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instcombine: Migrate stpcpy optimizations

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This patch migrates the stpcpy optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.  Note that the
__stpcpy_chk simplifications were migrated in a previous commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167083 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Meador Inge
2012-10-31 00:20:56 +00:00
parent fa9d1372c9
commit e6d781fd3c
6 changed files with 111 additions and 99 deletions
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55
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@@ -134,52 +134,6 @@ static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
//===----------------------------------------------------------------------===//
namespace {
//===---------------------------------------===//
// 'stpcpy' Optimizations
struct StpCpyOpt: public LibCallOptimization {
bool OptChkCall; // True if it's optimizing a __stpcpy_chk libcall.
StpCpyOpt(bool c) : OptChkCall(c) {}
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "stpcpy" function prototype.
unsigned NumParams = OptChkCall ? 3 : 2;
FunctionType *FT = Callee->getFunctionType();
if (FT->getNumParams() != NumParams ||
FT->getReturnType() != FT->getParamType(0) ||
FT->getParamType(0) != FT->getParamType(1) ||
FT->getParamType(0) != B.getInt8PtrTy())
return 0;
// These optimizations require DataLayout.
if (!TD) return 0;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) { // stpcpy(x,x) -> x+strlen(x)
Value *StrLen = EmitStrLen(Src, B, TD, TLI);
return StrLen ? B.CreateInBoundsGEP(Dst, StrLen) : 0;
}
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
Type *PT = FT->getParamType(0);
Value *LenV = ConstantInt::get(TD->getIntPtrType(PT), Len);
Value *DstEnd = B.CreateGEP(Dst,
ConstantInt::get(TD->getIntPtrType(PT),
Len - 1));
// We have enough information to now generate the memcpy call to do the
// copy for us. Make a memcpy to copy the nul byte with align = 1.
if (!OptChkCall || !EmitMemCpyChk(Dst, Src, LenV, CI->getArgOperand(2), B,
TD, TLI))
B.CreateMemCpy(Dst, Src, LenV, 1);
return DstEnd;
}
};
//===---------------------------------------===//
// 'strncpy' Optimizations
@@ -1242,7 +1196,6 @@ namespace {
StringMap<LibCallOptimization*> Optimizations;
// String and Memory LibCall Optimizations
StpCpyOpt StpCpy; StpCpyOpt StpCpyChk;
StrNCpyOpt StrNCpy;
StrLenOpt StrLen; StrPBrkOpt StrPBrk;
StrToOpt StrTo; StrSpnOpt StrSpn; StrCSpnOpt StrCSpn; StrStrOpt StrStr;
@@ -1261,8 +1214,8 @@ namespace {
bool Modified; // This is only used by doInitialization.
public:
static char ID; // Pass identification
SimplifyLibCalls() : FunctionPass(ID), StpCpy(false), StpCpyChk(true),
UnaryDoubleFP(false), UnsafeUnaryDoubleFP(true) {
SimplifyLibCalls() : FunctionPass(ID), UnaryDoubleFP(false),
UnsafeUnaryDoubleFP(true) {
initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
}
void AddOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1314,7 +1267,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
void SimplifyLibCalls::InitOptimizations() {
// String and Memory LibCall Optimizations
Optimizations["strncpy"] = &StrNCpy;
Optimizations["stpcpy"] = &StpCpy;
Optimizations["strlen"] = &StrLen;
Optimizations["strpbrk"] = &StrPBrk;
Optimizations["strtol"] = &StrTo;
@@ -1332,9 +1284,6 @@ void SimplifyLibCalls::InitOptimizations() {
Optimizations["memmove"] = &MemMove;
AddOpt(LibFunc::memset, &MemSet);
// _chk variants of String and Memory LibCall Optimizations.
Optimizations["__stpcpy_chk"] = &StpCpyChk;
// Math Library Optimizations
Optimizations["cosf"] = &Cos;
Optimizations["cos"] = &Cos;