[aarch64-port-dev ] RFR(XXS): 8201185 - AARCH64: bfm instruction encoding hits assert on zero register

[White, Derek]

Hi Dmitrij,

Looks good. Does this allow the equivalent of BFC instruction (Bitfield Clear)?

- Derek

> -----Original Message-----
> From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-
> bounces at openjdk.java.net] On Behalf Of Dmitrij Pochepko
> Sent: Thursday, April 05, 2018 12:08 PM
> To: Andrew Haley <aph at redhat.com>; hotspot-compiler-
> dev at openjdk.java.net; aarch64-port-dev at openjdk.java.net
> Subject: Re: [aarch64-port-dev ] RFR(XXS): 8201185 - AARCH64: bfm
> instruction encoding hits assert on zero register
> 
> Thank you for review.
> 
> 
> On 05.04.2018 18:38, Andrew Haley wrote:
> > On 04/05/2018 04:34 PM, Dmitrij Pochepko wrote:
> >> please review small fix for  8201185 - AARCH64: bfm instruction
> >> encoding hits assert on zero register
> >>
> >> bfm* instuctions encoding hits assert when using zero register as
> >> source, which should be allowed.
> >>
> >> Fix is trivial: change "general register encoding" call (rf) to
> >> "zero-or-general register encoding" call (zrf).
> >>
> >>
> >> CR: https://bugs.openjdk.java.net/browse/JDK-8201185
> >>
> >> webrev: http://cr.openjdk.java.net/~dpochepk/8201185/webrev.01/
> >>
> >>
> >> I've checked this patch (and actually found this bug) by creating
> >> intrinsic with such encoding usage.
> > Ooh, clever.  I never thought anyone would to that.  OK.
> >