The range analysis implements hoisting of bounds checks for Ion Jit code. However the approach is not applicable to Asm.js code and it is a waste of time scanning for bounds checks, so this patch disables this specific pass. It is a small step towards defining what is needed from Range Analysis for asm.js code. The actual loop analysis can be useful for asm.js when it proves limits to heap indexes as this can help avoid asm.js style heap access bounds checks, and knowing the loop stride could help avoid low bit masking (although the current code only handles a loop stride of one).

Comment on attachment 804839 [details] [diff] [review] Disable attempts to hoist bounds checks when compiling asm.js code as it is not applicable Great

Comment on attachment 804839 [details] [diff] [review] Disable attempts to hoist bounds checks when compiling asm.js code as it is not applicable [Approval Request Comment] Bug caused by (feature/regressing bug #): not a bug User impact if declined: minor performance improvement missed. Testing completed (on m-c, etc.): Risk to taking this patch (and alternatives if risky): low String or IDL/UUID changes made by this patch: