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From: "xry111 at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/110701] [14 Regression] Wrong code at -O1/2/3/s on x86_64-linux-gnu
Date: Mon, 17 Jul 2023 12:43:01 +0000 [thread overview]
Message-ID: <bug-110701-4-Giz2CZmitV@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-110701-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110701
Xi Ruoyao <xry111 at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |rtl-optimization
--- Comment #1 from Xi Ruoyao <xry111 at gcc dot gnu.org> ---
Combine pass seems guilty. Before combine:
(insn 21 20 23 2 (parallel [
(set (subreg:HI (reg:DI 92) 0)
(and:HI (subreg:HI (reg:DI 92) 0)
(const_int 340 [0x154])))
(clobber (reg:CC 17 flags))
]) "/app/example.c":5:39 596 {*andhi_1}
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil)))
(insn 23 21 24 2 (parallel [
(set (reg:HI 94)
(xor:HI (subreg:HI (reg:DI 92) 0)
(const_int 3 [0x3])))
(clobber (reg:CC 17 flags))
]) "/app/example.c":7:23 discrim 1 634 {*xorhi_1}
(expr_list:REG_DEAD (reg:DI 92)
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil))))
(insn 24 23 25 2 (set (reg:SI 95)
(sign_extend:SI (reg:HI 94))) "/app/example.c":7:23 discrim 1 179
{extendhisi2}
(expr_list:REG_DEAD (reg:HI 94)
(nil)))
(insn 25 24 26 2 (set (mem:SI (reg/f:DI 85 [ c.3_6 ]) [3 *c.3_6+0 S4 A32])
(reg:SI 95)) "/app/example.c":7:23 discrim 1 91 {*movsi_internal}
(expr_list:REG_DEAD (reg:SI 95)
(expr_list:REG_DEAD (reg/f:DI 85 [ c.3_6 ])
(nil))))
This is perfectly legal. After combine:
(insn 21 20 23 2 (parallel [
(set (subreg:HI (reg:DI 92) 0)
(and:HI (subreg:HI (reg:DI 92) 0)
(const_int 340 [0x154])))
(clobber (reg:CC 17 flags))
]) "/app/example.c":5:39 596 {*andhi_1}
(expr_list:REG_UNUSED (reg:CC 17 flags)
(nil)))
(note 23 21 24 2 NOTE_INSN_DELETED)
(insn 24 23 25 2 (parallel [
(set (reg:SI 95)
(ior:SI (subreg:SI (reg:DI 92) 0)
(const_int 3 [0x3])))
(clobber (reg:CC 17 flags))
]) "/app/example.c":7:23 discrim 1 635 {*iorsi_1}
(expr_list:REG_UNUSED (reg:CC 17 flags)
(expr_list:REG_DEAD (reg:DI 92)
(nil))))
(insn 25 24 26 2 (set (mem:SI (reg/f:DI 85 [ c.3_6 ]) [3 *c.3_6+0 S4 A32])
(reg:SI 95)) "/app/example.c":7:23 discrim 1 91 {*movsi_internal}
(expr_list:REG_DEAD (reg:SI 95)
(expr_list:REG_DEAD (reg/f:DI 85 [ c.3_6 ])
(nil))))
The removal of sign_extend seems wrong.
next prev parent reply other threads:[~2023-07-17 12:43 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-17 10:21 [Bug c/110701] New: " shaohua.li at inf dot ethz.ch
2023-07-17 12:43 ` xry111 at gcc dot gnu.org [this message]
2023-07-17 17:51 ` [Bug rtl-optimization/110701] [14 Regression] " pinskia at gcc dot gnu.org
2023-07-17 17:55 ` pinskia at gcc dot gnu.org
2023-07-17 17:58 ` pinskia at gcc dot gnu.org
2023-07-18 15:38 ` roger at nextmovesoftware dot com
2023-07-18 17:17 ` roger at nextmovesoftware dot com
2023-07-27 18:23 ` roger at nextmovesoftware dot com
2023-10-04 16:12 ` cvs-commit at gcc dot gnu.org
2023-10-11 7:59 ` roger at nextmovesoftware dot com
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