$x & 1 will probably have to convert the
double-precision floating point value stored in $x into
a "long int" before it can do the fast bit-wise "and".
This conversion may well take longer than the simple
floating-point division (which will have the aid of
floating-point acceleration hardware) that
$x % 2 must do.
This probably explains some of the benchmark results.
To me, a much worse problem than the misguided
"optimization" of such a simple operation is that
$x & 1 will only work for integral values
that fit within 32 bits (on most platforms). However,
$x % 2 will work correctly on integeral
values of approximately 57 bits (on most platforms).
Using % 2 will probably make your code handle a much huger
range of values correctly.
-
tye
(but my friends call me "Tye")
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