[grayrest]

It'd be related to inlining a function since size is a common rule there. Some searching turns up this[1] article on crankshaft from three years ago, which lists the restrictions as ">600 source characters including whitespace or 196 AST nodes".

[1] http://jayconrod.com/posts/54/a-tour-of-v8-crankshaft-the-op...