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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/25130] [4.1/4.2 Regression] miscompilation in GCSE Date: Sat, 17 Dec 2005 15:14:00 -0000 [thread overview] Message-ID: <20051217151403.12466.qmail@sourceware.org> (raw) In-Reply-To: <bug-25130-702@http.gcc.gnu.org/bugzilla/> ------- Comment #8 from steven at gcc dot gnu dot org 2005-12-17 15:14 ------- It looks like we're missing a memory modification. Yes, making this a load PRE problem after all, despite it failing for me even with -fno-gcse-lm, but oh well. I have these expressions in the table: Expression hash table (11 buckets, 3 entries) Index 0 (hash value 7) (mem/s/j:SI (plus:SI (reg/f:SI 20 frame) (const_int -8 [0xfffffff8])) [0 <variable>._M_impl._M_start_node+0 S4 A32]) Index 1 (hash value 10) (mem/s/j/c:SI (plus:SI (reg/f:SI 20 frame) (const_int -16 [0xfffffff0])) [0 clusters.D.1846._M_impl._M_start_cur+0 S4 A32]) Index 2 (hash value 3) (mem/s/j:SI (plus:SI (reg/f:SI 20 frame) (const_int -12 [0xfffffff4])) [0 <variable>._M_impl._M_start_node+0 S4 A32]) The second and third expressions don't do much. For the first expression we apply load PRE. But the local data flow sets look wrong. For TRANSP I have, transp 0 000 1 111 2 000 3 111 4 000 and block 3 for me looks like this: ;; Start of basic block 3, registers live: (nil) (code_label 57 94 58 3 8 "" [1 uses]) (note 58 57 59 3 [bb 3] NOTE_INSN_BASIC_BLOCK) (note 59 58 60 3 ("t.C") 55) (insn 60 59 96 3 t.C:55 (parallel [ (set (mem/s/j/c:SI (plus:SI (reg/f:SI 20 frame) (const_int -8 [0xfffffff8])) [0 clusters.D.1846._M_impl._M_finish_cur+0 S4 A32]) (plus:SI (mem/s/j/c:SI (plus:SI (reg/f:SI 20 frame) (const_int -8 [0xfffffff8])) [0 clusters.D.1846._M_impl._M_finish_cur+0 S4 A32]) (const_int 4 [0x4]))) (clobber (reg:CC 17 flags)) ]) 148 {*addsi_1} (nil) (nil)) (jump_insn 96 60 97 3 (set (pc) (label_ref 61)) -1 (nil) (nil)) ;; End of basic block 3, registers live: (nil) Looks to me that insn 60 should cause expression 1 to not be in TRANSP for this basic block. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25130
next prev parent reply other threads:[~2005-12-17 15:14 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2005-11-28 1:24 [Bug rtl-optimization/25130] New: 4.1: miscompilation in loop optimization gcc-bugzilla at gcc dot gnu dot org 2005-11-28 2:00 ` [Bug rtl-optimization/25130] [4.1/4.2 Regression] miscompilation in GCSE pinskia at gcc dot gnu dot org 2005-11-29 6:10 ` wilson at gcc dot gnu dot org 2005-12-16 23:58 ` steven at gcc dot gnu dot org 2005-12-17 11:27 ` steven at gcc dot gnu dot org 2005-12-17 11:31 ` steven at gcc dot gnu dot org 2005-12-17 15:09 ` steven at gcc dot gnu dot org 2005-12-17 15:14 ` steven at gcc dot gnu dot org [this message] 2005-12-17 18:24 ` steven at gcc dot gnu dot org 2005-12-18 0:49 ` steven at gcc dot gnu dot org 2005-12-18 1:38 ` steven at gcc dot gnu dot org 2005-12-19 18:33 ` mmitchel at gcc dot gnu dot org 2005-12-21 15:28 ` steven at gcc dot gnu dot org 2005-12-21 15:32 ` steven at gcc dot gnu dot org 2005-12-21 15:45 ` steven at gcc dot gnu dot org 2005-12-27 0:58 ` steven at gcc dot gnu dot org 2006-01-01 17:37 ` steven at gcc dot gnu dot org 2006-01-03 6:20 ` steven at gcc dot gnu dot org 2006-01-03 22:37 ` steven at gcc dot gnu dot org 2006-01-03 22:39 ` steven at gcc dot gnu dot org 2010-06-28 17:50 ` bernds at gcc dot gnu dot org 2010-06-29 22:41 ` bernds at gcc dot gnu dot org [not found] <bug-25130-4@http.gcc.gnu.org/bugzilla/> 2011-06-13 12:48 ` jakub at gcc dot gnu.org 2011-12-02 13:04 ` steven at gcc dot gnu.org
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