[aarch64-port-dev ] RFR(S): 8241091: AArch64: "bad AD file" with VM option "-XX:-UsePopCountInstruction"

[Pengfei Li]

Hi Andrew,

> We could go either way, but there's no point in disabling popcount on
> AArch64. So [2], but please produce an error message if "-
> UsePopCountInstruction" is used.

My understanding of your "error message" is a warning message instead of a hard error, as current "bad AD file" is already a hard error.

The general option UsePopCountInstruction is false by default. In my updated webrev [1], the default value is changed to true for AArch64 and a warning is printed if it's turned off manually.

$ java Foo
219504
$ java -XX:-UsePopCountInstruction Foo
OpenJDK 64-Bit Server VM warning: UsePopCountInstruction is always enabled on this CPU
219504

Jtreg tier1 passed. Is this ok?

[1] http://cr.openjdk.java.net/~pli/rfr/8241091/webrev.02/

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Thanks,
Pengfei