6502/llvm-6502
1
0
Fork 0
mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-07-03 11:24:18 +00:00
Code Issues Projects Releases Wiki Activity

instcombine: Migrate strncpy optimizations

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167102 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Meador Inge
2012-10-31 03:33:00 +00:00
parent 5b2c4dc5f8
commit a0885fb882
6 changed files with 175 additions and 90 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
lib/Transforms/Scalar/SimplifyLibCalls.cpp
View File

@ -134,56 +134,6 @@ static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
//===----------------------------------------------------------------------===//
namespace {
//===---------------------------------------===//
// 'strncpy' Optimizations
struct StrNCpyOpt : public LibCallOptimization {
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy() ||
!FT->getParamType(2)->isIntegerTy())
return 0;
Value *Dst = CI->getArgOperand(0);
Value *Src = CI->getArgOperand(1);
Value *LenOp = CI->getArgOperand(2);
// See if we can get the length of the input string.
uint64_t SrcLen = GetStringLength(Src);
if (SrcLen == 0) return 0;
--SrcLen;
if (SrcLen == 0) {
// strncpy(x, "", y) -> memset(x, '\0', y, 1)
B.CreateMemSet(Dst, B.getInt8('\0'), LenOp, 1);
return Dst;
}
uint64_t Len;
if (ConstantInt *LengthArg = dyn_cast<ConstantInt>(LenOp))
Len = LengthArg->getZExtValue();
else
return 0;
if (Len == 0) return Dst; // strncpy(x, y, 0) -> x
// These optimizations require DataLayout.
if (!TD) return 0;
// Let strncpy handle the zero padding
if (Len > SrcLen+1) return 0;
Type *PT = FT->getParamType(0);
// strncpy(x, s, c) -> memcpy(x, s, c, 1) [s and c are constant]
B.CreateMemCpy(Dst, Src,
ConstantInt::get(TD->getIntPtrType(PT), Len), 1);
return Dst;
}
};
//===---------------------------------------===//
// 'strlen' Optimizations
@ -1196,7 +1146,6 @@ namespace {
StringMap<LibCallOptimization*> Optimizations;
// String and Memory LibCall Optimizations
StrNCpyOpt StrNCpy;
StrLenOpt StrLen; StrPBrkOpt StrPBrk;
StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
MemCmpOpt MemCmp; MemCpyOpt MemCpy; MemMoveOpt MemMove; MemSetOpt MemSet;
@ -1266,7 +1215,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
/// we know.
void SimplifyLibCalls::InitOptimizations() {
// String and Memory LibCall Optimizations
Optimizations["strncpy"] = &StrNCpy;
Optimizations["strlen"] = &StrLen;
Optimizations["strpbrk"] = &StrPBrk;
Optimizations["strtol"] = &StrTo;