[objc-arc] Fixed comment typo.

llvm-svn: 179965
diff --git a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
index f2f82ba..4bab976 100644
--- a/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
+++ b/llvm/lib/Transforms/ObjCARC/ObjCARCOpts.cpp
@@ -2958,7 +2958,7 @@
 
     const Value *Arg = StripPointerCastsAndObjCCalls(Ret->getOperand(0));
 
-    // Look for an ``autorelease'' instruction that is a predecssor of Ret and
+    // Look for an ``autorelease'' instruction that is a predecessor of Ret and
     // dependent on Arg such that there are no instructions dependent on Arg
     // that need a positive ref count in between the autorelease and Ret.
     CallInst *Autorelease =