[Bug sanitizer/85230] asan: false positives in kernel on allocas

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85230

--- Comment #15 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to chefmax from comment #14)
> (In reply to Jakub Jelinek from comment #13)
> > or introduce a new virtual pseudo register that vregs pass would map directly to dynamic_offset.
> 
> Yeah, that's what I though about (LLVM does pretty the same thing). But
> (new_sp + virtual_stack_dynamic_rtx - stack_pointer_rtx) seems like an
> appropriate solution too. I'll cover the testing for both approaches.

The above patch passed
make -j16 -k check-gcc check-g++ RUNTESTFLAGS='--target_board=unix\{-m32,-m64\}
asan.exp=alloca*'
on x86_64-linux and powerpc64-linux and without the -m32, part also on
powerpc64le-linux.