[Bug target/110104] gcc produces sub-optimal code for _addcarry_u64 chain

[slash.tmp at free dot fr via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110104

--- Comment #4 from Mason <slash.tmp at free dot fr> ---
I confirm that trunk now emits the same code for testcase1 and testcase2.
Thanks Jakub and Roger, great work!