From: paulo@matos-sorge.com (Paulo J. Matos)
To: gcc@gcc.gnu.org
Subject: Re: missing conditional propagation in cprop.c pass
Date: Thu, 29 Sep 2011 15:26:00 -0000 [thread overview]
Message-ID: <86wrcra1p9.fsf@pm18pc01.europe.root.pri> (raw)
In-Reply-To: <CAHFci298XREmPEJ4n9S8u0p1n+Om581OJJ=s-GJGzCmiJXF1_Q@mail.gmail.com>
"Amker.Cheng" <amker.cheng@gmail.com> writes:
> (insn 882 881 883 96 (set (reg:CC 24 cc)
> (compare:CC (reg:SI 684 [ default_num_contexts ])
> (const_int 0 [0]))) core_main.c:265 211 {*arm_cmpsi_insn}
> (nil))
>
>
> The insn49 should be propagated with conditional const from insn882
> and jump_insn883, optimized into "r291<-0" as following code, then let
> pre do redundancy elimination work.
Unless there's something arch specific related to arm, insn 882 is a
compare, which won't change r684. Why do you think 0 should
propagated to r291 if r684 is not zero?
Cheers,
--
PMatos
next prev parent reply other threads:[~2011-09-29 14:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-27 14:56 Amker.Cheng
2011-09-29 14:25 ` Amker.Cheng
2011-09-29 15:26 ` Paulo J. Matos [this message]
2011-09-29 15:37 ` Amker.Cheng
2011-09-29 15:38 ` Rahul Kharche
2011-09-29 15:39 ` Bernd Schmidt
2011-09-29 16:06 ` Jeff Law
2011-09-29 18:38 ` Bernd Schmidt
2011-09-29 22:46 ` Rahul Kharche
2011-09-30 1:51 ` Jeff Law
2011-09-29 17:20 ` Jeff Law
2011-09-30 13:01 ` Amker.Cheng
2011-10-03 18:02 ` Jeff Law
2011-09-30 2:51 ` Paulo J. Matos
2011-09-30 9:00 ` Amker.Cheng
2011-10-03 22:30 Steven Bosscher
2011-10-10 10:29 ` Amker.Cheng
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