RFR(S): 8237524: AArch64: String.compareTo() may return incorrect result

[Pengfei Li]

Hi Andrew,

> Is this really a bug? The test case is violating the protections provided by the
> Java runtime, and the programmer deserves everything that happens.

To be honest, I don't know what kind of incorrect result should be classified as a bug. Indeed, I found this issue several months ago but didn't want to fix it because it doesn't break real Java workloads except the ones that use non-public string constructors.

But now I post this RFR with this thought: If the case that two strings with different encodings share the same memory cannot happen in normal applications, why don't we remove the redundant check to save 4 instructions in the generated intrinsics code? From this point, it's likely that this JBS should be classified as an enhancement instead of a bug.

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Thanks,
Pengfei