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More libcall transformations:

Browse Source 
printf("%s\n", str) -> puts(str)
printf("%c", c) -> putchar(c)
Also fixed fprintf(file, "%c", c) -> fputc(c, file)

llvm-svn: 28815
This commit is contained in:
Evan Cheng 2006-06-16 08:36:35 +00:00
parent bde00a97a7
commit 763d7462d5
1 changed files with 110 additions and 8 deletions
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118
lib/Transforms/IPO/SimplifyLibCalls.cpp
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@ -221,6 +221,23 @@ public:
/// @brief Return the size_t type -- syntactic shortcut
const Type* getIntPtrType() const { return TD->getIntPtrType(); }
/// @brief Return a Function* for the putchar libcall
Function* get_putchar() {
if (!putchar_func)
putchar_func = M->getOrInsertFunction("putchar", Type::IntTy, Type::IntTy,
NULL);
return putchar_func;
}
/// @brief Return a Function* for the puts libcall
Function* get_puts() {
if (!puts_func)
puts_func = M->getOrInsertFunction("puts", Type::IntTy,
PointerType::get(Type::SByteTy),
NULL);
return puts_func;
}
/// @brief Return a Function* for the fputc libcall
Function* get_fputc(const Type* FILEptr_type) {
if (!fputc_func)
@ -318,6 +335,8 @@ private:
void reset(Module& mod) {
M = &mod;
TD = &getAnalysis<TargetData>();
putchar_func = 0;
puts_func = 0;
fputc_func = 0;
fputs_func = 0;
fwrite_func = 0;
@ -335,6 +354,7 @@ private:
private:
/// Caches for function pointers.
Function *putchar_func, *puts_func;
Function *fputc_func, *fputs_func, *fwrite_func;
Function *memcpy_func, *memchr_func;
Function* sqrt_func;
@ -1264,10 +1284,94 @@ public:
}
} PowOptimizer;
/// This LibCallOptimization will simplify calls to the "printf" library
/// function. It looks for cases where the result of printf is not used and the
/// operation can be reduced to something simpler.
/// @brief Simplify the printf library function.
struct PrintfOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor
PrintfOptimization() : LibCallOptimization("printf",
"Number of 'printf' calls simplified") {}
/// @brief Make sure that the "printf" function has the right prototype
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC){
// Just make sure this has at least 1 arguments
return (f->arg_size() >= 1);
}
/// @brief Perform the printf optimization.
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC) {
// If the call has more than 2 operands, we can't optimize it
if (ci->getNumOperands() > 3 || ci->getNumOperands() <= 2)
return false;
// If the result of the printf call is used, none of these optimizations
// can be made.
if (!ci->use_empty())
return false;
// All the optimizations depend on the length of the first 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(1), len, &CA))
return false;
if (len != 2 && len != 3)
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':
{
if (len != 3 ||
dyn_cast<ConstantInt>(CA->getOperand(2))->getRawValue() != '\n')
return false;
// printf("%s\n",str) -> puts(str)
Function* puts_func = SLC.get_puts();
if (!puts_func)
return false;
std::vector<Value*> args;
args.push_back(ci->getOperand(2));
new CallInst(puts_func,args,ci->getName(),ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,len));
break;
}
case 'c':
{
// printf("%c",c) -> putchar(c)
if (len != 2)
return false;
Function* putchar_func = SLC.get_putchar();
if (!putchar_func)
return false;
CastInst* cast = new CastInst(ci->getOperand(2), Type::IntTy,
CI->getName()+".int", ci);
new CallInst(putchar_func, cast, "", ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy, 1));
break;
}
default:
return false;
}
ci->eraseFromParent();
return true;
}
} PrintfOptimizer;
/// This LibCallOptimization will simplify calls to the "fprintf" library
/// function. It looks for cases where the result of fprintf is not used and the
/// operation can be reduced to something simpler.
/// @brief Simplify the pow library function.
/// @brief Simplify the fprintf library function.
struct FPrintFOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor
@ -1379,15 +1483,13 @@ public:
}
case 'c':
{
ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(3));
if (!CI)
return false;
// fprintf(file,"%c",c) -> fputc(c,file)
const Type* FILEptr_type = ci->getOperand(1)->getType();
Function* fputc_func = SLC.get_fputc(FILEptr_type);
if (!fputc_func)
return false;
CastInst* cast = new CastInst(CI,Type::IntTy,CI->getName()+".int",ci);
CastInst* cast = new CastInst(ci->getOperand(3), Type::IntTy,
CI->getName()+".int", ci);
new CallInst(fputc_func,cast,ci->getOperand(1),"",ci);
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
break;
@ -1403,7 +1505,7 @@ public:
/// 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.
/// @brief Simplify the sprintf library function.
struct SPrintFOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor
@ -1530,7 +1632,7 @@ 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 pow library function.
/// @brief Simplify the puts library function.
struct PutsOptimization : public LibCallOptimization {
public:
/// @brief Default Constructor