Subzero: Improve class definition hygiene.

src/IceAPInt.h

Index: src/IceAPInt.h
diff --git a/src/IceAPInt.h b/src/IceAPInt.h
index 1789dd5751aa88d30d373579c19341884385ab44..01ce280991be1410e48dde299671b9bd44d67fb7 100644
--- a/src/IceAPInt.h
+++ b/src/IceAPInt.h
@@ -9,7 +9,7 @@
 ///
 /// \file
 /// \brief This file implements a class to represent 64 bit integer constant
-/// values, and thier conversion to variable bit sized integers.
+/// values, and their conversion to variable bit sized integers.
 ///
 /// Note: This is a simplified version of llvm/include/llvm/ADT/APInt.h for use
 /// with Subzero.
@@ -23,6 +23,10 @@
 namespace Ice {
 
 class APInt {
+  APInt() = delete;
+  APInt(const APInt &) = delete;
+  APInt &operator=(const APInt &) = delete;
+
 public:
   /// Bits in an (internal) value.
   static const SizeT APINT_BITS_PER_WORD = sizeof(uint64_t) * CHAR_BIT;