/// true for all i8 values obviously, but is also true for i32 0, i32 -1,
/// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated
/// byte store (e.g. i16 0x1234), return null.
-static Value *isBytewiseValue(Value *V, LLVMContext& Context) {
+static Value *isBytewiseValue(Value *V, LLVMContext &Context) {
// All byte-wide stores are splatable, even of arbitrary variables.
if (V->getType() == Type::getInt8Ty(Context)) return V;
}
// Helper fuctions
- bool processStore(StoreInst *SI, BasicBlock::iterator& BBI);
- bool processMemCpy(MemCpyInst* M);
- bool performCallSlotOptzn(MemCpyInst* cpy, CallInst* C);
+ bool processStore(StoreInst *SI, BasicBlock::iterator &BBI);
+ bool processMemCpy(MemCpyInst *M);
+ bool performCallSlotOptzn(MemCpyInst *cpy, CallInst *C);
bool iterateOnFunction(Function &F);
};
/// some other patterns to fold away. In particular, this looks for stores to
/// neighboring locations of memory. If it sees enough consequtive ones
/// (currently 4) it attempts to merge them together into a memcpy/memset.
-bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator& BBI) {
+bool MemCpyOpt::processStore(StoreInst *SI, BasicBlock::iterator &BBI) {
if (SI->isVolatile()) return false;
// There are two cases that are interesting for this code to handle: memcpy
// Deliberately get the source and destination with bitcasts stripped away,
// because we'll need to do type comparisons based on the underlying type.
- Value* cpyDest = cpy->getDest();
- Value* cpySrc = cpy->getSource();
+ Value *cpyDest = cpy->getDest();
+ Value *cpySrc = cpy->getSource();
CallSite CS = CallSite::get(C);
// We need to be able to reason about the size of the memcpy, so we require
// that it be a constant.
- ConstantInt* cpyLength = dyn_cast<ConstantInt>(cpy->getLength());
+ ConstantInt *cpyLength = dyn_cast<ConstantInt>(cpy->getLength());
if (!cpyLength)
return false;
// Require that src be an alloca. This simplifies the reasoning considerably.
- AllocaInst
* srcAlloca = dyn_cast<AllocaInst>(cpySrc);
+ AllocaInst
*srcAlloca = dyn_cast<AllocaInst>(cpySrc);
if (!srcAlloca)
return false;
// Check that all of src is copied to dest.
- TargetData* TD = getAnalysisIfAvailable<TargetData>();
+ TargetData *TD = getAnalysisIfAvailable<TargetData>();
if (!TD) return false;
- ConstantInt* srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize());
+ ConstantInt *srcArraySize = dyn_cast<ConstantInt>(srcAlloca->getArraySize());
if (!srcArraySize)
return false;
// Check that accessing the first srcSize bytes of dest will not cause a
// trap. Otherwise the transform is invalid since it might cause a trap
// to occur earlier than it otherwise would.
- if (AllocaInst
* A = dyn_cast<AllocaInst>(cpyDest)) {
+ if (AllocaInst
*A = dyn_cast<AllocaInst>(cpyDest)) {
// The destination is an alloca. Check it is larger than srcSize.
- ConstantInt* destArraySize = dyn_cast<ConstantInt>(A->getArraySize());
+ ConstantInt *destArraySize = dyn_cast<ConstantInt>(A->getArraySize());
if (!destArraySize)
return false;
if (destSize < srcSize)
return false;
- } else if (Argument
* A = dyn_cast<Argument>(cpyDest)) {
+ } else if (Argument
*A = dyn_cast<Argument>(cpyDest)) {
// If the destination is an sret parameter then only accesses that are
// outside of the returned struct type can trap.
if (!A->hasStructRetAttr())
return false;
- const Type
* StructTy = cast<PointerType>(A->getType())->getElementType();
+ const Type
*StructTy = cast<PointerType>(A->getType())->getElementType();
uint64_t destSize = TD->getTypeAllocSize(StructTy);
if (destSize < srcSize)
SmallVector<User*, 8> srcUseList(srcAlloca->use_begin(),
srcAlloca->use_end());
while (!srcUseList.empty()) {
- User* UI = srcUseList.back();
+ User *UI = srcUseList.back();
srcUseList.pop_back();
if (isa<BitCastInst>(UI)) {
for (User::use_iterator I = UI->use_begin(), E = UI->use_end();
I != E; ++I)
srcUseList.push_back(*I);
- } else if (GetElementPtrInst* G = dyn_cast<GetElementPtrInst>(UI)) {
+ } else if (GetElementPtrInst *G = dyn_cast<GetElementPtrInst>(UI)) {
if (G->hasAllZeroIndices())
for (User::use_iterator I = UI->use_begin(), E = UI->use_end();
I != E; ++I)
// Since we're changing the parameter to the callsite, we need to make sure
// that what would be the new parameter dominates the callsite.
- DominatorTree& DT = getAnalysis<DominatorTree>();
- if (Instruction* cpyDestInst = dyn_cast<Instruction>(cpyDest))
+ DominatorTree &DT = getAnalysis<DominatorTree>();
+ if (Instruction *cpyDestInst = dyn_cast<Instruction>(cpyDest))
if (!DT.dominates(cpyDestInst, C))
return false;
// unexpected manner, for example via a global, which we deduce from
// the use analysis, we also need to know that it does not sneakily
// access dest. We rely on AA to figure this out for us.
- AliasAnalysis
& AA = getAnalysis<AliasAnalysis>();
+ AliasAnalysis
&AA = getAnalysis<AliasAnalysis>();
if (AA.getModRefInfo(C, cpy->getRawDest(), srcSize) !=
AliasAnalysis::NoModRef)
return false;
cpyDest = CastInst::CreatePointerCast(cpyDest, cpySrc->getType(),
cpyDest->getName(), C);
changedArgument = true;
- if (CS.getArgument(i)->getType() != cpyDest->getType())
- CS.setArgument(i, CastInst::CreatePointerCast(cpyDest,
- CS.getArgument(i)->getType(), cpyDest->getName(), C));
- else
+ if (CS.getArgument(i)->getType() == cpyDest->getType())
CS.setArgument(i, cpyDest);
+ else
+ CS.setArgument(i, CastInst::CreatePointerCast(cpyDest,
+ CS.getArgument(i)->getType(), cpyDest->getName(), C));
}
if (!changedArgument)
// Drop any cached information about the call, because we may have changed
// its dependence information by changing its parameter.
- MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
+ MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>();
MD.removeInstruction(C);
// Remove the memcpy
/// copies X to Y, and memcpy B which copies Y to Z, then we can rewrite B to be
/// a memcpy from X to Z (or potentially a memmove, depending on circumstances).
/// This allows later passes to remove the first memcpy altogether.
-bool MemCpyOpt::processMemCpy(MemCpyInst* M) {
- MemoryDependenceAnalysis& MD = getAnalysis<MemoryDependenceAnalysis>();
+bool MemCpyOpt::processMemCpy(MemCpyInst *M) {
+ MemoryDependenceAnalysis &MD = getAnalysis<MemoryDependenceAnalysis>();
// The are two possible optimizations we can do for memcpy:
- // a) memcpy-memcpy xform which exposes redundance for DSE
- // b) call-memcpy xform for return slot optimization
+ // a) memcpy-memcpy xform which exposes redundance for DSE.
+ // b) call-memcpy xform for return slot optimization.
MemDepResult dep = MD.getDependency(M);
if (!dep.isClobber())
return false;
if (!isa<MemCpyInst>(dep.getInst())) {
- if (CallInst* C = dyn_cast<CallInst>(dep.getInst()))
+ if (CallInst *C = dyn_cast<CallInst>(dep.getInst()))
return performCallSlotOptzn(M, C);
return false;
}
- MemCpyInst* MDep = cast<MemCpyInst>(dep.getInst());
+ MemCpyInst *MDep = cast<MemCpyInst>(dep.getInst());
// We can only transforms memcpy's where the dest of one is the source of the
// other
// Second, the length of the memcpy's must be the same, or the preceeding one
// must be larger than the following one.
- ConstantInt* C1 = dyn_cast<ConstantInt>(MDep->getLength());
- ConstantInt* C2 = dyn_cast<ConstantInt>(M->getLength());
+ ConstantInt *C1 = dyn_cast<ConstantInt>(MDep->getLength());
+ ConstantInt *C2 = dyn_cast<ConstantInt>(M->getLength());
if (!C1 || !C2)
return false;
// Finally, we have to make sure that the dest of the second does not
// alias the source of the first
- AliasAnalysis
& AA = getAnalysis<AliasAnalysis>();
+ AliasAnalysis
&AA = getAnalysis<AliasAnalysis>();
if (AA.alias(M->getRawDest(), CpySize, MDep->getRawSource(), DepSize) !=
AliasAnalysis::NoAlias)
return false;
// If all checks passed, then we can transform these memcpy's
const Type *Tys[1];
Tys[0] = M->getLength()->getType();
- Function* MemCpyFun = Intrinsic::getDeclaration(
+ Function *MemCpyFun = Intrinsic::getDeclaration(
M->getParent()->getParent()->getParent(),
M->getIntrinsicID(), Tys, 1);
M->getRawDest(), MDep->getRawSource(), M->getLength(), M->getAlignmentCst()
};
- CallInst* C = CallInst::Create(MemCpyFun, Args, Args+4, "", M);
+ CallInst *C = CallInst::Create(MemCpyFun, Args, Args+4, "", M);
// If C and M don't interfere, then this is a valid transformation. If they
return false;
}
-// MemCpyOpt::runOnFunction - This is the main transformation entry point for a
-// function.
-//
-bool MemCpyOpt::runOnFunction(Function& F) {
-
- bool changed = false;
- bool shouldContinue = true;
-
- while (shouldContinue) {
- shouldContinue = iterateOnFunction(F);
- changed |= shouldContinue;
- }
-
- return changed;
-}
-
-
-// MemCpyOpt::iterateOnFunction - Executes one iteration of GVN
+// MemCpyOpt::iterateOnFunction - Executes one iteration of GVN.
bool MemCpyOpt::iterateOnFunction(Function &F) {
- bool changed_function = false;
+ bool MadeChange = false;
- // Walk all instruction in the function
+ // Walk all instruction in the function.
for (Function::iterator BB = F.begin(), BBE = F.end(); BB != BBE; ++BB) {
for (BasicBlock::iterator BI = BB->begin(), BE = BB->end();
BI != BE;) {
- // Avoid invalidating the iterator
- Instruction* I = BI++;
+ // Avoid invalidating the iterator.
+ Instruction *I = BI++;
if (StoreInst *SI = dyn_cast<StoreInst>(I))
- changed_function |= processStore(SI, BI);
- else if (MemCpyInst* M = dyn_cast<MemCpyInst>(I)) {
- changed_function |= processMemCpy(M);
- }
+ MadeChange |= processStore(SI, BI);
+ else if (MemCpyInst *M = dyn_cast<MemCpyInst>(I))
+ MadeChange |= processMemCpy(M);
}
}
- return changed_function;
+ return MadeChange;
}
+
+// MemCpyOpt::runOnFunction - This is the main transformation entry point for a
+// function.
+//
+bool MemCpyOpt::runOnFunction(Function &F) {
+ bool MadeChange = false;
+ while (1) {
+ if (!iterateOnFunction(F))
+ break;
+ MadeChange = true;
+ }
+
+ return MadeChange;
+}
+
+
+
projects / oota-llvm.git / commitdiff