RFR: 8282528: AArch64: Incorrect replicate2L_zero rule

[Andrew Haley]

On Thu, 24 Mar 2022 09:42:32 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> This patch fixes the wrong matching rule of replicate2L_zero. It was
>> matched "ReplicateI" by mistake so that long immediates(not only zero)
>> had to be moved to register first and matched to replicate2L finally. To
>> fix this trivial bug, this patch fixes the typo and extends the rule of
>> replicate2L_zero to replicate2L_imm, which now supports all possible
>> long immediate values.
>> 
>> The final code changes are shown as below:
>> 
>> replicate2L_imm:
>> 
>>         mov   x13, #0xff
>>         movk  x13, #0xff, lsl #16
>>         movk  x13, #0xff, lsl #32
>>         dup   v16.2d, x13
>> 
>>         =>
>> 
>>         movi  v16.2d, #0xff00ff00ff
>> 
>> [Test]
>> test/jdk/jdk/incubator/vector, test/hotspot/jtreg/compiler/vectorapi
>> passed without failure.
>
> src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp line 1363:
> 
>> 1361:       tmp = tmp >> 8;
>> 1362:     }
>> 1363: 
> 
> This logic should be in a separate function.

I think we need a `can_encode(imm, arrangement)` function.

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PR: https://git.openjdk.java.net/jdk/pull/7939