Initialize PunnedPointer

[vitalybuka]

Summary

Before D124571 PointerIntPair default constructor initialized to 0.

https://reviews.llvm.org/P8307

[brenoguim]

llvm/include/llvm/ADT/PointerIntPair.h

37

I wonder why this constructor didn't kick in.

[vitalybuka]

llvm/include/llvm/ADT/PointerIntPair.h

37

Oh, I was probably visually looking PunnedPointer() and somehow missed this one. Yes, it should.

So I guess the real issue is https://reviews.llvm.org/D150504

[vitalybuka]

We need D150504

llvm/include/llvm/ADT/PointerIntPair.h

template <typename Ptr> struct PunnedPointer {
   static_assert(sizeof(Ptr) == sizeof(intptr_t), "");
 
   // Asserts that allow us to let the compiler implement the destructor and
   // copy/move constructors
   static_assert(std::is_trivially_destructible<Ptr>::value, "");
   static_assert(std::is_trivially_copy_constructible<Ptr>::value, "");
   static_assert(std::is_trivially_move_constructible<Ptr>::value, "");
 
   explicit constexpr PunnedPointer(intptr_t i = 0) { *this = i; }
 
   constexpr intptr_t asInt() const {
     intptr_t R = 0;
     std::memcpy(&R, Data, sizeof(R));
     return R;
   }
 
   constexpr operator intptr_t() const { return asInt(); }
 
   constexpr PunnedPointer &operator=(intptr_t V) {
     std::memcpy(Data, &V, sizeof(Data));
     return *this;
   }
 
   Ptr *getPointerAddress() { return reinterpret_cast<Ptr *>(Data); }
   const Ptr *getPointerAddress() const { return reinterpret_cast<Ptr *>(Data); }
 
 private:
-  alignas(Ptr) unsigned char Data[sizeof(Ptr)];
+  alignas(Ptr) unsigned char Data[sizeof(Ptr)] = {};
 };
 } // namespace detail
 
 template <typename T, typename Enable> struct DenseMapInfo;
 template <typename PointerT, unsigned IntBits, typename PtrTraits>
 struct PointerIntPairInfo;
 
 /// PointerIntPair - This class implements a pair of a pointer and small