[arcmt] Allow removing an -autorelease of a variable initialized in the previous statement.

rdar://11074996

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@171485 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ARCMigrate/Transforms.cpp b/lib/ARCMigrate/Transforms.cpp
index 938f015..136f618 100644
--- a/lib/ARCMigrate/Transforms.cpp
+++ b/lib/ARCMigrate/Transforms.cpp
@@ -71,13 +71,22 @@
   if (E->getOpcode() != BO_Assign)
     return false;
 
+  return isPlusOne(E->getRHS());
+}
+
+bool trans::isPlusOne(const Expr *E) {
+  if (!E)
+    return false;
+  if (const ExprWithCleanups *EWC = dyn_cast<ExprWithCleanups>(E))
+    E = EWC->getSubExpr();
+
   if (const ObjCMessageExpr *
-        ME = dyn_cast<ObjCMessageExpr>(E->getRHS()->IgnoreParenCasts()))
+        ME = dyn_cast<ObjCMessageExpr>(E->IgnoreParenCasts()))
     if (ME->getMethodFamily() == OMF_retain)
       return true;
 
   if (const CallExpr *
-        callE = dyn_cast<CallExpr>(E->getRHS()->IgnoreParenCasts())) {
+        callE = dyn_cast<CallExpr>(E->IgnoreParenCasts())) {
     if (const FunctionDecl *FD = callE->getDirectCallee()) {
       if (FD->getAttr<CFReturnsRetainedAttr>())
         return true;
@@ -98,7 +107,7 @@
     }
   }
 
-  const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E->getRHS());
+  const ImplicitCastExpr *implCE = dyn_cast<ImplicitCastExpr>(E);
   while (implCE && implCE->getCastKind() ==  CK_BitCast)
     implCE = dyn_cast<ImplicitCastExpr>(implCE->getSubExpr());