Use | operator instead of Math.floor()

[oriSomething]

Use | operator instead of Math.floor().

Now, my name might be saved in history ;-)

[fengmk2]

Have benchmark for this performance improve?

[ai]

Yeap 6781f48

Exact numbers depends on machine and Node.js version. But I saw changes in result after this commit. To be honest, I am not sure way. Maybe math operator works faster because it doesn't call a additional method?

[oriSomething]

I think it's related to old optimizations for asm.js. asm.js uses a lot the | 0 expression to cast number to integer so V8 added optimization that consider some expressions that ends with | 0 as integers instead of floats. I'm not sure when Math.floor returned value treated as integer and when it just floored float, but | 0 always become integer.
By the way the BuckleScript compiler also uses | 0 optimization for intergers.