On Sun, 28 Feb 2021 13:31:38 GMT, Jie Fu <ji...@openjdk.org> wrote:
>> `@requires vm.compiler2.enabled` had been added.
>> Thanks.
>
> @PaulSandoz , are you also OK with the latest version?
> Thanks.
@DamonFool I think Vladimir is correct in the layering, in this respect i think
we can make things a littler clearer. This seems like a small thing but i think
its worth making very explicit as there is some hidden complexity.
What if we add the following method to `VectorShape`:
/**
* Returns the maximum vector bit size for a given element type.
*
* @param etype the element type.
* @return the maximum vector bit.
*/
/*package-private*/
static int getMaxVectorBitSize(Class<?> etype) {
// May return -1 if C2 is not enabled,
// or a value smaller than the S_64_BIT.vectorBitSize /
elementSizeInBits, on say 32-bit platforms
// If so default to S_64_BIT
int maxLaneCount = VectorSupport.getMaxLaneCount(etype);
int elementSizeInBits = LaneType.of(etype).elementSize;
return Math.max(maxLaneCount * elementSizeInBits,
S_64_BIT.vectorBitSize);
}
It is package private so it can be tested explicitly if need be.
Then we can reuse that method:
S_Max_BIT(getMaxVectorBitSize(byte.class));
static VectorShape largestShapeFor(Class<?> etype) {
return VectorShape.forBitSize(getMaxVectorBitSize(etype));
}
I think that's correct, but i have not tested. WDYT?
-------------
PR: https://git.openjdk.java.net/jdk/pull/2722
