}
/// ConstantIsDead - Return true if the specified constant is (transitively)
-/// dead. The constant may be used by other constants (e.g. constant arrays,
-/// constant exprs, constant global variables) as long as they are dead,
-/// but it cannot be used by anything else. If DeadGVs is not null then
-/// record dead constant GV users.
-static bool ConstantIsDead(Constant *C,
- SmallPtrSet<GlobalVariable *, 4> *DeadGVs = false) {
+/// dead. The constant may be used by other constants (e.g. constant arrays and
+/// constant exprs) as long as they are dead, but it cannot be used by anything
+/// else.
+static bool ConstantIsDead(Constant *C) {
if (isa<GlobalValue>(C)) return false;
- for (Value::use_iterator UI = C->use_begin(), E = C->use_end(); UI != E; ++UI) {
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(*UI)) {
- if (!GV->isConstant() || !GV->hasLocalLinkage() || !GV->use_empty())
- return false;
- else {
- if (DeadGVs)
- DeadGVs->insert(GV);
- }
- }
- else if (Constant *CU = dyn_cast<Constant>(*UI)) {
- if (!ConstantIsDead(CU, DeadGVs)) return false;
+ for (Value::use_iterator UI = C->use_begin(), E = C->use_end(); UI != E; ++UI)
+ if (Constant *CU = dyn_cast<Constant>(*UI)) {
+ if (!ConstantIsDead(CU)) return false;
} else
return false;
- }
return true;
}
} else if (Constant *C = dyn_cast<Constant>(U)) {
// If we have a chain of dead constantexprs or other things dangling from
// us, and if they are all dead, nuke them without remorse.
- SmallPtrSet<GlobalVariable *, 4> DeadGVs;
- if (ConstantIsDead(C, &DeadGVs)) {
- for (SmallPtrSet<GlobalVariable *, 4>::iterator TI = DeadGVs.begin(),
- TE = DeadGVs.end(); TI != TE; ) {
- GlobalVariable *TGV = *TI; ++TI;
- if (TGV == C)
- C = NULL;
- TGV->eraseFromParent();
- }
- if (GlobalVariable *GV = dyn_cast<GlobalVariable>(C))
- GV->eraseFromParent();
- else if (C)
- C->destroyConstant();
+ if (ConstantIsDead(C)) {
+ C->destroyConstant();
// This could have invalidated UI, start over from scratch.
CleanupConstantGlobalUsers(V, Init);
return true;