On Fri, Nov 30, 2018 at 09:08:34AM -0700, Jeff Law wrote:
> > Sth I don't like very much... maybe we can revisit removing
> > the few cases in fold-const.c (thus GENERIC folding) and rely
> > on later GIMPLE passes instead plus on RTL expansion to
> > do the reverse transform.
> >
> > Not for GCC 9 of course.
> Agreed, 100%. That was supposed to be where Kai's work was headed, but
> we never seemed to make significant headway. Getting BRANCH_COST out
> of the tree generation/folding would be a good thing at many levels.
>
> There'll be fallout, of course.
Note, for the GCC 9 timeframe, for PR85368 I wrote today
--param logical-op-non-short-circuit={0,1} support that allows
to override LOGICAL_OP_NON_SHORT_CIRCUIT, because clearly it is impossible
to handle it in testcases otherwise, just -mbranch-cost= and the defaults
aren't good enough, as some targets override LOGICAL_OP_NON_SHORT_CIRCUIT
and figuring out all the details is too hard in tcl.
I prefer a param to make it clear that it won't last too long if we
implement the above for GCC 10 or 11.
Jakub
