[9] RFR(S): 8073670: TypeF::eq and TypeD::eq do not handle NaNs correctly

[Zoltán Majó]

Hi,


please review the following patch.

Bug: https://bugs.openjdk.java.net/browse/JDK-8073670

Problem: The C2 compiler treats different NaN values as equivalent. As a 
result, if there are multiple NaN values used in a single method, those 
values can potentially be folded into a single value. That behavior is 
not consistent with the behavior of C1 and the interpreter that always 
treat different NaN values as different.

Solution: Change TypeF:eq and TypeD:eq to compare NaN values using a 
bitwise comparison (instead of using the g_isnan() function).

Webrev: http://cr.openjdk.java.net/~zmajo/8073670/webrev.00/

Testing: Added compiler/c2/DifferentNaNFoldingTest.java. Test behaves as 
expected if

- executed locally on linux_x64, solaris_sparc, solaris_x64 with/without fix
- executed in JPRT on all architectures targeted by the 
hotspot_compiler_1 target with/without fix

Thank you and best regards,


Zoltan