RFR 8196740 : Character.digit(int,int) returns wrong value for out of range radix

[Claes Redestad]

Hi Ivan,

On 2018-02-03 02:14, Ivan Gerasimov wrote:
> Would you please help review the fix?
>
> BUGURL: https://bugs.openjdk.java.net/browse/JDK-8196740
> WEBREV: http://cr.openjdk.java.net/~igerasim/8196740/00/webrev/

yes, an obvious error in hindsight!

>
>
> I suspect that this version may even work a tiny bit faster, as we 
> perform less comparisons in a common case. 

Counter-intuitively it actually seems the compiler generates faster code 
in the end when keeping the
value >= 0 test around.

Your version:

Benchmark Mode  Cnt     Score   Error  Units
UUIDBenchmark.benchmarkUUIDFromString avgt    4     0.326 ± 0.017  us/op
UUIDBenchmark.benchmarkUUIDFromString:branches avgt        
289.750           #/op
UUIDBenchmark.benchmarkUUIDFromString:cycles avgt       
1044.087           #/op

With:
         int value = DIGITS[ch];
         return (value >= 0 && value < radix && radix >= Character.MIN_RADIX
                 && radix <= Character.MAX_RADIX) ? value : -1;

Benchmark Mode  Cnt     Score   Error  Units
UUIDBenchmark.benchmarkUUIDFromString avgt    4     0.310 ± 0.018  us/op
UUIDBenchmark.benchmarkUUIDFromString:branches avgt        
256.489           #/op
UUIDBenchmark.benchmarkUUIDFromString:cycles avgt        
988.998           #/op

/Claes