diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index cd495bc..e327ffb 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -336,6 +336,10 @@
       return cast<CastExpr>(this)->getSubExpr()->hasLocalSideEffect();
     return false;
 
+  case ImplicitCastExprClass:
+    // Check the operand, since implicit casts are inserted by Sema
+    return cast<ImplicitCastExpr>(this)->getSubExpr()->hasLocalSideEffect();
+
   case CXXDefaultArgExprClass:
     return cast<CXXDefaultArgExpr>(this)->getExpr()->hasLocalSideEffect();
   }     
diff --git a/test/Sema/unused-expr.c b/test/Sema/unused-expr.c
index 305c2be..b14daa7 100644
--- a/test/Sema/unused-expr.c
+++ b/test/Sema/unused-expr.c
@@ -35,3 +35,8 @@
   return ({int _a = x, _b = y; _a > _b ? _a : _b; });
 }
 
+void nowarn(unsigned char* a, unsigned char* b)
+{
+  unsigned char c = 1;
+  *a |= c, *b += c;
+}