[PATCH] D50608: Silence GCC warning about broken strict aliasing rules

[Kim Gräsman via Phabricator via llvm-commits]

kimgr updated this revision to Diff 160260.
kimgr retitled this revision from "[Alt] Silence GCC warning about broken strict aliasing rules" to "Silence GCC warning about broken strict aliasing rules".
kimgr edited the summary of this revision.
kimgr added a comment.

- Clarify comment
- Fix naming
- Update differential title/summary


https://reviews.llvm.org/D50608

Files:
  include/llvm/Support/JSON.h


Index: include/llvm/Support/JSON.h
===================================================================
--- include/llvm/Support/JSON.h
+++ include/llvm/Support/JSON.h
@@ -452,7 +452,10 @@
     new (reinterpret_cast<T *>(Union.buffer)) T(std::forward<U>(V)...);
   }
   template <typename T> T &as() const {
-    return *reinterpret_cast<T *>(Union.buffer);
+    // Using this two-step static_cast via void * instead of reinterpret_cast
+    // silences a -Wstrict-aliasing false positive from GCC6 and earlier.
+    void *Storage = static_cast<void *>(Union.buffer);
+    return *static_cast<T *>(Storage);
   }
 
   template <typename Indenter>


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