args.push_back(PointerType::get(Type::SByteTy));
args.push_back(PointerType::get(Type::SByteTy));
FunctionType* strcpy_type =
FunctionType::get(PointerType::get(Type::SByteTy), args, false);
strcpy_func = M->getOrInsertFunction("strcpy",strcpy_type);
}
return strcpy_func;
}
/// @brief Return a Function* for the strlen libcall
Function* get_strlen()
{
@ -295,8 +310,8 @@ public:
std::vector<const Type*> args;
args.push_back(PointerType::get(Type::SByteTy));
args.push_back(PointerType::get(Type::SByteTy));
args.push_back(Type::IntTy);
args.push_back(Type::IntTy);
args.push_back(Type::UIntTy);
args.push_back(Type::UIntTy);
FunctionType* memcpy_type = FunctionType::get(Type::VoidTy, args, false);
memcpy_func = M->getOrInsertFunction("llvm.memcpy",memcpy_type);
}
@ -314,6 +329,7 @@ private:
memcpy_func = 0;
memchr_func = 0;
sqrt_func = 0;
strcpy_func = 0;
strlen_func = 0;
}
@ -323,6 +339,7 @@ private:
Function* memcpy_func; ///< Cached llvm.memcpy function
Function* memchr_func; ///< Cached memchr function
Function* sqrt_func; ///< Cached sqrt function
Function* strcpy_func; ///< Cached strcpy function
Function* strlen_func; ///< Cached strlen function
Module* M; ///< Cached Module
TargetData* TD; ///< Cached TargetData
@ -493,8 +510,8 @@ public:
std::vector<Value*> vals;
vals.push_back(gep); // destination
vals.push_back(ci->getOperand(2)); // source
vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
vals.push_back(ConstantUInt::get(Type::UIntTy,len)); // length
vals.push_back(ConstantUInt::get(Type::UIntTy,1)); // alignment
new CallInst(SLC.get_memcpy(), vals, "", ci);
// Finally, substitute the first operand of the strcat call for the
@ -862,8 +879,8 @@ public:
std::vector<Value*> vals;
vals.push_back(dest); // destination
vals.push_back(src); // source
vals.push_back(ConstantSInt::get(Type::IntTy,len)); // length
vals.push_back(ConstantSInt::get(Type::IntTy,1)); // alignment
vals.push_back(ConstantUInt::get(Type::UIntTy,len)); // length
vals.push_back(ConstantUInt::get(Type::UIntTy,1)); // alignment
new CallInst(SLC.get_memcpy(), vals, "", ci);
// Finally, substitute the first operand of the strcat call for the
@ -1255,7 +1272,8 @@ public:
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
args.push_back(ci->getOperand(1));
new CallInst(fwrite_func,args,"",ci);
new CallInst(fwrite_func,args,ci->getName(),ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
ci->eraseFromParent();
return true;
}
@ -1281,7 +1299,7 @@ public:
if (!getConstantStringLength(ci->getOperand(3), len, &CA))
return false;
// fprintf(file,fmt) -> fwrite(fmt,strlen(fmt),1,file)
// fprintf(file,"%s",str) -> fwrite(fmt,strlen(fmt),1,file)
const Type* FILEptr_type = ci->getOperand(1)->getType();
Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
if (!fwrite_func)
@ -1291,7 +1309,8 @@ public:
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));
args.push_back(ConstantUInt::get(SLC.getIntPtrType(),1));
args.push_back(ci->getOperand(1));
new CallInst(fwrite_func,args,"",ci);
new CallInst(fwrite_func,args,ci->getName(),ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
break;
}
case 'c':
@ -1306,6 +1325,7 @@ public:
return false;
CastInst* cast = new CastInst(CI,Type::IntTy,CI->getName()+".int",ci);
new CallInst(fputc_func,cast,ci->getOperand(1),"",ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
break;
}
default:
@ -1317,6 +1337,149 @@ public:
} FPrintFOptimizer;
/// This LibCallOptimization will simplify calls to the "sprintf" library
/// function. It looks for cases where the result of sprintf is not used and the
/// operation can be reduced to something simpler.
/// @brief Simplify the pow library function.
struct SPrintFOptimization : public LibCallOptimization
{
public:
/// @brief Default Constructor
SPrintFOptimization() : LibCallOptimization("sprintf",
"simplify-libcalls:sprintf", "Number of 'sprintf' calls simplified") {}
/// @brief Destructor
virtual ~SPrintFOptimization() {}
/// @brief Make sure that the "fprintf" function has the right prototype
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
{
// Just make sure this has at least 2 arguments
return (f->getReturnType() == Type::IntTy && f->arg_size() >= 2);
}
/// @brief Perform the sprintf optimization.
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
{
// If the call has more than 3 operands, we can't optimize it
if (ci->getNumOperands() > 4 || ci->getNumOperands() < 3)
return false;
// All the optimizations depend on the length of the second argument and the
// fact that it is a constant string array. Check that now
uint64_t len = 0;
ConstantArray* CA = 0;
if (!getConstantStringLength(ci->getOperand(2), len, &CA))
return false;
if (ci->getNumOperands() == 3)
{
if (len == 0)
{
// If the length is 0, we just need to store a null byte
new StoreInst(ConstantInt::get(Type::SByteTy,0),ci->getOperand(1),ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,0));
ci->eraseFromParent();
return true;
}
// Make sure there's no % in the constant array
for (unsigned i = 0; i < len; ++i)
{
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(i)))
{
// Check for the null terminator
if (CI->getRawValue() == '%')
return false; // we found a %, can't optimize
}
else
return false; // initializer is not constant int, can't optimize
}
// Increment length because we want to copy the null byte too
len++;
// sprintf(str,fmt) -> llvm.memcpy(str,fmt,strlen(fmt),1)
Function* memcpy_func = SLC.get_memcpy();
if (!memcpy_func)
return false;
std::vector<Value*> args;
args.push_back(ci->getOperand(1));
args.push_back(ci->getOperand(2));
args.push_back(ConstantUInt::get(Type::UIntTy,len));
args.push_back(ConstantUInt::get(Type::UIntTy,1));
new CallInst(memcpy_func,args,"",ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
ci->eraseFromParent();
return true;
}
// The remaining optimizations require the format string to be length 2
// "%s" or "%c".
if (len != 2)
return false;
// The first character has to be a %
if (ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(0)))
if (CI->getRawValue() != '%')
return false;
// Get the second character and switch on its value
ConstantInt* CI = dyn_cast<ConstantInt>(CA->getOperand(1));
switch (CI->getRawValue())
{
case 's':
{
uint64_t len = 0;
if (ci->hasNUses(0))
{
// sprintf(dest,"%s",str) -> strcpy(dest,str)
Function* strcpy_func = SLC.get_strcpy();
if (!strcpy_func)
return false;
std::vector<Value*> args;
args.push_back(ci->getOperand(1));
args.push_back(ci->getOperand(3));
new CallInst(strcpy_func,args,"",ci);
}
else if (getConstantStringLength(ci->getOperand(3),len))
{
// sprintf(dest,"%s",cstr) -> llvm.memcpy(dest,str,strlen(str),1)
len++; // get the null-terminator
Function* memcpy_func = SLC.get_memcpy();
if (!memcpy_func)
return false;
std::vector<Value*> args;
args.push_back(ci->getOperand(1));
args.push_back(ci->getOperand(3));
args.push_back(ConstantUInt::get(Type::UIntTy,len));
args.push_back(ConstantUInt::get(Type::UIntTy,1));
new CallInst(memcpy_func,args,"",ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
}
break;
}
case 'c':
{
// sprintf(dest,"%c",chr) -> store chr, dest
CastInst* cast =
new CastInst(ci->getOperand(3),Type::SByteTy,"char",ci);
new StoreInst(cast, ci->getOperand(1), ci);
GetElementPtrInst* gep = new GetElementPtrInst(ci->getOperand(1),
ConstantUInt::get(Type::UIntTy,1),ci->getOperand(1)->getName()+".end",
ci);
new StoreInst(ConstantInt::get(Type::SByteTy,0),gep,ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
break;
}
default:
return false;
}
ci->eraseFromParent();
return true;
}
} SPrintFOptimizer;
/// This LibCallOptimization will simplify calls to the "fputs" library
/// function. It looks for cases where the result of fputs is not used and the
/// operation can be reduced to something simpler.