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POAny significant performance improvement by using bitwise operators instead of plain int sums in C#?
 

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  1. POAny significant performance improvement by using bitwise operators instead of plain int sums in C#?
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    <p>I started working with C# a few weeks ago and I'm now in a situation where I need to build up a "bit set" flag to handle different cases in an algorithm. I have thus two options:</p> <pre><code> enum RelativePositioning { LEFT = 0, RIGHT = 1, BOTTOM = 2, TOP = 3, FRONT = 4, BACK = 5 } pos = ((eye.X &lt; minCorner.X ? 1 : 0) &lt;&lt; (int) RelativePositioning.LEFT) + ((eye.X &gt; maxCorner.X ? 1 : 0) &lt;&lt; (int) RelativePositioning.RIGHT) + ((eye.Y &lt; minCorner.Y ? 1 : 0) &lt;&lt; (int) RelativePositioning.BOTTOM) + ((eye.Y &gt; maxCorner.Y ? 1 : 0) &lt;&lt; (int) RelativePositioning.TOP) + ((eye.Z &lt; minCorner.Z ? 1 : 0) &lt;&lt; (int) RelativePositioning.FRONT) + ((eye.Z &gt; maxCorner.Z ? 1 : 0) &lt;&lt; (int) RelativePositioning.BACK); </code></pre> <p>Or:</p> <pre><code> enum RelativePositioning { LEFT = 1, RIGHT = 2, BOTTOM = 4, TOP = 8, FRONT = 16, BACK = 32 } if (eye.X &lt; minCorner.X) { pos += (int) RelativePositioning.LEFT; } if (eye.X &gt; maxCorner.X) { pos += (int) RelativePositioning.RIGHT; } if (eye.Y &lt; minCorner.Y) { pos += (int) RelativePositioning.BOTTOM; } if (eye.Y &gt; maxCorner.Y) { pos += (int) RelativePositioning.TOP; } if (eye.Z &gt; maxCorner.Z) { pos += (int) RelativePositioning.FRONT; } if (eye.Z &lt; minCorner.Z) { pos += (int) RelativePositioning.BACK; } </code></pre> <p>I could have used something as <code>((eye.X &gt; maxCorner.X) &lt;&lt; 1)</code> but C# does not allow implicit casting from bool to int and the ternary operator was similar enough. My question now is: is there any performance improvement in using the first version over the second?</p> <p>Thank you<br /> Tommaso</p>
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      1. POAny significant performance improvement by using bitwise operators instead of plain int sums in C#?
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    1. CObenchmark before performing micro-optimisations
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      1. POAny significant performance improvement by using bitwise operators instead of plain int sums in C#?
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    2. COAgree with Mitch Wheat. Also prefer readability over performance, unless you can prove a bottleneck with a profiler.
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    3. CO"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil" Donald Knuth
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      1. USCagdas
 

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