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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/102494] Failure to optimize vector reduction properly especially when using OpenMP
Date: Mon, 27 Sep 2021 05:08:08 +0000	[thread overview]
Message-ID: <bug-102494-4-cEDdzUk5hH@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102494-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102494

--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Hongtao.liu from comment #2)
> It seems x86 doesn't supports optab reduc_plus_scal_v8hi yet.
vectorizer does the work for backend. 

typedef short v8hi __attribute__((vector_size(16)));
short
foo1 (v8hi p, int n)
{
  short sum = 0;
  for (int i = 0; i != 8; i++)
    sum += p[i];
  return sum;
}

  # sum_21 = PHI <sum_9(3)>
  # vect_sum_9.26_5 = PHI <vect_sum_9.26_6(3)>
  _22 = (vector(8) unsigned short) vect_sum_9.26_5;
  _23 = VEC_PERM_EXPR <_22, { 0, 0, 0, 0, 0, 0, 0, 0 }, { 4, 5, 6, 7, 8, 9, 10,
11 }>;
  _24 = _23 + _22;
  _25 = VEC_PERM_EXPR <_24, { 0, 0, 0, 0, 0, 0, 0, 0 }, { 2, 3, 4, 5, 6, 7, 8,
9 }>;
  _26 = _25 + _24;
  _27 = VEC_PERM_EXPR <_26, { 0, 0, 0, 0, 0, 0, 0, 0 }, { 1, 2, 3, 4, 5, 6, 7,
8 }>;
  _28 = _27 + _26;
  stmp_sum_9.27_29 = BIT_FIELD_REF <_28, 16, 0>;


But for the case in PR, it's v8qi -> 2 v4hi, and no vector reduction for v4hi.

  parent reply	other threads:[~2021-09-27  5:08 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-27  0:52 [Bug tree-optimization/102494] New: Failure to optimize out " gabravier at gmail dot com
2021-09-27  1:45 ` [Bug tree-optimization/102494] " pinskia at gcc dot gnu.org
2021-09-27  3:01 ` crazylht at gmail dot com
2021-09-27  5:08 ` crazylht at gmail dot com [this message]
2021-09-27  5:13 ` [Bug tree-optimization/102494] Failure to optimize " crazylht at gmail dot com
2021-09-27  5:55 ` crazylht at gmail dot com
2021-09-27  8:47 ` rguenth at gcc dot gnu.org
2021-09-28  6:57 ` crazylht at gmail dot com
2021-09-28  7:09 ` rguenther at suse dot de
2021-10-08  2:10 ` cvs-commit at gcc dot gnu.org
2021-10-25 21:44 ` peter at cordes dot ca
2021-10-25 22:00 ` peter at cordes dot ca
2021-10-26  8:13 ` crazylht at gmail dot com

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