https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107831
Bug ID: 107831
Summary: Missed optimization: -fclash-stack-protection causes
unnecessary code generation for dynamic stack
allocations that are clearly less than a page
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: pskocik at gmail dot com
Target Milestone: ---
I'm talking allocations such as
char buf [ (uint8_t)size ];
The resulting code for this should ideally be the same with or without
-fstack-clash-protection as this can clearly never skip a whole page.
But gcc generates a big loop trying to touch every page-sized subpart of that
allocation.
https://godbolt.org/z/G8EbzbshK
