C++ Tail Recursion Using 64-bit variables – Part 2

In my previous post I talked about recursion problems in a Fibonacci function using 64-bit variables as function parameters, compiled using the Microsoft Visual C++ compiler. It turned out that while tail recursion was enabled by the compiler using 32-bit types it didn’t really when switching to 64-bit ones. Just as a reminder, Tail Recursion is an optimization performed by the compiler. It is the process of transforming certain types of tail calls into jumps instead of function calls. More about tail recursion here.

My conclusion was that tail recursion is not handled properly by the Visual C++ compiler and a possible explanation could be the presence of a bug.

The calculation of Fibonacci sequences of big integers is not an everyday task but it can still be a reliable example to show how tail calls are implemented.

Not happy with my conclusions and following several suggestions of users’ comments (here on the blog, on Reddit and on StackOverflow) I wanted to understand more about this issue and to explore other solutions using different compilers.

Continue reading “C++ Tail Recursion Using 64-bit variables – Part 2”