8144856 : fix assert in CompiledStaticCall::set_to_interpreted

[Lindenmaier, Goetz]

Hi Jamsheed,

thanks for fixing this. I think this way compiler optimizations should be
forbidden.  What about the other platforms? If no one else objects, 
take it as reviewed.

Best regards,
 Goetz.

> -----Original Message-----
> From: Jamsheed C m [mailto:jamsheed.c.m at oracle.com]
> Sent: Montag, 9. Mai 2016 13:59
> To: Lindenmaier, Goetz <goetz.lindenmaier at sap.com>; hotspot compiler
> <hotspot-compiler-dev at openjdk.java.net>
> Subject: Re: 8144856 : fix assert in CompiledStaticCall::set_to_interpreted
> 
> Hi Goetz,
> 
> Thank you for looking at this.
> 
> 
> On 5/9/2016 2:22 PM, Lindenmaier, Goetz wrote:
> 
> 
> 	Hi Jamsheed,
> 
> 	Do you want to avoid that data/destination are changed concurrently
> 	between the two compares? Or do you just want to save costs of the
> call?
> 
> This change was done in x86 as part of JDK-8062493
> <https://bugs.openjdk.java.net/browse/JDK-8062493>  .  from the comment
> in the change, it says its meant for first case. but, i couldn't find a case in
> current hotspot code where this could happen.
> may be its a precautionary change. ( Chris can help here).
> 
> 
> 
> 
> 	To assure the first, you need to make the two local variables volatile.
> 	Else the compilers can add reloads after inlining data() and
> jump_destination().
> 	We observed this with the Visual Studio compiler and xlC on aix.
> 
> i have made the two local variables as volatile.
> revised webrev: http://cr.openjdk.java.net/~jcm/8144856/webrev.01/
> 
> Best Regards,
> Jamsheed
> 
> 
> 
> 
> 	Besides that the change looks good.
> 
> 	Best regards,
> 	 Goetz.
> 
> 
> 
> 
> 		-----Original Message-----
> 		From: hotspot-compiler-dev [mailto:hotspot-compiler-dev-
> 		bounces at openjdk.java.net
> <mailto:bounces at openjdk.java.net> ] On Behalf Of Jamsheed C m
> 		Sent: Freitag, 6. Mai 2016 13:21
> 		To: hotspot compiler <hotspot-compiler-
> dev at openjdk.java.net> <mailto:hotspot-compiler-dev at openjdk.java.net>
> 		Subject: RFR: 8144856 : fix assert in
> CompiledStaticCall::set_to_interpreted
> 
> 
> 		Hi,
> 
> 		Request for review for an assert cleanup change.
> 		bug id : https://bugs.openjdk.java.net/browse/JDK-8144856
> 		webrev:
> http://cr.openjdk.java.net/~jcm/8144856/webrev.00/
> 
> 		Best Regards,
> 		Jamsheed
> 
> 
> 
>