Tail-call optimization in C is relatively recent [LWN.net]

A developer reflects on the history of tail-call optimization (TCO) in C, noting it was not always supported due to the C calling convention where the caller removes arguments from the stack, making true tail calls impossible. In 1994, no C compilers performed TCO for typical usage. Mark Probst implemented TCO in GCC in 2001 with a separate calling convention, but with limitations like no support for indirect calls. More recently, both GCC and Clang have gained working TCO support, as demonstrated by the Copy-and-Patch Compilation paper by Xu and Kjolstad, which uses 100,000 code snippets — far more than the ~2,000 used in Gforth's goto*-based system. The author notes this opens new possibilities for Gforth and congratulates the Python community for shipping TCO-based improvements first.

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