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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/60116] [4.8/4.9 Regression] wrong code at -Os on x86_64-linux-gnu in 32-bit mode
Date: Mon, 10 Feb 2014 16:48:00 -0000 [thread overview]
Message-ID: <bug-60116-4-38NVFxfnhU@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-60116-4@http.gcc.gnu.org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60116
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ebotcazou at gcc dot gnu.org,
| |law at gcc dot gnu.org
--- Comment #13 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So, what happens is that we have:
(insn 39 38 41 5 (set (reg:QI 119)
(const_int 1 [0x1])) pr60116.c:17 93 {*movqi_internal}
(expr_list:REG_DEAD (reg:CCZ 17 flags)
(nil)))
(insn 41 39 83 5 (set (reg:CCZ 17 flags)
(compare:CCZ (reg:SI 101 [ D.1460 ])
(const_int 0 [0]))) pr60116.c:18 3 {*cmpsi_ccno_1}
(nil))
(insn 83 41 42 5 (set (reg:SI 122 [ D.1465 ])
(zero_extend:SI (reg:QI 119))) 138 {*zero_extendqisi2}
(expr_list:REG_DEAD (reg:QI 119)
(nil)))
(the REG_DEAD on flags on the first insn supposedly comes from earlier
combining.
try_combine is then called on i3=insn83 and i2=insn39 and manages to combine
insn 83 into (set (reg:SI 122) (const_int 1 [0x1])).
The problem is when distribute_notes attempts to distribute the REG_DEAD
(reg:CCZ 17 flags) note from elim_i2=insn39 to i3=insn83.
next prev parent reply other threads:[~2014-02-10 16:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-08 7:26 [Bug tree-optimization/60116] New: " su at cs dot ucdavis.edu
2014-02-08 9:28 ` [Bug target/60116] [4.8/4.9 Regression] " mpolacek at gcc dot gnu.org
2014-02-09 18:04 ` ubizjak at gmail dot com
2014-02-09 20:19 ` jakub at gcc dot gnu.org
2014-02-09 21:13 ` glisse at gcc dot gnu.org
2014-02-09 21:17 ` mpolacek at gcc dot gnu.org
2014-02-09 21:26 ` ubizjak at gmail dot com
2014-02-09 21:38 ` glisse at gcc dot gnu.org
2014-02-09 21:51 ` glisse at gcc dot gnu.org
2014-02-10 9:21 ` ubizjak at gmail dot com
2014-02-10 9:44 ` [Bug rtl-optimization/60116] " rguenth at gcc dot gnu.org
2014-02-10 16:48 ` jakub at gcc dot gnu.org [this message]
2014-02-10 17:16 ` jakub at gcc dot gnu.org
2014-02-10 18:24 ` ebotcazou at gcc dot gnu.org
2014-02-12 8:50 ` ebotcazou at gcc dot gnu.org
2014-02-12 8:52 ` ebotcazou at gcc dot gnu.org
2014-02-12 8:53 ` ebotcazou at gcc dot gnu.org
2014-02-12 10:17 ` ebotcazou at gcc dot gnu.org
2014-02-12 10:17 ` ebotcazou at gcc dot gnu.org
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