VectorAPI and C2 compiler

[Vladimir Ivanov]

Thanks for the test case, Jose.

I see the following intrinsification failure when running it:

     572   69    b        Cast::vectorCastIntToShort (28 bytes)
   ** missing constant: opr=ConI vclass_from=ConP etype_from=ConP 
vlen_from=ConI vclass_to=ConP etype_to=ConP vlen_to=LoadI

...

128   jdk.internal.vm.vector.VectorSupport::convert (39 bytes)   failed 
to inline (intrinsic)

I'll take a look why it happens.

Best regards,
Vladimir Ivanov

[1] java --add-modules jdk.incubator.vector -Xbatch 
-XX:+PrintCompilation -XX:-TieredCompilation -XX:CICompilerCount=1 
-XX:+PrintInlining -XX:CompileCommand=quiet 
-XX:CompileCommand=compileonly,*::vectorCastIntToShort 
-XX:+PrintIntrinsics Cast

On 12.01.2021 22:11, joserz at linux.ibm.com wrote:
> Hi Paul,
> 
> Thank you for your response!! :-)
> 
> This is my test case for x86 (basically got from VectorReshapeTests.java).
> ```
> import java.io.IOException;
> import java.util.Arrays;
> import jdk.incubator.vector.IntVector;
> import jdk.incubator.vector.ShortVector;
> import jdk.incubator.vector.DoubleVector;
> import jdk.incubator.vector.VectorSpecies;
> import jdk.incubator.vector.LongVector;
> 
> class Cast
> {
>      static void vectorCastIntToShort(VectorSpecies<Integer> i,
>                                       VectorSpecies<Short> s,
>                                       int[] input,
>                                       short[] output)
>      {
>          IntVector iv = IntVector.fromArray(i, input, 0);
>          ShortVector sv = (ShortVector) iv.castShape(s, 0);
>          sv.intoArray(output, 0);
>      }
> 
>      public static void main(String[] args) throws IOException
>      {
>          for (int j = 0; j < 1_000_000; j++) {
>              int[] iin128 = {25, -398, 415, Short.MAX_VALUE + 2};
>              short[] sout64 = new short[ShortVector.SPECIES_64.length()];
> 
>              vectorCastIntToShort(IntVector.SPECIES_128,
>                                   ShortVector.SPECIES_64,
>                                   iin128, sout64);
>          }
> 
>          //System.out.println(Arrays.toString(iin128));
>          //System.out.println(Arrays.toString(sout64));
>      }
> }
> ```
> 
> Then, after compiling and running like:
> $ javac Cast.java
> $ java -Xcomp -XX:-TieredCompilation -XX:CompileThreshold=1 -XX:+UnlockDiagnosticVMOptions -XX:+PrintAssembly -XX:+PrintOptoAssembly -XX:+UnlockExperimentalVMOptions -XX:+EnableVectorSupport -XX:+EnableVectorReboxing -XX:+EnableVectorAggressiveReboxing -XX:UseAVX=2 Cast
> 
> I was expecting to see instructions from x86.ad, like "vector_cast_i2x" being printed but it seems that VectorCastI2X pattern isn't be generated because I see compiler C2 kicking in during the program execution.
> 
> Thank you very much!
> 
> Jose
> 
> 
> On Tue, Jan 12, 2021 at 09:07:49AM -0800, Paul Sandoz wrote:
>> Hi Jose,
>>
>> Shifting over to panama-dev (bcc’ing discuss at openjdk.java.net <mailto:discuss at openjdk.java.net>).
>>
>> Can you share a complete example on x86 that is not producing what you expect?
>>
>> I suspect in the PPC case some wiring up to the vector intrinsics are missing.
>>
>> Paul.
>>
>>> On Jan 11, 2021, at 1:07 PM, joserz at linux.ibm.com wrote:
>>>
>>> Hello team,
>>>
>>> I'm currently working on the VectorAPI support to PowerPC64 but none of my instructions, defined in ppc64.ad, gets executed. I decided to take a look at x86, but again no Vector instructions printed.
>>>
>>> Basically, I have a test case like this:
>>>         for (int j = 0; j < 1_000_000; j++) {
>>>             int[] iin128 = {25, -398, 415, Short.MAX_VALUE + 2};
>>>             short[] sout64 = new short[ShortVector.SPECIES_64.length()];
>>>
>>>             vectorCastIntToShort(IntVector.SPECIES_128,
>>>                                  ShortVector.SPECIES_64,
>>>                                  iin128, sout64);
>>>         }
>>>
>>> That I execute like:
>>>         java -Xcomp -XX:-TieredCompilation -XX:CompileThreshold=1 \
>>>              -XX:+UnlockDiagnosticVMOptions -XX:+PrintAssembly \
>>>              -XX:+PrintOptoAssembly -XX:+UnlockExperimentalVMOptions \
>>>              -XX:+EnableVectorSupport -XX:+EnableVectorReboxing \
>>>              -XX:+EnableVectorAggressiveReboxing -XX:UseAVX=2 Cast
>>>
>>> And expected to see any of `format %{ "vector_* ... %}` instructions, defined in x86.ad, being printed.
>>>
>>> Am I missing anything?
>>>
>>> Thank you,
>>>
>>> Jose R Ziviani
>>