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From: "goldstein.w.n at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug target/106038] New: x86_64 vectorization of ALU ops using xmm
 registers prematurely
Date: Mon, 20 Jun 2022 23:49:52 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106038

            Bug ID: 106038
           Summary: x86_64 vectorization of ALU ops using xmm registers
                    prematurely
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: goldstein.w.n at gmail dot com
  Target Milestone: ---

See: https://godbolt.org/z/YxWEn6Y65

Basically in all cases where the total amount of memory touched is <=3D 8 b=
ytes
(word size) the vectorization pass is choosing to inefficiently use xmm
registers to vectorize the unrolled loops.=20

GPRs (as GCC <=3D 9.5 was doing) is faster / less code size.


Related to: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D106022=