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.
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.
Please let me know what you think.
BR,
Fei
>
>jeff
