https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117359
--- Comment #4 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Richard Biener from comment #3) > asm() modifying the stack pointer are invalid. Yeah, but the construct in Comment 0 is what kernel people use to prevent asm from being scheduled before frame is set up. The asm does not modify the stack pointer (the SP after the asm is the same), but can clobber the redzone. The proposed patch improves stack pointer RTX detection in notice_stack_pointer_modification_1 to look at RTL and everything, including redzone prevention, starts to work.
