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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 tree-optimization/42494] [4.4 Regression] Missed dead-code-elimination Date: Thu, 07 Jan 2010 21:36:00 -0000 [thread overview] Message-ID: <20100107213643.29107.qmail@sourceware.org> (raw) In-Reply-To: <bug-42494-17572@http.gcc.gnu.org/bugzilla/> ------- Comment #9 from steven at gcc dot gnu dot org 2010-01-07 21:36 ------- At -Os, in the .188r.postreload RTL dump: (insn 46 12 17 2 t.c:8 (parallel [ (set (reg/v:SI 2 r2 [orig:133 flags ] [133]) (if_then_else:SI (ne (reg:SI 2 r2 [orig:138 bool_var ] [138]) (const_int 0 [0x0])) (const_int 2 [0x2]) (const_int 0 [0x0]))) (clobber (reg:CC 24 cc)) ]) 291 {movcond} (nil)) And one pass later, in the .190r.split2 RTL dump: (insn 49 12 50 2 t.c:8 (set (reg:CC 24 cc) (compare:CC (reg:SI 2 r2 [orig:138 bool_var ] [138]) (const_int 0 [0x0]))) 220 {*arm_cmpsi_insn} (nil)) (insn 50 49 51 2 t.c:8 (cond_exec (ne (reg:CC 24 cc) (const_int 0 [0x0])) (set (reg/v:SI 2 r2 [orig:133 flags ] [133]) (const_int 2 [0x2]))) 2367 {neon_vornv2di+77} (nil)) (insn 51 50 17 2 t.c:8 (cond_exec (eq (reg:CC 24 cc) (const_int 0 [0x0])) (set (reg/v:SI 2 r2 [orig:133 flags ] [133]) (const_int 0 [0x0]))) 2367 {neon_vornv2di+77} (nil)) There's your redundant mov, from an insn splitter. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42494
next prev parent reply other threads:[~2010-01-07 21:36 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2009-12-25 5:42 [Bug c/42494] New: Regression on dead-code-elimination: GCC 4.2.1 generates better code than 4.4.0 sliao at google dot com 2009-12-29 10:35 ` [Bug c/42494] [4.4 only] " ramana at gcc dot gnu dot org 2009-12-29 11:31 ` [Bug c/42494] [4.4 Regression] Missed " steven at gcc dot gnu dot org 2009-12-29 12:45 ` [Bug tree-optimization/42494] " ramana at gcc dot gnu dot org 2009-12-30 23:21 ` [Bug tree-optimization/42494] [4.4 Regression] Missed dead-code-elimination rguenth at gcc dot gnu dot org 2009-12-30 23:34 ` rguenth at gcc dot gnu dot org 2009-12-31 15:36 ` rguenth at gcc dot gnu dot org 2010-01-07 9:19 ` sliao at google dot com 2010-01-07 9:49 ` steven at gcc dot gnu dot org 2010-01-07 21:30 ` steven at gcc dot gnu dot org 2010-01-07 21:36 ` steven at gcc dot gnu dot org [this message] 2010-01-07 22:08 ` steven at gcc dot gnu dot org 2010-01-07 22:08 ` steven at gcc dot gnu dot org 2010-01-21 13:19 ` jakub at gcc dot gnu dot org 2010-02-08 16:45 ` steven at gcc dot gnu dot org 2010-04-30 8:58 ` jakub at gcc dot gnu dot org [not found] <bug-42494-4@http.gcc.gnu.org/bugzilla/> 2010-10-01 11:59 ` jakub at gcc dot gnu.org 2011-04-16 11:02 ` jakub at gcc dot gnu.org 2011-04-16 11:29 ` jingyu at google dot com 2011-05-13 19:46 ` lacombar at gmail dot com 2011-05-13 20:19 ` jingyu at google dot com 2011-05-13 20:51 ` lacombar at gmail dot com 2011-05-18 11:21 ` rguenth at gcc dot gnu.org 2011-05-18 11:46 ` jingyu at google dot com 2011-05-18 15:29 ` lacombar at gmail dot com 2012-03-13 16:01 ` jakub at gcc dot gnu.org
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