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Re: A question about redudant load elimination

From: Michael Matz <matz at suse dot de>
To: Eric Botcazou <ebotcazou at adacore dot com>
Cc: Richard Guenther <richard dot guenther at gmail dot com>, gcc at gcc dot gnu dot org, Jiangning Liu <jiangning dot liu at arm dot com>
Date: Wed, 16 Nov 2011 14:49:50 +0100 (CET)
Subject: Re: A question about redudant load elimination
References: <4ec0cb02.a424440a.6fba.ffffb618SMTPIN_ADDED@mx.google.com> <CAFiYyc1enGX_gk0swvaXc9t=YUMUvJiZ-EidL3KRXT9TqDaZ1A@mail.gmail.com> <201111161232.11369.ebotcazou@adacore.com>

Hi,

On Wed, 16 Nov 2011, Eric Botcazou wrote:

> > f() may change the value of x, so you cannot optimize away the load on that
> > execution path.
> 
> This looks more like an aliasing issue with a, doesn't it?

Correct.  There's no call to f() between a[x] and x==100, but the store to 
a[x] might change x if x==0&&a==&x.

Ciao,
Michael.

References:
- Re: A question about redudant load elimination
  - From: Richard Guenther
- Re: A question about redudant load elimination
  - From: Eric Botcazou

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