On Thu, Nov 01, 2007 at 12:55:26AM +0300, Andrey Chernov wrote: > On Tue, Oct 30, 2007 at 10:03:31AM -1000, Juli Mallett wrote: > > * "Andrey A. Chernov" <[EMAIL PROTECTED]> [ 2007-10-27 ] > > [ cvs commit: src/include _ctype.h ] > > > ache 2007-10-27 22:32:28 UTC > > > > > > FreeBSD src repository > > > > > > Modified files: > > > include _ctype.h > > > Log: > > > Micro-optimization of prev. commit, change > > > (_c < 0 || _c >= 128) to (_c & ~0x7F) > > > > Isn't that a non-optimization in code and a minor pessimization of > > readability? > > Maybe I'm getting rusty, but those seem to result in nearly identical code > > on > > i386 with a relatively modern GCC. Did you look at the compiler output for > > this > > optimization? Is there a specific expensive instruction you're trying to > > avoid? > > For such thoroughyl bit-aligned range checks, you shouldn't even get a > > branch > > for the former case. Is there a platform other than i386 I should look at > > where > > the previous expression is more clearly pessimized? Or a different compiler > > than GCC? > > For ones who doubts there two tests compiled with -O2. As you may see the > result is almost identical (andl vs cmpl):
Q.E.D. How about to restore original, more reader-friendly version then? ./danfe _______________________________________________ cvs-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/cvs-all To unsubscribe, send any mail to "[EMAIL PROTECTED]"
