RFR: 8276453: Undefined behavior in C1 LIR_OprDesc causes SEGV in fastdebug build [v5]

[Dean Long]

On Wed, 3 Nov 2021 20:01:37 GMT, Man Cao <manc at openjdk.org> wrote:

>> Hi all,
>> 
>> Could anyone provide some feedback on this bug fix and refactoring change? See https://bugs.openjdk.java.net/browse/JDK-8276453 for more details.
>> If the direction of this change looks good, we can proceed removing the "UGLY HACK" in c1_LIR.hpp and refactor occurrences of "opr->fn()" to "opr.fn()".
>
> Man Cao has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix aarch64 and arm builds

This looks like a similar problem to JDK-8276563.  It would be nice if both problems had the same solution, minimize unnecessary renames, and does not significantly impact performance.

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PR: https://git.openjdk.java.net/jdk/pull/6221