RFR: 8241095: x86: Improve prefix handling in Assembler

[Vladimir Kozlov]

Looks good.

I checked that moved methods stay the same. You only modified prefixq(Address adr) and prefixq(Address adr, Register 
src) as we discussed. Good.

Thanks,
Vladimir

On 3/18/20 6:46 AM, Claes Redestad wrote:
> Hej,
> 
> this patch enable folding emitted prefixq bytes into multi-byte emitter
> functions (emit_int16(int8, int8) etc).
> 
> Only those functions where there is always a prefix being emitted have
> been adjusted. Other variants could improve slightly by doing similar
> tricks, but with a smaller payoff and more complexity.
> 
> Webrev: http://cr.openjdk.java.net/~redestad/8241095/open.00
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8241095
> 
> Testing: tier1-4 (ongoing)
> 
> Thanks,
> 
> /Claes