Sei Lisa 4ba71993a4 Optimize min/max in comparisons; undo problematic optimization. ...

For floats:

When const >= function.max, comparisons of function > const always yield FALSE.

When const <  function.min, comparisons of function > const always yield TRUE.

When const >  function.max, comparisons of function < const always yield TRUE.

When const <= function.min, comparisons of function < const always yield FALSE.

For integers:

When min = -1, cond(function > -1) is the same as cond(!~function).

When min = -1, cond(function < 0) is the same as cond(~function).

To implement the above, we got rid of the cond(x < 0)  ->  cond(x & 0x80000000) optimization, which has caused more trouble than it has solved for just 1 byte gain.

When min = 0, cond(function > 0) is the same as cond(function).

When min = 0, cond(function < 1) is the same as cond(!function).

Similar expressions can be obtained for max in [-1, 0], but it's not worth it, as there are no functions with -1 as maximum, and the ones with max=0 also have min=0 (always return 0).

2017-10-26 00:58:14 +02:00

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