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

[Vladimir Kozlov]

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

Changes looks fine for me (it is easy to see if exclude LIR_OprDesc:: -> LIR_Opr::). It used the same approach as 8229258.
It is not very performance critical since it is C1 code. But I would like to see some numbers how it affect C1 compilation time (may be using -XX:+LogCompilation).

-------------

Marked as reviewed by kvn (Reviewer).

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