Re: Re: [PATCH v1] RISC-V: Revert RVV wv instructions overlap and xfail tests

[钟居哲 <juzhe.zhong@rivai.ai>]

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Apologize that we didn't post our (me, kito and Li Pan) disscussions.

This is the story:
We found that my previous patches which support highpart register overlap with register filter for instructions like (vwadd.wv)
cause ICE reported by:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114714
and this is obviously a regression (No ICE on GCC 13.2, but ICE on GCC 14)

We have tried several fixes to work around this ICE, however, we failed.
And also I found my previous patches are quite wrong which is not the perfect solution to support register group overlap
for vwadd.wv. 
So, finally we decide to revert those patches.

Kito knows the details of this story, kito can share more details in GNU patche meeting.

Thanks.


juzhe.zhong@rivai.ai
 
From: Patrick O'Neill
Date: 2024-04-23 01:20
To: Li, Pan2; Robin Dapp; gcc-patches@gcc.gnu.org
CC: juzhe.zhong@rivai.ai; kito.cheng@gmail.com
Subject: Re: [PATCH v1] RISC-V: Revert RVV wv instructions overlap and xfail tests
Hi Pan,
I'm not sure I'm following.  Did we miss something that should have been
covered?  Like only an overlap on the srcs but not the dest?
Are there testcases that fail?  If so we should definitely have one.
Can you give some additional information on why these reverts are needed?
+1 to the request for a failing testcase if there is one. Patrick If something is broken then indeed we should revert it.
Yes, we may need to support these in gcc-15.
... why not just revert everything and xfail all the tests in a
follow up?  Your patch is essentially a revert but doesn't look like
it.  I'd rather we let a revert be a revert and adjust the tests
separately so it becomes clear.
Sure, will revert b3b2799b872 and then file the patch for the xfail tests.
Pan