On 8/28/23 19:28, Fei Gao wrote:
On 2023-08-29 06:54 Jeff Law <jeffreya...@gmail.com> wrote:
On 8/28/23 01:47, Fei Gao wrote:
no functional changes but allow targets to check shrink-wrap-separate enabled
or not.
gcc/ChangeLog:
* shrink-wrap.cc (try_shrink_wrapping_separate):call
use_shrink_wrapping_separate.
(use_shrink_wrapping_separate): wrap the condition
check in use_shrink_wrapping_separate.
* shrink-wrap.h (use_shrink_wrapping_separate): add to extern
So as I mentioned earlier today in the older thread, can we use
override_options to do this?
If we look at aarch64_override_options we have this:
/* The pass to insert speculation tracking runs before
shrink-wrapping and the latter does not know how to update the
tracking status. So disable it in this case. */
if (aarch64_track_speculation)
flag_shrink_wrap = 0;
We kind of want this instead
if (flag_shrink_wrap)
{
turn off whatever target bits enable the cm.push/cm.pop insns
}
This does imply that we have a distinct target flag to enable/disable
those instructions. But that seems like a good thing to have anyway.
I'm afraid we cannot simply resolve the confilict based on
flag_shrink_wrap/flag_shrink_wrap_separate only, as they're set true from -O1
onwards,
which means zcmp is disabled almostly unless
-fno-shrink-warp/-fno-shrink-warp-separate
are explictly given.
Yea, but I would generally expect that if someone is really concerned
about code size, they're probably using -Os which (hopefully) would not
have shrink-wrapping enabled.
So after discussion with Kito, we would like to turn on zcmp for -Os and
shrink-warp-separate
for the speed perfered optimization. use_shrink_wrapping_separate in this patch
provide the
chance for this check. No new hook is needed.
Seems reasonable to me if Kito is OK with it.
jeff
