RFR: 8288445: AArch64: C2 compilation fails with guarantee(!true || (true && (shift != 0))) failed: impossible encoding [v2]

[Dean Long]

On Mon, 20 Jun 2022 05:49:25 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

> What instruction will the zero-shift be matched with then?

The shift instruction that takes a vector register shift count rather than an immediate.

> test/hotspot/jtreg/compiler/codegen/ShiftByZero.java line 29:
> 
>> 27:  * @summary Test shift by 0
>> 28:  * @library /test/lib
>> 29:  * @run main compiler.codegen.ShiftByZero
> 
> I don't think these two lines are needed.

Thanks for catching it!

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PR: https://git.openjdk.org/jdk19/pull/40