From: "Li, Pan2" <pan2.li@intel.com>
To: Jeff Law <jeffreyalaw@gmail.com>,
Robin Dapp <rdapp.gcc@gmail.com>,
"gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: "juzhe.zhong@rivai.ai" <juzhe.zhong@rivai.ai>,
"kito.cheng@gmail.com" <kito.cheng@gmail.com>,
"richard.guenther@gmail.com" <richard.guenther@gmail.com>,
"Liu, Hongtao" <hongtao.liu@intel.com>
Subject: RE: [PATCH v2] DSE: Bugfix ICE after allow vector type in get_stored_val
Date: Thu, 18 Apr 2024 01:46:16 +0000 [thread overview]
Message-ID: <MW5PR11MB5908DCD1C2B3F1C7971FF54CA90E2@MW5PR11MB5908.namprd11.prod.outlook.com> (raw)
In-Reply-To: <MW5PR11MB5908AD1598D00DBCF6C97E63A9022@MW5PR11MB5908.namprd11.prod.outlook.com>
Kindly ping^ for this ice fix.
Pan
-----Original Message-----
From: Li, Pan2
Sent: Saturday, April 6, 2024 8:02 PM
To: Li, Pan2 <pan2.li@intel.com>; Jeff Law <jeffreyalaw@gmail.com>; Robin Dapp <rdapp.gcc@gmail.com>; gcc-patches@gcc.gnu.org
Cc: juzhe.zhong@rivai.ai; kito.cheng@gmail.com; richard.guenther@gmail.com; Wang, Yanzhang <yanzhang.wang@intel.com>; Liu, Hongtao <Hongtao.Liu@intel.com>
Subject: RE: [PATCH v2] DSE: Bugfix ICE after allow vector type in get_stored_val
Kindly ping for this ice.
Pan
-----Original Message-----
From: Li, Pan2 <pan2.li@intel.com>
Sent: Saturday, March 23, 2024 1:45 PM
To: Jeff Law <jeffreyalaw@gmail.com>; Robin Dapp <rdapp.gcc@gmail.com>; gcc-patches@gcc.gnu.org
Cc: juzhe.zhong@rivai.ai; kito.cheng@gmail.com; richard.guenther@gmail.com; Wang, Yanzhang <yanzhang.wang@intel.com>; Liu, Hongtao <hongtao.liu@intel.com>
Subject: RE: [PATCH v2] DSE: Bugfix ICE after allow vector type in get_stored_val
Thanks Jeff for comments.
> As Richi noted using validate_subreg here isn't great. Does it work to
> factor out this code from extract_low_bits
>
>> if (!int_mode_for_mode (src_mode).exists (&src_int_mode)
>> || !int_mode_for_mode (mode).exists (&int_mode))
>> return NULL_RTX;
>>
>> if (!targetm.modes_tieable_p (src_int_mode, src_mode))
>> return NULL_RTX;
>> if (!targetm.modes_tieable_p (int_mode, mode))
>> return NULL_RTX;
> And use that in the condition (and in extract_low_bits rather than
> duplicating the code)?
It can solve the ICE but will forbid all vector modes goes gen_lowpart.
Actually only the vector mode size is less than reg nature size will trigger the ICE.
Thus, how about just add one more condition before goes to gen_lowpart as below?
Feel free to correct me if any misunderstandings. 😉!
diff --git a/gcc/dse.cc b/gcc/dse.cc
index edc7a1dfecf..258d2ccc299 100644
--- a/gcc/dse.cc
+++ b/gcc/dse.cc
@@ -1946,7 +1946,9 @@ get_stored_val (store_info *store_info, machine_mode read_mode,
copy_rtx (store_info->const_rhs));
else if (VECTOR_MODE_P (read_mode) && VECTOR_MODE_P (store_mode)
&& known_le (GET_MODE_BITSIZE (read_mode), GET_MODE_BITSIZE (store_mode))
- && targetm.modes_tieable_p (read_mode, store_mode))
+ && targetm.modes_tieable_p (read_mode, store_mode)
+ /* It's invalid in validate_subreg if read_mode size is < reg natural. */
+ && known_ge (GET_MODE_SIZE (read_mode), REGMODE_NATURAL_SIZE (read_mode)))
read_reg = gen_lowpart (read_mode, copy_rtx (store_info->rhs));
else
read_reg = extract_low_bits (read_mode, store_mode,
Pan
-----Original Message-----
From: Jeff Law <jeffreyalaw@gmail.com>
Sent: Saturday, March 23, 2024 2:54 AM
To: Li, Pan2 <pan2.li@intel.com>; Robin Dapp <rdapp.gcc@gmail.com>; gcc-patches@gcc.gnu.org
Cc: juzhe.zhong@rivai.ai; kito.cheng@gmail.com; richard.guenther@gmail.com; Wang, Yanzhang <yanzhang.wang@intel.com>; Liu, Hongtao <hongtao.liu@intel.com>
Subject: Re: [PATCH v2] DSE: Bugfix ICE after allow vector type in get_stored_val
On 3/4/24 11:22 PM, Li, Pan2 wrote:
> Thanks Jeff for comments.
>
>> But in the case of a vector modes, we can usually reinterpret the
>> underlying bits in whatever mode we want and do any of the usual
>> operations on those bits.
>
> Yes, I think that is why we can allow vector mode in get_stored_val if my understanding is correct.
> And then the different modes will return by gen_low_part. Unfortunately, there are some modes
> (less than a vector bit size like V2SF, V2QI for vlen=128) are considered as invalid by validate_subreg,
> and return NULL_RTX result in the final ICE.
That doesn't make a lot of sense to me. Even for vlen=128 I would have
expected that we can still use a subreg to access low bits. After all
we might have had a V16QI vector and done a reduction of some sort
storing the result in the first element and we have to be able to
extract that result and move it around.
I'm not real keen on a target workaround. While extremely safe, I
wouldn't be surprised if other ports could trigger the ICE and we'd end
up patching up multiple targets for what is, IMHO, a more generic issue.
As Richi noted using validate_subreg here isn't great. Does it work to
factor out this code from extract_low_bits:
> if (!int_mode_for_mode (src_mode).exists (&src_int_mode)
> || !int_mode_for_mode (mode).exists (&int_mode))
> return NULL_RTX;
>
> if (!targetm.modes_tieable_p (src_int_mode, src_mode))
> return NULL_RTX;
> if (!targetm.modes_tieable_p (int_mode, mode))
> return NULL_RTX;
And use that in the condition (and in extract_low_bits rather than
duplicating the code)?
jeff
ps. No need to apologize for the pings. This completely fell off my radar.
next prev parent reply other threads:[~2024-04-18 1:46 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-26 3:25 [PATCH v1] RTL: Bugfix ICE after allow vector type in DSE pan2.li
2024-02-26 3:41 ` Hongtao Liu
2024-02-26 3:42 ` Li, Pan2
2024-02-26 5:13 ` Hongtao Liu
2024-02-26 7:38 ` Richard Biener
2024-02-26 7:41 ` Li, Pan2
2024-02-26 14:22 ` [PATCH v2] DSE: Bugfix ICE after allow vector type in get_stored_val pan2.li
2024-02-27 9:47 ` Richard Biener
2024-02-27 15:02 ` Jeff Law
2024-02-28 1:40 ` Li, Pan2
2024-02-28 4:51 ` Li, Pan2
2024-02-28 17:33 ` Jeff Law
2024-02-29 1:38 ` Li, Pan2
2024-02-29 13:28 ` Robin Dapp
2024-03-02 1:04 ` Li, Pan2
2024-03-03 22:46 ` Jeff Law
2024-03-05 6:22 ` Li, Pan2
2024-03-12 2:08 ` Li, Pan2
2024-03-22 1:15 ` Li, Pan2
2024-03-22 18:53 ` Jeff Law
2024-03-23 5:45 ` Li, Pan2
2024-04-06 12:02 ` Li, Pan2
2024-04-18 1:46 ` Li, Pan2 [this message]
2024-04-28 12:10 ` Li, Pan2
2024-04-29 15:20 ` Jeff Law
2024-04-30 1:02 ` Li, Pan2
2024-04-30 7:17 ` [PATCH v3] DSE: Fix " pan2.li
2024-04-30 11:35 ` Li, Pan2
2024-05-03 1:57 ` Li, Pan2
2024-05-03 1:51 ` [PATCH v4] " pan2.li
2024-05-16 4:06 ` Li, Pan2
2024-05-19 16:23 ` Jeff Law
2024-05-20 1:08 ` Li, Pan2
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