RFR: 8293991: java/lang/Float/Binary16ConversionNaN.java fails on silent NaN conversions [v2]

[Aleksey Shipilev]

> 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_32 fastdebug, `-XX:UseAVX=0 -XX:UseSSE=1`, affected test still passes
>  - [x]  Linux x86_64 fastdebug, affected test still passes

Aleksey Shipilev has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Just exclude the test with x87
 - Revert test
 - Merge branch 'master' into JDK-8293991-x86-32-fp16
 - Indenting
 - Fix

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/10333/files
  - new: https://git.openjdk.org/jdk/pull/10333/files/6d101550..d8019dcc

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=10333&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10333&range=00-01

  Stats: 8561 lines in 331 files changed: 5037 ins; 2476 del; 1048 mod
  Patch: https://git.openjdk.org/jdk/pull/10333.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/10333/head:pull/10333

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