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Date: Mon, 13 May 2002 18:28:00 -0000
From: Daniel Berlin <dberlin@dberlin.org>
To: Andrew Cagney <ac131313@cygnus.com>
Cc: Jim Blandy <jimb@redhat.com>, <gdb-patches@sources.redhat.com>
Subject: Re: RFA: coding style tweaks
In-Reply-To: <3CE0666F.1000304@cygnus.com>
Message-ID: <Pine.LNX.4.44.0205132126170.4005-100000@dberlin.org>
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On Mon, 13 May 2002, Andrew Cagney wrote:

> > for the code:
> >> 
> >>     /* It's not us.  Try all our children, and return the lowest.  */
> >>     {
> >>       struct macro_source_file *child;
> >>       struct macro_source_file *best = 0;
> >>       int best_depth;
> >> 
> >>       for (child = source->includes; child; child = child->next_included)
> >>         {
> >>           struct macro_source_file *result
> >>             = macro_lookup_inclusion (child, name);
> >> 
> >>           if (result)
> >>             {
> >>               int result_depth = inclusion_depth (result);
> >> 
> >>               if (! best || result_depth < best_depth) <-- HERE
> > 
> > 
> > It's an obvious false positive (!best will be true the first time through, 
> > meaning the only time we check best_depth, it's already been set at 
> > least once).
> 
> (I know it is a ``false positive'' but then again if GCC can't figure it 
> out, how will I :-)

Depends on which version of gcc. Some can figure it out.
:)
Fun, isn't -Wuninitialized?


> 
> > Here, you can't just initialize best_depth to 0, you have to initialize it 
> > to either INT_MAX, or inclusion_depth (result).
> 
> Since || is a short-circuit, the RHS really doesn't matter.
Yeah, yer right.

> INT_MAX, though, would make it clearer, could even drop ``!best''.

And 3 years from now, when someone decides to rewrite this code, they 
won't break it if they decide to transform that way.


> 
> enjoy,
> Andrew
> 
> 
> 
> 
>