OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 6
Code Issues Packages Projects Releases Wiki Activity

Implement the IsDigitOptimization for simplifying calls to the isdigit 

library function:
  isdigit(chr) -> 0 or 1 if chr is constant
  isdigit(chr) -> chr - '0' <= 9 otherwise

Although there are many calls to isdigit in llvm-test, most of them are
compiled away by macros leaving only this:

2 MultiSource/Applications/hexxagon

llvm-svn: 21688
This commit is contained in:
Reid Spencer 2005-05-04 18:58:28 +00:00
parent f9a4a9681d
commit 282d057485
1 changed files with 54 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

60
llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp
View File

@ -1554,6 +1554,60 @@ public:
}
} PutsOptimizer;
/// This LibCallOptimization will simplify calls to the "isdigit" library
/// function. It simply does range checks the parameter explicitly.
/// @brief Simplify the isdigit library function.
struct IsDigitOptimization : public LibCallOptimization
{
public:
/// @brief Default Constructor
IsDigitOptimization() : LibCallOptimization("isdigit",
"simplify-libcalls:isdigit", "Number of 'isdigit' calls simplified") {}
/// @brief Destructor
virtual ~IsDigitOptimization() {}
/// @brief Make sure that the "fputs" function has the right prototype
virtual bool ValidateCalledFunction(const Function* f, SimplifyLibCalls& SLC)
{
// Just make sure this has 1 argument
return (f->arg_size() == 1);
}
/// @brief Perform the toascii optimization.
virtual bool OptimizeCall(CallInst* ci, SimplifyLibCalls& SLC)
{
if (ConstantInt* CI = dyn_cast<ConstantInt>(ci->getOperand(1)))
{
// isdigit(c) -> 0 or 1, if 'c' is constant
uint64_t val = CI->getRawValue();
if (val >= '0' && val <='9')
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,1));
else
ci->replaceAllUsesWith(ConstantSInt::get(Type::IntTy,0));
ci->eraseFromParent();
return true;
}
// isdigit(c) -> (unsigned)c - '0' <= 9
CastInst* cast =
new CastInst(ci->getOperand(1),Type::UIntTy,
ci->getOperand(1)->getName()+".uint",ci);
BinaryOperator* sub_inst = BinaryOperator::create(Instruction::Sub,cast,
ConstantUInt::get(Type::UIntTy,0x30),
ci->getOperand(1)->getName()+".sub",ci);
SetCondInst* setcond_inst = new SetCondInst(Instruction::SetLE,sub_inst,
ConstantUInt::get(Type::UIntTy,9),
ci->getOperand(1)->getName()+".cmp",ci);
CastInst* c2 =
new CastInst(setcond_inst,Type::IntTy,
ci->getOperand(1)->getName()+".isdigit",ci);
ci->replaceAllUsesWith(c2);
ci->eraseFromParent();
return true;
}
} IsDigitOptimizer;
/// This LibCallOptimization will simplify calls to the "toascii" library
/// function. It simply does the corresponding and operation to restrict the
/// range of values to the ASCII character set (0-127).
@ -1751,12 +1805,6 @@ bool getConstantStringLength(Value* V, uint64_t& len, ConstantArray** CA )
// * signbit(cnst) -> cnst'
// * signbit(nncst) -> 0 (if pstv is a non-negative constant)
//
// sprintf:
// * sprintf(dest,fmt) -> strcpy(dest,fmt)
// (if fmt is constant and constains no % characters)
// * sprintf(dest,"%s",orig) -> strcpy(dest,orig)
// (only if the sprintf result is not used)
//
// sqrt, sqrtf, sqrtl:
// * sqrt(expN(x)) -> expN(x*0.5)
// * sqrt(Nroot(x)) -> pow(x,1/(2*N))