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Re: Looking for unsigned comparison warning
From: |
Bernd Strieder |
Subject: |
Re: Looking for unsigned comparison warning |
Date: |
Mon, 05 Mar 2007 12:56:08 +0100 |
User-agent: |
KNode/0.10.4 |
mathieu wrote:
> Hello,
>
> I am looking for a flag that would warn me about someting like this
> (*). I have tried so far:
I don't think that there is a warning, because AFAIK wrap around is the
only option for chip and compiler makers not killing performance in the
known safe cases. I'm not fully sure, but I think that there has been
some recent discussion about even mandating wrap-around.
The right thing to do would be correcting the source code
> if ( index <= s - 1 )
if (index < s)
avoiding all problems, and following the C++ iterator range idiom. s==0
means never true, instead of always true as before. All occurences of
<= in index or iterator comparisions are suspicious.
Bernd Strieder