Steven Bosscher <stevenb....@gmail.com> writes:
>
> I suppose it's theoretically possible to make a good initial guess of
> what registers might be not-clobbered by a function even if the ABI
> says so. For instance, perhaps it's possible to assume that a function
> that doesn't touch any variables in a floating point mode also doesn't
> use/clobber any floating point registers. This assumption could be
> propagated via LTO/WHOPR. If the function turns out to clobber
> registers that were assumed to be untouched, you could just save and
> restore them in the function ("callee saved" so to speak). But I don't
> know how useful that would be.
>There was a discussion on this some time ago. The conclusion was that the partition should help: if the partitions works right the callers and callees that are commonly should be commonly in the same partition, and those need RA between themselves. Between partitions you couldn't do RA. -Andi -- a...@linux.intel.com -- Speaking for myself only
