[vectorIntrinsics] RFR: 8274631: assert(false) failed: bad AD file with -XX:UseKNLSetting [v2]

[Jatin Bhateja]

On Fri, 1 Oct 2021 18:45:13 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Also can we double check if this only arises for debug builds?
>
> From X86 standpoint, this case will only arise over KNL, where certain masks (depending on the species) are either propagated through a vector or predicate register.  This is exactly what the code checks. I did not add a comment in code since its a common IR code.  Over KNL predicate registers are used only if corresponding vector is 512 bit wide.
> Thus a casting b/w Int256Mask and Double512Mask is not being handled over KNL currently under the assumption that most mask are used for vector predication and since KNL does not support EVEX instruction over partial vectors (128 and 256 bits) so masks corresponding these sizes will be propagated using vectors and not predicate registers.

> Also can we double check if this only arises for debug builds?

There are not casting patterns between predicate register and regular vectors. So problem will also show up on non-debug builds.

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PR: https://git.openjdk.java.net/panama-vector/pull/141