The tale of -mrtd in GCC and Clang

[John Paul Adrian Glaubitz]

Good Morning!

While working on the RTD issue in the M68k backend in LLVM, Min dug a bit into
the hisstory of the "-mrtd" flag in GCC and Clang and turns out it's actually
much more interesting than we first thought.

See: https://m680x0.github.io/blog/2023/05/the-tale-of-mrtd.html

Adrian

[Richard Z]

Hi,

very interesting. Somewhere deep in my memory I have the idea that the mrtd option or rtd instruction was designed for Modula 2 which was modern at that time. It was probably pretty useless for a classical K&R c compiler that didn't even understand prototypes until 1989 or so... I assume GCC -mrtd predated c prototypes.

Richard