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List:       linux-sparse
Subject:    Re: [PATCH v2 05/13] expression: examine constness of conditionals at evaluation only
From:       Luc Van Oostenryck <luc.vanoostenryck () gmail ! com>
Date:       2016-01-26 1:16:30
Message-ID: 20160126011629.GC46188 () macpro ! local
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On Mon, Jan 25, 2016 at 03:55:09PM +0100, Nicolai Stange wrote:
> Currently, the propagation of expressions' constness flags through
> conditional expressions is done in two steps:
> - Several flags are speculatively set at expression parsing time
> - and possibly cleared again at evaluation time.
> 
> Set aside this unfortunate split of code, the early propagation of
> constness flags is not able to recognize constant expressions such as
>   0 ? __builtin_choose_expr(0, 0, 0) : 0
>   0 ? 0 : __builtin_choose_expr(0, 0, 0)
> since the final expression to be thrown into the conditional
> expression is known only after evaluation.
> 
> Move the whole calculation of conditional expressions' constness flags
> to the evaluation phase.
> 
> Introduce support for tracking arithmetic constness propagation through
> conditional expressions.

Same comments about the description as for the previous patches.

Good otherwise.


Luc
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