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    <p>Find minimum of two integers without branching:</p> <p><a href="http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax" rel="nofollow">http://graphics.stanford.edu/~seander/bithacks.html#IntegerMinOrMax</a></p> <blockquote> <p>On some rare machines where branching is very expensive and no condition move instructions exist, the above expression might be faster than the obvious approach, r = (x &lt; y) ? x : y, even though it involves two more instructions. (Typically, the obvious approach is best, though.)</p> </blockquote> <p>Just to kick things off, here's a brain-dead benchmark. I'm trying to get a 50/50 mix of large and small values "at random":</p> <pre><code>#include &lt;iostream&gt; #include &lt;stdint.h&gt; int main() { uint32_t total = 0; uint32_t n = 27465; for (int i = 0; i &lt; 1000*1000*500; ++i) { n *= 30029; // worst PRNG in the world uint32_t a = n &amp; 0x1ffff; #ifdef EMPTY uint16_t b = a; // gives the wrong total, of course. #endif #ifdef NORMAL uint16_t b = (a &gt; 0xffff) ? 0xffff : a; #endif #ifdef RUSLIK uint16_t b = (-(a &gt;&gt; 16) &gt;&gt; 16) | a; #endif #ifdef BITHACK uint16_t b = a ^ ((0xffff ^ a) &amp; -(0xffff &lt; a)); #endif total += b; } std::cout &lt;&lt; total &lt;&lt; "\n"; } </code></pre> <p>On my compiler (gcc 4.3.4 on cygwin with -O3), <code>NORMAL</code> wins, followed by <code>RUSLIK</code>, then <code>BITHACK</code>, respectively 0.3, 0.5 and 0.9 seconds slower than the empty loop. Really this benchmark means nothing, I haven't even checked the emitted code to see whether the compiler's smart enough to outwit me somewhere. But I like ruslik's anyway.</p>
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    1. COI was looking a minute ago exactly at this but could not figure out how this apply to operands of different type.
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    2. COThat has a `<` in it, which many compilers (but not modern gcc) would compile to a branch..
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    3. CO@Ross: I was thinking, take the minimum in 32-bit, then convert to 16-bit. @R..: true, but hopefully not compilers for architectures on which branching is so slow that it's worth avoiding in a case like this. For that matter, the obvious approach won't branch on architectures with conditional instructions (ARM), if the compiler's any good at all.
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