[llvm] r341900 - NCF: use bit_cast in IntervalMap

[JF Bastien via llvm-commits]

Author: jfb
Date: Mon Sep 10 21:52:21 2018
New Revision: 341900

URL: http://llvm.org/viewvc/llvm-project?rev=341900&view=rev
Log:
NCF: use bit_cast in IntervalMap

This use is sketchy because it basically reinterprets a pointer to another pointer, but right now it's hiding in a union. After this change it'll be easy to grep for bit_cast of a pointer and un-sketch things if we want. This patch therefore obeys the law of conservation of sketch, with minor improvement.

Modified:
    llvm/trunk/include/llvm/ADT/IntervalMap.h

Modified: llvm/trunk/include/llvm/ADT/IntervalMap.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/IntervalMap.h?rev=341900&r1=341899&r2=341900&view=diff
==============================================================================
--- llvm/trunk/include/llvm/ADT/IntervalMap.h (original)
+++ llvm/trunk/include/llvm/ADT/IntervalMap.h Mon Sep 10 21:52:21 2018
@@ -101,6 +101,7 @@
 
 #include "llvm/ADT/PointerIntPair.h"
 #include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/bit.h"
 #include "llvm/Support/AlignOf.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/RecyclingAllocator.h"
@@ -977,15 +978,10 @@ private:
   // Allocator used for creating external nodes.
   Allocator &allocator;
 
-  /// dataAs - Represent data as a node type without breaking aliasing rules.
+  /// Represent data as a node type without breaking aliasing rules.
   template <typename T>
   T &dataAs() const {
-    union {
-      const char *d;
-      T *t;
-    } u;
-    u.d = data.buffer;
-    return *u.t;
+    return *bit_cast<T *>(const_cast<char *>(data.buffer));
   }
 
   const RootLeaf &rootLeaf() const {