IntVector.fromValues is not optimized away ?

[forax at univ-mlv.fr]

Ok, will test ! 

Rémi 

> De: "Paul Sandoz" <paul.sandoz at oracle.com>
> À: "Remi Forax" <forax at univ-mlv.fr>
> Cc: "panama-dev at openjdk.java.net'" <panama-dev at openjdk.java.net>
> Envoyé: Lundi 11 Mai 2020 20:02:14
> Objet: Re: IntVector.fromValues is not optimized away ?

> Hi Remi,

> For some reason this method does not defer to the fromArray equivalent.

> Can you try with the following patch?

> [
> http://cr.openjdk.java.net/~psandoz/panama/vector-from-values-using-from-array/webrev/
> |
> http://cr.openjdk.java.net/~psandoz/panama/vector-from-values-using-from-array/webrev/
> ]

> I shall also investigate further.

> Paul.

>> On May 9, 2020, at 11:52 AM, Remi Forax < [ mailto:forax at univ-mlv.fr |
>> forax at univ-mlv.fr ] > wrote:

>> Hi all,
>> this may be obvious but do we agree that IntVector.fromValues is not optimized
>> thus really create an array destroying any hope of perf ?

>> I'm trying to see the difference between

>> public int hashCode() {
>> return i1 ^ i2 ^ i3 ^ i4;
>> }

>> and

>> public int hashCode() {
>> var v1 = IntVector.fromValues(IntVector.SPECIES_64, i1, i3);
>> var v2 = IntVector.fromValues(IntVector.SPECIES_64, i2, i4);
>> var result = v1.lanewise(VectorOperators.XOR, v2);
>> return result.lane(0) ^ result.lane(1);
>> }

>> but taking a look to the generated assembly (below), the allocation of the two
>> arrays are still there,
>> too bad because the last 6 instructions are more or less what i was expecting.

>> 0x00007fbb383324dc: mov 0x14(%rsi),%r11d ;*getfield i3 {reexecute=0 rethrow=0
>> return_oop=0}
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 16 (line 14)
>> 0x00007fbb383324e0: mov 0xc(%rsi),%ebp
>> 0x00007fbb383324e3: mov 0x120(%r15),%r8
>> 0x00007fbb383324ea: mov %r8,%r10
>> 0x00007fbb383324ed: add $0x18,%r10
>> 0x00007fbb383324f1: cmp 0x130(%r15),%r10
>> 0x00007fbb383324f8: jae 0x00007fbb383325db
>> 0x00007fbb383324fe: mov %r10,0x120(%r15)
>> 0x00007fbb38332505: prefetchw 0xc0(%r10)
>> 0x00007fbb3833250d: movq $0x1,(%r8)
>> 0x00007fbb38332514: prefetchw 0x100(%r10)
>> 0x00007fbb3833251c: movl $0x70cb1,0x8(%r8) ; {metadata({type array int})}
>> 0x00007fbb38332524: prefetchw 0x140(%r10)
>> 0x00007fbb3833252c: movl $0x2,0xc(%r8)
>> 0x00007fbb38332534: prefetchw 0x180(%r10)
>> 0x00007fbb3833253c: mov %ebp,0x10(%r8)
>> 0x00007fbb38332540: mov %r11d,0x14(%r8) ;*newarray {reexecute=0 rethrow=0
>> return_oop=0}
>> ; - java.util.Arrays::copyOf at 1 (line 3584)
>> ; - jdk.incubator.vector.IntVector::fromValues at 19 (line 553)
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 20 (line 14)
>> 0x00007fbb38332544: mov 0x18(%rsi),%r9d
>> 0x00007fbb38332548: mov 0x120(%r15),%rax ;*invokestatic extract {reexecute=0
>> rethrow=0 return_oop=0}
>> ; - jdk.incubator.vector.Int64Vector::laneHelper at 16 (line 482)
>> ; - jdk.incubator.vector.Int64Vector::lane at 36 (line 476)
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 64 (line 17)
>> 0x00007fbb3833254f: mov 0x10(%rsi),%ebp ;*getfield i2 {reexecute=0 rethrow=0
>> return_oop=0}
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 33 (line 15)
>> 0x00007fbb38332552: mov %rax,%r10
>> 0x00007fbb38332555: add $0x18,%r10
>> 0x00007fbb38332559: nopl 0x0(%rax)
>> 0x00007fbb38332560: cmp 0x130(%r15),%r10
>> 0x00007fbb38332567: jae 0x00007fbb3833260d
>> 0x00007fbb3833256d: mov %r10,0x120(%r15)
>> 0x00007fbb38332574: prefetchw 0xc0(%r10)
>> 0x00007fbb3833257c: movq $0x1,(%rax)
>> 0x00007fbb38332583: prefetchw 0x100(%r10)
>> 0x00007fbb3833258b: movl $0x70cb1,0x8(%rax) ; {metadata({type array int})}
>> 0x00007fbb38332592: prefetchw 0x140(%r10)
>> 0x00007fbb3833259a: movl $0x2,0xc(%rax)
>> 0x00007fbb383325a1: prefetchw 0x180(%r10)
>> 0x00007fbb383325a9: mov %ebp,0x10(%rax)
>> 0x00007fbb383325ac: mov %r9d,0x14(%rax) ;*newarray {reexecute=0 rethrow=0
>> return_oop=0}
>> ; - java.util.Arrays::copyOf at 1 (line 3584)
>> ; - jdk.incubator.vector.IntVector::fromValues at 19 (line 553)
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 44 (line 15)
>> 0x00007fbb383325b0: vmovq 0x10(%rax),%xmm0 ;*invokestatic extract {reexecute=0
>> rethrow=0 return_oop=0}
>> ; - jdk.incubator.vector.Int64Vector::laneHelper at 16 (line 482)
>> ; - jdk.incubator.vector.Int64Vector::lane at 36 (line 476)
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 64 (line 17)
>> 0x00007fbb383325b5: vpxor 0x10(%r8),%xmm0,%xmm0 ;*invokespecial <init>
>> {reexecute=0 rethrow=0 return_oop=0}
>> ; - jdk.internal.vm.vector.VectorSupport$Vector::<init>@2 (line 104)
>> ; - jdk.incubator.vector.Vector::<init>@2 (line 1122)
>> ; - jdk.incubator.vector.AbstractVector::<init>@2 (line 67)
>> ; - jdk.incubator.vector.IntVector::<init>@2 (line 55)
>> ; - jdk.incubator.vector.Int64Vector::<init>@2 (line 58)
>> ; - jdk.incubator.vector.Int64Vector::vectorFactory at 5 (line 169)
>> ; - jdk.incubator.vector.Int64Vector::vectorFactory at 2 (line 41)
>> ; - jdk.incubator.vector.IntVector$IntSpecies::vectorFactory at 5 (line 3718)
>> ; - jdk.incubator.vector.IntVector::fromValues at 22 (line 553)
>> ; - fr.umlv.vector.VectorizedHashCode$Data::hashCode2 at 44 (line 15)
>> 0x00007fbb383325bb: vpextrd $0x1,%xmm0,%r11d
>> 0x00007fbb383325c1: vmovd %xmm0,%eax
>> 0x00007fbb383325c5: xor %r11d,%eax
>> 0x00007fbb383325c8: vzeroupper

>> regards,
>> Rémi