Full v2 patch including leak fix with wrapper object:

http://80x24.org/spew/20151208050811.6803-1-e%4080x24.org/t/raw

Slightly smaller improvements with leak fix, but it could be noise
for the small cases.

2015-12-08 05:06:17 +0000
target 0: a (ruby 2.3.0dev (2015-12-08 trunk 52938) [x86_64-linux]) at "/home/ew/rrrr/b/ruby"
target 1: b (ruby 2.3.0dev (2015-12-08 master 52938) [x86_64-linux]
last_commit=compile.c: wrap literal object) at "/home/ew/ruby/b/ruby"

benchmark results:

minimum results in each 5 measurements.
Execution time (sec)
name	a	b
loop_whileloop2	0.103	0.103
vm2_case*	0.075	0.064
vm2_case_lit*	0.560	0.561
vm2_case_small*	0.061	0.055

Speedup ratio: compare with the result of `a' (greater is better)
name	b
loop_whileloop2	1.000
vm2_case*	1.169
vm2_case_lit*	1.000
vm2_case_small*	1.119