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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/110428] New: missed CSE with VLA vectors
Date: Tue, 27 Jun 2023 08:37:29 +0000	[thread overview]
Message-ID: <bug-110428-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110428

            Bug ID: 110428
           Summary: missed CSE with VLA vectors
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

#include <stdint.h>

void __attribute__((noinline,noclone))
foo (uint16_t *out, uint16_t *res)
{
  int mask[] = { 0, 1, 1, 1, 1, 1, 1, 1 };
  int i;
  for (i = 0; i < 8; ++i)
    {
      if (mask[i])
        out[i] = 33;
    }
  uint16_t o0 = out[0];
  uint16_t o7 = out[3];
  uint16_t o14 = out[6];
  uint16_t o15 = out[7];
  res[0] = o0;
  res[2] = o7;
  res[4] = o14;
  res[6] = o15;
}

With -march=armv9.3-a -O3 -g0 -fno-vect-cost-model we fail to CSE the
out[] loads after vectorization.

             reply	other threads:[~2023-06-27  8:37 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-27  8:37 rguenth at gcc dot gnu.org [this message]
2023-06-27  8:39 ` [Bug tree-optimization/110428] " rguenth at gcc dot gnu.org
2023-06-27 10:12 ` rguenth at gcc dot gnu.org
2023-06-27 10:23 ` juzhe.zhong at rivai dot ai
2023-06-27 10:34 ` juzhe.zhong at rivai dot ai

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