RFR: 8265491: Math Signum optimization for x86 [v2]
Marcus G K Williams
github.com+168222+mgkwill at openjdk.java.net
Wed Apr 21 16:59:39 UTC 2021
On Wed, 21 Apr 2021 16:47:20 GMT, Marcus G K Williams <github.com+168222+mgkwill at openjdk.org> wrote:
>> src/hotspot/cpu/x86/x86.ad line 5780:
>>
>>> 5778: // --------------------------------- Signum ---------------------------
>>> 5779:
>>> 5780: instruct signumF_reg(regF dst, regF zero, regF one, rFlagsReg cr) %{
>>
>> Do we need `predicate(UseSSE>=2);` here?
>
> It seems ucomiss is SSE, but ucomisd is SSE2. I will add a SSE predicate to `instruct signumF_reg` and an SSE2 predicate to `instruct signumD_reg`. Thanks for the suggestion.
It looks like subss, subsd are also SSE, SSE2 respectively.
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PR: https://git.openjdk.java.net/jdk/pull/3581
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