[Bug other/87220] -fstack-check produces inefficient and wrong tests

[bugdal at aerifal dot cx]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87220

--- Comment #2 from Rich Felker <bugdal at aerifal dot cx> ---
-fstack-clash-protection works as desired.

Based on the documentation:

"Most targets do not fully support stack clash protection. However, on those
targets -fstack-clash-protection will protect dynamic stack allocations.
-fstack-clash-protection may also provide limited protection for static stack
allocations if the target supports -fstack-check=specific. "

I understood that -fstack-check would still be needed to get reliable
protection on all targets. Perhaps that's wrong. Is there a recommended
approach for determining at build time the right options for the target to
ensure that code which jumps over the guard page is not generated?