From: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
To: Richard Henderson <richard.henderson@linaro.org>,
libc-alpha@sourceware.org, Jeff Law <jeffreyalaw@gmail.com>,
Xi Ruoyao <xry111@xry111.site>,
Noah Goldstein <goldstein.w.n@gmail.com>
Subject: Re: [PATCH v12 14/31] string: Improve generic strrchr with memrchr and strlen
Date: Mon, 6 Feb 2023 11:01:04 -0300 [thread overview]
Message-ID: <a248b824-6d81-c4ae-52ed-8deaa7836e15@linaro.org> (raw)
In-Reply-To: <f9005160-0a35-8a2c-1307-ee86aedf7071@linaro.org>
On 04/02/23 00:06, Richard Henderson wrote:
> On 2/2/23 08:11, Adhemerval Zanella wrote:
>> Now that both strlen and memrchr have word vectorized implementation,
>> it should be faster to implement strrchr based on memrchr over the
>> string length instead of calling strchr on a loop.
>>
>> Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu,
>> and powerpc64-linux-gnu by removing the arch-specific assembly
>> implementation and disabling multi-arch (it covers both LE and BE
>> for 64 and 32 bits).
>> ---
>> string/strrchr.c | 18 +-----------------
>> 1 file changed, 1 insertion(+), 17 deletions(-)
>
> memrchr needs libc_hidden_builtin_proto. On riscv64:
>
> c: 00000097 auipc ra,0x0
> c: R_RISCV_CALL __GI_strlen
> c: R_RISCV_RELAX *ABS*
> 10: 000080e7 jalr ra # c <__GI_strrchr+0xc>
> ...
> 24: 00000317 auipc t1,0x0
> 24: R_RISCV_CALL_PLT __memrchr
> 24: R_RISCV_RELAX *ABS*
> 28: 00030067 jr t1 # 24 <.LVL2+0x8>
>
>
> r~
Similar to strchr [1], static linker ends up creating the expected local
call:
$ riscv64-glibc-linux-gnu-objdump -dr libc.so
[...]
0000000000088f5c <strrchr>:
88f5c: 7179 addi sp,sp,-48
88f5e: e84a sd s2,16(sp)
88f60: 000e7917 auipc s2,0xe7
88f64: 73893903 ld s2,1848(s2) # 170698 <__stack_chk_guard@GLIBC_2.27>
88f68: 00093783 ld a5,0(s2)
[...]
88f9a: 6145 addi sp,sp,48
88f9c: c70fd06f j 8640c <memrchr>
88fa0: 193500ef jal ra,d9932 <__stack_chk_fail>
[...]
But I agree that we should change to have the libc_hidden_builin_proto
in this case. I will send a patch to fix it.
[1] https://sourceware.org/pipermail/libc-alpha/2023-February/145322.html
next prev parent reply other threads:[~2023-02-06 14:01 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-02 18:11 [PATCH v12 00/31] Improve generic string routines Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 01/31] Parameterize op_t from memcopy.h Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 02/31] Parameterize OP_T_THRES " Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 03/31] Add string vectorized find and detection functions Adhemerval Zanella
2023-02-03 0:24 ` Richard Henderson
2023-02-03 12:39 ` Adhemerval Zanella Netto
2023-02-03 13:40 ` Adhemerval Zanella Netto
2023-02-04 2:54 ` Richard Henderson
2023-02-02 18:11 ` [PATCH v12 04/31] string: Improve generic strlen Adhemerval Zanella
2023-02-03 23:23 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 05/31] string: Improve generic strchrnul Adhemerval Zanella
2023-02-03 23:23 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 06/31] string: Improve generic strchr Adhemerval Zanella
2023-02-03 23:24 ` Noah Goldstein
2023-02-04 2:58 ` Richard Henderson
2023-02-06 13:07 ` Adhemerval Zanella Netto
2023-02-02 18:11 ` [PATCH v12 07/31] string: Improve generic strcmp Adhemerval Zanella
2023-02-03 23:25 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 08/31] string: Improve generic strncmp Adhemerval Zanella
2023-02-03 0:34 ` Richard Henderson
2023-02-21 9:28 ` Szabolcs Nagy
2023-02-21 12:24 ` Adhemerval Zanella Netto
2023-02-02 18:11 ` [PATCH v12 09/31] string: Improve generic stpcpy Adhemerval Zanella
2023-02-03 23:26 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 10/31] string: Improve generic strcpy Adhemerval Zanella
2023-02-03 23:26 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 11/31] string: Improve generic memchr Adhemerval Zanella
2023-02-03 23:26 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 12/31] string: Improve generic strnlen with memchr Adhemerval Zanella
2023-02-03 23:27 ` Noah Goldstein
2023-02-02 18:11 ` [PATCH v12 13/31] string: Improve generic memrchr Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 14/31] string: Improve generic strrchr with memrchr and strlen Adhemerval Zanella
2023-02-04 3:06 ` Richard Henderson
2023-02-06 14:01 ` Adhemerval Zanella Netto [this message]
2023-02-02 18:11 ` [PATCH v12 15/31] hppa: Add memcopy.h Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 16/31] hppa: Add string-fza.h, string-fzc.h, and string-fzi.h Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 17/31] alpha: Add string-fza, string-fzb.h, string-fzi.h, and string-shift.h Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 18/31] arm: Add string-fza.h Adhemerval Zanella
2023-02-20 13:24 ` Szabolcs Nagy
2023-02-20 13:45 ` Szabolcs Nagy
2023-02-20 14:01 ` Adhemerval Zanella Netto
2023-02-20 16:12 ` Szabolcs Nagy
2023-02-02 18:11 ` [PATCH v12 19/31] powerpc: " Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 20/31] sh: Add string-fzb.h Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 21/31] riscv: Add string-fza.h and string-fzi.h Adhemerval Zanella
2023-02-03 19:47 ` Noah Goldstein
2023-02-06 16:14 ` Adhemerval Zanella Netto
2023-02-02 18:11 ` [PATCH v12 22/31] string: Hook up the default implementation on test-strlen Adhemerval Zanella
2023-02-03 23:30 ` Noah Goldstein
2023-02-06 17:36 ` Adhemerval Zanella Netto
2023-02-02 18:11 ` [PATCH v12 23/31] string: Hook up the default implementation on test-strnlen Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 24/31] string: Hook up the default implementation on test-strchr Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 25/31] string: Hook up the default implementation on test-strcmp Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 26/31] string: Hook up the default implementation on test-strncmp Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 27/31] string: Hook up the default implementation on test-stpcpy Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 28/31] string: Hook up the default implementation on test-strcpy Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 29/31] string: Hook up the default implementation on test-memchr Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 30/31] string: Hook up the default implementation on test-memrchr Adhemerval Zanella
2023-02-02 18:11 ` [PATCH v12 31/31] string: Hook up the default implementation on test-strrchr Adhemerval Zanella
2023-02-03 1:55 ` Richard Henderson
2023-02-02 18:17 ` [PATCH v12 00/31] Improve generic string routines Adhemerval Zanella Netto
2023-02-02 19:54 [PATCH v12 14/31] string: Improve generic strrchr with memrchr and strlen Wilco Dijkstra
2023-02-03 12:15 ` Adhemerval Zanella Netto
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=a248b824-6d81-c4ae-52ed-8deaa7836e15@linaro.org \
--to=adhemerval.zanella@linaro.org \
--cc=goldstein.w.n@gmail.com \
--cc=jeffreyalaw@gmail.com \
--cc=libc-alpha@sourceware.org \
--cc=richard.henderson@linaro.org \
--cc=xry111@xry111.site \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).