RFR: 8293991: java/lang/Float/Binary16ConversionNaN.java fails on silent NaN conversions

[Raffaello Giulietti]

On Thu, 22 Sep 2022 13:23:23 GMT, Raffaello Giulietti <duke at openjdk.org> wrote:

>> Reliably reproduces on x86-32 with FPU:
>> 
>> 
>> $ CONF=linux-x86-server-fastdebug make test TEST=java/lang/Float/Binary16ConversionNaN.java TEST_VM_OPTS="-XX:UseAVX=0 -XX:UseSSE=0"
>> ...
>> Roundtrip failure on NaN value 7de2 got back 7fe2
>> Roundtrip failure on NaN value fde2 got back ffe2
>> 
>> 
>> Since there are many NaN values in FP16 -- basically any non-zero significand works, we should probably just relax the test a bit.
>> 
>> Attn @jddarcy ;)
>> 
>> Additional testing:
>>  - [x] Linux x86_32 fastdebug, `-XX:UseAVX=0 -XX:UseSSE=0`, affected test now passes
>>  - [x]  Linux x86_64 fastdebug, affected test still passes
>
> test/jdk/java/lang/Float/Binary16ConversionNaN.java line 81:
> 
>> 79: 
>> 80:     private static int sign(short binary16) {
>> 81:         return (binary16 & 0xf000);
> 
> I think this should read
> `return binary16 & 0x8000;`

Further, if the only modified bit is the quier/signaling bit the test could be more specific

-------------

PR: https://git.openjdk.org/jdk/pull/10333