8225716: G1 GC: Undefined behaviour in G1BlockOffsetTablePart::block_at_or_preceding

[Andrew Haley]

This is a crash caused by a bug that I have only ever seen on 32-bit
x86 GCC.  However, it is possible that it could manifest with other
compilers and other targets.

https://bugs.openjdk.java.net/browse/JDK-8225716

Should we try to get this in to the July CPU? If we don't, people
targeting 32-bit x86 may have to apply their own patches.

-- 
Andrew Haley
Java Platform Lead Engineer
Red Hat UK Ltd. <https://www.redhat.com>
https://keybase.io/andrewhaley
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