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From: "jiwang at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/67305] [6 Regression] gcc.c-torture/compile/20121027-1.c ICE
Date: Fri, 28 Aug 2015 15:05:00 -0000	[thread overview]
Message-ID: <bug-67305-4-jr5FAgXI1F@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-67305-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67305

--- Comment #3 from Jiong Wang <jiwang at gcc dot gnu.org> ---
>From the tree dump .pre, I understand the tree shape is improved as we deleted
one redundant Phi, but we also noticed there is one regression, we are turning

   _6 = bl_20 >> 6

into something like:

    _5 = c_16 / 64;

While for signed division, we need to generate extra check instruction
sequences, although rtl passes should handle this, but seems to me this is
still a regression, Richard, is it because we have lost some range info after
your patch? the division was turned into right shift after vrp pass.

Anyway, we also need to figure out why after this division change, the rtl pass
crash.


  parent reply	other threads:[~2015-08-28 15:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-21  9:55 [Bug tree-optimization/67305] New: " jiwang at gcc dot gnu.org
2015-08-21 10:30 ` [Bug rtl-optimization/67305] " rguenth at gcc dot gnu.org
2015-08-26 17:29 ` vmakarov at gcc dot gnu.org
2015-08-28 15:05 ` jiwang at gcc dot gnu.org [this message]
2015-08-28 15:33 ` jiwang at gcc dot gnu.org
2015-08-28 16:56 ` segher at gcc dot gnu.org
2015-08-28 20:13 ` [Bug target/67305] " segher at gcc dot gnu.org
2015-09-28 21:23 ` [Bug target/67305] [6 Regression] gcc.c-torture/compile/20121027-1.c ICE on arm-none-eabi wilson at gcc dot gnu.org

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