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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/97459] __uint128_t remainder for division by 3
Date: Fri, 27 Nov 2020 13:26:32 +0000 [thread overview]
Message-ID: <bug-97459-4-uUhdIfKDls@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-97459-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97459
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Attachment #49633|0 |1
is obsolete| |
--- Comment #19 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 49634
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=49634&action=edit
gcc11-pr97459-wip.patch
The earlier patch was buggy, we can't really consider the bit 63 for 128-bit
umod or 31 for 64-bit umod, because the sum of the 3 numbers like:
0x7fffffffffffffffULL + 0x7fffffffffffffffULL + 0x3ULL can overflow and unlike
the bit 64 (or 32) case it would need more code to handle those 2 values where
it overflowed.
I'll see if I figure out how to do signed modulo too.
next prev parent reply other threads:[~2020-11-27 13:26 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 13:33 [Bug rtl-optimization/97459] New: " tkoenig at gcc dot gnu.org
2020-10-16 15:22 ` [Bug rtl-optimization/97459] " jakub at gcc dot gnu.org
2020-10-16 15:52 ` jakub at gcc dot gnu.org
2020-10-16 15:57 ` jakub at gcc dot gnu.org
2020-10-17 12:22 ` tkoenig at gcc dot gnu.org
2020-10-18 7:33 ` tkoenig at gcc dot gnu.org
2020-10-18 9:11 ` jakub at gcc dot gnu.org
2020-10-19 11:51 ` jakub at gcc dot gnu.org
2020-10-19 12:05 ` jakub at gcc dot gnu.org
2020-10-20 18:16 ` tkoenig at gcc dot gnu.org
2020-10-23 16:56 ` tkoenig at gcc dot gnu.org
2020-10-24 18:09 ` tkoenig at gcc dot gnu.org
2020-10-24 18:14 ` tkoenig at gcc dot gnu.org
2020-10-26 5:28 ` tkoenig at gcc dot gnu.org
2020-11-08 9:31 ` tkoenig at gcc dot gnu.org
2020-11-08 10:24 ` jakub at gcc dot gnu.org
2020-11-08 19:28 ` tkoenig at gcc dot gnu.org
2020-11-08 19:33 ` tkoenig at gcc dot gnu.org
2020-11-26 19:12 ` jakub at gcc dot gnu.org
2020-11-27 13:26 ` jakub at gcc dot gnu.org [this message]
2020-11-27 15:10 ` jakub at gcc dot gnu.org
2020-11-27 18:34 ` jakub at gcc dot gnu.org
2020-11-30 9:57 ` cvs-commit at gcc dot gnu.org
2020-12-01 15:25 ` cvs-commit at gcc dot gnu.org
2020-12-02 10:41 ` cvs-commit at gcc dot gnu.org
2020-12-02 13:36 ` jakub at gcc dot gnu.org
2020-12-03 19:55 ` tkoenig at gcc dot gnu.org
2021-08-15 11:24 ` pinskia at gcc dot gnu.org
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