https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96017
--- Comment #11 from Segher Boessenkool <segher at gcc dot gnu.org> ---
(In reply to Peter Bergner from comment #9)
> (In reply to Peter Bergner from comment #8)
> > At first, I thought that split_live_ranges_for_shrink_wrap() split this
> > nicely, but what I found is that IRA assigned a volatile register to a
> > pseudo that is live across a call.
>
> ...and that is because somehow flag_caller_saves is true. I can't believe
> that is a good idea in general.
'-fcaller-saves'
Enable allocation of values to registers that are clobbered by
function calls, by emitting extra instructions to save and restore
the registers around such calls. Such allocation is done only when
it seems to result in better code.
This option is always enabled by default on certain machines,
usually those which have no call-preserved registers to use
instead.
Enabled at levels '-O2', '-O3', '-Os'.
Note the "only when" line... It sounds like (in spite of that promise) we
do it too aggressively currently?
