[Bug tree-optimization/92229] Optimization makes it impossible to read overflow flag

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92229

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot 
com> ---
Built-in functions related to integer overflow should be defined in terms 
of the C abstract machine model, not in terms of processor flags.

See recent WG14 discussions around this issue for various language design 
ideas.