[Bug rtl-optimization/89965] [8 Regression] wrong code with -O -mtune=nano-x2 -fcaller-saves -fexpensive-optimizations -fno-tree-dce -fno-tree-ter

[williambader at hotmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89965

--- Comment #18 from William Bader <williambader at hotmail dot com> ---
I did a bisection for the bug from my previous comment (which is still present
in the current gcc 11 in master):

058e97ecf33ad0dfd926b3876a4bcf59ac9556ff is the first bad commit
commit 058e97ecf33ad0dfd926b3876a4bcf59ac9556ff
Author: Vladimir Makarov <vmakarov@redhat.com>
Date:   Tue Aug 26 12:39:58 2008 +0000

`git diff '058e97ecf33ad0dfd926b3876a4bcf59ac9556ff^!' | wc -l` shows 16192
lines.

gcc/caller-save.c has a lot of changes. I want it fixed in the current gcc. I
don't care about gcc 4, other than that the git bisect found that the bug was
introduced in a commit to gcc 4. Is it worth trying to fix it in gcc 4, or
would that just waste time making a patch that would not apply to the current
gcc?