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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/110202] _mm512_ternarylogic_epi64 generates unnecessary operations
Date: Sat, 10 Jun 2023 18:36:46 +0000 [thread overview]
Message-ID: <bug-110202-4-4m1AAtlC2o@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110202-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110202
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |hjl.tools at gmail dot com,
| |jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Well, there is nothing magic on exactly 0x55 immediate, there are 256 possible
immediates, most of them use all of A, B, C, some of them use just A, B, others
just B, C, others just A, C, others just A, others just B, others just C,
others none of them.
And I must say I don't immediately see easy rules how to find out from the
immediate value which set is which, so unless we find some easy rule for that,
we'd need to hardcode the mapping between the 256 values to a bitmask which
inputs are actually used.
And then the question is how to represent that in RTL to make it clear that
some operands are mentioned but their value isn't really used.
next prev parent reply other threads:[~2023-06-10 18:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-10 10:37 [Bug c++/110202] New: " fabio at cannizzo dot net
2023-06-10 16:07 ` [Bug target/110202] " pinskia at gcc dot gnu.org
2023-06-10 16:14 ` [Bug rtl-optimization/110202] " pinskia at gcc dot gnu.org
2023-06-10 18:36 ` jakub at gcc dot gnu.org [this message]
2023-06-10 21:10 ` pinskia at gcc dot gnu.org
2023-06-12 17:14 ` fabio at cannizzo dot net
2023-06-12 19:04 ` amonakov at gcc dot gnu.org
2023-06-27 17:59 ` amonakov at gcc dot gnu.org
2023-06-28 0:47 ` crazylht at gmail dot com
2023-06-28 5:07 ` amonakov at gcc dot gnu.org
2023-07-12 7:51 ` cvs-commit at gcc dot gnu.org
2023-08-04 16:44 ` [Bug target/110202] " cvs-commit at gcc dot gnu.org
2023-08-05 15:32 ` amonakov at gcc dot gnu.org
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