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From: "juzhe.zhong at rivai dot ai" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/113583] Main loop in 519.lbm not vectorized. Date: Wed, 07 Feb 2024 07:48:29 +0000 [thread overview] Message-ID: <bug-113583-4-gJc5LLDZu5@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-113583-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113583 --- Comment #13 from JuzheZhong <juzhe.zhong at rivai dot ai> --- Ok. I found the optimized tree: _5 = 3.33333333333333314829616256247390992939472198486328125e-1 - _4; _8 = .FMA (_5, 1.229999999999999982236431605997495353221893310546875e-1, _4); Let CST0 = 3.33333333333333314829616256247390992939472198486328125e-1, CST1 = 1.229999999999999982236431605997495353221893310546875e-1 The expression is equivalent to the following: _5 = CST0 - _4; _8 = _5 * CST1 + 4; That is: _8 = (CST0 - _4) * CST1 + 4; So, We should be able to re-associate it like Clang: _8 = CST0 * CST1 - _4 * CST1 + 4; ---> _8 = CST0 * CST1 + _4 * (1 - CST1); Since both CST0 * CST1 and 1 - CST1 can be pre-computed during compilation time. Let say CST2 = CST0 * CST1, CST3 = 1 - CST1, then we can re-associate as Clang: _8 = FMA (_4, CST3, CST2). Any suggestions for this re-association ? Is match.pd the right place to do it ? Thanks.
next prev parent reply other threads:[~2024-02-07 7:48 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-01-24 14:21 [Bug tree-optimization/113583] New: " rdapp at gcc dot gnu.org 2024-01-24 14:42 ` [Bug tree-optimization/113583] " juzhe.zhong at rivai dot ai 2024-01-24 14:44 ` rdapp at gcc dot gnu.org 2024-01-24 15:00 ` juzhe.zhong at rivai dot ai 2024-01-25 3:06 ` juzhe.zhong at rivai dot ai 2024-01-25 3:13 ` juzhe.zhong at rivai dot ai 2024-01-25 5:41 ` pinskia at gcc dot gnu.org 2024-01-25 9:05 ` rguenther at suse dot de 2024-01-25 9:16 ` juzhe.zhong at rivai dot ai 2024-01-25 9:34 ` rguenth at gcc dot gnu.org 2024-01-26 9:50 ` rdapp at gcc dot gnu.org 2024-01-26 10:21 ` rguenther at suse dot de 2024-02-05 6:59 ` juzhe.zhong at rivai dot ai 2024-02-07 3:39 ` juzhe.zhong at rivai dot ai 2024-02-07 7:48 ` juzhe.zhong at rivai dot ai [this message] 2024-02-07 8:04 ` rguenther at suse dot de 2024-02-07 8:08 ` juzhe.zhong at rivai dot ai 2024-02-07 8:13 ` juzhe.zhong at rivai dot ai 2024-02-07 10:24 ` rguenther at suse dot de 2024-05-13 14:17 ` rdapp at gcc dot gnu.org 2024-05-16 12:41 ` rguenth at gcc dot gnu.org
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