Re:Ask HN: Can someone explain why this line exists?
by ranman on Thursday May 30, 2013 @01:42AM
(#5791116)
are you sure the compiler is smart enough to do that? I think we frequently assume compilers are smarter than they really are because we don't fully understand them anymore... but in practice I find they often do very dumb things.
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Re:Ask HN: Can someone explain why this line exists?
by lmm on Thursday May 30, 2013 @08:18AM
(#5792005)
No, but I am sure that my automated performance testing procedures will detect if I've introduced a significant performance problem, and it would be an inefficient use of my time to worry about insignificant performance effects.
Re:Ask HN: Can someone explain why this line exists?
by Dylan16807 on Thursday May 30, 2013 @09:26PM
(#5796336)
Register renaming is one of the most very basic levels of optimization. I challenge you to find me a single optimizing compiler that slows down when you give names to temporary results. Hell, I can show you non-optimizing compilers that suffer no slowdown from code like this.