RFR: 8346039: [BACKOUT] - [C1] LIR Operations with one input should be implemented as LIR_Op1

[Martin Doerr]

On Wed, 11 Dec 2024 20:41:29 GMT, David Holmes <dholmes at openjdk.org> wrote:

> Revert "8345609: [C1] LIR Operations with one input should be implemented as LIR_Op1"
> 
> This reverts commit a21d21f4d7b74e21f68b6bf9c5dc9ba7d3f9963c.
> 
> Testing tiers 1-3 in progress
> 
> Thanks

Thanks everyone for looking into the issue and the assistance. I have understood the problem. C1 allows using the same register for a temp and an input operand. Another problem is that the `UseKNLSetting` code needs the `floatConst(-0.0)` for `lir_abs` and `lir_neg`.
Only the code for `UseAVX > 2 && !VM_Version::supports_avx512vl()` is affected. The rest looks correct and all tests had passed without this mode.
I'll check with @sviswa7 if we can remove this extra code from C1.

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PR Comment: https://git.openjdk.org/jdk/pull/22690#issuecomment-2538508923