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Re: Suspicious warning in W64 build

From: Eli Zaretskii
Subject: Re: Suspicious warning in W64 build
Date: Thu, 07 Sep 2017 23:20:51 +0300

> Cc: address@hidden, address@hidden
> From: Paul Eggert <address@hidden>
> Date: Thu, 7 Sep 2017 12:26:06 -0700
> > Yes, I know.  I just don't understand why GCC things that
> > 
> >     nglyphs * sizeof (WORD) * 2
> > 
> > can have a value in this range.  The type of nglyphs is 'int', and
> > sizeof(WORD) gives 2.  So the range should be between 0 (or 4) and 4
> > times INT_MAX, which is nowhere near the values GCC displays.
> > 
> If nglyphs is negative the first multiplication is done using unsigned 
> arithmetic, which could result in huge results. Presumably GCC does not know 
> that nglyphs must be nonnegative. Try putting an 'eassume (0 <= nglyphs);' 
> before the line in question. That is, if you're sure that nglyphs is 
> nonnegative: if you're not, GCC has found a real bug here.

nglyphs is always positive, it comes from nchars of a glyph_string, or

Angelo and Richard, can you please try that eassume and see if it
shuts up the warning?

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