RFR: 8286847: Rotate vectors don't support byte or short

[Haomin]

On Tue, 17 May 2022 06:53:31 GMT, Eric Liu <eliu at openjdk.org> wrote:

>> static void test_fun(byte[] a0, int[] b0, byte[] c0) {
>>     for (int i=0; i<ARRLEN; i++) {
>>       c0[i] = (byte)(a0[i] << (7) | a0[i] >>> (-7));
>>     }   
>>   }
>> 
>> 
>> when I implement RotateLeftV in loongarch.ad, I found this executed by c2 vector and executed by interpreter are not equal.
>> 
>> It's executed on x86 would create an assert error.
>> 
>> 
>>  # Internal Error (/home/wanghaomin/jdk/src/hotspot/share/opto/vectornode.cpp:347), pid=26469, tid=26485
>>  # assert(false) failed: not supported: byte
>> 
>> 
>> RotateLeftV for byte, short values produces incorrect Java result. Because java code should convert a byte, short value into int value, and then do RotateI.
>
> test/hotspot/jtreg/compiler/vectorization/TestRotateByteVector.java line 90:
> 
>> 88:             res[i] = (byte) ((arr[i] << shift) | (arr[i] >>> -shift));
>> 89:         }
>> 90:     }
> 
> This function is duplicated with with `testRotateLeft`.  It's not enough to verify the correctness by comparing the results of these two functions.

Yes, `rotateLeftRes` is duplicated with  `testRotateLeft`. But compile only `testRotateLeft`,  and then compare the result between the two function. Could you give me some suggestions ? How should I modify this ?

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PR: https://git.openjdk.java.net/jdk/pull/8740