objc-arc: fix a IRGen crash when checking for

accessibility of an initializer which is a compound 
statement. // rdar://9694706


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@134091 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 31 insertions, 1 deletions

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 68b1d3be66..d508ff7390 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -454,7 +454,8 @@ static bool isAccessedBy(const VarDecl &var, const Stmt *s) {
   }
 
   for (Stmt::const_child_range children = s->children(); children; ++children)
-    if (isAccessedBy(var, *children))
+    // children might be null; as in missing decl or conditional of an if-stmt.
+    if ((*children) && isAccessedBy(var, *children))
       return true;
 
   return false;
diff --git a/test/CodeGenObjC/arc-compound-stmt.m b/test/CodeGenObjC/arc-compound-stmt.m
new file mode 100644
index 0000000000..946d72f005
--- /dev/null
+++ b/test/CodeGenObjC/arc-compound-stmt.m
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin10 -emit-llvm -fobjc-nonfragile-abi -fobjc-arc -o - %s
+// rdar://9694706
+
+typedef unsigned long NSUInteger;
+
+@interface NSString
+- (NSString *)stringByAppendingString:(NSString *)aString;
+- (NSString *)substringFromIndex:(NSUInteger)from;
+@end
+
+@interface MyClass
+- (void)inst;
+@end
+
+@implementation MyClass
+
+- (void)inst;
+{
+    NSString *propName;
+
+    NSString *capitalPropName = ({
+        NSString *cap;
+        if (propName)
+            cap = [cap stringByAppendingString:[propName substringFromIndex:1]];
+        cap;
+    });
+}
+
+@end