[PATCH] rs6000: Disable -fcaller-saves by default

[Segher Boessenkool]

On Tue, Aug 25, 2020 at 02:35:51PM -0600, Jeff Law wrote:
> I've gone back and forth on pre allocation splitting as well as post-allocating
> splitting and re-allocation.   I could argue either side of that discussion --

If you end up wanting something split it is best to do it early.  But if
you cannot predict well if you want it split eventually, there is no
good way to do this afaics :-(

> given we've got a bit of special code for splitting to help shrink wrapping,

Only very minimal stuff for splitting copies from a hard reg (argument reg)
to a pseudo.  And then only for all together.

> I'd probably start by making sure the cost computation is sane though.

Yeah.


Segher