RFR: JDK-8214113: Switch expressions may have constant type and may be skipped during write

Maurizio Cimadamore maurizio.cimadamore at oracle.com
Wed Nov 21 17:39:12 UTC 2018

Looks good


On 21/11/2018 12:41, Jan Lahoda wrote:
> Hi,
> Consider switch expression produces only a single constant value, like:
> switch (expr) {
>     default:
>         counter++;
>         break 1;
> }
> Then Attr.condType returns the type of the given constant value, and 
> if that is a constant type, the type of the whole switch expression is 
> a constant type. And Gen may then elide the whole switch expression, 
> which is wrong, as it may contain side-effects, or all the other arms 
> may the throwing an exception.
> The solution would be to simply call .baseType() on the result, but 
> simply deleting the special case for a single output value should work 
> as well, as the following condition should handle the single output 
> value case well.
> Bug: https://bugs.openjdk.java.net/browse/JDK-8214113
> Webrev: http://cr.openjdk.java.net/~jlahoda/8214113/webrev.00/
> How does this look?
> Thanks,
>     Jan

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