RFR: JDK-8293978: Duplicate simple loop back-edge will crash the vm [v4]

[Christian Hagedorn]

On Tue, 20 Sep 2022 01:22:48 GMT, 王超 <duke at openjdk.org> wrote:

>> Duplicate back-edge of the following simple loop will make jvm crash.
>> 
>> <img width="458" alt="image" src="https://user-images.githubusercontent.com/25214855/190945327-ebce5342-bede-4fad-b940-088753034fa6.png">
>
> 王超 has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Change test

Otherwise, looks good!

test/hotspot/jtreg/compiler/c2/TestDuplicateSimpleLoopBackedge.java line 27:

> 25:   * @test
> 26:   * @bug 8293978
> 27:   * @library /test/lib

Not required anymore.

test/hotspot/jtreg/compiler/c2/TestDuplicateSimpleLoopBackedge.java line 36:

> 34: public class TestDuplicateSimpleLoopBackedge {
> 35:     static void zero(Byte[] a) {
> 36:         for (int e = 0; e < a.length; e++)

I think it's better to always add braces, same below for the `while` and `if`.

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Marked as reviewed by chagedorn (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10329