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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/114932] Improvement in CHREC can give large performance gains
Date: Fri, 03 May 2024 09:12:10 +0000	[thread overview]
Message-ID: <bug-114932-4-1TZn8o9a9N@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-114932-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114932

--- Comment #7 from Richard Biener <rguenth at gcc dot gnu.org> ---
Likely

  Base: (integer(kind=4) *) &block + ((sizetype) ((unsigned long) l0_19(D) *
324) + 36)

vs.

  Base: (integer(kind=4) *) &block + ((sizetype) ((integer(kind=8)) l0_19(D)
* 81) + 9) * 4

where we fail to optimize the outer multiply.  It's

 ((unsigned)((signed)x * 81) + 9) * 4

and likely done by extract_muldiv for the case of (unsigned)x.  The trick
would be to promote the inner multiply to unsigned to make the otherwise
profitable transform valid.  But best not by enhancing extract_muldiv ...

  parent reply	other threads:[~2024-05-03  9:12 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-03  5:51 [Bug tree-optimization/114932] New: " tnfchris at gcc dot gnu.org
2024-05-03  6:26 ` [Bug tree-optimization/114932] " rguenth at gcc dot gnu.org
2024-05-03  7:03 ` pinskia at gcc dot gnu.org
2024-05-03  8:09 ` tnfchris at gcc dot gnu.org
2024-05-03  8:41 ` tnfchris at gcc dot gnu.org
2024-05-03  8:44 ` tnfchris at gcc dot gnu.org
2024-05-03  8:45 ` tnfchris at gcc dot gnu.org
2024-05-03  9:12 ` rguenth at gcc dot gnu.org [this message]
2024-05-13  8:28 ` tnfchris at gcc dot gnu.org
2024-06-05  9:42 ` [Bug tree-optimization/114932] IVopts inefficient handling of signed IV used for addressing tnfchris at gcc dot gnu.org
2024-06-05 10:23 ` rguenth at gcc dot gnu.org
2024-06-05 19:02 ` tnfchris at gcc dot gnu.org
2024-06-06  6:17 ` rguenther at suse dot de
2024-06-06  6:40 ` tnfchris at gcc dot gnu.org
2024-06-06  7:55 ` rguenther at suse dot de
2024-06-06  8:01 ` tnfchris at gcc dot gnu.org

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