RFR: 8265940: Enable C2's optimization for Math.pow(x, 0.5) on all platforms

[Nils Eliasson]

On Wed, 28 Apr 2021 08:10:36 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> Hi all,
> 
> I'd like to enable C2's optimization for Math.pow(x, 0.5) on all platforms.
> 
> This is fine because:
>  1) For x86, it will call the assembly stubs.
>     This opt has already been implemented for x86_64 [1]. 
>     And the x86_32 version is added in this patch.
>  2) For non-x86, it will call the shared runtime c code [2], which does the same opt too.
> 
> Testing:
>   - tier1~3 on Linux/{x86_32, x86_64}, no regression
> 
> Thanks,
> Best regards,
> Jie
> 
> 
> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/macroAssembler_x86_pow.cpp#L838
> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/share/runtime/sharedRuntimeTrans.cpp#L497

Looks good.

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Marked as reviewed by neliasso (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/3755