Constant pointers to objects don't need reference counting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138242 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/ObjCARC.cpp b/lib/Transforms/Scalar/ObjCARC.cpp
index fea03b5..9654b1e 100644
--- a/lib/Transforms/Scalar/ObjCARC.cpp
+++ b/lib/Transforms/Scalar/ObjCARC.cpp
@@ -515,6 +515,10 @@
const Value *Pointer =
StripPointerCastsAndObjCCalls(LI->getPointerOperand());
if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(Pointer)) {
+ // A constant pointer can't be pointing to an object on the heap. It may
+ // be reference-counted, but it won't be deleted.
+ if (GV->isConstant())
+ return true;
StringRef Name = GV->getName();
// These special variables are known to hold values which are not
// reference-counted pointers.
@@ -2744,6 +2748,15 @@
// regardless of what possible decrements or uses lie between them.
bool KnownSafe = isa<Constant>(Arg) || isa<AllocaInst>(Arg);
+ // A constant pointer can't be pointing to an object on the heap. It may
+ // be reference-counted, but it won't be deleted.
+ if (const LoadInst *LI = dyn_cast<LoadInst>(Arg))
+ if (const GlobalVariable *GV =
+ dyn_cast<GlobalVariable>(
+ StripPointerCastsAndObjCCalls(LI->getPointerOperand())))
+ if (GV->isConstant())
+ KnownSafe = true;
+
// If a pair happens in a region where it is known that the reference count
// is already incremented, we can similarly ignore possible decrements.
bool KnownSafeTD = true, KnownSafeBU = true;