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From: David Chisnall <theraven@FreeBSD.org>
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To: Bruce Evans <brde@optusnet.com.au>
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Cc: svn-src-head@FreeBSD.org, mdf@FreeBSD.org, svn-src-all@FreeBSD.org,
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Subject: Re: svn commit: r227812 - head/lib/libc/string
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On 22 Nov 2011, at 11:21, Bruce Evans wrote:

> If this optimization were any good, then the compiler would already do
> it.  In fact, gcc-4.2.1 already does it -- the reverse of it -- it =
rewrites:
>=20
> 	"if ((i =3D=3D 0) | (j =3D=3D 0)) return; test();"
>=20
> into:
>=20
> 	"if (i =3D=3D 0 || j =3D=3D 0) return; test();"

In general, I prefer | in cases where execution order does not matter =
because it frees the compiler up to insert branches or not, depending on =
which is more efficient for the target. =20

In this case, either | or || is fine, because neither reads any memory =
or has side effects so | and || are equivalent to the compiler, but the =
use of | tells a human reading the code that the order is unimportant. =20=


David=