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From: "nok.raven at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/96166] New: [10/11 Regression] -O3/-ftree-slp-vectorize turns ROL into a mess
Date: Sat, 11 Jul 2020 16:01:41 +0000	[thread overview]
Message-ID: <bug-96166-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96166

            Bug ID: 96166
           Summary: [10/11 Regression] -O3/-ftree-slp-vectorize turns ROL
                    into a mess
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: nok.raven at gmail dot com
  Target Milestone: ---

inline void swap(int &x, int &y)
{
  int tmp = x;
  x = y;
  y = tmp;
}

void bar(int (&x)[2])
{
  int y[2];
  __builtin_memcpy(&y, &x, sizeof x);
  swap(y[0], y[1]);
  __builtin_memcpy(&x, &y, sizeof x);
}


GCC 9 (-Os/O2/O3) produces:
  rolq $32, (%rdi)

GCC 10/trunk (-O3/-ftree-slp-vectorize) produces:
  movq (%rdi), %rax
  movd (%rdi), %xmm1
  sarq $32, %rax
  movq %rax, %xmm0
  punpckldq %xmm1, %xmm0
  movq %xmm0, (%rdi)


https://godbolt.org/z/5h3bW8

             reply	other threads:[~2020-07-11 16:01 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-11 16:01 nok.raven at gmail dot com [this message]
2020-07-13  8:05 ` [Bug target/96166] " rguenth at gcc dot gnu.org
2020-07-23  6:51 ` rguenth at gcc dot gnu.org
2020-10-12 12:47 ` rguenth at gcc dot gnu.org
2021-02-11 15:00 ` jakub at gcc dot gnu.org
2021-02-12 10:11 ` jakub at gcc dot gnu.org
2021-02-12 11:18 ` jakub at gcc dot gnu.org
2021-02-12 12:17 ` pinskia at gcc dot gnu.org
2021-02-12 12:21 ` jakub at gcc dot gnu.org
2021-02-12 13:53 ` jakub at gcc dot gnu.org
2021-02-12 14:03 ` rguenth at gcc dot gnu.org
2021-02-12 14:40 ` jakub at gcc dot gnu.org
2021-02-13  9:33 ` cvs-commit at gcc dot gnu.org
2021-02-13  9:34 ` [Bug target/96166] [10 " jakub at gcc dot gnu.org
2021-04-08 12:02 ` rguenth at gcc dot gnu.org
2022-06-28 10:41 ` jakub at gcc dot gnu.org
2023-07-07  8:55 ` rguenth at gcc dot gnu.org

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