ReleaseNotes: sinking of instructions without uses

           jmp     qword ptr [8*rax + .LJTI0_0]

* LLVM can now sink similar instructions to a common successor block also when

  the instructions have no uses, such as calls to void functions. This allows

  code such as

  .. code-block:: c

   void g(int);

   enum e { A, B, C, D };

   void f(e x, int y, int z) {

       switch(x) {

           case A: g(6); break;

           case B: g(3); break;

           case C: g(9); break;

           case D: g(2); break;

       }

   }

  to be optimized to a single call to ``g``, with the argument loaded from a

  lookup table.

Changes to the LLVM IR

----------------------