[ReachableCode] Skip over ExprWithCleanups in isConfigurationValue

Summary: Fixes pr29152.

Reviewers: rsmith, pirama, krememek

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D24010

llvm-svn: 285657
diff --git a/clang/lib/Analysis/ReachableCode.cpp b/clang/lib/Analysis/ReachableCode.cpp
index 8165b09..69d000c 100644
--- a/clang/lib/Analysis/ReachableCode.cpp
+++ b/clang/lib/Analysis/ReachableCode.cpp
@@ -164,6 +164,8 @@
   if (!S)
     return false;
 
+  S = S->IgnoreImplicit();
+
   if (const Expr *Ex = dyn_cast<Expr>(S))
     S = Ex->IgnoreCasts();