2 files changed, 50 insertions, 3 deletions
diff --git a/clang/lib/StaticAnalyzer/Core/RegionStore.cpp b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
index 7f2a481c6b0..e2e69bb28ec 100644
--- a/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
+++ b/clang/lib/StaticAnalyzer/Core/RegionStore.cpp
@@ -2132,9 +2132,10 @@ RegionStoreManager::bindArray(RegionBindingsConstRef B,
       NewB = bind(NewB, loc::MemRegionVal(ER), *VI);
   }
 
-  // If the init list is shorter than the array length, set the
-  // array default value.
-  if (Size.hasValue() && i < Size.getValue())
+  // If the init list is shorter than the array length (or the array has
+  // variable length), set the array default value. Values that are already set
+  // are not overwritten.
+  if (!Size.hasValue() || i < Size.getValue())
     NewB = setImplicitDefaultValue(NewB, R, ElementTy);
 
   return NewB;
diff --git a/clang/test/Analysis/arc-zero-init.m b/clang/test/Analysis/arc-zero-init.m
new file mode 100644
index 00000000000..de1e978cd0d
--- /dev/null
+++ b/clang/test/Analysis/arc-zero-init.m
@@ -0,0 +1,46 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify %s
+// RUN: %clang_analyze_cc1 -analyzer-checker=core -verify -fobjc-arc %s
+
+#if __has_feature(objc_arc)
+// expected-no-diagnostics
+#endif
+
+@interface SomeClass
+@end
+
+void simpleStrongPointerValue() {
+  SomeClass *x;
+  if (x) {}
+#if !__has_feature(objc_arc)
+// expected-warning@-2{{Branch condition evaluates to a garbage value}}
+#endif
+}
+
+void simpleArray() {
+  SomeClass *vlaArray[5];
+
+  if (vlaArray[0]) {}
+#if !__has_feature(objc_arc)
+// expected-warning@-2{{Branch condition evaluates to a garbage value}}
+#endif
+}
+
+void variableLengthArray() {
+   int count = 1;
+   SomeClass * vlaArray[count];
+
+   if (vlaArray[0]) {}
+#if !__has_feature(objc_arc)
+  // expected-warning@-2{{Branch condition evaluates to a garbage value}}
+#endif
+}
+
+void variableLengthArrayWithExplicitStrongAttribute() {
+   int count = 1;
+   __attribute__((objc_ownership(strong))) SomeClass * vlaArray[count];
+
+   if (vlaArray[0]) {}
+#if !__has_feature(objc_arc)
+  // expected-warning@-2{{Branch condition evaluates to a garbage value}}
+#endif
+}