switching on keys of type long

[Doug Simon]

On Nov 7, 2013, at 9:49 PM, Venkatachalam, Vasanth <Vasanth.Venkatachalam at amd.com> wrote:

> I assume that the case for handling Object keys also comes from TypeSwitchNOde? 
> 
> I  also had a similar question about LIRGenerator.emitSwitch( )
> 
> The line that says:
> 
> If(keyCount == 0) { ...
> 
> Javac optimizes away switch statements that have no keys (e.g., cases) so that the switch doesn't appear in bytecode.
> Was this condition also added to handle the TypeSwitchNode?

Not necessarily. It used to be that javac generated switch bytecodes for switch statements that have only a default case.
If you want to find out, run Graal over a number of applications/benchmarks in a debugger and place a breakpoint on the code path of interest.
That’s what I’d have to do to provide you with a more accurate answer ;-)

-Doug

> -----Original Message-----
> From: Doug Simon [mailto:doug.simon at oracle.com] 
> Sent: Wednesday, November 06, 2013 12:58 PM
> To: Venkatachalam, Vasanth
> Cc: graal-dev at openjdk.java.net
> Subject: Re: switching on keys of type long
> 
> This comes from TypeSwitchNode.
> 
> On Nov 6, 2013, at 7:43 PM, Venkatachalam, Vasanth <Vasanth.Venkatachalam at amd.com> wrote:
> 
>> Can someone explain why the emitCode( ) routine of AMD64ControlFlow.SequentialSwitchOp is handling the case:
>> 
>> else if (key.getKind() = Kind.Long)  ?
>> 
>>> From my understanding of Java, it's not possible to switch on keys of type long. You get a compile time error.
>> 
>> Vasanth
> 
> 
>