Revert r111922, "MapValue support for MDNodes. This is similar to r109117,

except ...", it is causing *massive* performance regressions when building Clang
with itself (-O3 -g).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@112158 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Daniel Dunbar 2010-08-26 03:48:11 +00:00
parent fd406f1ee2
commit 076137c424

View File

@ -27,36 +27,17 @@ Value *llvm::MapValue(const Value *V, ValueToValueMapTy &VM) {
// NOTE: VMSlot can be invalidated by any reference to VM, which can grow the
// DenseMap. This includes any recursive calls to MapValue.
// Global values do not need to be seeded into the VM if they
// are using the identity mapping.
if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V))
// Global values and non-function-local metadata do not need to be seeded into
// the VM if they are using the identity mapping.
if (isa<GlobalValue>(V) || isa<InlineAsm>(V) || isa<MDString>(V) ||
(isa<MDNode>(V) && !cast<MDNode>(V)->isFunctionLocal()))
return VMSlot = const_cast<Value*>(V);
if (const MDNode *MD = dyn_cast<MDNode>(V)) {
// Start by assuming that we'll use the identity mapping.
VMSlot = const_cast<Value*>(V);
// Check all operands to see if any need to be remapped.
for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i) {
Value *OP = MD->getOperand(i);
if (!OP || MapValue(OP, VM) == OP) continue;
// Ok, at least one operand needs remapping.
MDNode *Dummy = MDNode::getTemporary(V->getContext(), 0, 0);
VM[V] = Dummy;
SmallVector<Value*, 4> Elts;
Elts.reserve(MD->getNumOperands());
for (i = 0; i != e; ++i)
Elts.push_back(MD->getOperand(i) ?
MapValue(MD->getOperand(i), VM) : 0);
MDNode *NewMD = MDNode::get(V->getContext(), Elts.data(), Elts.size());
Dummy->replaceAllUsesWith(NewMD);
MDNode::deleteTemporary(Dummy);
return VM[V] = NewMD;
}
// No operands needed remapping; keep the identity map.
return const_cast<Value*>(V);
SmallVector<Value*, 4> Elts;
for (unsigned i = 0, e = MD->getNumOperands(); i != e; ++i)
Elts.push_back(MD->getOperand(i) ? MapValue(MD->getOperand(i), VM) : 0);
return VM[V] = MDNode::get(V->getContext(), Elts.data(), Elts.size());
}
Constant *C = const_cast<Constant*>(dyn_cast<Constant>(V));