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instcombine: Migrate strcpy optimizations

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This patch migrates the strcpy optimizations from the simplify-libcalls pass
into the instcombine library call simplifier.  Note also that StrCpyChkOpt
has been updated with a few simplifications that were being done in the
simplify-libcalls version of StrCpyOpt, but not in the migrated implementation
of StrCpyOpt.  There is no reason to overload StrCpyOpt with fortified and
regular simplifications in the new model since there is already a dedicated
simplifier for __strcpy_chk.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166198 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Meador Inge
2012-10-18 18:12:40 +00:00
parent 77ed3424e4
commit 0c41d57b09
6 changed files with 153 additions and 115 deletions
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47
lib/Transforms/Scalar/SimplifyLibCalls.cpp
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@@ -134,47 +134,6 @@ static bool IsOnlyUsedInEqualityComparison(Value *V, Value *With) {
//===----------------------------------------------------------------------===//
namespace {
//===---------------------------------------===//
// 'strcpy' Optimizations
struct StrCpyOpt : public LibCallOptimization {
bool OptChkCall; // True if it's optimizing a __strcpy_chk libcall.
StrCpyOpt(bool c) : OptChkCall(c) {}
virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
// Verify the "strcpy" 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;
Value *Dst = CI->getArgOperand(0), *Src = CI->getArgOperand(1);
if (Dst == Src) // strcpy(x,x) -> x
return Src;
// These optimizations require DataLayout.
if (!TD) return 0;
// See if we can get the length of the input string.
uint64_t Len = GetStringLength(Src);
if (Len == 0) return 0;
// We have enough information to now generate the memcpy call to do the
// concatenation for us. Make a memcpy to copy the nul byte with align = 1.
if (!OptChkCall ||
!EmitMemCpyChk(Dst, Src,
ConstantInt::get(TD->getIntPtrType(*Context), Len),
CI->getArgOperand(2), B, TD, TLI))
B.CreateMemCpy(Dst, Src,
ConstantInt::get(TD->getIntPtrType(*Context), Len), 1);
return Dst;
}
};
//===---------------------------------------===//
// 'stpcpy' Optimizations
@@ -1275,7 +1234,6 @@ namespace {
StringMap<LibCallOptimization*> Optimizations;
// String and Memory LibCall Optimizations
StrCpyOpt StrCpy; StrCpyOpt StrCpyChk;
StpCpyOpt StpCpy; StpCpyOpt StpCpyChk;
StrNCpyOpt StrNCpy;
StrLenOpt StrLen; StrPBrkOpt StrPBrk;
@@ -1295,8 +1253,7 @@ namespace {
bool Modified; // This is only used by doInitialization.
public:
static char ID; // Pass identification
SimplifyLibCalls() : FunctionPass(ID), StrCpy(false), StrCpyChk(true),
StpCpy(false), StpCpyChk(true),
SimplifyLibCalls() : FunctionPass(ID), StpCpy(false), StpCpyChk(true),
UnaryDoubleFP(false), UnsafeUnaryDoubleFP(true) {
initializeSimplifyLibCallsPass(*PassRegistry::getPassRegistry());
}
@@ -1348,7 +1305,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
/// we know.
void SimplifyLibCalls::InitOptimizations() {
// String and Memory LibCall Optimizations
Optimizations["strcpy"] = &StrCpy;
Optimizations["strncpy"] = &StrNCpy;
Optimizations["stpcpy"] = &StpCpy;
Optimizations["strlen"] = &StrLen;
@@ -1369,7 +1325,6 @@ void SimplifyLibCalls::InitOptimizations() {
AddOpt(LibFunc::memset, &MemSet);
// _chk variants of String and Memory LibCall Optimizations.
Optimizations["__strcpy_chk"] = &StrCpyChk;
Optimizations["__stpcpy_chk"] = &StpCpyChk;
// Math Library Optimizations