ext/bcmath: use vector in compare

[SakiTakamachi]

Benchmark

The theoretical expectation is that it should be just slightly slower with small values, but in practice, it seems almost unchanged.

Small value

for ($i = 0; $i < 10000000; $i++) {
    bccomp('1.2345', '1.23456', 5);
}

Benchmark 1: /php-dev2/sapi/cli/php /mount/bc/cmp/0.php
  Time (mean ± σ):     439.0 ms ±   2.6 ms    [User: 433.7 ms, System: 2.9 ms]
  Range (min … max):   434.4 ms … 444.2 ms    10 runs
 
Benchmark 2: /master/sapi/cli/php /mount/bc/cmp/0.php
  Time (mean ± σ):     443.4 ms ±   5.5 ms    [User: 437.4 ms, System: 3.5 ms]
  Range (min … max):   434.0 ms … 452.2 ms    10 runs
 
Summary
  '/php-dev2/sapi/cli/php /mount/bc/cmp/0.php' ran
    1.01 ± 0.01 times faster than '/master/sapi/cli/php /mount/bc/cmp/0.php'

Middle value 1

for ($i = 0; $i < 10000000; $i++) {
    bccomp('1.234567890123', '1.234567890123', 15);
}

Benchmark 1: /php-dev2/sapi/cli/php /mount/bc/cmp/1.php
  Time (mean ± σ):     475.9 ms ±   1.7 ms    [User: 469.5 ms, System: 3.9 ms]
  Range (min … max):   472.0 ms … 477.4 ms    10 runs
 
Benchmark 2: /master/sapi/cli/php /mount/bc/cmp/1.php
  Time (mean ± σ):     489.9 ms ±   4.3 ms    [User: 483.9 ms, System: 3.5 ms]
  Range (min … max):   485.0 ms … 497.7 ms    10 runs
 
Summary
  '/php-dev2/sapi/cli/php /mount/bc/cmp/1.php' ran
    1.03 ± 0.01 times faster than '/master/sapi/cli/php /mount/bc/cmp/1.php'

Middle value 2

for ($i = 0; $i < 10000000; $i++) {
    bccomp('1.23456789012345678901234567890123456789012345678901234567890123456789', '1.23456789012345678901234567890123456789012345678901234567890123456789', 40);
}

Benchmark 1: /php-dev2/sapi/cli/php /mount/bc/cmp/2.php
  Time (mean ± σ):     492.9 ms ±   3.0 ms    [User: 486.2 ms, System: 4.3 ms]
  Range (min … max):   487.9 ms … 498.1 ms    10 runs
 
Benchmark 2: /master/sapi/cli/php /mount/bc/cmp/2.php
  Time (mean ± σ):     590.1 ms ±   2.9 ms    [User: 584.2 ms, System: 3.4 ms]
  Range (min … max):   585.6 ms … 593.9 ms    10 runs
 
Summary
  '/php-dev2/sapi/cli/php /mount/bc/cmp/2.php' ran
    1.20 ± 0.01 times faster than '/master/sapi/cli/php /mount/bc/cmp/2.php'

Large value

for ($i = 0; $i < 100000; $i++) {
    bccomp(str_repeat('1234567890', 3000), str_repeat('1234567890', 3000), 0);
}

Benchmark 1: /php-dev2/sapi/cli/php /mount/bc/cmp/3.php
  Time (mean ± σ):     571.7 ms ±  22.2 ms    [User: 566.5 ms, System: 2.8 ms]
  Range (min … max):   561.6 ms … 634.5 ms    10 runs

Benchmark 2: /master/sapi/cli/php /mount/bc/cmp/3.php
  Time (mean ± σ):      1.322 s ±  0.002 s    [User: 1.316 s, System: 0.004 s]
  Range (min … max):    1.319 s …  1.326 s    10 runs
 
Summary
  '/php-dev2/sapi/cli/php /mount/bc/cmp/3.php' ran
    2.31 ± 0.09 times faster than '/master/sapi/cli/php /mount/bc/cmp/3.php'