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From: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
To: Dibyendu Majumdar <mobile@majumdar.org.uk>
Cc: Linux-Sparse <linux-sparse@vger.kernel.org>
Subject: Re: Potential incorrect simplification
Date: Tue, 28 Mar 2017 16:11:14 +0200	[thread overview]
Message-ID: <20170328141113.kbrwdva6ttsrokts@macpro.local> (raw)
In-Reply-To: <CACXZuxfxNNh+ThcT=7Xr98tToL2GimFi7UOTSwgNq6mfLLGNfA@mail.gmail.com>

On Tue, Mar 28, 2017 at 02:58:57PM +0100, Dibyendu Majumdar wrote:
> Hi Luc,
> 
> 
> The first instruction and.32 refers to %r4 which is undefined.

Yes, I saw.
This %r4 corresponds (somehow) to s3 which isn't initialized.

But yes, there is two problems here:
*) we should use something explicit, like VOID
*) there is a circulary dependence between %r3 & %r4, the first %r4
   being obviously wrong.

I suspect there is a lot of problems present once there is some
undefined variables.

Thanks for the repoort.

-- Luc

  reply	other threads:[~2017-03-28 14:11 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-28 12:40 Potential incorrect simplification Dibyendu Majumdar
2017-03-28 13:34 ` Luc Van Oostenryck
2017-03-28 13:58   ` Dibyendu Majumdar
2017-03-28 14:11     ` Luc Van Oostenryck [this message]
2017-03-28 14:19       ` Dibyendu Majumdar
2017-03-28 16:20         ` Linus Torvalds
2017-03-28 17:00           ` Luc Van Oostenryck
2017-03-28 18:02             ` Linus Torvalds
2017-03-28 20:27               ` Luc Van Oostenryck
2017-03-28 21:57                 ` Linus Torvalds
2017-03-28 22:28                   ` Luc Van Oostenryck
2017-03-28 22:22           ` Dibyendu Majumdar
2017-08-06 12:46           ` Christopher Li
2017-08-06 14:00             ` Luc Van Oostenryck
2017-08-06 14:24               ` Christopher Li
2017-08-06 14:54                 ` Christopher Li
2017-08-06 15:07                 ` Luc Van Oostenryck
2017-08-06 15:51                   ` Christopher Li
2017-08-06 16:51                     ` Luc Van Oostenryck
2017-08-06 18:35                       ` Christopher Li
2017-08-06 19:51                         ` Dibyendu Majumdar
2017-08-06 20:08                           ` Luc Van Oostenryck
2017-08-06 19:52                         ` Luc Van Oostenryck
2017-08-06 23:34                           ` Christopher Li
2017-08-07  0:31                             ` Luc Van Oostenryck
2017-08-07  0:38                               ` Christopher Li
2017-08-06 15:52                 ` Dibyendu Majumdar
2017-08-06 16:56                   ` Luc Van Oostenryck
2017-08-06 17:04                     ` Dibyendu Majumdar
2017-08-06 17:45                       ` Luc Van Oostenryck
2017-08-06 17:58                         ` Dibyendu Majumdar
2017-08-06 18:15                           ` Luc Van Oostenryck
2017-08-06 18:18                             ` Dibyendu Majumdar
2017-08-06 18:31                               ` Luc Van Oostenryck
2017-08-07 19:11                   ` [PATCH v2 0/8] fix loading of partially defined bitfield Luc Van Oostenryck
2017-08-07 19:11                     ` [PATCH v2 1/8] Remove single-store shortcut Luc Van Oostenryck
2017-08-07 21:42                       ` Linus Torvalds
2017-08-10  0:29                         ` Christopher Li
2017-08-10  0:41                           ` Luc Van Oostenryck
2017-08-10  0:53                             ` Christopher Li
2017-08-10 11:01                       ` Christopher Li
2017-08-10 12:26                         ` Luc Van Oostenryck
2017-08-10 13:25                           ` Christopher Li
2017-08-07 19:11                     ` [PATCH v2 2/8] new helper: def_opcode() Luc Van Oostenryck
2017-08-07 19:12                     ` [PATCH v2 3/8] reuse nbr_pseudo_users() Luc Van Oostenryck
2017-08-07 19:12                     ` [PATCH v2 4/8] change the masking when loading bitfields Luc Van Oostenryck
2017-08-07 19:12                     ` [PATCH v2 5/8] simplify ((A & M') | B ) & M when M' & M == 0 Luc Van Oostenryck
2017-08-07 19:12                     ` [PATCH v2 6/8] transform (A & M) >> S to (A >> S) & (M >> S) Luc Van Oostenryck
2017-08-08  0:22                       ` Christopher Li
2017-08-08  0:29                         ` Luc Van Oostenryck
2017-08-08  1:48                           ` Christopher Li
2017-08-08  1:00                         ` Linus Torvalds
2017-08-08  1:38                           ` Luc Van Oostenryck
2017-08-08  1:50                           ` Christopher Li
2017-08-07 19:12                     ` [PATCH v2 7/8] transform (A << S) >> S into A & (-1 " Luc Van Oostenryck
2017-08-07 21:54                       ` Linus Torvalds
2017-08-07 22:08                         ` Luc Van Oostenryck
2017-08-07 22:27                           ` Luc Van Oostenryck
2017-08-07 19:12                     ` [PATCH v2 8/8] fix: cast of OP_AND only valid if it's an OP_CAST Luc Van Oostenryck

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