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Re: [Ada] Fix bugs with volatile and components of aggregate types

From: Richard Guenther <richard dot guenther at gmail dot com>
To: Eric Botcazou <ebotcazou at adacore dot com>
Cc: Duncan Sands <baldrick at free dot fr>, gcc-patches at gcc dot gnu dot org
Date: Mon, 20 Jun 2011 13:23:37 +0200
Subject: Re: [Ada] Fix bugs with volatile and components of aggregate types
References: <201106181255.09679.ebotcazou@adacore.com> <4DFDF18E.8090201@free.fr> <201106200124.49880.ebotcazou@adacore.com>

On Mon, Jun 20, 2011 at 1:24 AM, Eric Botcazou <ebotcazou@adacore.com> wrote:
>> if T is a non-volatile composite type with volatile components, and O is an
>> object of type T, are the optimizers allowed to remove the assignment "O :=
>> O"?
>
> Good question, that I'm not really qualified to answer. ?Any language lawyer?

Optimizers will test the TREE_THIS_VOLATILE flag on the expression
codes performing the load/store.  So if O is not TREE_THIS_VOLATILE
they won't care.  If frontends want something different in the above case
they have to make sure to properly set TREE_THIS_VOLATILE.

Richard.

> --
> Eric Botcazou
>

References:
- [Ada] Fix bugs with volatile and components of aggregate types
  - From: Eric Botcazou
- Re: [Ada] Fix bugs with volatile and components of aggregate types
  - From: Duncan Sands
- Re: [Ada] Fix bugs with volatile and components of aggregate types
  - From: Eric Botcazou

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