From: Richard Sandiford <richard.sandiford@arm.com>
To: Jakub Jelinek <jakub@redhat.com>
Cc: Hongtao Liu <crazylht@gmail.com>,
Eric Botcazou <ebotcazou@libertysurf.fr>,
gcc-patches@gcc.gnu.org, Uros Bizjak <ubizjak@gmail.com>,
"H. J. Lu" <hjl.tools@gmail.com>
Subject: Re: [PATCH] [i386] Fix _mm256_zeroupper to notify LRA that vzeroupper will kill sse registers. [PR target/82735]
Date: Thu, 27 May 2021 11:50:18 +0100 [thread overview]
Message-ID: <mptk0nk1mdx.fsf@arm.com> (raw)
In-Reply-To: <20210527072006.GL7746@tucnak> (Jakub Jelinek's message of "Thu, 27 May 2021 09:20:06 +0200")
Jakub Jelinek <jakub@redhat.com> writes:
> On Thu, May 27, 2021 at 01:07:09PM +0800, Hongtao Liu via Gcc-patches wrote:
>> + /* Flag used for call_insn indicates it's a fake call. */
>> + RTX_FLAG (insn, used) = 1;
>
>> + /* CALL_INSN use "used" flag to indicate it's a fake call. */
>> + if (i == STACK_POINTER_REGNUM
>> + && !RTX_FLAG (insn_info->insn, used))
>
>> - && ! SIBLING_CALL_P (insn))
>> + && ! SIBLING_CALL_P (insn)
>> + && !RTX_FLAG (insn, used))
>
>> - /* For all other RTXes clear the used flag on the copy. */
>> - RTX_FLAG (copy, used) = 0;
>> + /* For all other RTXes clear the used flag on the copy.
>> + CALL_INSN use "used" flag to indicate it's a fake call. */
>> + if (!INSN_P (orig))
>> + RTX_FLAG (copy, used) = 0;
>> break;
>> }
>> return copy;
>> @@ -57,7 +57,8 @@ requires_stack_frame_p (rtx_insn *insn, HARD_REG_SET prologue_used,
>> HARD_REG_SET hardregs;
>> unsigned regno;
>>
>> - if (CALL_P (insn))
>> + /* CALL_INSN use "used" flag to indicate it's a fake call. */
>> + if (CALL_P (insn) && !RTX_FLAG (insn, used))
>> return !SIBLING_CALL_P (insn);
>
> Please define a macro for this in rtl.h (and mention it above used;
> member too in a comment, see all the other comments in there), like:
> /* 1 if RTX is a call_insn for a fake call. */
> #define FAKE_CALL_P(RTX) \
> (RTL_FLAG_CHECK1 ("FAKE_CALL_P", (RTX), CALL_INSN)->used)
> Though, I'm also not sure if used can be actually used for this,
> because it is used e.g. in emit-rtl.c for verification of RTL sharing.
I thought it should be OK, since:
- copy_rtx_if_shared_1 and mark_used_flags do nothing for insns
- verify_rtx_sharing is only called for parts of an insn, rather than
an insn itself
I guess an alternative would be to add a new rtx_code for fake call
insns and use CALL_P to test for both. However, that would lose the
property that the default behaviour is conservatively correct
(even for direct checks of CALL_INSN), so the flag IMO seems better.
Thanks,
Richard
> Though, it seems no other rtl flag is free for CALL_INSN.
> Could this fake call flag sit on the CALL rtx instead?
>
> Jakub
next prev parent reply other threads:[~2021-05-27 10:50 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-13 9:23 Hongtao Liu
2021-05-13 9:40 ` Uros Bizjak
2021-05-13 9:43 ` Uros Bizjak
2021-05-13 9:54 ` Jakub Jelinek
2021-05-13 11:32 ` Richard Sandiford
2021-05-13 11:37 ` Jakub Jelinek
2021-05-13 11:52 ` Richard Sandiford
2021-05-14 2:27 ` Hongtao Liu
2021-05-17 8:44 ` Hongtao Liu
2021-05-17 9:56 ` Richard Sandiford
2021-05-18 13:12 ` Hongtao Liu
2021-05-18 15:18 ` Richard Sandiford
2021-05-25 6:04 ` Hongtao Liu
2021-05-25 6:30 ` Hongtao Liu
2021-05-27 5:07 ` Hongtao Liu
2021-05-27 7:05 ` Uros Bizjak
2021-06-01 2:24 ` Hongtao Liu
2021-06-03 6:54 ` [PATCH 1/2] CALL_INSN may not be a real function call liuhongt
2021-06-03 6:54 ` [PATCH 2/2] Fix _mm256_zeroupper by representing the instructions as call_insns in which the call has a special vzeroupper ABI liuhongt
2021-06-04 2:56 ` Hongtao Liu
2021-06-04 6:26 ` Uros Bizjak
2021-06-04 6:34 ` Hongtao Liu
2021-06-07 19:04 ` [PATCH] x86: Don't compile pr82735-[345].c for x32 H.J. Lu
2021-06-04 2:55 ` [PATCH 1/2] CALL_INSN may not be a real function call Hongtao Liu
2021-06-04 7:50 ` Jakub Jelinek
2021-07-05 23:30 ` Segher Boessenkool
2021-07-06 0:03 ` Jeff Law
2021-07-06 1:49 ` Hongtao Liu
2021-07-07 14:55 ` Segher Boessenkool
2021-07-07 17:56 ` Jeff Law
2021-07-06 1:37 ` Hongtao Liu
2021-07-07 2:44 ` Hongtao Liu
2021-07-07 8:15 ` Richard Biener
2021-07-07 14:52 ` Segher Boessenkool
2021-07-07 15:23 ` Hongtao Liu
2021-07-07 23:42 ` Segher Boessenkool
2021-07-08 4:14 ` Hongtao Liu
2021-07-07 15:32 ` Hongtao Liu
2021-07-07 23:54 ` Segher Boessenkool
2021-07-09 7:20 ` Hongtao Liu
2021-07-07 15:52 ` Hongtao Liu
2021-05-27 7:20 ` [PATCH] [i386] Fix _mm256_zeroupper to notify LRA that vzeroupper will kill sse registers. [PR target/82735] Jakub Jelinek
2021-05-27 10:50 ` Richard Sandiford [this message]
2021-06-01 2:22 ` Hongtao Liu
2021-06-01 2:25 ` Hongtao Liu
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