svn commit: r227812 - head/lib/libc/string

[John Baldwin]

On Tuesday, November 22, 2011 10:33:32 am David Schultz wrote:
> On Tue, Nov 22, 2011, Eitan Adler wrote:
> > +	/* use a bitwise or to avoid an additional branch instruction */
> > +	if ((s1 == s2) | (n == 0))
> > +		return (0);
> 
> I think there are three issues with this.
> 
> First, the comment suggesting that using '|' instead of '||' isn't
> correct; any reasonable compiler knows how to optimize
> side-effect-free expressions like these.  (The reverse
> transformation, from the arithmetic expression to the boolean one,
> is actually harder for the compiler in general.)
> 
> Second, the overwhelming precedent in FreeBSD is to use boolean
> operators to combine boolean expressions, so you might try to get
> some consensus on the issue before you go around replacing them
> with bitwise operators.  I for one don't find the bitwise
> operators clearer, but I don't speak for everyone else.

I concur, it should just use boolean logic since it is doing a boolean
test.

-- 
John Baldwin