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From: "juzhe.zhong at rivai dot ai" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/110751] RISC-V: Suport undefined value that allows VSETVL PASS use TA/MA
Date: Tue, 12 Sep 2023 14:53:51 +0000 [thread overview]
Message-ID: <bug-110751-4-MjoID3L5hK@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110751-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110751
--- Comment #25 from JuzheZhong <juzhe.zhong at rivai dot ai> ---
(In reply to rsandifo@gcc.gnu.org from comment #24)
> Heh, nice hack. :) But I guess this shows that the type checking of
> internal functions isn't as strong it should be.
>
> IMO it's wrong to pass a scalar else value to a vector operation.
> Even if it happens to work now, it's likely to fail in the future.
> E.g. I think match.pd fold rules should be entitled to assume
> (without checking) that all data operands to a COND_* function
> have compatible types.
>
> If we want an undefined operand value, I think we'll need add to
> add one that specifically has that meaning.
Yes. I am also worrying about GIMPLE_FOLD stuff will check all arguments
type are compatible for COND_LEN_xxx in the future (Currently, it's obviously
not checking this). Then, it will cause ICE.
Adding undefine value will be the optimal solution.
However, it will be a big project:
1. Add undefine in tree.def
2. Add undefine in RTL representation.
3. Adjust each PASS to handle undefine value.
4. Adjust register allocation to handle undefine value.
... etc
I can image it will be long term project to support undefine.
But we want to fix this inferior codegen of RVV currently since
I have tested various benchmark, the ELSE value hurt the performance
so much so that I want to use current infrastructure GCC to fix
this issue.
next prev parent reply other threads:[~2023-09-12 14:53 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-20 9:03 [Bug target/110751] New: " xuli1 at eswincomputing dot com
2023-07-20 9:10 ` [Bug target/110751] " juzhe.zhong at rivai dot ai
2023-07-20 9:30 ` rguenth at gcc dot gnu.org
2023-07-20 9:37 ` rguenth at gcc dot gnu.org
2023-07-20 9:58 ` kito at gcc dot gnu.org
2023-07-20 11:28 ` rguenther at suse dot de
2023-07-20 11:43 ` juzhe.zhong at rivai dot ai
2023-07-20 12:00 ` juzhe.zhong at rivai dot ai
2023-07-20 12:35 ` rguenther at suse dot de
2023-07-20 12:42 ` juzhe.zhong at rivai dot ai
2023-07-20 12:45 ` rguenther at suse dot de
2023-07-20 12:50 ` juzhe.zhong at rivai dot ai
2023-07-20 12:56 ` rguenther at suse dot de
2023-07-20 13:29 ` rsandifo at gcc dot gnu.org
2023-07-20 13:32 ` rguenther at suse dot de
2023-07-20 22:03 ` juzhe.zhong at rivai dot ai
2023-07-21 1:53 ` xuli1 at eswincomputing dot com
2023-07-21 6:17 ` rguenth at gcc dot gnu.org
2023-07-21 12:47 ` rsandifo at gcc dot gnu.org
2023-07-21 12:53 ` rguenth at gcc dot gnu.org
2023-07-21 13:23 ` rsandifo at gcc dot gnu.org
2023-07-24 6:20 ` rguenther at suse dot de
2023-07-25 7:05 ` juzhe.zhong at rivai dot ai
2023-09-12 11:44 ` juzhe.zhong at rivai dot ai
2023-09-12 14:24 ` rsandifo at gcc dot gnu.org
2023-09-12 14:53 ` juzhe.zhong at rivai dot ai [this message]
2023-09-12 15:59 ` rsandifo at gcc dot gnu.org
2023-09-12 16:21 ` juzhe.zhong at rivai dot ai
2023-09-12 16:27 ` juzhe.zhong at rivai dot ai
2023-09-12 16:31 ` juzhe.zhong at rivai dot ai
2023-09-12 22:44 ` juzhe.zhong at rivai dot ai
2023-09-13 7:56 ` rguenth at gcc dot gnu.org
2023-09-13 8:34 ` juzhe.zhong at rivai dot ai
2023-09-13 8:39 ` juzhe.zhong at rivai dot ai
2023-09-13 9:38 ` rguenth at gcc dot gnu.org
2023-09-13 9:39 ` rguenth at gcc dot gnu.org
2023-09-13 9:48 ` juzhe.zhong at rivai dot ai
2023-09-13 9:48 ` juzhe.zhong at rivai dot ai
2023-09-13 10:15 ` rguenther at suse dot de
2023-09-13 22:39 ` rsandifo at gcc dot gnu.org
2023-09-14 8:53 ` juzhe.zhong at rivai dot ai
2023-09-14 9:15 ` richard.sandiford at arm dot com
2023-09-20 16:27 ` cvs-commit at gcc dot gnu.org
2023-09-21 9:13 ` cvs-commit at gcc dot gnu.org
2023-09-21 9:28 ` juzhe.zhong at rivai dot ai
2023-09-22 7:31 ` xuli1 at eswincomputing dot com
2023-09-22 7:33 ` xuli1 at eswincomputing dot com
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