6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-06-13 22:24:07 +00:00
Code Issues Projects Releases Wiki Activity

instcombine: Migrate strchr and strrchr optimizations

Browse Source 
This patch migrates the strchr and strrchr optimizations from the
simplify-libcalls pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165875 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Meador Inge
2012-10-13 16:45:37 +00:00
parent 73d8a5864f
commit 186f8d90df
8 changed files with 236 additions and 140 deletions
Download Patch File Download Diff File Expand all files Collapse all files

86
lib/Transforms/Utils/SimplifyLibCalls.cpp
View File

@ -320,6 +320,88 @@ struct StrNCatOpt : public StrCatOpt {
}
};
struct StrChrOpt : public LibCallOptimization {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// 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 0;
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 == 0) {
// These optimizations require DataLayout.
if (!TD) return 0;
uint64_t Len = GetStringLength(SrcStr);
if (Len == 0 || !FT->getParamType(1)->isIntegerTy(32))// memchr needs i32.
return 0;
return EmitMemChr(SrcStr, CI->getArgOperand(1), // include nul.
ConstantInt::get(TD->getIntPtrType(*Context), Len),
B, TD, 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))
return 0;
// Compute the offset, make sure to handle the case when we're searching for
// zero (a weird way to spell strlen).
size_t I = 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 {
virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// 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 0;
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 0;
StringRef Str;
if (!getConstantStringInfo(SrcStr, Str)) {
// strrchr(s, 0) -> strchr(s, 0)
if (TD && CharC->isZero())
return EmitStrChr(SrcStr, '\0', B, TD, TLI);
return 0;
}
// Compute the offset.
size_t I = 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");
}
};
} // End anonymous namespace.
namespace llvm {
@ -340,6 +422,8 @@ class LibCallSimplifierImpl {
// String and memory library call optimizations.
StrCatOpt StrCat;
StrNCatOpt StrNCat;
StrChrOpt StrChr;
StrRChrOpt StrRChr;
void initOptimizations();
public:
@ -364,6 +448,8 @@ void LibCallSimplifierImpl::initOptimizations() {
// String and memory library call optimizations.
Optimizations["strcat"] = &StrCat;
Optimizations["strncat"] = &StrNCat;
Optimizations["strchr"] = &StrChr;
Optimizations["strrchr"] = &StrRChr;
}
Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {