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From: "segher at gcc dot gnu.org" <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 16:57:45 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106770

Segher Boessenkool <segher at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
             Target|powerpc                     |powerpc64le
   Last reconfirmed|                            |2023-02-28
     Ever confirmed|0                           |1

--- Comment #7 from Segher Boessenkool <segher at gcc dot gnu.org> ---
The mystery is not where the permutations came from: they were added during
expand to make correct code, just like many unnecessary register moves are
added at that time.  This is normal, and even good in many ways.

The question is why they weren't optimised better.  This is either due to
some bug, or this is an enhancement request.=