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From: "steven at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/17387] Redundant instructions in loop optimization
Date: Thu, 27 Jan 2005 01:43:00 -0000 [thread overview]
Message-ID: <20050127014334.2874.qmail@sourceware.org> (raw)
In-Reply-To: <20040909235415.17387.hjl@lucon.org>
------- Additional Comments From steven at gcc dot gnu dot org 2005-01-27 01:43 -------
GCC can't see that this is a NOP because of the zero_extend:
#(insn 34 30 37 (set (reg:DI 0 ax [orig:76 D.1460 ] [76])
# (zero_extend:DI (reg:SI 0 ax [orig:70 D.1460 ] [70]))) 111
{zero_extendsidi2_rex64} (insn_list:REG_DEP_ANTI 30 (insn_list:REG_DEP_TRUE 29
(nil)))
# (nil))
mov %eax, %eax # D.1460, D.1460 # 34
zero_extendsidi2_rex64/1 [length = 3]
Perhaps we should have a peephole2 for this. I'm curious why we can not
eliminate the move earlier on, though.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17387
next prev parent reply other threads:[~2005-01-27 1:43 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-09-09 23:54 [Bug c/17387] New: " hjl at lucon dot org
2004-09-10 0:36 ` [Bug rtl-optimization/17387] " pinskia at gcc dot gnu dot org
2004-09-10 2:50 ` law at gcc dot gnu dot org
2004-09-10 8:05 ` pinskia at gcc dot gnu dot org
2004-09-10 9:53 ` hubicka at gcc dot gnu dot org
2004-09-10 23:22 ` pinskia at gcc dot gnu dot org
2004-09-11 19:55 ` rakdver at gcc dot gnu dot org
2004-11-27 20:49 ` pinskia at gcc dot gnu dot org
2005-01-23 13:36 ` steven at gcc dot gnu dot org
2005-01-24 18:17 ` hjl at lucon dot org
2005-01-24 18:53 ` pinskia at gcc dot gnu dot org
2005-01-27 1:27 ` steven at gcc dot gnu dot org
2005-01-27 1:36 ` steven at gcc dot gnu dot org
2005-01-27 1:43 ` steven at gcc dot gnu dot org [this message]
2005-01-27 4:03 ` hjl at lucon dot org
2005-01-27 6:05 ` rth at gcc dot gnu dot org
2005-01-27 7:14 ` stevenb at suse dot de
2005-01-27 10:14 ` steven at gcc dot gnu dot org
2005-01-27 10:27 ` steven at gcc dot gnu dot org
2005-01-27 10:28 ` steven at gcc dot gnu dot org
2005-01-27 13:36 ` pinskia at gcc dot gnu dot org
2005-09-29 3:44 ` pinskia at gcc dot gnu dot org
[not found] <bug-17387-682@http.gcc.gnu.org/bugzilla/>
2006-01-15 20:30 ` pinskia at gcc dot gnu dot org
2006-02-27 23:55 ` hjl at lucon dot org
2007-04-20 20:58 ` steven at gcc dot gnu dot org
2007-04-20 21:10 ` steven at gcc dot gnu dot org
2007-05-25 20:32 ` steven at gcc dot gnu dot org
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