Remove an unused function SafeToDestroyConstant(). Rename an almost
identical function ConstantIsDead() to SafeToDestroyConstant(), to
emphasise the connection with Constant::destroyConstant().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73149 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/GlobalOpt.cpp b/lib/Transforms/IPO/GlobalOpt.cpp
index 5f12825..f881e08 100644
--- a/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/lib/Transforms/IPO/GlobalOpt.cpp
@@ -136,16 +136,16 @@
}
-/// ConstantIsDead - Return true if the specified constant is (transitively)
-/// 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) {
+// SafeToDestroyConstant - It is safe to destroy a constant iff it is only used
+// by constants itself. Note that constants cannot be cyclic, so this test is
+// pretty easy to implement recursively.
+//
+static bool SafeToDestroyConstant(Constant *C) {
if (isa<GlobalValue>(C)) 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;
+ if (!SafeToDestroyConstant(CU)) return false;
} else
return false;
return true;
@@ -233,7 +233,7 @@
} else if (Constant *C = dyn_cast<Constant>(*UI)) {
GS.HasNonInstructionUser = true;
// We might have a dead and dangling constant hanging off of here.
- if (!ConstantIsDead(C))
+ if (!SafeToDestroyConstant(C))
return true;
} else {
GS.HasNonInstructionUser = true;
@@ -338,7 +338,7 @@
} 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.
- if (ConstantIsDead(C)) {
+ if (SafeToDestroyConstant(C)) {
C->destroyConstant();
// This could have invalidated UI, start over from scratch.
CleanupConstantGlobalUsers(V, Init);
@@ -354,7 +354,7 @@
static bool isSafeSROAElementUse(Value *V) {
// We might have a dead and dangling constant hanging off of here.
if (Constant *C = dyn_cast<Constant>(V))
- return ConstantIsDead(C);
+ return SafeToDestroyConstant(C);
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return false;