https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89853
--- Comment #3 from Peter Bergner <bergner at gcc dot gnu.org> --- I don't have access to that type of machine and honestly don't know the ISA well enough to know the differences between what runs well and what doesn't just by looking at the code. Can you point out some code/function where the assembler code is worse? The patch you bisected to only removes unneeded conflicts in the conflict graph, which gives the allocators more freedom, which in general is a good thing. That said, since these are all heuristics built on top of heuristics, it's not impossible that giving more freedom could lead to worse code. My guess is though, we're probably tickling a AMD specific hardware pipeline feature, since you said you don't see the same thing on Intel.
