[Bug rtl-optimization/70164] [6 Regression] Code/performance regression due to poor register allocation on Cortex-M0

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70164

--- Comment #9 from Jeffrey A. Law <law at redhat dot com> ---
I think that's a fair characterization.  The extra copy emitted by the older
compiler gives the allocator more freedom.   With coalescing getting more
aggressive, the copy is gone and the allocator's freedom is reduced.

I'll try to have a look at what the allocator is doing, but I doubt it's
realistically something that can be addressed in this release cycle.