vsqrt is used to calculate Math.sqrt(x), Math.pow(x, 0.5) and Math.pow(x, -0.5). Code size doesn't matter, as %_MathSqrt and %_MathPow are only called in one place each.
Review URL: http://codereview.chromium.org/2885002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4974 ce2b1a6d-e550-0410-aec6-3dcde31c8c00