Re: Ternary operator performance improvements

Hi, As I already said, I don't see any technical issues with the patch. I don't like it very mach, but it looks robust, and I don't object about it. Thanks. Dmitry. On 10/14/2011 10:08 PM, Arnaud Le Blanc wrote:

Hi, I've already posted this patch and it has since been reviewed and improved. I'm re-posting it for discussion before eventually commiting it. The ternary operator always copies its second or third operand, which is very slow compared to an if/else when the operand is an array for example: $a = range(0,9); // this takes 0.3 seconds here: for ($i = 0; $i< 5000000; ++$i) {

         if (true) {
                 $b = $a;
         } else {
                 $b = $a;
         }

} // this takes 3.8 seconds: for ($i = 0; $i< 5000000; ++$i) {

         $b = true ? $a : $a;

} I've tried to reduce the performance hit by avoiding the copy when possible (patch attached). Benchmark: Without patch: (the numbers are the time taken to run the code a certain amount of times) $int = 0; $ary = array(1,2,3,4,5,6,7,8,9);

true ? 1 : 0        0.124
true ? 1+0 : 0      0.109
true ? $ary : 0     2.020 !
true ? $int : 0     0.103

true ? ${'ary'} : 0 2.290 !

true ?: 0           0.091
1+0 ?: 0            0.086
$ary ?: 0           2.151 !
${'var'} ?: 0       2.317 !

With patch:

true ? 1 : 0        0.124
true ? 1+0 : 0      0.195
true ? $ary : 0     0.103
true ? $int : 0     0.089

true ? ${'ary'} : 0 0.103

true ?: 0           0.086
1+0 ?: 0            0.159
$cv ?: 0            0.090
${'var'} ?: 0       0.089

The array copying overhead is eliminated. There is however a slowdown in some of the cases, but overall there is no completely unexpected performance hit as it is the case currently. What do you think ? Is there any objection ? Best regards,