Comparable#clamp improvement

clamp_bench.rb

require 'benchmark'

Benchmark.bmbm do |x|
  v = Random.rand(-10..110)

  x.report "minmax:" do
    10000000.times { [99, [0, v].max].min }
  end

  x.report "clamp: " do
    10000000.times { v.clamp(0, 99) }
  end
end

compar.diff

diff --git a/compar.c b/compar.c
index 02529c9960..5cfcccf36e 100644
--- a/compar.c
+++ b/compar.c
@@ -9,9 +9,12 @@
 
 **********************************************************************/
 
+#include "internal.h"
 #include "ruby/ruby.h"
 #include "id.h"
 
+#define id_cmp  idCmp
+
 VALUE rb_mComparable;
 
 static VALUE
@@ -87,7 +90,8 @@ cmp_equal(VALUE x, VALUE y)
 static int
 cmpint(VALUE x, VALUE y)
 {
-    return rb_cmpint(rb_cmp(x, y), x, y);
+    struct cmp_opt_data cmp_opt = { 0, 0 };
+    return OPTIMIZED_CMP(x, y, cmp_opt);
 }
 
 /*

gistfile1.txt

# ruby -v
ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-linux]

# ruby /src/github.com/kei-s/sketch/ruby/clamp_bench.rb
Rehearsal -------------------------------------------
minmax:   0.870000   0.000000   0.870000 (  0.872666)
clamp:    1.920000   0.000000   1.920000 (  1.924521)
---------------------------------- total: 2.790000sec

              user     system      total        real
minmax:   0.740000   0.000000   0.740000 (  0.732744)
clamp:    2.060000   0.010000   2.070000 (  2.072794)

# /usr/local/bin/ruby -v
ruby 2.5.0dev (2017-09-13 trunk 59863) [x86_64-linux]

# /usr/local/bin/ruby /src/github.com/kei-s/sketch/ruby/clamp_bench.rb
Rehearsal -------------------------------------------
minmax:   0.890000   0.010000   0.900000 (  0.900237)
clamp:    1.120000   0.000000   1.120000 (  1.120490)
---------------------------------- total: 2.020000sec

              user     system      total        real
minmax:   0.820000   0.000000   0.820000 (  0.822517)
clamp:    1.090000   0.000000   1.090000 (  1.087491)