RFR: 8285868: x86_64 intrinsics for floating point methods isNaN, isFinite and isInfinite [v4]

[Srinivas Vamsi Parasa]

On Wed, 18 May 2022 04:23:33 GMT, Srinivas Vamsi Parasa <duke at openjdk.java.net> wrote:

>> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 4753:
>> 
>>> 4751:   switch (opcode) {
>>> 4752:     case Op_IsFiniteF:
>>> 4753:       setb(Assembler::below, dst);
>> 
>> This partial write may stall later reads on `dst`, you could emit a `xor dst, dst` before doing the comparison.
>
> Will try the `xor dst, dst` and see the performance changes.

setb either writes a 0 or 1 based on the condition. So, will it cause partial writes?

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PR: https://git.openjdk.java.net/jdk/pull/8459