RFR(M): 7133857: exp() and pow() should use the x87 ISA on x86

[Roland Westrelin]

Hi Christian,

Thanks for the review.

> The changes look good.  I'd prefer to not call pow_or_exp directly with a boolean argument:
> 
> +  // computes pow(x,y) or exp(x). Fallback to runtime call included.
> +  void pow_or_exp(bool is_exp, int num_fpu_regs_in_use);
> 
> It's not quite obvious which is which (I'd expected the argument to be is_pow).  Maybe something like:
> 
> void pow_with_fallback(...) { pow_or_exp(false, ...); }

Here is a new webrev that implements your naming suggestion:

http://cr.openjdk.java.net/~roland/7133857/webrev.01/

Roland.