RFR: 8262355: Support for AVX-512 opmask register allocation. [v20]
jbhateja at openjdk.java.net
Sun Apr 4 10:50:39 UTC 2021
On Sun, 4 Apr 2021 03:30:58 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:
> In general looks better.
> But it seems you added new instructions into .ad files for ClearArray and String compare which was not in original changes and should not be.
Hi @vnkozlov ,
Thanks for reviewing the patch, new instruction pattern hold a temporary opmask operand needed only for AVX512 flovour of instruction.
Earleir same pattern was being used for non-AVX512 instruction which could have posed issues while accessing the encoding for these temporaries in emit routines using as_KRegister()(as pointed by @iwanowww) which internally asserts is_KRegister() having UseAVX > 2 check.
We can look at opportunities to reducing redundancies around these new instruction pattern (if any) in subsiquent patches.
More information about the hotspot-compiler-dev