Re: [PATCH] Enable shrink wrapping for the RISC-V target.

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/16/22 03:26, Manolis Tsamis wrote:
> On Sun, Nov 13, 2022 at 3:33 AM Jeff Law via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>>
>> On 11/7/22 15:07, Palmer Dabbelt wrote:
>>> On Thu, 03 Nov 2022 15:23:28 PDT (-0700), jlaw@ventanamicro.com wrote:
>>>> On 11/2/22 18:26, Palmer Dabbelt wrote:
>>>>>>> I also tried to remove that restriction but it looks like it can't
>>>>>>> work because we can't create
>>>>>>> pseudo-registers during shrink wrapping and shrink wrapping can't
>>>>>>> work either.
>>>>>>>
>>>>>>> I believe this means that shrink wrapping cannot interfere with a
>>>>>>> long
>>>>>>> stack frame
>>>>>>> so there is nothing to test against in this case?
>>>>>> It'd be marginally better to have such a test case to ensure we don't
>>>>>> shrink wrap it -- that would ensure that someone doesn't accidentally
>>>>>> introduce shrink wrapping with large offsets.   Just a bit of future
>>>>>> proofing.
>>>>> If there's passing test cases that fail with that check removed then
>>>>> it's probably good enough, though I think in this case just having a
>>>>> comment there saying why the short-stack check is necessary should be
>>>>> fine.
>>>> I can live with this.
>>> Which one (or either)?  I'm fine with either option, just trying to
>>> avoid another re-spin as this one is a bit vague.
>> Sorry I wasn't clear.  Either is fine with me.
>>
> Since all issues/concerns around this are resolved, is the v2 of this patch
> good for merging?
>
> Link for v2 patch is
> https://gcc.gnu.org/pipermail/gcc-patches/2022-October/603822.html

You just need to add a comment to get_separate_components indicating 
that the SMALL_OPERAND_P check is required as we do not support 
shrink-wrapping with large stack frames.


OK with that comment.  Just post the final version and commit, no need 
to wait for another review.


jeff