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From: "jens.seifert at de dot ibm.com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/106770] PPCLE: Unnecessary xxpermdi before mfvsrd
Date: Tue, 28 Feb 2023 07:23:17 +0000	[thread overview]
Message-ID: <bug-106770-4-KpoNBwHWqn@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-106770-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106770

--- Comment #6 from Jens Seifert <jens.seifert at de dot ibm.com> ---
The left part of VSX registers overlaps with floating point registers, that is
why no register xxpermdi is required and mfvsrd can access all (left) parts of
VSX registers directly.
The xxpermdi x,y,y,3 indicates to me that gcc prefers right part of register
which might also cause the xxpermdi at the beginning. At the end the mystery is
why gcc adds 3 xxpermdi to the code.

  parent reply	other threads:[~2023-02-28  7:23 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-29  7:52 [Bug target/106770] New: " jens.seifert at de dot ibm.com
2022-08-29  8:16 ` [Bug target/106770] " jens.seifert at de dot ibm.com
2022-08-29  9:57 ` jens.seifert at de dot ibm.com
2023-02-27 16:26 ` segher at gcc dot gnu.org
2023-02-27 17:57 ` jens.seifert at de dot ibm.com
2023-02-27 23:06 ` segher at gcc dot gnu.org
2023-02-28  7:23 ` jens.seifert at de dot ibm.com [this message]
2023-02-28 16:57 ` segher at gcc dot gnu.org
2023-03-02  6:11 ` [Bug target/106770] powerpc64le: " jskumari at gcc dot gnu.org
2023-03-02  7:36 ` jskumari at gcc dot gnu.org
2023-03-02 12:42 ` jskumari at gcc dot gnu.org
2023-03-02 13:26 ` segher at gcc dot gnu.org
2023-03-03  6:02 ` jskumari at gcc dot gnu.org

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