RFR: 8286972: Support the new loop induction variable related PopulateIndex IR node on x86 [v2]

[Vladimir Kozlov]

On Thu, 19 May 2022 00:04:05 GMT, Sandhya Viswanathan <sviswanathan at openjdk.org> wrote:

>> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp line 2282:
>> 
>>> 2280:   bool is_bw_supported = VM_Version::supports_avx512bw();
>>> 2281:   if (is_bw && !is_bw_supported) {
>>> 2282:     assert(vlen_enc != Assembler::AVX_512bit, "required");
>> 
>> What are acceptable values of `vlen_enc`?
>
> For KNL, PopulateIndex support is limited to 256-bit as we need avx512bw() for the 512-bit support.
> For other AVX2 and AVX512 architectures, all vector widths up to and including 512-bit are supported.

Okay.

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PR: https://git.openjdk.java.net/jdk/pull/8778