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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/109048] [13 regression] redundant mask compare generated by vectorizer.
Date: Mon, 27 Mar 2023 08:26:41 +0000	[thread overview]
Message-ID: <bug-109048-4-ALd6Co0rvo@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-109048-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109048

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
The first threadfull pass ends up producing the three-argument PHI:

<bb 7> [local count: 1063004408]:
_7 = (long unsigned int) i_14;
_8 = _7 * 4;
_9 = af_24(D) + _8;
x_25 = *_9;
if (x_25 >= 0.0)
  goto <bb 9>; [59.00%]
else
  goto <bb 8>; [41.00%]

<bb 8> [local count: 435831803]:

<bb 9> [local count: 1063004408]:
# iftmp.2_17 = PHI <iftmp.1_16(7), 1.0e+0(8)>
if (iftmp.0_15 > x_25)
  goto <bb 11>; [50.00%]
else
  goto <bb 10>; [50.00%]

and we thread 9->11 from 8->9 (so when !(x_25 >= 0.0)).  Like a related PR
this is a threading that turns a "conditional move" diamond into something more
complicated.  We could heuristically decide that we don't want to do this
[early?].  But it might be more honest to more aggressively represent
those as COND_EXPRs then.

So I think we have a duplicate for this.

  parent reply	other threads:[~2023-03-27  8:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-07  6:01 [Bug tree-optimization/109048] New: " crazylht at gmail dot com
2023-03-07  6:03 ` [Bug tree-optimization/109048] " crazylht at gmail dot com
2023-03-07  6:13 ` crazylht at gmail dot com
2023-03-07  6:22 ` crazylht at gmail dot com
2023-03-07  6:34 ` crazylht at gmail dot com
2023-03-07  9:17 ` rguenth at gcc dot gnu.org
2023-03-07  9:38 ` jakub at gcc dot gnu.org
2023-03-07 10:09 ` rguenther at suse dot de
2023-03-27  8:26 ` rguenth at gcc dot gnu.org [this message]
2023-03-27  9:18 ` rguenth at gcc dot gnu.org
2023-03-27 10:37 ` rguenth at gcc dot gnu.org
2023-03-28 12:20 ` rguenth at gcc dot gnu.org
2023-04-13  7:30 ` rguenth at gcc dot gnu.org
2023-04-13  8:14 ` crazylht at gmail dot com

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